Digital Coherent Ranging Accuracy Improvement Method Based on Interpolation Resampling Algorithm

Abstract

In applications requiring time-frequency synchronization, not only is the precision of synchronization important, but the synchronization accuracy is also of great concern. Time-frequency synchronization is based on the ranging principle. In the case of a high signal-to-noise ratio, precision can be achieved by improving the received signal-to-noise ratio, but the ranging accuracy is mainly limited by the sampling rate of the analog-to-digital converter in the system. In order to solve this contradiction, we propose an interpolation resampling method based on a curve model which is constructed with the priori information of the system and is a linear function of the phase difference of pseudo-random code and conduct experimental verification. The experimental results show that for the static target, the ranging accuracy is not more than 0.55 mm, corresponding to a time accuracy of 3.67 ps. For the moving target, the ranging accuracy does not exceed 0.38 mm, corresponding to a time accuracy of 2.53 ps. The proposed method achieved time synchronization to the order of picoseconds.

Keywords: Time-frequency synchronization, Pseudo-random code, Range and velocity measurement, Interpolation resampling.