text:
|Publication number
|Publication type
|Application number
|Publication date
|Nov 3, 1998
|Filing date
|Jun 25, 1997
|Priority date
|Jun 2, 1994
|Fee status
|Also published as
|Publication number
|Len Sheynblat
|Original Assignee
|Trimble Navigation Limited
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (1), Referenced by (53), Classifications (14), Legal Events (8)
|External Links: USPTO, USPTO Assignment, Espacenet
PRR(t;i;j)= Φ(t;i;j)-Φ(t-Δt;i;j)!/Δt,
y(t)=yn +an (t-tn)+bn (t-tn)2,
PRR(tn ;i;j)RS =y(tn)=an ={(tn -tn-1)2 y(tn+1)-y(tn)!+(tn+1 -tn)2 y(tn-1)-y(tn) !}/(tn+1 -tn)(tn+1 -tn-1)(tn+1 -tn-1).
PRR(t;i;j)= Φ(t;i;j)-Φ(t-Δt;i;j)!/Δt,
y(t)=yn +an (t-tn)+bn (t-tn)2,
PRR(tn ;i;j)RS =y(tn)=an ={(tn -tn-1)2 y(tn+1)-y(tn)!+(tn+1 -tn)2 y(tn-1)-y(tn) !}/(tn+1 -tn)(tn+1 -tn-1)(tn+1 -tn-1).
PRR(t;i;j)= Φ(t;i;j)-Φ(t-Δt;i;j)!/Δt,
y(t)=yn +an (t-tn)+bn (t-tn)2,
PRR(tn ;i;j)RS =y(tn)=an ={(tn -tn-1)2 y(tn+1)-y(tn)!+(tn+1 -tn)2 y(tn-1)-y(tn) !}/(tn+1 -tn)(tn+1 -tn-1)(tn+1 -tn-1).
PRR(t;i;j)= Φ(t;i;j)-Φ(t-Δt;i;j)!/Δt
y(t)=yn +an (t-tn)+bn (t-tn)2,
PRR(tn ;i;j)RS =y(tn)=an ={(tn -tn-1)2 y(tn+1)-y(tn)!+(tn+1 -tn)2 y(tn-1)-y(tn)!}/(tn+1 -tn)(tn+1 -tn-1)(tn+1 -tn-1).
This application is a continuation of an application entitled "Integrity Monitoring of Location and Velocity Coordinates From Differential Satellite Positioning System Signals," U.S. Ser. No. 08/414,374, (now abandoned) filed on Mar. 31, 1995 which is a continuation of 08/252,681 filed Jun. 2, 1994 now U.S. Pat. No. 5,436,632, and assigned to the assignee of this application. This invention relates to use of pseudorange and pseudorange rate signals from SATPS satellites to monitor location and velocity coordinates to evaluate satellite signal integrity.
Where differential Satellite Positioning System (DSATPS) signals are combined with SATPS signals to enhance the accuracy of the present location of a mobile user, such as a marine or airborne vessel or land vehicle, one concern is how to monitor the quality or integrity of the signals used in the location computations. Monitoring of signal quality or integrity has thus far used calculations based only on SATPS pseudorange signals. This approach has built-in limitations arising from the fact that the same data are being used to compute SATPS-determined location and to evaluate the quality or integrity of the underlying SATPS signals.
Although measurements and use of pseudoranges are fundamental to SATPS-assisted determination of location and/or time coordinates, only a few patents disclose procedures that work directly with the pseudorange or pseudorange rate values. In U.S. Pat. No. 4,578,678, Hurd discloses a GPS receiver that receives a plurality of pseudorange signals, compares these signals with replicas of the expected pseudorange signals, using a correlation technique, and determines the associated time delay, frequency and other variables of interest for these signals to determine receiver location, velocity, clock offset and clock rate. Several references discuss monitoring one or more parameters associated with a location determination (LD) system, such as GPS or Loran-C, and use of this information in subsequent decisions. Gray et al, in U.S. Pat. No. 4,651,157, disclose use of a plurality of Loran-C or satellites for determining the location of a land-based, marine or airborne vehicle by a receiver/sensor/transmitter (RST) carried on the vehicle. This RST receives the LD signals from the Loran-C or satellite transmitters and retransmits these signals and the values of one or more monitored parameters to a central station that processes this information and determines the RST's present location.
In U.S. Pat. No. 4,791,572, Green et al disclose a system for providing differential corrections to locations determined by a Loran-C LD system that is analogous to a well known system for providing differential corrections for GPS. Another Loran-C differential positioning system is disclosed by Duffet-Smith in U.S. Pat. No. 5,045,861.
Use of a plurality of GPS receivers and antennas to accurately determine the location of a seismic survey vessel is disclosed by Counselman in U.S. Pat. No. 4,809,005. L1 and L2 band carrier waves are received and used (1) to correct for ionospheric time delay and (2) to determine a bias-free pseudorange from each GPS satellite to a given receiver, using signal time averaging. A plurality of receivers, spaced apart from each other on the vessel, is used to compensate for signal blocking by the vessel, to sense and compensate for false signals, and to receive GPS signals by at least one receiver at all times. Another patent issued to Counselman, U.S. Pat. No. 4,894,662, also identifies bias and ionospheric time delay in the pseudorange signals, using C/A signals.
Olsen et al disclose a GPS-based geophysical survey system that includes a fixed GPS reference station and a plurality of mobile survey stations that also use GPS signals, in U.S. Pat. No. 4,814,711. The reference station transmits time-varying signals indicating the desired location of each mobile station. Each mobile station receives these desired-location signals, receives GPS signals, determines the actual location of that mobile station, and periodically transmits to the reference station this actual location and the survey parameters sensed or measured by the mobile station. The reference station compares the actual location and desired location for each reporting mobile station and correlates the reported geophysical information with the corresponding location of that mobile station.
A system that measures velocity of a given object relative to a fixed surface by using Doppler shifts of radio waves received by two receiver/sensor/transmitter combinations is disclosed by Stratton et al in U.S. Pat. No. 4,893,287. Two RSTs face each other and are preferably directed toward the same location on the surface, and the system monitors assertedly random, non-real velocity values by comparison of velocity components at a sequence of times.
Bice et al disclose an aircraft ground collision avoidance system in U.S. Pat. No. 4,924,401. Each aircraft carries an autopilot that monitors "flight states," such as aircraft speed, angle of attack, bank angle and velocity coordinates.
In U.S. Pat. No. 4,970,523, Braistead et al disclose a system that determines differential Doppler frequency shifts received at a vehicle and estimates the present vehicle velocity from these differential shifts.
Keegan discloses a P-code receiver/processor, in U.S. Pat. No. 4,972,431, that analyzes pseudorange and phase for encrypted GPS signals by squaring and filtering the incoming signals. Weaker signals can be analyzed using this technique.
A system for determining the location, orientation and velocity of an airborne vehicle is disclosed in U.S. Pat. No. 4,990,922, issued to Young et al. The system uses two or more antennas, spaced apart on the vehicle to receive GPS signals for this purpose. Post processing of the GPS signal information is performed at a central station. U.S. Pat. No. 5,017,930, issued to Stoltz et al, discloses an aircraft precision landing system that uses four or more signal receivers at fixed, known locations and a centrally located radio signal source. This source transmits an interrogation signal that is received and answered by transponders on the aircraft as the aircraft approaches a landing site. A central station receives the transponder signals and determines the aircraft's computed location along an approach path is compared with the desired path. Location errors are communicated to the aircraft by the central station so that the aircraft can make appropriate adjustments in its present approach path.
A system for monitoring and reporting on the present location of a vehicle generally traveling along a prescribed route is disclosed by Sutherland in U.S. Pat. No. 5,068,656. The vehicle determines its location, compares the present vehicle location with the desired location, and transmits exception reports to a central station if these two locations differ by more than a threshold value.
Allison, in U.S. Pat. No. 5,148,179, discloses a method for using double differences of pseudorange and carrier phase measurements. The technique uses double differences formed from signals received from four satellites by two different receivers to eliminate certain bias and atmospheric perturbation terms.
Harigae et al, in U.S. Pat. No. 5,153,599, disclose clock testing apparatus, connected to a GPS signal receiver on a moving station, that counts clock pulses issued by this receiver. The system determines a receiver clock error and models error in the velocity of the moving station relative to each GPS satellite.
A GPS receiver that uses conventional pseudorange and carrier phase measurements to provide a directional indicator, such as a compass, with improved accuracy is disclosed in U.S. Pat. No. 5,266,958, issued to Durboraw. A single antenna is moved in a closed path, and differences between predicted and actual carrier phases are used to determine location perturbations, which are then resolved into components parallel and perpendicular to a desired path heading in a given plane.
None of the references discussed above examines and uses the pseudorange rate signals derived from Doppler or carrier phase information used to compute pseudorange rate corrections for a DSATPS reference station or to monitor the integrity of the signals received by a DSATPS reference station or by an associated signal integrity monitoring station. Where a reference discusses use of velocity information, it is usually the mobile station velocity that is determined or compared. Only a few U.S. patents innovatively use pseudorange or pseudorange rate signals for any purpose.
What is needed is a system that uses data for signal integrity monitoring that are at least partly independent of the signals used for computation of the pseudorange corrections by a DSATPS reference station. Preferably, independent signal integrity monitoring at a nearby fixed station should be provided to identify or detect anomalous differential correction signals that arise at the reference station and/or anomalous signals used in the computation of the location and/or velocity of the nearby station.
These needs are met by the invention, which provides method and apparatus for evaluating the quality or integrity of SATPS satellite pseudorange and pseudorange rate signals by monitoring the code and carrier phase signals or Doppler shifts of the incoming satellite signals. Pseudorange and pseudorange rate corrections PRC(t;i;j) and PRRC(t;i;j) are computed for a given DSATPS reference station number i and for each satellite number j that contributes to these corrections. A signal monitoring station performs integrity monitoring by analyzing the pseudorange and pseudorange rate residuals that exclude the reference station clock bias and frequency offset. At the known location of the reference station, clock bias and frequency offset are the only unknown parameters that are part of the computation processes of both pseudorange and pseudorange rate corrections. Integrity monitoring is performed using a fault vector approach, or any equivalent approach.
When a faulty SATPS signal from a particular satellite is detected and identified, this satellite signal is removed from the clock bias and frequency offset estimations. Different criteria apply for correcting and for monitoring the relevant parameters at a reference station.
