Improved method of distance measurement accuracy of linear frequency-modulated continuous wave detection system

Abstract

The invention relates to an improved method of distance measurement accuracy of a linear frequency-modulated continuous wave detection system. The linear frequency-modulated continuous wave detectionsystem has outstanding advantages of low transmission power, high receiving sensitivity, high range resolution and simple structure and the like and has the stronger target identification, anti-background clutter and anti-interference abilities than the pulse system. In addition, for spectrums obtained by fast Fourier transform (FFT), discrete spectrums occur in a frequency range with the frequency component as the center under the non-simultaneous sampling; spectral lines beyond the signal frequency component are indicated to be leaked from the signal component, so that the spectrum leakage occurs. Moreover, offsets exit between the frequencies corresponding to all discrete spectral lines and the signal frequency component, so that the fence effect exists. In order to avoid the phenomena,the invention puts forward a method for improving the measurement accuracy of the signal frequency based on the invariable point number N of FFT to improve the distance measurement accuracy by usingthe signal amplitude distribution caused by spectral leakage.

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.