针对加速度表存在受过载影响的误差项和累计误差,提出多点分层式差动激光多普勒自身测速仪(LDV),为车载导航系统提供自身的速度参数。阐述了激光多普勒测量自身速度的基本原理,设计了多点分层差动LDV,并运用跟踪滤波和数字自相关技术对多普勒信号进行处理。理论分析和实验结果表明,多点分层差动LDV解决了双光束不能进行离焦测量的难题;跟踪滤波器实时跟踪多普勒信号,去除基底信号并抑制通带外噪声,数字自相关技术去除残留噪声,提高了信噪比和系统的灵敏度。与全球定位系统(GPS)的测量结果比较,系统的相对测量精度约为2％。

An idea of using multipoint layer-type laser Doppler self-velocimeter (LDV) to offer velocity for vehicle navigation system is proposed,because the accelerometer has the error term generated by overload. The principle of measuring its own velocity with laser Doppler is expounded while multipoint layer-type LDV is designed. And Doppler signal is processed with the technique of tracking filter and digital autocorrelation. The results of theory and experiment show that,multipoint layer-type LDV can solve the problem that dual-beam LDV can not measure the velocity while out of focus. Background signal and part of noise in the passband are restrained by tracking filter,and residual noise is removed by digital autocorrelator so that the signal-to-noise and sensibility of the system are raised. Comparing with global position system (GPS),the relative accuracy of the system is about 2%.