Multifunctional double-frequency-modulation coherent laser radar

Abstract

The invention relates to a multifunctional double-frequency-modulation coherent laser radar, which comprises: a single-frequency laser, a beam splitter, a first optical frequency modulator, a laser amplifier, a transmitting-receiving telescope, an optical scanner, a second optical frequency modulator, an optical pluralizing device, a signal generator, a digital delay controller and a signal acquisition and processor. The multifunctional double-frequency-modulation coherent laser radar can realize laser ranging, speed measurement, three-dimensional scanning imaging, laser synthetic aperture imaging and other functions, has the characteristics of simple system structure, easy integration and miniaturization, can realize high-precision data acquisition of a target, inhibits background light interference, effectively improves the imaging sensitivity, and is particularly suitable for multi-dimensional information detection of a long-distance target.

Description

technical field [0001] The invention relates to a coherent laser radar, in particular to a multifunctional double frequency modulation coherent laser radar. Background technique [0002] LiDAR has very obvious technical advantages in target recognition, classification and precise targeting. At present, a large number of laser radars with different technical systems have been developed and developed. It can be mainly divided into incoherent light direct detection method and coherent light heterodyne detection method. The most typical incoherent 3D lidar is a pulsed laser 3D imaging radar based on time of flight (TOF) [see literature [1] S.Hu, S.S.Young, T.Hong, J.P.Reynolds, K.Krapels, B.Miller, J.Thomas, and O. Nguyen.Super-resolution for flash ladar imagery.Appl.Opt.49,772(2010); Literature [2]P.Cho,H.Anderson,R.Hatch,P.Ramaswami.Real-time 3D ladarimaging.Linc.Lab.J.16,147(2006).], has been widely used in the fields of unmanned aerial vehicles, automatic driving, etc., a...

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Problems solved by technology

[0003] For coherent lidar, there is coherent lidar based on pseudo-random codes [see literature 9: JosephBuck, Andrew Malm, Andrew Zakel, Brian Krause, et al. High-resolution 3D CoherentLaser Radar Imaging. SPIE, 2007, 6550, 655002.] , with high detection bandwidth and complex hardware

There is NASA's Autonomous Landing and Hazard Avoidance project (ALHAT), which is used for the landing process in NASA's manned and robotic space exploration programs to the Moon and Mars, where Doppler radar for distance and velocity measurements is a All-fiber chirped frequency-modulated continuous-wave coherent (FMCW) lidar, using single-channel frequency modulation and fiber delay to achieve distance and velocity measurements [see literature 10: F.Amzajerdian, D.Pierrottet, L.Petway, et al.Lidar systems for precisionnavigation and safe landing on planetary bodies, 2011:819202-819202-819207. Literature 11: D.F.Pierrottet, F.Amzajerdian, L.Petway, et al. Linear FMCW laser radar for precision range and vector velocity measurements.In:Proc.Mater. Res.Soc.Symp:Cambridge Univ Press,2008:1076-K1004.], there is a limited range of distance measurement and low repetition frequency

There is also Guy NPearson [see literature 12: Guy N Pearson, Kevin D Ridley and David V Willetts. Longrange 3D active imagery with a scanned single element 1.55m coherent lidarsystem. SPIE, 2005, 5988, 59880M.] using jagged low-weight Frequency-modulated continuous wave realizes outdoor coherent three-dimensional laser imaging, but also has long imaging time, low repetition frequency, etc.

[0004] Coherent lidar has the advantages of high sensitivity and multi-dimensional information detection. Coherent lidar is developing in the direction of long-distance, high repetition frequency, wide range, and multi-function. However, the existing coherent lidar system has a single function and uses a single-channel fixed Physical delay, generally current modulation, cavity length modulation and other internal modulations will easily lead to poor laser coherence and low repetition frequency, which will affect the imaging distance, etc.

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