The Design And Implementation Of Satellite Navigation Receiver High Precision Timing Based On SOC

With the development of the contemporary satellite navigation system,the satellite clock uses high precision atomic clock,the clock can run stably for a long time.Because the price of clock is very expensive,it is not used extensively.The satellite navigation receiver often uses inexpensive crystal oscillator as the reference clock,in order to get accurate time like atomic clock,the timing of the satellite navigation receiver is of great significance.This paper introduces the design and implementation of satellite navigation receiver high precision timing based on SOC.The satellite navigation receiver can use three navigation satellite systems to fixed positioning,they are GPS,GLONASS,BDS.In order to realize the high precision timing,the satellite navigation receiver completes the calculating of positioning by receiving satellite signal.The satellite navigation receiver uses XC7Z020 chip that is produced by Xilinx,there are many advantages,its size is smaller,its power is lower and the processing speed of chip is faster,so it contributes to improve the performance of the satellite navigation receiver.The paper introduces the receiver's the principle and method of timing about general mode and trigger mode carefully.General mode completes timing by a normal positioning,it is a working mode mainly.Trigger mode completes timing by a external signal trigger,it is used to test the synchronization of time mainly.What's more,the paper introduces the key technologies of satellite navigation that can improve the performance about timing.The paper solves the problem of signal unlock under special circumstances by improving unlocking threshold of tracking loop.The calculation of SNR is not accurate when the signal intensity gets weaker,so the paper puts forward a new algorithm of SNR to improve it.The paper solves the problem of positional accuracy by improving the optimized method of the least square's weight,in addition,the paper puts forward a effective way of satellite's weight based on the residual error of pseudo-range,it solves positional error that was caused by pseudo-range inaccuracy.By improving it,the receiver can complete high precision timing and it can also output the accurate result of position.