Linear frequency modulation radar signal generation system and generation method

Abstract

The invention discloses a linear frequency modulation radar signal generation system. The system comprises a continuous wave laser, a first optical coupler, an IQ modulator, an arbitrary waveform generator and a second optical coupler, wherein the continuous wave laser is used for generating laser signals and inputting the laser signals into the first optical coupler; the first optical coupler isused for coupling the laser signals and then inputting the laser signals into the IQ modulator; the arbitrary waveform generator is used for generating a linear frequency modulation signal to drive the IQ modulator; the IQ modulator is used for generating a carrier suppression single-sideband optical signal and inputting the carrier suppression single-sideband optical signal into the second optical coupler; and the second optical coupler is used for dividing the carrier suppression single-sideband optical signal into an optical signal of a carrier suppression single-sideband positive first-order sideband and an optical signal of a carrier suppression single-sideband negative first-order sideband and generating a linear frequency modulation radar signal. A stable linear frequency modulationradar signal can be generated, the method has high distance resolution, high power and low angular resolution, and the laser external modulation technology is optimized.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a system and method for generating a chirp radar signal. Background technique [0002] Lidar is an active remote sensing technology that uses lasers for imaging, detection and ranging. It has the advantages of high resolution, high precision, light equipment, and strong anti-interference ability. At present, the detection mechanism of lidar is mainly divided into two types: non-coherent detection and coherent detection. Incoherent detection, also known as direct detection, detects by directly measuring the change in the intensity of the reflected light signal. Because the detection method is relatively simple and direct, it is widely used in time-of-flight lidar or AM continuous wave lidar. Coherent detection uses a heterodyne detection method to achieve detection by measuring the frequency or phase difference between the echo signal and the local oscillator signal. The c...

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Problems solved by technology

Most of the light sources with good tunability are not stable enough, and most of the stable light sources cannot be widely tunable

From the point of view of the modulation method, since the internal modulation method directly changes the parameters of the resonator, it is relatively easy to obtain a large tuning range, but due to the existence of the laser settling time, the instantaneous line width of the output FM light is relatively wide, resulting in a decrease in the coherence length of the light source ; or the tuning rate must be limited in order to establish a stable optical field

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