A signal integrity monitoring (SIM) station receives pseudorange and pseudorange rate corrections and uses these values to compute its own differentially corrected pseudorange and pseudorange rate residuals. The only unknown parameters involved in the computations at a (fixed) SIM station are its own clock bias and frequency offset, computed relative to the clock bias and frequency offset at the reference station. The SIM station computes its own location and velocity fix coordinates in the same manner as for any other station that is remote from the reference station. Because the SIM station location is fixed and the noise characteristics of the velocity-related measurements are less affected by multipath errors, the fault detection where fault isolation are performed in the velocity domain and complements the monitoring done in the position domain.
FIG. 1 is a schematic view illustrating use of the invention to monitor the satellite signal quality or integrity of signals received at a plurality of SATPS stations.
FIG. 2 is a table of dimensionless threshold values useful in certain fault vector tests discussed in the text.
FIGS. 3A, 3B, and 4 illustrate procedures used to correct or monitor signal integrity according to embodiments of the invention.
FIG. 1 illustrates a network of differential SATPS (DSATPS) or reference stations 11A, 11B, 11C, 11D, whose GPS correction signals provide a mobile station 12 with pseudorange AND pseudorange rate signals of enhanced accuracy. Adjacent DSATPS stations are spaced apart by distances of about 200-300 km, or more if desired. Each DSATPS station 11A, 11B, 11C, 11D is "paired" with a DSATPS signal integrity monitoring (SIM) station 13A, 13B, 13C, 13D, and the antenna of each pair of stations 11i and 13i (i=A, B, C, D) are located within a relatively short distance (≦1 kilometer, preferably≦20-30 meters) of each other. The location of each DSATPS station 11i and of each SIM station 13i is known with high accuracy, through surveying or another suitable measurement technique. A DSATPS station and its associated SIM station can be both stationary or can move slowly along separate paths with location coordinates that are known at (at least) a sequence of times.
Each DSATPS station 11i and each SIM station 13i receives pseudorange information from a plurality of SATPS satellites 15-1, 15-2, 15-3, 15-4, 15-5 and computes the pseudorange corrections PRC(t;i;j) and pseudorange rate corrections PRRC(t;i;j), corresponding to the SATPS signals received from the satellite 15-j=1, 2, 3, 4, 5), for its own known location. Residual error computations, Doppler shift measurements and/or carrier phase measurements for the SATPS signals can be used for the pseudorange rate measurements. Pseudorange corrections alone are presently used to compute differentially corrected locations of each SIM station. Pseudorange rate corrections have not been used for monitoring or related purposes. One advantage of use of pseudorange rate corrections for signal integrity monitoring is that different data are used here so that an independent check is provided on the integrity of the pseudorange corrections that are determined by the reference station. The pseudorange signals PR, Doppler-based pseudorange rate signals PRR and carrier phase signals Φ received from a satellite j by a reference station or SIM station i are expressed as
PR(t;i;j)=R(t;i;j)+SCB(t;j)+RCB(t;i)+τT (t;i;j)+τI (t;i;j)+m(t;i;j)+η(t;i;j), (1)
PRR(t;i;j)=RR(t;i;j)+SFE(t;j)+RFE(t;i)+τT (t;i;j)+τT (t;i;j)+τI (t;i;j)+m'(t;i;j)+η'(t;i;j), (b 2)
Φt;i;j)=λN(i;j)+R(t;i;j)+SCB(t;j)+RCB(t;i)+τT (t;i;j) -τI (t;i;j)+m"(t;i;j)+η"(t;i;j), (3)
where R(t;i;j) represents the "true" SATPS range and RR(t;i;j) represents the "true" range rate from the station number i to the satellite number j at the time t, as determined from the SATPS navigation ephemeris (or almanac information) received by the reference station 11i or SIM stations 13i, λ is the SATPS carrier signal wavelength, and N(i,j) is the integer number of wavelengths associated with the carrier phase signal. The number N is initially ambiguous; but once N is found it does not change with time as long as continuous carrier lock is maintained. The carrier phase signal Φ(t;i;j) is obtained from analysis of integrated Doppler shifts of the SATPS signals received and includes error contributions from the sources indicated on the right hand side of Eq. (3). Here, SCB (t;j) is the satellite clock bias error, RCB (t;i) is the receiver clock bias error, SFE(t;j) and RFE (t;i) are the satellite frequency offset error and receiver frequency offset error, τT (t;i;j) and τI (t;i;j) are the tropospheric signal propagation time delay and ionospheric signal propagation time delay, m(t;i;j), m'(t;i;j) and m"(t;i;j) are the multipath signal error contributions for the pseudorange, pseudorange rate and carrier phase signals, and η(t;i;j), η'(t;i;j) and η"(t;i;j) are the receiver noise error contributions for the pseudorange, pseudorange rate and carrier phase signals.
The pseudorange rate values PRR(t;i;j) for a reference station 11i or a SIM station 13i can also be obtained by forming a time derivative (or a simple time difference ratio) of the carrier phase signal Φ(t;i;j) for the reference station or SIM station from Eq. (3). For example, this time derivative can be formed as
PRR(t;i;j)= Φ((t;i;j)-Φ(t-t;i;j)!Δt, (4)
where the carrier phase values Φ(t;i;j) are assumed known for the times t-Δt and t. A first alternative definition for this time derivative uses a three-term approximation
y(t)=yn +an (t-tn)+bn (t-tn (2, (5)
for the variable y(t)=Φ(t;i;j), using known values of y at three consecutive time values t=tn-1, t=tn and t=tn+1, with the time derivative at t=tn being defined as
PRR(tn ;i;j)=y(tn)=tn ={(tn -tn-1)2 y(tn+1)-y(tn)!+(tn+1 -tn)2 y(tn-1)-y(tn) !}/(tn+1 -tn)(tn+1 -tn-1)(tn+1 -tn-1). (6)
A second alternative definition uses the Doppler shift signals from Eq. (2) for the station i and satellite j. Recall that the reference station and the SIM station, for which the pseudorange rate values are computed from incoming SATPS signals, have fixed, known locations. Thus, the pseudorange and pseudorange rate correction values PRC(t;i;j) and PRRC(t;i;j) for a particular station/satellite pair (i,j) are the negatives of the corresponding pseudorange and pseudorange rate residual error value computed using the incoming SATPS signals, viz.
PRC(t;i,j)=-PRRE(t;i;j), (7)
PRRC(t;i;j)=-PRRRE(t;i;j). (8)
This last equation is easily changed if the SIM station has (small) known velocity components relative to a fixed location.
At the reference or DSATPS station, the pseudorange correction and pseudorange rate correction are computed according to
PRC(t;i;j)RS =R(t;i;j)- PR(t;i;j)-SCB(t;i;j)-RCB(t;i;j)!=- PRE(t;i;j)RS +τT (t;i;j)+τI (t;i;j)+m(t;i;j)+η(t;i;j)!, =-PRRE(t;i;j)RS, (9)
PRRC(t;i;j)RS =RR(t;i;j)- PRR(t;i;j)-SFE(t;i;j)-RFE(t;i;j)!=- RRE(t;i;j)RS +τT (t;i;j)-τI (t;i;j)+m'(t;i;j)+η'(t;i;j)!, =-PRRRE(t;i;j)RS, (10)
where PRE(t;i,j) and RRE(t;i;j) are the residual errors at the reference station for the pseudorange and pseudorange rate values due to Selective availability errors and other errors.
At the SIM station, the pseudorange residual error and pseudorange rate residual error values PRRE(t;i;j)SIM and PRRRE(t;i,j)SIM are computed in a similar manner. The differentially corrected pseudorange and pseudorange rate residual errors at the SIM station then become
DPRE(t;i;j)SIM =PRRE(t;i;j)SIM +PRC(t;i;j)RS =PRE(t;i;j)SIM -PRE(t;i;j)RS +m(t;i;j)SIM -m(t;i;j)RS +η(t;i,j)SIM -η(t;i;j)RS +ε(t;i;j), (11)
DPRRE(t;i;j)SIM =PRRRE(t;i;j)SIM +PRRC(t;i;j)RS =RRE(t;i,j)SIM -RRE(t;i;j)RS +m'(t;i;j)SIM -m'(t;i;j)RS +η'(t;i,j)SIM -η'(t;i;j)RS +ε'(t;i,j), (12)
where ε(t;i;j) and ε'(t;i;j) are uncompensated errors for pseudorange and pseudorange rate measurements, respectively, arising from a satellite malfunction. The differentially corrected residual errors in Eqs. (11) and (12) are linearized with respect to the nominal reference station and SIM station locations, clock biases and frequency offset errors.
Errors arising from M measurements with K unknowns (M≧K+1) are developed from an overdetermined array of linear equations of the form
y=H x+w. (13)
Here, y is an (K+i)�1 vector (M>K+1 for monitoring K-dimensional location or velocity solutions; K=0, 1, 2 or 3) whose components (1) are the differential range residuals DPRE(t;i;j)SIM for each in-view satellite (j) between the measured pseudorange and the predicted range, or (2) are the differential range rate residuals DPRRE(t;i;j)SIM between the measured pseudorange rate and the predicted range rate at the SIM station. Here, H is an M�(k+1) matrix, referred to as a "Jorgensen matrix" for convenience, that transforms from the space of M pseudorange (or pseudorange rate) measurements to the state space of K location coordinates plus clock bias coordinates (or to the state space of K velocity coordinates plus frequency offset coordinates). These K+1 location and clock bias values (or K+1 velocity and frequency offset values) are referred to collectively as K+1 "location parameters" (or as K+1 "velocity parameters") in the following discussion. The H matrix entries are "1" in the last row, and direction cosines of the line of sight from the SATPS station antenna to the M SATPS satellites in the other rows of the matrix. The matrix H corresponds to an N�4 matrix G discussed by R. G. Brown in "A Baseline RAIM Scheme and a Note on the Equivalence of Three RAIM Methods," presented at the Institute Of Navigation National Technical Meeting, San Diego, Calif., Jan. 27-29 1992. Computation of the components of the observation matrix H is discussed by P. S. Jorgensen in "Navstar/Global Positioning System 18-Satellite Configurations," Navigation, vol. 2, 1984, pp. 1-12, Appendix B, incorporated by reference herein. The (K+1)�1 vector w in Eq. (13) contains errors due to receiver noise, multipath and other uncommon errors between the reference station and the integrity monitor, and errors εand ε' arising from a satellite failure. Normally, ε and ε' are zero. For the SIM station, where the only unknowns are the SIM station clock bias RCB and the receiver clock frequency error RFE, the requirement for monitoring location is M>1.
A weighted least squares solution of Eq. (13) is
xLS =H*y, (14)
H*=(Htr R-1 H)-1 Htr R-1. (15)
Here, H* is the (K+1)�M pseudoinverse matrix for H. Fault detection computations are performed based on fault vector hypothesis testing, using an M�1 fault vector
f=SR-1/2 y, (16)
where f=f(t;i;j) represents the residual error vector of the overdetermined solutions for Eq. (13), weighted by the expected accuracy of the measurements. Here, R=R(t;i;j) is an (K+1)�(K+1) measurement error covariance matrix for the noise vector w and is defined by the relation
R=Expectation w wtr !, (17)
S=S(t;i,j)= I-R -1/2 H(Htr R-1 H)-1 Htr R-1/2 ! (18)
is the M�M fault vector covariance matrix.
The fault vector magnitude (a scalar)
D(t)=ftr f (19)
is computed, and a suitable test for failure is whether
D>Dthr, (20)
where Dthr is a threshold value that is based on the false alarm rate and has M-(K+1) statistical degrees of freedom. If D≦Dthr, no fault is detected. A normalized statistical variable
