Synthetic Aperture Lidar System

Abstract

The present invention relates to a synthetic aperture laser radar system, including at least a tunable laser module arranged on a flight vehicle platform, the system also includes a feedback control module, an imaging module and a phase compensation module, and the chirp signal light generated by the tunable laser module is respectively Enter the target channel, common channel and reference channel to generate a difference frequency signal, and the feedback control module drives the tunable laser module to tune in real time based on the difference frequency signal so that the phase difference value remains constant to avoid distance distortion. In the imaging module based on the difference frequency signal imaging During the process, the phase compensation module gradually approaches the residual phase in the difference frequency signal in an iterative manner to compensate and avoid azimuth distortion. The invention can monitor and compensate the nonlinearity of the frequency-modulated laser source in real time, and can also compensate the non-ideal optical path caused by the atmospheric turbulence and the vibration of the satellite platform to realize high-resolution imaging in the range direction and the azimuth direction.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a synthetic aperture laser radar system. Background technique [0002] Lidar is a high-sensitivity radar with high resolution, good concealment, small size, light weight, strong anti-interference ability, and insensitive to multi-path effects. It can detect stealth aircraft, submarines, and biological and chemical warfare agents. However, the lidar beam is narrow, not suitable for large-scale search, and it is greatly affected by the atmosphere and weather, making it difficult to search and capture targets. Moreover, its spatial resolution is limited by the optical aperture and decreases with the increase of distance. Therefore, a new system of lidar—Synthetic Aperture Laser Radar (SAL) emerged as the times require. [0003] The working principle of SAL is similar to that of Synthetic Aperture Radar (SAR), except that the transmitted signal is different. It achieves high resolutio...

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Problems solved by technology

However, the improved system provided by this patent also does not monitor and compensate the nonlinearity of the tunable laser source in real time, and the optical bandwidth filter has a limited effect on the phase error caused by atmospheric turbulence and platform vibration in the azimuth direction, and cannot greatly Increased imaging resolution in azimuth

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