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Comparison of GPS Velocity Obtained Using Three Different Estimation Models

This study analyses the GPS velocity estimation performances of three different estimation models, namely, the time-differenced carrier phase velocity estimation (TDCPVE), Doppler observation velocity estimation (DopplerVE), and precise point positioning velocity estimation (PPPVE). Static and vehicle kinematic experiments are conducted for validation. Under simulated kinematic conditions using static data, the accuracy of the DopplerVE is the worst, and the precision of the velocity by the PPPVE is the same as with the TDCPVE. Under kinematic conditions, the accuracies of the three methods are related to the motion state of the mobile carrier (such as its acceleration and turning). When the sampling interval is 1 s, the TDCPVE can obtain precise velocity using a single-frequency stand-alone GPS receiver; the TDCPVE and DopplerVE can obtain accuracies of the same order of magnitude with broadcast and precise ephemerides, and can be used for real-time velocity measurement; the PPPVE can obtain not only an accurate position, but also an accurate velocity.