U(t)=D(t)/(M-K-1) (21)
can be computed to verify the proper modelling of the weighted solution. If the measurement errors are suitably described by the measurement error covariance matrix R(t;i,j), the expected value of U(t;i;j) is 1.0. If the expected value of U(t;i;j) is >1.0(<1.0), the modelling has been too optimistic (too pessimistic) and should, perhaps, be recomputed. If the components of the fault vector are not equally important in a given situation, the fault vector magnitude in Eq. (19) can be replaced by
D'(t;i;j)=ftr V f, (19')
where V is a diagonal matrix with non-negative diagonal entries chosen to reflect the relative importance of the components of f.
FIG. 2 is a table setting forth dimensionless threshold values Dthr for different values M-(K+1)=1 through 9 of the statistical degrees of freedom and for different significance levels, or acceptable probabilities of a Type 1 error (probability of rejection of satellite signals that are valid). The threshold values in FIG. 2 are based upon a chi-square distribution.
A sequence of quantities
τj =fj 2 /Sij (j=1, 2, . . . , K+1) (22)
is computed, where fj and Sjj are the jth entry and the jth diagonal entry for the vector f and matrix S, respectively. One first selects the largest value τJ1 and the second largest value τJ2 from the sequence of values τj and forms the difference
ΔτJ1, J2 =τJ1 -τJ2. (23)
Let pJ1 and pJ2 be the probabilities that the quantity τj defined in Eq. (22) attains the respective values τJ1 and τJ2. The probability values pJ1 and pJ2 are either estimated from a sequence of measurements or computed from first principles. The likelihood ratio RJ1,J2 =2 loge (pJ1 /pJ2) is determined and compared with the difference value ΔτJ1,J2. If Eq. (20) is valid and
ΔτJ1,J2 >RJ1,J2, (24)
this indicates that the pseudorange information or the pseudorange rate signals received from the satellite j=J1 are unreliable, and the pseudorange and pseudorange rate signals received from this satellite must be removed from the set of SATPS satellite signals used for correcting and/or monitoring signals received at the SIM station. If ΔτJ1,J2 ≦RJ1,J2, but D>Dthr, as in Eq. (20), it cannot be determined from this analysis whether the set of satellite signals received from the SATPS satellite j=J1 should be removed from the set of signals used for correcting and/or monitoring. One may repeat the analysis associated with Eqs. (22), (23) and (24) with the values τJ2 and τJ3, substituted for τJ1 and τJ2, respectively, where τJ3 is the third largest value in the sequence of values τj. If appropriate, this analysis can be extended to other consecutive members τJm and τJ(m+1) of the sequence to determine if SATPS signals from the SATPS satellite corresponding to j=Jm should be removed from the usable satellite signals.
If the number M of SATPS signals from distinct satellites and corresponding corrections received by the SIM station satisfies M≧1, the clock bias (or frequency offset) for the SIM station can be corrected. If M≧2, the clock bias (or frequency offset) of the SIM station can be monitored, as well as corrected. If M≧K (K=1, 2, 3), K location coordinates (or K velocity coordinates) for the SIM station can be corrected. If M≧K+1(K=1, 2, 3), the clock bias (or frequency offset) plus K location coordinates (or K velocity coordinates) for the SIM station can be corrected; or, alternatively, K location coordinates for the SIM station can be monitored. If M≧K+2(K=0,1,2,3), a satellite, if any, whose SATPS signals are not acceptable, based on the preceding analysis, can be identified or isolated, in addition to correction of the clock bias (or frequency offset) and of K location coordinates (or velocity coordinates); or in addition to monitoring of location coordinates (or velocity coordinates) for the SIM station. For notational convenience, a set including clock bias and K location coordinates, or a set of K+1 location coordinates, will be referred to as a set of K+1 "location parameters"; and a set including frequency offset and K velocity coordinates, or a set of K+1 velocity coordinates, will be referred to as a set of K+1 "velocity parameters". Reference to "parameters," without further specification, will refer either to location parameters or to velocity parameters. Where K location coordinates or K velocity coordinates are being corrected or monitored, it is assumed that a precise clock bias parameter or a precise frequency offset parameter, respectively, is available to and used by the SIM station for the clock bias or frequency offset value.
Sturza, in "Navigation System Integrity Monitoring Using Redundant Measurements," Navigation, vol. 25 (1988-1989) pp. 483-501, analyzes an equation similar to Eq. (13), using similar techniques as in Eqs. (13)-(20).
The Sturza article limits its fault testing to pseudorange values. The approach disclosed here talkes further advantage of the stationary or known locations of the reference station and associated SIM station.
In one embodiment of the invention, the magnitudes of the pseudorange rate corrections PRRC(t;i;j) are determined for a SIM station 13i and compared with a selected rate threshold PRRC(i;j)thr, which may be the same or different for each SIM station i and each satellite j. Here, it is required that
|PRRC(t;i;j)|≦PRRC(i;j)thr. (25)
in order that the pseudorange rate corrections for the reference station-satellite combination (i;j) be acceptable. The pseudorange rate corrections PRRC(t;i;j) are analyzed to determine which, if any, of the SATPS satellites or reference (DSATPS) stations is providing erroneous information. This information might identify a faulty satellite clock, a faulty reference station clock or frequency offset, presence of multipath signals, or presence of ionospheric time delay or tropospheric time delay that is not adequately accounted for, or other error sources.
The differentially corrected range residual error magnitudes DPRE(t;i;j)! and the differentially corrected range rate residual error magnitudes DRRE(t;i;j)! are used in the fault vector analysis discussed above. If one or more of these magnitudes is greater than a corresponding selected threshold, that is, if at least one of the two constraints
|DPRE(t;i;j)|≦DPRE(i;j)thr, (26)
|DPRRE(t;i;j)|≦DPRRE(i;j)thr (27)
is violated, the accuracy of the corresponding pseudorange value PR(t;i;j) or pseudorange rate value PRR(t;i;j) is assumed to be unacceptably inaccurate, and the SATPS signals received from another SATPS satellite (j') are substituted for the SATPS signals received from the satellite number j. If at least four satellites (j) can be found that satisfy all of the constraints set forth in Eqs. (26) and (27), the corresponding DSATPS corrections for that reference station have acceptable accuracy and can be used for correcting the pseudorange and/or pseudorange rate values for nearby mobile SATPS stations.
If any satellite (j) is found that does not satisfy the constraints of Eqs. (26) and (27), the accuracies of the pseudorange and/or pseudorange rate corrections for that reference station (i) and that satellite (j) are assumed to be compromised. In this instance, this reference station (i) transmits its DSATPS corrections to nearby users but notifies the users that these DSATPS corrections are of questionable accuracy. Optionally, this reference station (i) can also transmit the differential residual magnitudes |DPRE(t;i;j')| and |DPRRE(t;i;j)| and allow the mobile user to determine if the DSATPS corrections from this reference station will be accepted and used.
The results of comparison of the pseudorange and pseudorange rate corrections can be broadcast by a reference (DSATPS) station (or by the adjacent SIM station) for use by an SATPS mobile station 17 that is operating in the vicinity of that DSATPS station. Alternatively, the results of comparison of the pseudorange rate corrections for the SIM station or a DSATPS station can be transmitted to a central station 19 for further signal processing or for retransmission to the mobile station 17.
The pseudorange residuals and pseudorange rate residuals, including the corrections thereto, are given by the respective relations
DPRE(t;ij)=PR(t;i;j)-R(t;i;j)-b(t;i;j)+PRC(t;i;j), (28)
DPRRE(t;i;j)=PRR(t;i;j)-RD(t;i;j)-b(t;i;j)+RRC(t;i;j), (29)
where PR and PRR represent the pseudorange and pseudorange rate, R and RD represent the "true" range and "true" range rate (given by Doppler, carrier phase or other measurements), b and b represent the clock bias and clock bias rate, and PRC and RRC represent the corrections for pseudorange and pseudorange rate for a particular DSATPS station/satellite combination (i,j).
FIGS. 3A and 3B together illustrate a procedure for monitoring and checking the integrity of the signals received in a neighborhood of the DSATPS reference station according to the invention. In steps 31 and 33, the reference station receives and measures the pseudorange signals PR and pseudorange rate signals PRR from M SATPS satellites and determines the pseudorange corrections PRCRS =-PRRERS and pseudorange rate corrections PRRCRS =-PRRRERS to be applied to these signals, by comparing the psuedorange and pseudorange rate signals received to the computed range and range rate values based on the known location and velocity coordinates.
In steps 35 and 37, the SIM station receives and measures the pseudorange signals PR and pseudorange rate signals PRR from the same M satellites and determines the pseudorange corrections PRCSIM =-PRRESIM and pseudorange rate corrections PRRCSIM =-PRRRESIM by similar comparisons.
In step 39, the residual differential errors DPRESIM and DPRRESIM are computed. In step 41, the pseudorange residual error |DPRE(t;i;j)SIM | compared with its corresponding threshold DPRE(i,j)thr. If Eq. (26) is not satisfied, the system chooses another satellite j=j' and repeats the analysis of the quantities PRRE, PRRRE, DPRE and DPRRE, in step 43. If Eq. (26) is satisfied, the system proceeds to step 45. Steps 39 and beyond are implemented at the SIM station.
In step 45, the pseudorange residual error DPRRE(t;i;j)SIM is compared with its corresponding threshold DPRRE(i;j)thr. If Eq. (27) is not satisfied, the system chooses another satellite j=j" and repeats the analysis of the quantities PRRE, PRRRE, DPRE and DPRRE, in step 47. If Eqs. (26) and (27) are satisfied, the reference station can use the measured pseudorange and pseudorange rate values from that satellite (j) to determine the pseudorange and pseudorange rate corrections that are broadcast to nearby mobile stations.
In step 51, a counter L, which is initially=0 and satisfies L≦M if M satellites are presently in view, is incremented by ΔL=1 each time another satellite (j) satisfies Eqs. (26) and (27). In step 53, the system checks whether L≧1. If L is not ≧1 (step 55), no SATPS parameters (e.g., clock bias and/or frequency offset and/or location coordinates and/or velocity coordinates) are correctable. If L≧1, at least one parameter is correctable, as in step 57, and the system proceeds to step 59.
In step 59, the system checks whether L≧2. If L is not ≧2, L=1 and one parameter is correctable, as in step 61. If L≧2, at least two parameters are correctable, or at least one parameter can be monitored, as in step 63, and the system proceeds to step 65.
