基于时频二维估计的卫星导航失锁快速重定位技术

卫星导航接收机在天线受到遮挡或者弱信号环境中易出现信号失锁现象,信号恢复后的重定位时间成为接收机的一项重要性能指标。提出一种基于时频二维估计、适用于中低动态应用场景的失锁快速重定位技术,利用信号失锁前测量的载波多普勒频率和码相位等信息对失锁后的多普勒频率及码相位进行估计,信号恢复后直接启用信号跟踪,无需进行位同步和帧同步,即可实现快速重定位。对该技术进行工程实现及试验验证,结果表明信号输入功率高于–145dBm(积分时间为10ms)、失锁时间小于60s时,接收机重定位时间在1s以内。

Rapid Repositioning Method after Satellite Navigation Signal Loss Based on Time-Frequency Estimation

When the antenna is blocked or the satellite navigation signal is weak, the receiver can easily lose the lock on signal, so the time of repositioning after signal recovery becomes an important indicator of receivers. A rapid repositioning method based on time-frequency estimation in low and middle dynamic scene is proposed. The carrier Doppler frequency and PN code phase are estimated by the information before loss of signal lock, and the receiver can rapidly reposition the satellite without signal recapture, bit synchronization and frame synchronization. The engineering realization and experimental verification of this algorithm are carried out. The result shows that when the signal input power is greater than-145 dBm(the integral time is 10 ms) and the loss of signal lock persists in less than 60 s, the time of repositioning is less than 1 s.