21. Research on Ranging Algorithm Based on Combined-Process Method Using Frequency-Difference, Time-Difference and Relative-Velocity

The Dual One Way Ranging (DOWR) technique with PRN-code, which can remove the effect of time-asynchronous and improve ranging precision, is widely used in Inter-Satellite-Ranging. The ranging value based on DOWR is delayed, thus cannot match the actual distance at the time the value got within a dynamic environment. In this paper, a synchronous ranging algorithm based on combined-process method using Frequency-difference, Time-difference and relative velocity is proposed, which can realize real-time measurement in high precision by the calibration of ranging value. A dynamic model based on DOWR is introduced first. then, a general analytic expression of distance measurement is constructed, which involves the frequency-difference, the time-difference and the velocity between two aerocraft in different receiving patterns. Thus, the distance measurement can be deduced to a certain time, and then, a current-time ranging value would be extrapolated with local pseudo-speed information. The experiments results of certain product demonstrate the effectiveness of the proposed algorithm, the precision of synchronous distance measurement is better than 0.1 m in a dynamic environment.