In step 65, the system checks whether L≧3. If L is not ≧3, L=2 and two parameters are correctable, or one parameter can be monitored, as in step 67. If L≧3, at least three parameters are correctable, or at least two parameters can be monitored, or a group containing one or more satellites can be isolated, as in step 69, and the system proceeds to step 71.
In step 71, the system checks whether L≧4. If L is not ≧4, L=3 and three parameters are correctable, or two parameters can be monitored, or one parameter can be isolated, as in step 73. If L>4, at least four parameters are correctable, or at least three parameters can be monitored, or a group with at least two satellites can be isolated, as in step 75, and the system proceeds to step 77.
In step 77, the system checks whether L≧5. If L is not ≧5, L=4 and four parameters are correctable, or three parameters can be monitored, or two parameters can be isolated, as in step 79. If L≧5, at least five parameters are correctable, or at least four parameters can be monitored, or a group with at least three satellites can be isolated, as in step 81. The system need not inquire further here, because monitoring four parameters is sufficient.
If at least one parameter can be isolated, as in steps 73, 75, 79 and/or 81, the system may use the fault vector isolation analysis set forth in connection with Eqs. (22), (23) and (24) to attempt to determine if a particular satellite is at fault, as illustrated in the diagram in FIG. 4. In step 91, the system first inquires if D>Dthr ? If D≦Dthr, the set of location parameters or velocity parameters can be used for correction and/or monitoring, as in step 93. If D>Dthr, the sequence of values τj =fj 2 /Sjj is formed, in step 95, and the largest and second largest values, τJ1 and τJ2, respectively, are identified, in step 97. In steps 99 and 101, the likelihood ratio RJ1,J2 =2 loge (pJ1 /PJ2) is computed and compared with ΔτJ1,J2 =τJ1 -τJ2. -τJ2. If ΔτJ1,J2 ≦RJ1,J2, as in step 103, the satellite(s) at fault cannot be isolated. If ΔτJ1,J2 >RJ1,J2, as in step 105, the signals from satellite j=J1 are faulty and should be isolated. In step 107 (optional), the DSATPS reference station transmits the PRC(t;i;j) and PRRC(t;i;j) corrections for that reference station-satellite combination but also transmits an error flag indicating that the accuracy of SATPS signals received from this satellite is unacceptable for use by a mobile station. The foregoing computations are repeated after removing the effects of SATPS signals received from satellite number J1.
In the foregoing discussion, it is assumed that the SIM station is stationary so that the location coordinates are fixed and known and the velocity coordinates are zero for that station. A mobile SATPS station that is near, but spaced apart from, the reference station (referred to for convenience as a "remote station" or REM station), can be substituted for the SIM station, and K (=4, preferably) location or velocity parameters can be corrected, if the number M of in-view SATPS satellites with acceptable SATPS signals satisfies the constraint M≧K. If M≧K+1 (or M≧K+2), K location or velocity coordinates can be monitored (or M-K-1 can be isolated). This allows use of a mobile SATPS station, whose location and/or velocity parameters are merely estimated initially, as a SIM, and does not require surveying, construction and operation of a separate, stationary SIM station.
In a conceptually simpler approach, the location coordinates x(t;i)SIM, y(t;i)SIM, z(t;i)SIM and the velocity coordinates v(t;i)x,SIM, v(t;i)y,SIM, 30 v(t;i)z,SIM of the SIM station are computed from the SATPS signals received from the satellites. Location difference values and velocity difference values
Δx(t;i)SIM =x(t;i)SIM -x(i)SIM,known, (30)
Δy(t;i)SIM =y(t;i)SIM -y)i)SIM,known, (31)
Δz(t;i)SIM =z(t;i)SIM -z(i)SIM,known, (32)
Δv(t;i)x,SIM =v(t;i)x,SIM -v(i)x,SIM,known, (33)
Δv(t;i)y,SIM =v(t;i)y,SIM -v(i)y,SIM,known, (34)
Δv(t;i)z,SIM =v(t;i)z,SIM -v(i)z,SIM,known, (35)
are then formed, where the location coordinates x(i)SIM,known, y(i)SIM,known, Z(i)SIM,known and the velocity coordinates v(i)x,SIM,known, v(i)y,SIM,known, V(i)z,SIM,known are the known location coordinates and velocity coordinates of the SIM station. The magnitudes of the six difference values in Eqs. (30)-(35) are then compared with respective selected threshold values Δx(i)thr, Δy(i)thr, Δz(i)thr, Δv(i)x,thr, Δv(i)y,thr, and Δv(i)z,thr, to determine whether the set of pseudorange and/or pseudorange rate signals received by the SIM station from the M SATPS satellites are of acceptable accuracy for use in correcting the location coordinates and/or the velocity coordinates of a nearby mobile SATPS station. If the conditions
|Δx(t;i)SIM |≦Δx(i)thr, (36)
|Δy(t;i)SIM |≦Δy(i)thr, (37)
|Δz(t;i)SIM |≦Δz(i)thr, (38)
|Δv(t;i)x,SIM |≦Δv(i)x,thr, (39)
|Δv(t;i)y,SIM |≦Δv(i)y,thr, (40)
|Δv(t;i)z,SIM |≦Δv(i)z,thr, (41)
are all satisfied, the set of M pseudorange and/or pseudorange rate measurements can be used to correct K of the location coordinates and/or velocity coordinates of a nearby mobile station, provided that M≧K. If at least one of the Eqs. (36)-(41) is not satisfied, the set of M pseudorange and/or pseudorange rate measurements cannot be used to correct K of the location coordinates and/or velocity coordinates of a nearby mobile station. Preferably, the location difference thresholds Δx(i)thr, etc. are chosen in the approximate range 10-30 meters and the velocity difference thresholds Δv(i)x,thr, etc. are chosen in the range 0.5-1.6 meters/sec.
Alternatively, the three location differences, and also the three velocity differences, for the SIM station (i) may be combined in 2-D or 3-D Euclidean differences and compared with selected location difference thresholds Δdthr and velocity difference thresholds Δvthr in the forms
(Δx(t;i)SIM)2 +(Δy(t;i)SIM)2! 1/2 ≦Δd2,thr, (42)
(Δv(t;i)x,SIM)2 +(Δv(t;i)y,SIM)2 !1/2 ≦Δv2,thr, (43)
(Δx(t;i)SIM)2 +(Δy(t;i)SIM)2 +(Δz(t;i)SIM)2 !1/2 ≦Δd3,thr, (44)
(Δv(t;i)x,SIM)2 +(Δv(it;i)y,SIM)2 +(Δv(t;i)z,SIM) 2 !1/2 ≦v3,thr. (45)
In a similar manner, if all the Eqs. (36)-(41), or Eqs. (42)-(43), or Eqs (44)-(45) are satisfied and if M≧1, the set of M pseudorange and/or pseudorange rate measurements can be used to correct the clock bias and frequency offset parameters of a nearby mobile station. If at least one of the Eqs. (36)-(41), or Eqs. (42)-(45), is not satisfied, clock bias and frequency offset parameters for a mobile station cannot be corrected using pseudorange and pseudorange rate measurements from the set of M SATPS satellites.
A Satellite Positioning System (SATPS) is a system of satellite signal transmitters, with receivers located on the Earth's surface or adjacent to the Earth surface, that transmits information from which an observer's present location and/or the time of observation can be determined. Two operational systems, each of which qualifies as an SATPS, are the Global Positioning System and the Global Orbiting Navigation Satellite System.
The Global Positioning System (GPS) is part of a satellite-based navigation system developed by the United States Defense Department under its NAVSTAR satellite program. A fully operational GPS includes up to 24 satellites approximately uniformly dispersed around six circular orbits with four satellites each, the orbits being inclined at an angle of 55� relative to the equator and being separated from each other by multiples of 60� longitude. The orbits have radii of 26,560 kilometers and are approximately circular.
The orbits are non-geosynchronous, with 0.5 sidereal day (11.967 hours) orbital time intervals, so that the satellites move with time relative to the Earth below. Theoretically, three or more GPS satellites will be visible from most points on the Earth's surface, and visual access to two or more such satellites can be used to determine an observer's position anywhere on the Earth's surface, 24 hours per day. Each satellite carries a cesium or rubidium atomic clock to provide timing information for the signals transmitted by the satellites. Internal clock correction is provided for each satellite clock.
Each GPS satellite transmits two spread spectrum, L-band carrier signals: an L1 signal having a frequency f1=1575.42 MHz and an L2 signal having a frequency f2=1227.6 MHz. These two frequencies are integral multiples f1=1540 f0 and f2=1200 f0 of a base frequency f0=1.023 MHz.
The Li signal from each satellite is binary phase shift key (BPSK) modulated by two pseudo-random noise (PRN) codes in phase quadrature, designated as the C/A-code and P-code. The L2 signal from each satellite is BPSK modulated by only the P-code. The nature of these PRN codes is described below.
One motivation for use of two carrier signals Li and L2 is to allow partial compensation for propagation delay of such a signal through the ionosphere, which delay varies approximately as the inverse square of signal frequency f (delay ∝f-2). This phenomenon is discussed by MacDoran in U.S. Pat. No. 4,463,357, which discussion is incorporated by reference herein. When transit time delay through the ionosphere is determined, a phase delay associated with a given carrier signal can be determined.
Use of the PRN codes allows use of a plurality of GPS satellite signals for determining an observer's position and for providing navigation information. A signal transmitted by a particular GPS signal is selected by generating and matching, or correlating, the PRN code for that particular satellite. All PRN codes are known and are generated or stored in GPS satellite signal receivers carried by ground observers. A first PRN code for each GPS satellite, sometimes referred to as a precision code or P-code, is a relatively long, fine-grained code having an associated clock or chip rate of 10 f0=10.23 MHz. A second PRN code for each GPS satellite, sometimes referred to as a clear/acquisition code or C/A-code, is intended to facilitate rapid satellite signal acquisition and hand-over to the P-code and is a relatively short, coarser-grained code having a clock or chip rate of f0=1.023 MHz. The C/A-code for any GPS satellite has a length of 1023 chips or time increments before this code repeats. The full P-code has a length of 259 days, with each satellite transmitting a unique portion of the full P-code. The portion of P-code used for a given GPS satellite has a length of precisely one week (7.000 days) before this code portion repeats. Accepted methods for generating the C/A-code and P-code are set forth in the document GPS Interface Control Document ICD-GPS-200, published by Rockwell International Corporation, Satellite Systems Division, Revision A, 26 September 1984, which is incorporated by reference herein.
The GPS satellite bit stream includes navigational information on the ephemeris of the transmitting GPS satellite and an almanac for all GPS satellites, with parameters providing corrections for ionospheric signal propagation delays suitable for single frequency receivers and for an offset time between satellite clock time and true GPS time. The navigational information is transmitted at a rate of 50 Baud. A useful discussion of the GPS and techniques for obtaining position information from the satellite signals is found in Tom Logsdon, The NAVSTAR Global Positioning System, Van Nostrand Reinhold, New York, 1992, incorporated by reference herein.
