星载时差定位中的时差测量技术

Time Difference Measurement for TDOA Location on Satellite

时差定位是一种定位精度较高的定位方法。星载平台上受空间尺寸的影响，基线长度有限，这样星载时差定位的精度主要与时差测量的精度的有关。本文主要研究基于相位法的时差测量的技术和影响其测量精度的因素。本文首先介绍了相位法测时差的原理，给出了实现框图，详细分析了影响其测量精度的因素，仿真了AD有效量化位数对于测时差的影响。理论分析和仿真结果都显示出，提高AD的有效量化位数可提高精度，实现皮秒级的时差测量精度。

TDOA location is a high precision location technique. The satellite size is limited to the length of the base line, so that the location accuracy of the time difference on satellite relates mainly to the accuracy of time difference measurement. The Time Difference Measurement based on signal phase and the factors relative to the time accuracy are introduced. The principle of Time Difference Measurement based on signal phase and the block diagram are provided. The factors relative to time accuracy are detailed. The influence of the effective bits number of AD on time accuracy measurement is simulated. The results showed that the method of increasing the effective bits number of AD can greatly improve the accuracy and achieve time accuracy in ps.