An Improved Method of Distance Measurement Accuracy of LFM Continuous Wave Detection System

Abstract

An improved method for distance measurement accuracy of a chirp continuous wave detection system. The linear frequency modulation continuous wave detection system in the present invention has outstanding advantages such as low transmission power, high receiving sensitivity, high distance resolution and simple structure, and has stronger target identification, anti-background clutter and anti-jamming capabilities than the pulse system; In the case of synchronous sampling, discrete spectra appear in the frequency range centered on the frequency component of the frequency spectrum obtained by the fast Fourier transform FFT. The spectral lines outside the signal frequency component can be understood as leaked from the signal component, and there is a spectrum Leakage; and, there is a deviation between the frequency corresponding to each discrete spectrum line and the signal frequency component, and there is a fence effect. Aiming at these phenomena, the present invention uses the signal amplitude distribution caused by spectrum leakage to propose a method for improving the measurement accuracy of signal frequency and further improving the measurement accuracy of distance on the basis that the number N of FFT points remains unchanged.

Description

technical field [0001] The invention relates to an improved method for improving distance detection accuracy of a linear frequency modulation continuous wave detection system. Background technique [0002] The linear frequency modulation continuous wave detection system has outstanding advantages such as low transmission power, high receiving sensitivity, high distance resolution and simple structure. to develop rapidly. [0003] The operating frequency of the linear frequency modulation continuous wave detection system changes continuously in a linear manner. In a scanning period, the transmitting antenna radiates a group of equal amplitude frequency modulation continuous waves, and the signal frequency increases linearly from the start frequency to the stop frequency. The receiving antenna receives the reflected signal from the target. Due to the transmission delay of the transmitted wave, there is a time difference and a frequency difference between the reflected signal ...

AI Technical Summary

Problems solved by technology

The target distance detection accuracy is affected by the sampling interval of the difference frequency signal. The usual method is to increase the number of FFT points N, but increasing the number of FFT points N will greatly increase the amount of calculation, which is difficult to achieve in real-time signal processing.

Moreover, due to the comprehensive influence of the system's linear frequency conversion coefficient, frequency conversion range, scanning repetition period, and detection distance, the increase in the number of FFT points N is also limited.