A second configuration for global positioning is the Global Orbiting Navigation Satellite System (GLONASS), placed in orbit by the former Soviet Union and now maintained by the Russian Republic. GLONASS also uses 24 satellites, distributed approximately uniformly in three orbital planes of eight satellites each. Each orbital plane has a nominal inclination of 64.8� relative to the equator, and the three orbital planes are separated from each other by multiples of 120� longitude. The GLONASS circular orbits have smaller radii, about 25,510 kilometers, and a satellite period of revolution of 8/17 of a sidereal day (11.26 hours). A GLONASS satellite and a GPS satellite will thus complete 17 and 16 revolutions, respectively, around the Earth every 8 days. The GLONASS system uses two carrier signals L1 and L2 with frequencies of f1=(1.602+9k/16) GHz and f2=(1.246+7k/16) GHz, where k (=0, 1, 2,..., 23) is the channel or satellite number. These frequencies lie in two bands at 1.597-1.617 GHz (LI) and 1,240-1,260 GHz (L2). The L1 code is modulated by a C/A-code (chip rate=0.511 MHz) and by a P-code (chip rate=5.11 MHz). The L2 code is presently modulated only by the P-code. The GLONASS satellites also transmit navigational data at at rate of 50 Baud. Because the channel frequencies are distinguishable from each other, the P-code is the same, and the C/A-code is the same, for each satellite. The methods for receiving and analyzing the GLONASS signals are similar to the methods used for the GPS signals.
Reference to a Satellite Positioning System or SATPS herein refers to a Global Positioning System, to a Global Orbiting Navigation System, and to any other compatible satellite-based system that provides information by which an observer's position and the time of observation can be determined, all of which meet the requirements of the present invention.
A Satellite Positioning System (SATPS), such as the Global Positioning System (GPS) or the Global Orbiting Navigation Satellite System (GLONASS), uses transmission of coded radio signals, with the structure described above, from a plurality of Earth-orbiting satellites. A single passive receiver of such signals is capable of determining receiver absolute position in an Earth-centered, Earth-fixed coordinate reference system utilized by the SATPS.
A configuration of two or more receivers can be used to accurately determine the relative positions between the receivers or stations. This method, known as differential positioning, is far more accurate than absolute positioning, provided that the distances between these stations are substantially less than the distances from these stations to the satellites, which is the usual case. Differential positioning can be used for survey or construction work in the field, providing location coordinates and distances that are accurate to within a few centimeters.
In differential position determination, many of the errors in the SATPS that compromise the accuracy of absolute position determination are similar in magnitude for stations that are physically close. The effect of these errors on the accuracy of differential position determination is therefore substantially reduced by a process of partial error cancellation.
An SATPS antenna receives SATPS signals from a plurality (preferably four or more) of SATPS satellites and passes these signals to an SATPS signal receiver/processor, which (1) identifies the SATPS satellite source for each SATPS signal, (2) determines the time at which each identified SATPS signal arrives at the antenna, and (3) determines the present location of the SATPS antenna from this information and from information on the ephemerides for each identified SATPS satellite. The SATPS signal antenna and signal receiver/processor are part of the user segment of a particular SATPS, the Global Positioning System, as discussed by Logsdon, op. cit., pp. 17-90, incorporated by reference herein.
|Cited Patent
|Filing date
|Publication date
|Feb 26, 1996
|Oct 21, 1997
|Trimble Navigation Limited
|Post-processing of inverse differential corrections for SATPS mobile stations
|Citing Patent
|Filing date
|Publication date
|Aug 18, 1997
|May 9, 2000
|Trimble Navigation Limited
|Receiver with seamless correction capacity
|Dec 18, 1997
|Jul 4, 2000
|Ericsson Inc.
|Method for determining the location of a GPS receiver using an estimated reference time
|Sep 2, 1997
|Sep 5, 2000
|Sextant Avionique
|Method of air navigation assistance for guiding a moving vehicle towards a moving target
|Apr 9, 1999
|Dec 19, 2000
|Vsis, Inc.
|Ionospheric correction for single frequency GPS receivers using two satellites
|Jun 3, 1997
|Jan 9, 2001
|Sextant Avionique
|Satellite signal receiver with detector of incoherence between code phase and carrier frequency measurements
|Apr 16, 1998
|Apr 10, 2001
|Snaptrack, Inc.
|Method and apparatus for determining time in a satellite positioning system
|Oct 6, 2000
|Aug 13, 2002
|Snaptrack, Inc.
|Method and apparatus for determining time in a satellite positioning system
|Feb 21, 2001
|Oct 15, 2002
|United Parcel Service Of America, Inc.
|Method, apparatus, system, and computer software program product for determining position integrity in a system having a global navigation satellite system (GNSS) component
|Nov 26, 2001
|Jan 21, 2003
|Global Locate, Inc.
|Correction of a pseudo-range model from a GPS almanac
|Jun 26, 2002
|Jul 22, 2003
|Snaptrack, Inc.
|Method and apparatus for determining time in a satellite positioning system
|Nov 18, 2002
|Oct 26, 2004
|Honeywell International Inc.
|Portable tester for LAAS ground facility
|Jun 13, 2003
|Jan 4, 2005
|Qualcomm Incorporated
|Method and apparatus for determining time in a satellite positioning system
|Nov 15, 2002
|Feb 8, 2005
|Global Locate, Inc.
|Method and apparatus for forming a pseudo-range model
|Jun 3, 2002
|Jun 20, 2006
|Motorola, Inc.
|Method and apparatus for assisted GPS
|Nov 14, 2003
|Aug 29, 2006
|Lockheed Martin Corporation
|All-weather precision guidance and navigation system
|Jul 8, 2005
|Aug 28, 2007
|David Gary Meyer
|Active geophysical prospecting system
|Jun 3, 2005
|Nov 20, 2007
|Novatel, Inc.
|Apparatus for and method of improving position and time estimation of radio location devices using calibrated pulse shapes
|Oct 25, 2005
|Dec 11, 2007
|Norbelle, Llc
|Locating system and method
|Jun 8, 2006
|Mar 10, 2009
|Texas Instruments Incorporated
|Methods and apparatus to detect and correct integrity failures in satellite positioning system receivers
|Dec 14, 2007
|Feb 9, 2010
|Westerngeco L.L.C.
|Segmented antenna system for offshore radio networks and method of using same
|Mar 17, 2005
|Jul 6, 2010
|Sirf Technology, Inc.
|Navigation processing for a satellite positioning system receiver
|Jun 29, 2005
|Aug 24, 2010
|Rockwell Collins, Inc.
|Integrity-optimized receiver autonomous integrity monitoring (RAIM)
|Apr 14, 2008
|Sep 6, 2011
|Honeywell International Inc.
|Navigation system with apparatus for detecting accuracy failures
|Apr 14, 2008
|Sep 13, 2011
|Honeywell International Inc.
|Navigation system with apparatus for detecting accuracy failures
|Feb 26, 2009
|Mar 6, 2012
|Gmv Aerospace And Defence, S.A.
|GNSS navigation solution integrity in non-controlled environments
|Nov 22, 2011
|Jul 3, 2012
|Google Inc.
|Finding nearby users without revealing own location
|Jun 26, 2012
|May 27, 2014
|Google Inc.
|Finding nearby users without revealing own location
|Feb 7, 2013
|Mar 22, 2016
|Samsung Electronics Co., Ltd
|Method and apparatus for determining physical characteristics of a receiving device in a navigation system
|Sep 7, 2012
|May 17, 2016
|Honeywell International Inc.
|Method and system for providing integrity for hybrid attitude and true heading
|Jun 3, 2002
|Jan 16, 2003
|King Thomas M.
|Method and apparatus for assisted GPS
|Nov 15, 2002
|Apr 10, 2003
|Global Locate Inc.
|Method and apparatus for forming a pseudo-range model
|Nov 18, 2002
|May 20, 2004
|Honeywell International Inc.
|Portable tester for LAAS ground facility
|Nov 14, 2003
|Jan 20, 2005
|Lockheed Martin Corporation
|All-weather precision guidance and navigation system
|Mar 17, 2005
|Dec 1, 2005
|Brodie Keith J
|Navigation processing for a satellite positioning system receiver
|Oct 25, 2005
|Feb 16, 2006
|Norman Mohi
|Locating system and method
|Sep 30, 2004
|Apr 6, 2006
|Lockheed Martin Corporation
|Tactical all weather precision guidance and navigation system
|Jun 3, 2005
|Dec 7, 2006
|Allan Manz
|Apparatus for and method of improving position and time estimation of radio location devises using calibrated pulse shapes
|Jul 8, 2005
|Jan 11, 2007
|Meyer David G
|Active geophysical prospecting system
|Jun 8, 2006
|May 24, 2007
|Rahman Mohammad A
|Methods and apparatus to detect and correct integrity failures in satellite positioning system receivers
|Oct 31, 2007
|Feb 28, 2008
|Norman Mohi
|Locating System and Method
|Dec 14, 2007
|May 29, 2008
|Westerngeco, L.L.C.
|Segmented Antenna System for Offshore Radio Networks and Method of Using Same
|Apr 14, 2008
|Jun 11, 2009
|Honeywell International Inc.
|Navigation system with apparatus for detecting accuracy failures
|Apr 14, 2008
|Jun 11, 2009
|Honeywell International Inc.
|Navigation system with apparatus for detecting accuracy failures
|Jan 15, 2008
|Jul 16, 2009
|Honeywell International, Inc.
|Navigation system with apparatus for detecting accuracy failures
|Jan 15, 2008
|Jul 16, 2009
|Honeywell International, Inc.
|Navigation system with apparatus for detecting accuracy failures
|Jan 15, 2008
|Jul 16, 2009
|Honeywell International, Inc.
|Navigation system with apparatus for detecting accuracy failures
|Feb 26, 2009
|Feb 11, 2010
|Gmv Aerospace And Defence, S.A.
|Gnss navigation solution integrity in non-controlled environments
|Dec 30, 2008
|Dec 8, 2010
|THALES ATM GmbH
|Monitoring device for an augmented satellite-based positioning system and augmented satellite-based positioning system
|Jul 9, 2001
|Jan 17, 2002
|United Parcel Service Of America, Inc.
|Method, apparatus and system for determining position integrity in a global satellite navigation system
|Jul 9, 2001
|Mar 21, 2002
|United Parcel Service Inc
|Method, apparatus and system for determining position integrity in a global satellite navigation system
|Nov 14, 2003
|Jun 3, 2004
|Lockheed Martin Corporation
|All-weather precision guidance and navigation system
|Nov 14, 2003
|Feb 10, 2005
|Richard Kirchofer
|All-weather precision guidance and navigation system
|Jun 2, 2006
|Dec 7, 2006
|Novatel, Inc.
|Apparatus for and method of improving position and time estimation of radio location devices using calibrated pulse shapes
|U.S. Classification
|342/357.64, 701/470
|International Classification
|Cooperative Classification
|European Classification
|Jul 31, 2000
Owner name: ABN AMRO BANK N.V., AS AGENT, ILLINOIS
Free format text: SECURITY AGREEMENT;ASSIGNOR:TRIMBLE NAVIGATION LIMITED;REEL/FRAME:010996/0643
Effective date: 20000714
|May 2, 2002
|Fee payment
Year of fee payment: 4
|May 21, 2002
|Maintenance fee reminder mailed
|Jul 27, 2005
Owner name: TRIMBLE NAVIGATION LIMITED, CALIFORNIA
Free format text: RELEASE OF SECURITY INTEREST;ASSIGNOR:ABN AMRO BANK N.V.;REEL/FRAME:016345/0177
Effective date: 20050620
|May 3, 2006
|Fee payment
Year of fee payment: 8
|Jun 7, 2010
|Maintenance fee reminder mailed
|Nov 3, 2010
|Lapse for failure to pay maintenance fees
|Dec 21, 2010
|Expired due to failure to pay maintenance fee
Effective date: 20101103


