{'fraction_non_alphanumeric': 0.016178736517719568, 'fraction_numerical': 0.0, 'mean_word_length': 5.098591549295775, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Simulation and experimental verification of a low-cost pseudo-noise modulated optical radar

Our paper presents a new optical distance sensor, which can be used in applications. The sensor measures the time interval between the emission of a modulated laser signal and the detection of a small fraction of the signal reflected from the measured object. Maximum likelihood optimization of the transmitted signal and the structure of the receiver lead to a pseudo noise (PN) signal, which modulates a cw diode laser in conjunction with a delay locked loop (DLL) receiver. The measured distance is determined from the zero crossing of the crosscorrelation of the received and the transmitted signal. The variation of time delay is realized by means of the variation of the frequency of the voltage controlled oscillator (VCO), which provides the clock signal for the PN-generator. The VCO frequency is inversely proportional to the distance to be measured so that the spatial resolution is directly proportional to the distance. The theoretical results are verified by means of more detailed numerical simulations. The simulations were also used for the optimization of the whole system as well as the particular subsystems. Results of measurements demonstrate the practical feasibility of the system.