A dual‐frequency continuous wave doppler lidar for velocity measurement at far distance

Abstract

A dual-frequency continuous wave Doppler lidar for long-distance and high-precision velocity measurement is experimentally demonstrated in this article. The lidar system uses the optical heterodyne detection method to avoid complicated optical coherent configuration. All Phase Fast Fourier Transform and Chirp-Z Transform are used to obtain the Doppler frequency shift. The maximum of the calculated Doppler shift was 999.83 Hz with the frequency resolution of 0.54 Hz, and the corresponding theoretical velocity was determined to be 749.87 m/s. During the experiment, the speed of the car was successfully measured in the outdoor environment, the frequency and velocity resolutions were less than 0.5 Hz and AE 0.2 m/s, respectively, and the detection distance of moving and stationary targets reached 1100 m and 2300 m. The capability of the dual-frequency Doppler lidar system has been verified.

High-precision ranging and speed measurement technology based on coherent dual-frequency laser

“…[2] Dual-frequency LiDAR is a new type of LiDAR. [3,4] It uses dual-frequency laser as the detection laser, and uses the characteristics of dual-frequency laser to solve the problem of coherence preservation under long-distance conditions of laser, reduce the influence of backscattered speckle noise [5] , and enhance the anti-atmospheric turbulence interference ability of radar signals. [6] At the same time, relatively mature microwave radar signal processing algorithms can also be used in signal processing, which reduces the difficulty of signal processing and the hardware requirements of solving equipment to a certain extent.…”

The single‐wavelength 561 nm laser based on reflective volume Bragg grating

“…With the progress and development of laser technology, lasers have been widely used in communication, military, industrial, and biomedical fields 1–8 . Lasers in the 561 nm band are frequently used in fluorescence spectroscopy, Raman spectroscopy, photoacoustic spectroscopy, and absorption spectroscopy 9–13 .…”

“…With the progress and development of laser technology, lasers have been widely used in communication, military, industrial, and biomedical fields. [1][2][3][4][5][6][7][8] Lasers in the 561 nm band are frequently used in fluorescence spectroscopy, Raman spectroscopy, photoacoustic spectroscopy, and absorption spectroscopy. [9][10][11][12][13] In addition, lasers in this band can also be used as ideal light sources for biomedical or microscopic imaging instruments such as flow cytometers and confocal microscopy.…”

High‐power, continuous‐wave optical parametric oscillator based on MgO:sPPLT crystal

“…Near-infrared lasers have important applications in nonlinear optics, material processing, medical diagnosis, laser ranging, and other fields. [1][2][3][4][5][6] The optical parametric oscillator (OPO) based on the quasi-phase matching (QPM) technology can realize the tuning and expansion of the laser wavelength, which provides more possibilities for laser applications in many fields of science and technology including laser measurement, 7,8 and fingerprint imaging. 9 Periodically poled LiNbO 3 (PPLN), MgO-doped PPLN (PPMgLN), and periodically poled LiTaO 3 (PPLT) crystals are commonly used.…”