卫星双向时间传递调制解调器跟踪环路设计

Design of Two-Way Satellite Time Transfer Modem Tracking Loop

精密跟踪技术是高精度伪码测距系统中的关键技术,根据卫星双向时间比对调制解调器的工作特点,对解调器的跟踪环路进行了研究,并利用Matlab进行环路设计与仿真,分析了不同载噪比、不同环路带宽条件下跟踪环路的性能;根据软件仿真结果,在DSP+FPGA硬件平台上加以实现,给出测试结果,并最终应用到自主开发的卫星双向时间比对调制解调器上,测量不确定度优于1ns。

The tracking technology is the key of pseudo noise（ PN） ranging system. Referring to the character of Two-Way Satellite Time Transfer modem,A tracking loop of demodulator has been researched. The tracking loop was designed and simulated Using Matlab software,and the tracking capability with different carrier to noise ratio and loop bandwidth was analyzed. Referring to the simulation results,The tracking loop was implemented based on DSP and FPGA,and the test results was obtained.The tracking loop has used in Two-Way Satellite Time Transfer modem,which is developed by our own and the uncertainty is within one nanosecond.