Symmetrical triangular linear frequency modulation continuous wave type laser radar target detecting method

A technology of linear frequency modulation and laser radar, which is applied in the direction of radio wave measurement system, electromagnetic wave reradiation, and measurement device

Inactive Publication Date: 2015-05-06
SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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  • Application Information

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Problems solved by technology

[0005] The problem solved by the present invention is that the existing symmetrical triangular chirp continuous wave laser radar can only detect the flight distance and the dynamic range is less than Problems with goals within

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  • Symmetrical triangular linear frequency modulation continuous wave type laser radar target detecting method
  • Symmetrical triangular linear frequency modulation continuous wave type laser radar target detecting method
  • Symmetrical triangular linear frequency modulation continuous wave type laser radar target detecting method

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no. 1 approach

[0054] Based on the above principles, combined with figure 2 The first embodiment of the present invention is described as follows:

[0055] When the radar is being processed, it is triggered by the up-conversion stage and the down-conversion stage of the first local oscillator Aloa and the second local oscillator Alob respectively, and the echo signal is collected and the first local oscillator signal Aloa and the second local oscillator signal Alob are in the up-conversion stage, The data in the down-conversion stage is used for spectrum analysis. When the SNR of the spectrum line after filtering out the environment-specific interference after spectrum analysis exceeds the preset threshold (the threshold is set according to the actual system design), this coherent method is selected. When the threshold is exceeded, the following two situations will occur:

[0056] 1. In the same-phase coherence or anti-phase coherence, only one coherent spectral line exceeds the preset thr...

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Abstract

The invention discloses a symmetrical triangular linear frequency modulation continuous wave type laser radar target detecting method. The method comprises the steps of modulating a laser signal through a chirped signal to obtain a modulating signal; processing the modulating signal to obtain an emission signal, a first intrinsic signal and a second intrinsic signal; performing coherence for the first intrinsic signal and the second intrinsic signal through an echo signal to calculate a fixed part of a frequency difference value due to the frequency variation caused by the distance in the difference frequency between the echo signal and the first intrinsic signal and the second intrinsic signal and Doppler shift fd caused by speed; calculating the target speed v through fd; calculating t through fx; calculating Tfly-in, r=cTfly-in and S=r/2 through t so as to solve the distance. According to the method, the echo signal is subjected to coherence with the first intrinsic signal and the second intrinsic signal, and the mutually combined result enables the dynamic range of the laser flying range of the detected target to reach the distance corresponding to the whole symmetric triangular linear frequency modulating cycle; the dynamic range of the radar detecting range is doubled that in the prior art.

Description

[0001] technical field [0002] The present invention relates to a coherent laser radar, in particular to a method for detecting a target with a double symmetrical triangular linear frequency modulation continuous wave laser radar. Repetition frequency (DRF) for detection. Background technique [0003] see figure 1 , the current high-precision speed measurement lidar adopts a coherent system, and calculates the Doppler frequency shift caused by the speed by analyzing the frequency change in the echo signal. For the ranging radar of the coherent system, a linear frequency modulation signal (LFM signal, namely a chirp signal) is usually used to modulate the laser signal of the lidar to obtain a symmetrical triangular chirp signal, figure 1 shows such a triangular chirp signal, the figure 1 middle, : chirp modulation bandwidth; : a modulation period of Symmetrical Triangular Linear Frequency Modulation (STLFM); : frequency...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S17/50
CPCG01S17/50
Inventor 舒嵘吴军洪光烈
Owner SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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