text:
IP Camera software driver or firmware
This project received 7 bids from talented freelancers with an average bid price of $849 USD.Get free quotes for a project like this
Project Budget$250 - $750 USD
Total Bids7
Project Description
Or you could use some of the open source programas out there...
Basically I bought an IP wireless camera from Tenvis in China, and their software really really sucks, the cameras get desconfigured all the time, and they pretty unpredictable, so I need a new software to run them smooth and without any fails... and a friendlier UI... And that they can be seen on any device, pc, mobile, tablets, and all plattforms.... I see many open source softwares can accomplish this... but the original software that operates the camera must be changed....
Skills Required
Looking to make some money?
- Set your budget and the timeframe
- Outline your proposal
- Get paid for your work
Hire Freelancers who also bid on this project
Looking for work?
Work on projects like this and make money from home!Sign Up Now
- Forbes
- The New York Times
- Time
- Wall Street Journal
- Times Online

subset: commoncrawl


text:
11 Of The Best Cruise Tips We've Ever Heard!
February 24, 2016
Here at www.CRUISE.co.uk we love it when customers leave us detailed reviews of their cruises. Whether it's to complain about something, to praise the staff or to give fellow passengers advice – we want to hear it!
These reviews (which you can have a look at here) are all completely unedited by us or the cruise lines. You have your say and we listen – no matter how positive or negative the review.
It's great to hear how much fun they've had on their holiday, and we've recently combed the reviews to find the best tips we've heard from passengers to help new cruisers or existing cruisers have the holiday of a lifetime!
Read on to find out what advice they have for you…
Beware Of Belts At Airports!
One passenger told us that he bought a special metallic free belt so that he would not have to remove it at the airport – but once arriving was asked to remove it anyway as it was the airports policy! His advice? Don't waste your money on a non-metallic belt – stick with your old one!
You can read more of his review here.
Remember To Pick Up Any Photographs
One passenger found out the hard way that if you don't go and get your photographs of your cruise – it's too late! Few cruise lines post these photos online, and you will have lost out if you wait until you leave as your pictures won't follow you home – even if you've already paid for them.
Read more tips from a passengers time on-board Royal Caribbean here.
Don't Panic If You Can't Book
If you haven't booked speciality restaurants or shows in advance on a Royal Caribbean cruise and want to do so on the Royal IQ app – and then find you don't know how to make it work… Do things the old fashioned way! Reeve from Halifax told us that the staff at Guest Services or the Booking Desk can be much more helpful – and a little easier to use! So if you are technophobic and still prefer to do things in person, you don't need to worry.
Read more about his tips and tricks from his time on Quantum of the Seas here.
How To Make New Friends
If you're travelling solo or as a couple, you will probably want to make some new friends! But what exactly is the best way to go about meeting new people? Our cruisers told us that even if you are travelling as a couple – you should ask to sit at a table of 6 to meet interesting like-minded cruisers to enjoy your holiday experience with!
Read more top tips from Shore here.
Double Check What's Included
Sounds like an obvious tip – but you'd be amazed by how many passengers are taken by surprise by what is included. Double check if things such as water are included if you haven't opted for a drinks package and find out its price on-board to see if you choice is actually the best option!
Find out more about why this was necessary for one passenger here.
Don't Be Afraid To Go It Alone
One passenger told us her heartfelt account of going it alone for the first time after becoming widowed. Despite being worried her disability would hold her back she managed to have a great holiday. Her advice? Set yourself a daily routine to increase a feeling of stability on-board.
"I felt a stronger person for having achieved this break on my own. So to all those people reading this who might be wondering if they could manage a holiday on their own then I'd say go for it and to all of the people on the ship who went out of their way to talk to me and offer support then I give them my heartfelt thanks."
If you are thinking about sailing solo, read her brave account here.
How To Mingle As A Solo Traveller
After reading her account, another solo passenger left us with this advice in the comments:
"Ask for a place at first or second sitting on a circular table for six – all solos – and preferably without a 'drinks package' amongst them… & Attend the solos gatherings. You won't remember the names but you will get a free drink and no doubt meet at least one soulmate."
Sounds like great advice to us!
Be Careful With An Upgrade
We've lost count of the number of times we've read a review where a passenger has had an upgrade they didn't like! One passenger told us that they were upgraded to a balcony – but the room they were given was actually smaller than their original cabin. An upgrade is always a gamble – so be careful when saying yes!
You can read more about this passenger's experience of an upgrade here.
Watch Out For Port Taxi Drivers
Many cruisers recommend hopping in a taxi rather than taking a shore excursion with a cruise line. Whilst this can save you a lot of money – you need to be careful. Haylett from Southampton told us about their experience of being driven a mere 200 yards down the road – as the taxi driver drove them around in a large circle to rip them off! Our advice? Always check how far you need to travel in your taxi before you get in it so you know if you are being taken for a ride or whether the location could actually be in walking distance.
You can read more of their review here.
Bring A Tea Bag!
As our customer advised us here, sometimes you just can't beat a perfect cup of tea! The problem is that you can't always guarantee that your cruise will provide you with your favourite bag, particularly if you like speciality teas or have a fondness for earl grey. Solve this by packing a few of your favourite tea bags in your suitcase. Then you only need ask for hot water!
Go Behind The Scenes
You may have heard of behind the scenes tours on cruise ships and dismissed them as a waste of time. But again and again we hear from passengers who have raved about their tour! Partington left us a review telling us how much they had enjoyed their tour (which you can read here)! Have you ever been on a behind the scenes tour?
If you're interested in reading more reviews or want to write your own review to help your fellow cruisers – click here!
So there you have it! Have you heard any of these tips before? Will you be trying them on your next cruise? Let us know in the comments below!
Other Articles you may be interested in
- Passenger Pressure Strikes Victory As Major C...
- Welcome To Japan's Secret Island For A Volcan...
- NCL Confirms €3.2 Billion Order Of Next Fou...
- Top Ten Things You Just HAVE To Do In Japan
- Exclusive: Ask Your Burning Questions To A Wo...
- 15 Japanese Customs That May Seem Crazy But Y...
- Adventure And Love Finally Combined: The Most...
- The Dreamy Definitive Guide To Amsterdam, The...
- Twelve Things All First Time Cruisers Get Wro...
- How To Cruise Hawaii, The State With Everythi...
- The Next Big Thing For The Cruising World: Is...
- 10 Airplane Hacks To Keep You Sane On Your Ne...


text:
Emergency? Call: 911
Other emergencies: 613-230-6211
Call centre: To report theft, property damage, missing person or stolen vehicle. 613-236-1222 ext 7300 (TTY: 613-760-8100)
Community Police Centres and all other enquiries 613-236-1222 (TTY: 613-232-1123)
FOR IMMEDIATE RELEASE: Wednesday March 2, 2016 3:00pm
(Ottawa)—The Ottawa Police Sexual Assault and Child Abuse Section is seeking public assistance to identify a male suspect in relation to an ongoing investigation.
On Sunday, February 28, 2016 at approximately 3:00am, an unidentified male approached a female in her early 20's from behind in the Carling and Alpine Avenues area and attempted to remove her pants. When the complainant resisted, the unidentified male fled on foot.
The suspect is described as a Caucasian male, thin build, approximately 5'7" to 5'11" (170 cm – 180 cm), unknown age. He was dressed in a black bomber style winter jacket and bulky black boots to his mid calf.
Anyone with information is asked to contact the Ottawa Police Service Sexual Assault and Child Abuse Unit at 613-236-1222, ext. 5944. Anonymous tips can be submitted by calling Crime Stoppers at 613-233-8477 (TIPS), toll-free at 1-800-222-8477 or downloading the Ottawa Police iOS app.
Media Relations Section
Tel: 613-236-1222, ext. 5366
© 2017 Ottawa Police Service
Ottawa Police Service P.O. Box 9634 Station T, Ottawa, Ontario, K1G 6H5, T: 613-236-1222, TTY: 613-232-1123 (for hearing impaired)


text:
You Need a Nice Household
If you are intending in order to be starting a new college in The state of florida, you are probably questioning where you are planning to dwell. You already know that you are going to choose to live in a safe place that is very well looked after also something that is economical. To make this approach take place, you are going to want to visit this excellent website to understand more about UCF moving information. This is certainly going to supply you with a variety of choices concerning where you're probably going to be living.
If you'd prefer, you can also submit an application for you to be considered of such apartments on this internet site. You will be blown away at just how very helpful it might be to benefit from UCF storage and moving facilities. In the end, you are probably intending to possess quite a few things that will need to wait directly into storage space. When you arrange them in storeroom, you will always have the ability to access these as much as essential but you simply won't need to panic about stumbling over them on a daily basis.
Visit this website to get a listing of issues that are allowed and also things which ought to be eventually left at home. If you have any queries, you may also phone. They're good sites to book while you are attending university. You may enjoy this fact that you will be in close proximity to others at college campus. This way, you will end up living your life around those who are working for the similar desired goals. Click here now to get yourself a UCF housing move guide. Using this method, you won't have to worry about passing up on a single thing.
You'll comprehend the fact that there may be a lot of auto parking for you personally and your guests. It will likely be at your decision to ensure that the immunizations tend to be updated. When you find yourself attending higher education, you are working with a large amount of people every day. You must know for sure that you are not getting unwell. This really is something you could find out more on when you check out the UCF student moving information. Visit this website how to discover more about how you can apply at have a home in this place. You're going to do something awesome on your own. An advanced education and learning can change your life for your better. Visit this website to acquire more information.


text:
So here we are again, ready for another exciting Super Bowl game. No matter which team is your favorite, we need nourishment to get us through! So, lets get some party food in the works. Looking for some delicious things to cook up? Try … [Read More...]
From My Portuguese Kitchen
Savor the flavors of Portugal with recipes that merge the essence and techniques of a melting pot of Mediterranean cultures. My cookbooks explore the influences on the Portuguese cuisine and embrace the spices and ingredients typical of Mediterranean countries dating back centuries including olive oil, onions, bay leaves, garlic, coriander, paprika, chili peppers and red sweet peppers. I hope you find my website as delicious as my recipes.
Look for my newest book, Authentic Portuguese Cooking,to be that was released in October 2015, with more than 185 Mediterranean style recipes.Learn more about Portuguese cooking with my first book Portuguese Homestyle Cooking. The recipes in this book exemplify the heartwarming, soul-comforting food prepared and enjoyed in Portuguese homes. [ Home Cooking ]
Cooking Classes
Hands-On PreparationTake an authentic Portuguese cooking class in the comfort of your home. With a group of your favorite friends and I will plan an intimate evening centered around good food and friendship. To reserve your class email me at firstname.lastname@example.com.
Visiting Portugal
It's impossible not to fall in love with Portugal with its old-fashioned traditions and its rustic seafood cuisine. Whether it's the Algarve coast with stunning beaches, the upper Douro valley where port wine grapes grow or living the high life in Bairro Alto that intrigues you, Portugal has something for everyone. [ Must Do's ]


text:
Is Safety Consultant Singapore incorrect or missing key business information? Update your Hotfrog listing today.
Contact details
Are these details correct?
Hotfrog Singapore provides information regarding Safety Consultant Singapore. Safety Consultant Singapore provides Workplace Safety services. Contact them on +65 6264 1500 or by visiting them on their website http://www.safetyconsultantsingapore.com.
Is Safety Consultant Singapore your business? Claim your listing and attract more leads by adding more content, photos and other business details.
We have more Workplace Safety services available on Hotfrog Singapore. You can update your search for Workplace Safety by location, keyword or service options.
Small Business Hub
Sharing tips, ideas and advice to help grow your small business.
Create your free Hotfrog business profile
Follow Hotfrog on:
Share on:
Hotfrog Small Business Hub


text:
Articles re:Webmaster Training
- Status Closed
- Budget $100 - $300 USD
- Total Bids 18
Project Description
We are looking for fresh new infomative and training articles regarding every aspect of Becoming a Webmaster and operating a business on the internet.
You will need to be well versed in the following subjects and many more:
1. Hosting a Website and various options including dedicated hosting, reseller hosting, shared hosting, cpanel, bandwidth etc,
2. Site Design / Logo Design
3. HTML including metatags, Alt tags, body tags
4. HTML editing software, Dreamweaver, FP, etc
5. Shopping Carts
6. Merchant accounts
7. Link Popularity
8. ebooks
9. Affiliate Programs
And about 100 more related topics.
We will need ultimately need 100 articles, but we are doing projects in blocks of 25 so that we are certain of the quality and we are satisfied with the provider.
You are bidding on the first block of 25 Webmaster/Internet Marketer articles. Articles will be between 500-800 words each. You will be able to provide examples of your writing style and work. You will be able to deliver on schedule fully proof read work, in blocks of 5 for approval, until you have an understanding of our expectations.
Excellent work will lead to awarding additional projects.
Get free quotes for a project like this
Awarded to:
Skills Required
Looking to make some money?
- Set your budget and the timeframe
- Outline your proposal
- Get paid for your work
Hire Freelancers who also bid on this project
Looking for work?
Work on projects like this and make money from home!Sign Up Now
- Forbes
- The New York Times
- Time
- Wall Street Journal
- Times Online


text:
The Pride Consultants
RS 1,25,000 To 3,00,000 Chandigarh, Bhiwani, Faridabad, Panipat, Rohtak, Kangra, Mandi, Shimla, Jalandhar, Ludhiana, Moga, Patiala
We have Immediate Openings for B Com / M Com Fresher students with Accounts knowledge . Starting Salary - 9000 to 14000/m. Job Location - Near Ludhiana. Industry - A Branded company ( FMCG ). No. of vacancies - 8 to 10 vacant positions.
Key Skills : accounts assistant,accountant,accounts executive,accounts officer,accounts associate,accounts...
Marketing Executive ( Fresher)
Job Options
RS 1,75,000 To 2,25,000 Gurgaon, Karnal, Amritsar, Ludhiana, Moga, Kanpur, Saharanpur, Kurukshetra, New Delhi,Delhi,Luckhnow,Ferozpur
- Good Communication Skills - Presentable - Should Done Mba/ Btech
Key Skills : marketing assistant,marketing associate,marketing engineer,marketing executive
Jobs Guru the Placement Consultants
RS 50000 To 50,000 Mohali ( Chandigarh ), Jagraon, Jalandhar, Ludhiana, Moga
Accountant B.Com / M.Com degree holders, having sound knowledge in all aspects of accounting, auditing, taxes etc. Over all experience of 2 Years or above need to apply. Preference given to the candidates having experience in Garments , Spinning mil...
Key Skills : tally,accountant,accounts assistant,accounts clerk,accounts manager,accounts head,accountant executive,head corporate...


