Speed ​​and distance measurement system and method based on pseudo-random code phase modulation and heterodyne detection

Abstract

The invention provides a speed measurement and distance measurement system and a speed measurement and distance measurement method based on pseudo-random code phase modulation and heterodyne detection. The basic principle is that laser is divided into two parts via a coupler. The majority part is subjected to phase modulation through an electro-optic phase modulator according to a pseudo-random code signal and is transmitted by a telescope as emergent laser; the other part is subjected to frequency shift through an acousto-optic frequency shifter and is used for coherent detection as a local oscillator signal; a laser echo signal and the local oscillator signal are subjected to a coherent action in the coupler, an electric signal is converted through a photoelectric balance detector, and a digital signal is converted through a dual-channel AD acquisition card; the other channel of the dual-channel AD acquisition card acquires a driving signal of the electro-optic phase modulator; and the acquired two ways of signals are subjected to signal processing in a computer. The invention provides a new method of simultaneously acquiring the target speed and the distance information in a high-precision mode.

Description

technical field

[0001] The invention relates to a high-precision laser radar speed-measuring and distance-measuring system combined with pseudo-random code phase modulation technology and heterodyne detection technology and a speed-measuring and distance-measuring method based on the system. Background technique

[0002] Missiles need to obtain accurate target position and speed information during military strikes, which plays a very important role in the missile hit rate, especially for constantly moving targets, such as anti-missile missions. However, the early traditional method of measuring the distance and then differentiating the distance to obtain the speed cannot obtain the correct speed information because of the discontinuity of the distance. However, the method of cutting the echo signal into multiple small time periods, measuring the Doppler frequency shift of each time period to obtain the speed information, and then calculating the distance information accordin...

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