Fully-coherent continuous-wave Doppler radar and distance measurement and velocity measurement method thereof

Abstract

The invention discloses a fully-coherent continuous-wave Doppler radar and a distance measurement and velocity measurement method thereof. According to the fully-coherent continuous-wave Doppler radar and the distance measurement and speed measurement method thereof, difference-frequency complex signals obtained by mixing echo signals and transmitted signals are acquired; according to the modulation characteristics of distance difference-Doppler frequency and target distance-velocity, a distance-dimension FFT and azimuth-dimension MTD-combined two-dimensional joint detection method is adopted to independently obtain fuzziness-free radial velocity information based on a plurality of coherent high-repetition frequency modulation signals; Doppler information introduced by velocity is removed from the frequency-domain information in the distance dimension, so that the influence of distance-velocity coupling can be eliminated, and therefore, accurate distance information can be obtained. The fully-coherent continuous-wave Doppler radar and the distance measurement and velocity measurement method thereof of the invention have coherent radar velocity measurement function and a continuous-wave radar distance blind zone-free distance measurement function and can satisfy requirements for distance blind zone-free and simultaneous distance measurement and velocity measurement, real-time performance, miniaturization and low power consumption.

Description

technical field [0001] The invention relates to the field of continuous wave measuring radar, in particular to a fully coherent continuous wave Doppler radar and a method for measuring distance and speed. Background technique [0002] The traditional full-coherent radar that can measure distance and speed at the same time adopts the pulse Doppler system. The distance between the target is determined by measuring the time difference between the target reflection signal and the transmitted pulse by transmitting a coherent pulse train, and the Doppler of the echo signal is analyzed by FFT between pulses. The spectrum obtains the speed information of the target, so it has the two-dimensional measurement capability of distance and speed. However, there is a distance blind zone in this system, and in the case of high resolution requirements, the pulse system needs to take into account the requirements of both narrow pulse and large bandwidth, which increases the difficulty of sign...

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Problems solved by technology

However, there is a distance blind zone in this system, and in the case of high resolution requirements, the pulse system needs to take into account the requirements of both narrow pulse and large bandwidth, which increases the difficulty of signal generation, and the back-end signal processing requires high sampling rate. greatly increased the complexity of the system

[0003] The traditional continuous wave radar does not have a distance blind zone. On the one hand, a coherent system can be used. By analyzing the frequency spectrum of the echo signal received by the radar, the speed measurement function can be completed but the distance measurement capability is not available; on the other hand, a non-coherent system can be used. By transmitting the linear FM signal, the distance information is extracted by using the characteristics of the received frequency difference signal and the target distance mapping relationship, which has the advantages of extremely high distance resolution, greatly reduced signal processing bandwidth and no distance blind zone. However, due to the non-phase In the system, there is no Doppler information at the same time as the distance measurement, so the speed cannot be measured, and the Doppler information brought by the speed is coupled into the signal, which will lead to a large distance measurement error

[0004] The currently commonly used triangular FM continuous wave can measure distance and speed at the same time, and complete the distance-speed decoupling through positive and negative frequency sweeps, but it needs to be paired in the frequency domain

In the complex high-resolution multi-target environment background, it is difficult to achieve accurate pairing in the frequency domain, which may easily lead to target information measurement errors

Moreover, the triangular wave modulation method will double the bandwidth of the intermediate frequency at the same distance resolution, thereby increasing the sampling rate of the intermediate frequency and the amount of signal processing calculations, making it difficult to meet the real-time requirements of the system

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