text:
There are many men who suffer from low testosterone levels as they age. This is a condition marked by a decline is sexual function, a reduced sex drive and loss of overall energy. Many people wonder, "What can I do about my low T?" There are options available for those who suffer from this condition. Testosterone is a hormone produced in the testicles of a male, and is responsible for many bodily functions. When the levels of this hormone are low, there are many ways that the body can become affected. A man's overall health can decline.
Testosterone is produced when the brain signals to the testes that production should occur. There can oftentimes be a disconnection with this communication, causing a decline in the testosterone production. Sometimes the brain can also receive incorrect signals from the body signaling that there is too much testosterone. This causes a the testes to slow production of the hormone, which can decrease sexual function as well causing as cause many other health related issues. These men should ask their doctors, "What can I do about my low T?" There are several treatment options available, and groundbreaking new drugs that help to increase the testosterone levels in men with this condition.
When a man asks his doctor, "What types of treatments are available for my low T?" The doctor should have several different options available to choose from that best fits his condition. It is also important to rule out any other conditions that may be affecting the levels of testosterone. Some men suffering from type 2 diabetes can have a reduced production of testosterone. This can often go unnoticed, because the diabetes is not always thought of as the culprit. Those who are suffering from type 2 diabetes and have the symptoms related to low testosterone production, should have their levels checked by a physician.
Symptoms that can be common among men with low testosterone levels can include the typical low sex drive as well as the loss of sexual function. In addition to these apparent symptoms, long term results from a decrease in testosterone include loss of hair on the body, weight gain, low bone strength and decline in muscle strength. Asking a physician the question, "Can my low T levels be increased?" can be a very important question that may lead to successful treatment options. These treatments can alleviate the symptoms and prevent long term damage to the body.


text:
The Ministerial Committee for Legislation is due to discuss a bill today (Sunday) that would defer military service in the reserves for newlywed men.
Under the bill, which was initiated by MK Avraham Michaeli (Shas), a recently-married man would not be called in to serve in the reserves during the first year of his marriage.
Tags:Reserves, MK Michaeli, Newlyweds


text:
In many places in India, girls aren't allowed to participate in their future. Denied education and access to resources, they are trapped in a cycle of poverty. Given the chance to learn and create their own way, successful women and girls uplift their families and communities in a direct and lasting way.
"Udaan" is an accelerated learning program that targets older girls who dropped out or never attended school and brings students up to a fifth-grade level in just 11 months, created especially for older girls who may never have set foot in school before.
After completing the program, 89% of girls go onto secondary school or college.


text:
Listing information
- Stories: 0
- Lot Area: 0.30
- County: Ottawa
- Elementary School: Grandville Public Schools
- Style: Lot/Land
- New Construction: No
- Lot Size: 106' x 136' x 82' x 155'
- High School: Grandville Public Schools
- School District: Grandville
- Status: Active
- Foreclosure: No
- Estimated Annual Taxes: $200
- Middle School: Grandville Public Schools
- Subdivision: G70 - Ottawa County
Assoc. Fee Incl. Other
Auction or For Sale For Sale
Docs at List Office Aerial Photo, Plat Map, Survey
Lot Description Buildable, Cleared, Level, Rolling Hills, Sidewalk, Site Condo
Mineral Rights No
Other Lot Square Footage - 13008.00, Road Frontage - 106.00
Property Sub-Type Lot
Sale Conditions None
Street Type Private
Terms Available Cash/Conventional
Util Avail at Street Broadband, Cable, Electric, Natural Gas, Public Sewer, Public Water, Telephone
Utilities Attached None
Waterfront Options: Waterfront Y/N No
Listing Courtesy of Jeffrey a Rogers of Fs Realty Llc


text:
Lovely song fills the night
For her soul is found
She enters not a vacant flight
Forever her song shall resound
She must never be without
She eternally will be devout
Lovely song fills the night
She has found her home
Not upon unwelcome blight
But above the sea and foam
She cannot be without
She eternally will be devout
Lovely song fills the night
From heaven back she comes
Away from heavenly light
She enriches many homes
She will not be without
She eternally will be devout
© Copyright 2017 Briiee. All rights reserved.
Status: Finished
Genre: Other
I rely like it. I especially like the verse "forever her song shell resound". It was the attention getter for me.
I absolutely loved this! So well written and amazing! wow... (:
A very soothing poem for the soul, I loved it, great job!
Book / Fantasy
Book / Fantasy
Book / Fantasy
Paste the link to picture in the entry below:
Paste the link to Youtube video in the following entry:
Cannot annotate a non-flat selection. Make sure your selection starts and ends within the same node.
An annotation cannot contain another annotation.
There was an error uploading your file.


text:
- Photos
- Map/Street View
- Things Nearby
img src="http://www.ardorny.com/i.aspx?t=a&s=t2&r=1681946" / Ardor Web ID: 1681946 - NEW EXCLUSIVE! Amazing REAL 1 bedroom on beautiful 13th street. This lovely prewar building offers both laundry and an elevator. The apartment features a queen sized bedroom with closet space, a classic and functional open kitchen with full sized appliances, → Read More
Share this listing: Email Print


text:
A camera application that is capable of superimposing an existing image over the camera live view.
This project was successfully completed by bsrcom for $100 USD in 3 days.Get free quotes for a project like this
Project Budget$30 - $250 USD
Completed In3 days
Total Bids14
Project Description
I would like an Android app that can be used to assist in recreating old photographs.
The user must be able to launch the app select an existing image file. That image file is then superimposed over the live image from the camera so the user can see when the old image and the new image are framed identically.
When the image is captured just the new image is captured.
Completed by:
Skills Required
Looking to make some money?
- Set your budget and the timeframe
- Outline your proposal
- Get paid for your work
Hire Freelancers who also bid on this project
Looking for work?
Work on projects like this and make money from home!Sign Up Now
- Forbes
- The New York Times
- Time
- Wall Street Journal
- Times Online


text:
El Forestal Vacation Rentals, Spain (2)
- Showing 1-2 of 2
Additional fees apply. Taxes may be added.
View Map Map
Sort By:HomeAway Sort Price: Low to High Distance from Destination Guest Rating
There are no results which match your criteria. Try refining your search parameters.
Didn't find what you're looking for?
View all 192 La Manga Club or all 1282 Cartagena - Mar Menor


text:
Here on Borneo you will find an astonishing range of Wildlife to create a truly memorable holiday experience.
Cycling is a great way to see Borneo all levels of experience catered for. With the largest selection of bikes on the island.
You too can experience jungle life in a safe and exciting environment..
Here on Borneo you will find an astonishing range of diving to create a truly memorable holiday experience.
With huge experience in helping leaders organise trips to Borneo with so much to see make sure you do not miss anything.
With sand sea and so much to do Borneo is a great location for a truly fantastic honeymoon. Packages to suit all budgets.
Formed in 1989 Borneo Travel has unrivalled experience in matching clients expectations and all of the variety that Borneo has to offer to ensure your stay is truly one to remember.
Based here on the Island you can be sure you are dealing with a company which has an intimate local knowledge which will ensure you will take away memories to last a life-time.
No website can answer every question - please do ask, I'm known as Borneo Bob, if I do not know the answer I will for sure know who to ask to ensure your trip fulfills your dreams.
Borneo Travel based here on the stunning island of Borneo with a European marketing office in the UK.
Clients can rely upon the fact that we employ fully trained
and licensed local experts as our adventure, birding and
wildlife specialists/guides. Founded by Bob Jones and Tham Yau Kong in 1989 we are a specialist holiday company who has over 25+ years direct hands on experience
in Borneo wildlife tours and travel. Bob is eagerly waiting to
help and guide you through your tours and holidays in Borneo.
Tham Yau Kong is our local travel & tours expert, who heads
the operation in Borneo. He has been awarded Malaysia's Best Tour Guide,
and has also received the country's Best Tour Programme Award,
Best Tour Package Award, and Best Innovative Package Award.
You can choose one of our itineraries including tailor-made holidays in Borneo,
or we can create a customized Borneo wildlife tour, ground handling services,
expedition planning and logistics, exciting Borneo honeymoon packages,
local accounting advise, incentive, team-building programmes and other
adventurous activities. We work with local communities and are committed
to sustainable tourism development. Our adventure activities include
jungle and mountain trekking, mountain biking, rafting and diving.
Our clients include:
For any questions regarding our company and the various customized
Borneo wildlife tours we offer, please feel free to contact us.
School TripsLuxury HoneymoonsPrivacyTermsSite Map


text:
DK DANCE STUDIO - experience the passion
We are located just North of Rt 104 in the Village of Webster. We have been sharing our passion for dance in Webster for 13 years! There is a multitude of programs offered at DK Dance Studio, for all ages and levels. We offer Recreational classes, as well as having a Performance Team for those who wish to compete and perform more!
- Tap
- Ballet
- Jazz
- Lyrical
- Contemporary
- Hip-Hop
- Musical Theater
- more!!!
Beyond the traditional dance classes, we offer Adult Fitness Classes, Wedding Choreography, and Birthday Parties.
Register Now with the convenient Parent Portal !
At DK Dance, you will find QUALITY dance education from well EDUCATED instructors in a FUN, POSITIVE and FRIENDLY atmosphere.
We are also happy to partner with the Webster Parks and Rec to offer more classes for the Webster Community, and beyond!


