SPIE Journal Paper | 3 March 2020
KEYWORDS: Ranging, Clocks, Receivers, Error analysis, Satellites, Laser applications, Signal to noise ratio, Optical engineering, Semiconductor lasers, Laser range finders
The millimeter-level bidirectional long-distance asynchronous ranging has long been a huge challenge in the field of measurement and instrumentation. Correspondingly, a laser pseudocode ranging algorithm based on regenerative synchronization mechanism is proposed to address the problems obstructing precise distance measurement between asynchronous satellites. First, the synchronization strategy of a double-ended asynchronous terminal based on the regenerative pseudocode is discussed. Subsequently, we look at the algorithm of the generation, transmission, detection, and the code phase tracking loop, which forms the base of obtaining high precision of pseudocode ranging. On this basis, the error of laser pseudocode ranging link is analyzed, which mainly incorporates receiver noise and clock error. In terms of receiver noise, the influence of the photodetector carrier-to-noise ratio on random noise distribution is evaluated, and the design of receiver parameters is guided as such. As for the clock error, we look at the constraint relationship between the range and the precision under the action of the clock error, which provides the basis for the selection of the clock. Finally, the optimized system is tested when a double-ended laser link is set up in the laboratory. As a result, the comprehensive accuracy results of 3.47 mm systematic error and ±1.73 mm random error is obtained, and the long-scale measurement performance has been tested by the temperature-compensated crystal oscillator pulse frequency experiment. In conclusion, the experiment is consistent with the theory proposed in this study, which provides a theoretical and experimental basis for long-distance high-precision intersatellite ranging.
