一种兼容接收高中低轨导航信号捕获方法研究与仿真实现

Research and Implementation of A Compatible Reception Method for High， Medium， and Low Orbit Navigation Signals Capture

摘要:

近年来，由于低轨导航增强系统逐步纳入综合PNT体系建设，如何对低轨信号的捕获跟踪逐渐成为热点研究问题。在综合PNT应用终端需要同时接收北斗+低轨导航增强信号的场景下，由于捕获模块的资源庞大，利用两套硬件资源分别对高、中、低轨信号进行兼容接收会造成极大的资源浪费，无法实现用户终端的小体积、低功耗需求。本文在现有北斗信号捕获模块基础上进一步优化算法，通过设计灵活可复用的匹配滤波加FFT结构实现匹配滤波器的长度与FFT点数灵活可配，片内分布式处理加片外超长存储架构存储超长数据，以及高多普勒伪码、载波频率补偿等方法，完成了对高、中、低轨信号的兼容接收，同时可实现对中、高轨北斗B1C信号-145 dBm捕获灵敏度和低轨±40 kHz STL(卫星时间和位置)突发信号的捕获。

Abstract:

In recent years, low-orbit navigation enhancement system has been gradually incorporated into the construction of integrated PNT system, and the capture and tracking of low-orbit signals has gradually become a hot research issue. In the scenario that the integrated PNT application terminal needs to receive BeiDou + LEO navigation augmentation signals at the same time, due to the large resource consumption of the capture module, using two sets of hardware resources to compatibly receive high, medium and low orbit-signals will cause a great waste of resources, and it is not possible to realize the small size and low power consumption requirements of the user terminal. This paper further optimizes the algorithm on the basis of the existing BeiDou signal capture module, and through the design of flexible and reusable matched filter plus FFT structure, on-chip distributed processing and off-chip ultra-long storage architecture, and techniques such as high Doppler pseudo-code, carrier frequency compensation, etc., it realizes the compatible reception of high, medium and low-orbit signals, and at the same time, it can realize the capture of high and medium orbit BeiDou B1C signals with a capture sensitivity of -145 dBm capture sensitivity and 40 kHz STL burst signal in low orbit.