text:
Regional Europe United Kingdom England Northumberland Travel and Tourism Accommodation Self Catering
This category deals with self catering accommodation.
Subcategories 13
Related categories 2
Sites 14
Eshott Hall Estate Holiday Cottages
Offer a choice of two self catering holiday cottages on Eshott Hall Estate between Alnwick and Morpeth. Describes accommodation and facilities. Prices, photographs and contacts.
Grace Darling Holidays
A selection of more than 30 holiday cottages in Northumberland in areas around Bamburgh and Seahouses.
Holiday cottages in Northumberland
Self-catering accommodation service for holiday makers in Northumberland.
The Hytte
A mountain lodge with a grass roof. Description and photographs of the accommodation, prices, local information and photographs of the area.
Lambley Farm Holiday Cottages
Offer six self catering holiday cottages in Lambley. Describes accommodation and facilities. Prices, photographs and contacts.
Long Barn
A 250 year old stone barn converted into a holiday home. Describes facilities and accommodation. Prices, photographs, local activities and contacts. Located in Berrington Lough.
North East Coastal Cottages
Cottages for holiday lets in Beadnell, Seahouses and Embleton. Information on accommodation, availability and rates.
Northumberland Cottages
Provides self catering accommodation in the county. General information, properties, about Northumberland, and contacts.
Northumberland Cottages
Offer a selection of holiday cottages located throughout the county.
Northumbria Byways
Self catering cottages in Northumberland and the Border regions of England and Scotland.
Northumbria Coast and Country Cottages
A selection of over 200 holiday cottages in Northumberland and the Scottish borders.
Parmontley Hall Country Lodges
A development of lodges to let and for sale next to the West Allen river at Whitfield. Profile, availability and prices.
Tidal Holidays
Offer two self catering holiday cottages in Alnmouth and Warkworth. Accommodation, prices, photographs and contacts.
Westnewton Estate
Self catering dog friendly cottages in a rural location. Profile and facilities. [Kirknewton]
Last update:October 24, 2015 at 14:15:03 UTC
All Languages


text:
The Anchorage Guest House, Waterford
Main amenities
- 12 guestrooms
- Breakfast available
- Tour/ticket assistance
Feel at home
- Free cribs/infant beds
- Rollaway/extra beds (surcharge)
- Private bathroom
- Television
- Hair dryer
- Coffee/tea maker
What's around
- On the waterfront
- House of Waterford Crystal (0.7 mi / 1.1 km)
- Waterford Treasures Museum (0.2 mi / 0.3 km)
- Garter Lane Arts Centre (0.2 mi / 0.3 km)
- St. Patrick's Church (0.3 mi / 0.5 km)
- Reginald's Tower (0.3 mi / 0.5 km)
It was nice family-style hotel very near the city center. Basic rooms, nice breakfast.…
The hotel lost our reservation and had no rooms available for the 1st night, but said we…
The Anchorage Guest House, Waterford
Hotel Info: 866-209-9122from $42
- Standard Room, 2 Single Beds
- Family Room
- Double Room
- Single Room
- Standard Room, 2 Single Beds
- Family Room
- Single Room
- Double Room
More great choices
At a glance
Key facts
Hotel size
- This hotel has 12 rooms
- Check-in time noon-10 PM
- Check-out time is 11:30 AM
Required at check in
- Credit card or cash deposit required
- Government-issued photo ID required
Travelling with others
- Pets not allowed
Nearby Three Star Waterford hotels
In the hotel
- Breakfast (surcharge)
- Golfing nearby
- Tours/ticket assistance
In the room
- Coffee/tea maker
- Private bathroom
- Shower only
- Hair dryer
- Digital TV channels
- Phone
Top Waterford hotels
Recently reviewed hotels in Waterford
- Mount Juliet EstateFrom
"Wow. Just wow. This will be our first choice of where to spend more time on our next visit to Ireland. First rate accommodations, food and staff. So glad we stayed at the end of a…"Oct 18, 2016
- Cloneen B&BFrom
" Beautiful home with nice layout. Very gracious hosts, very helpful with information and directions. Large spacious bedrooms and very comfortable beds. "Oct 7, 2016
- Grove Farm House B&BFrom
"Grove Farm was everything I had hoped it would be. Nellie was a wonderful host and went out of her way to make our stay very enjoyable and memorable. The breakfast was…"Sep 30, 2016
- Fern Hill Guest HouseFrom
"We had a lovely, albeit short, one night stay at Fern Hill. Our hosts, Anne and Tom, were among the nicest, friendliest (and funniest) people we met on our trip to Ireland. They…"Sep 28, 2016
Nearby hotels
Also popular with travelers from the USA
The Anchorage Guest House, Waterford's small print
Also known as
- Anchorage Guest House Waterford
- Anchorage Waterford
One child under 12 years stays free of charge when using existing bedding. Any additional children under 12 years are charged 50% of the room rate per night when using existing bedding. All children under 2 years stay free of charge in a crib. The maximum number of cribs in a room is 1. For more details, please contact the office using the information on the reservation confirmation received after booking.
Optional extras
Parking is available nearby and costs EUR 5 per night
Rollaway beds are available for EUR 30 per night
Breakfast is offered for an extra charge of EUR 5 per person (approximately)
We have included all charges provided to us by this hotel. However, charges can vary, for example, based on length of stay or the room you book.
Recent reviews
Good 3.3 /5 from 39 reviews
Michael was ace... convienient, helpful & flexible.... Great Value, Great Service...
Fair priced room, great breakfast.
Very affordable and close to everything. The rooms are ok but the beds need replaced. It is street side so if you are a light sleeper wear ear plugs.
A very pleasant stay and a good lot of hospitable and helping people in Hotel.I would boldly recommend this place to anyone who wanted to stay at Waterford city center and with a delicious set of items for breakfast.
Very convenient B&B in Waterford city centre. I spotted it whilst driving over the bridge so didn't have to spend ages looking for it. Friendly and helpful staff, great breakfast. It is an old building but that adds character!
Is the description of this hotel not correct? Tell us


text:
The primary goal of the Gene Targeting core will be to make available to the investigators of individual projects all available expertise, facilities, techniques and technical support required for generating /-/p/ttargeted mice, knockout/knockin mice and BAC transgenics. In addition, the core will provide reagents and advice on how to construct plasmids for use in Hprt targeting. In the case of knockout/knockin and BAC transgenic approaches, the core will also provide technical expertise in constructing targeting vectors.
|Rowe, Glenn C; Raghuram, Srilatha; Jang, Cholsoon et al. (2014) PGC-1? induces SPP1 to activate macrophages and orchestrate functional angiogenesis in skeletal muscle. Circ Res 115:504-17
|Turgeon, Paul J; Sukumar, Aravin N; Marsden, Philip A (2014) Epigenetics of Cardiovascular Disease - A New "Beat" in Coronary Artery Disease. Med Epigenet 2:37-52
|Aird, William C; Mosnier, Laurent O; Fairhurst, Rick M (2014) Plasmodium falciparum picks (on) EPCR. Blood 123:163-7
|Bai, Aiping; Moss, Alan; Kokkotou, Efi et al. (2014) CD39 and CD161 modulate Th17 responses in Crohn's disease. J Immunol 193:3366-77
|Bian, Shu; Sun, Xiaofeng; Bai, Aiping et al. (2013) P2X7 integrates PI3K/AKT and AMPK-PRAS40-mTOR signaling pathways to mediate tumor cell death. PLoS One 8:e60184
|Adams, William J; Zhang, Yuzhi; Cloutier, Jennifer et al. (2013) Functional vascular endothelium derived from human induced pluripotent stem cells. Stem Cell Reports 1:105-13
|Shirodkar, Apurva V; St Bernard, Rosanne; Gavryushova, Anna et al. (2013) A mechanistic role for DNA methylation in endothelial cell (EC)-enriched gene expression: relationship with DNA replication timing. Blood 121:3531-40
|Webster, Andrew L H; Yan, Matthew Shu-Ching; Marsden, Philip A (2013) Epigenetics and cardiovascular disease. Can J Cardiol 29:46-57
|Sun, Xiaofeng; Han, Lihui; Seth, Pankaj et al. (2013) Disordered purinergic signaling and abnormal cellular metabolism are associated with development of liver cancer in Cd39/ENTPD1 null mice. Hepatology 57:205-16
|Petruzziello-Pellegrini, Tania N; Moslemi-Naeini, Mozhgan; Marsden, Philip A (2013) New insights into Shiga toxin-mediated endothelial dysfunction in hemolytic uremic syndrome. Virulence 4:556-63
Showing the most recent 10 out of 89 publications


text:
[1.7.10] Nether Star Tools Mod Download
Category: Minecraft Mods, Mods 1.7.10
This mod adds new type of tools – nether star tools. They are very strong and fast. To make them you have to put nether star in furnace, you'll get 8 NetherStar Gems. Use them to craft tools.
- Download and install Minecraft Forge.
- Download Nether Star Tools Mod
- Put zip file into your /.minecraft/mods folder. Do not unzip it.
- Run minecraft and enjoy
More posts of Nether Star Tools Mod :


text:
How To Make Chilean Extra Virgin Olive Oil Martini From Olives
Today's cocktail recipe comes to us from Todd English over at Olives in Union Square. The Chilean Extra Virgin Olive Oil Martini is a specialty cocktail that's one of its more popular drinks. It doesn't have the thick, oily feel you might expect. There's a sort of robust freshness that comes with it.
The drink: Chilean Extra Virgin Olive Oil Martini
The bar: Olives
The price: $15
The ingredients: One orange segment, three to five fresh basil leaves, 3 ounces vodka, 1/2 ounce dry vermouth, 1/2 ounce Cointreau, 1/4 ounce simple syrup, 1/4 ounce Chilean extra virgin olive oil (CEVOO)
The process: In a shaker, muddle orange segment and basil leaves. Add vodka, Cointreau, dry vermouth, simple syrup, and CEVOO. Then add ice and shake well. Strain into a martini glass and float a drop of CEVOO over the top.
Contact me here or follow me @dearclarissa & on Facebook. To keep up with all of our food coverage go to Fork in The Road or follow us on Twitter @ForkintheRoadVV.
Get the Food & Drink Newsletter
Our weekly guide to New York dining includes food news and reviews, as well as dining events and interviews with chefs and restaurant owners.
In Case You Missed It
Popular Stories
Sponsor Content


text:
$ 17.99
$ 35.99
Notify me when this product is available:
Protective, Attractive, and Exclusive.This product was designed perfectly to suit all of your needs. Carefully structured to become the ultimate phone case. This phone case includes:
Sign up to get the latest on sales, new releases and more …
© 2017 Zizo.
All Rights Reserved.


text:
More Videos...
Ronnie Peterson on-board Monza 1973
onboard Jim Clark 1963
Black and white video onboard Jim Clark on Lotus. Gp Oulton park 1963.
Vintage Juan Manuel Fangio onboard camera Monaco
Vintage footage of the "Maestro" at the Monaco street circuit. It's poetry on four wheels :)
1973 Formula1 GP Nurburgring Jackie Stewart onboard lap commentary
Jackie Stewart narrates a lap of the 'ring in the 1973 GP 1:10: "you're going up here with so much G forces on that you can't take your foot off the throttle and get it on the brake"


text:
|Message view
|« Date » · « Thread »
|« Date » · « Thread »
|Re: [jira] Updated: (DERBY-31) Statement.setQueryTimeout() support.
|Thu, 16 Jun 2005 08:05:23 GMT
Hi Deepa, please see comments inline: Deepa Remesh wrote: > Hi, > > I am Deepa Remesh and I work for IBM. I am just starting to work on > Derby and was trying to apply the patch for DERBY-31. I noticed that > the file QueryTimer.java is not in the patch file but is attached > separately. I had to manually add it to the Eclipse project before > compiling. It would be good if this file is added to the patch. If you look at the dates and origin of the attachments to DERBY-31, you will notice the following: The "QueryTimer.java" and "Derby-31.patch" files were submitted by someone else on February 24. Unfortunately, this patch is too simple and does not fix the issue. The patch I submitted on June 15 is in DERBY-31.svn.diff; my attachments are the three files listed further below in this email message. QueryTimer.java is not a part of this patch. > > Thanks, > Deepa > > On 6/15/05, Oyvind Bakksjo (JIRA) <email@example.com> wrote: > >> [ http://issues.apache.org/jira/browse/DERBY-31?page=all ] >> >>Oyvind Bakksjo updated DERBY-31: >>-------------------------------- >> >> Attachment: DERBY-31.svn.status >> DERBY-31.svn.diff >> derbyall_report.txt >> >>Attached patch addresses the following issues: [...] -- Øyvind Bakksjø Sun Microsystems, Web Services, Database Technology Group Haakon VII gt. 7b, N-7485 Trondheim, Norway Tel: x43419 / +47 73842119, Fax: +47 73842101
|View raw message