Research Of The Key Technology Of Coherent Range And Range-rate Detection Ladar With Large Dynamic Range And High-repetition-rate

The technical of “coherent range and range-rate detection ladar with large dynamic range and high-repetition-rate” has an important value in the relative positioning and autonomous vehicle navigation of the space target. How to detect with a wider range of distance, detect with higher repetition-rate, and effectively improve the measurement accuracy of the range and spped, is currently blank in the technology, which also needs to be solved urgently.This thesis focuses on the key technology of the coherent range and range-rate detection with large ranging dynamic range and high-repetition-rate and the main contents are as follows: 1) typical technology principles and theory of coherent laser radar are described, proposed and experimental verificated the theory of optical quadrature I/Q detect method to get the beat frequency difference and the plus-minus of the difference; 2) analysised the typical characteristics of the current international range and range-rate detection method and it’s limitations, and proposed a " dualfrequency dual-modulation dual-LO(DFDMDL) symmetrical triangular linear frequency modulation coherent range and range-rate detection ladar mechanism ", and simulated and experimental verificated the feasibility of the mechanism, analyzed the advantages and disadvantages of the system such as at large dynamic range of ranging, high-repetition-rate detection and so on; 3) to achieve optimal performance of the DFDMDL system, analyzed frequency modulation linearity, modulation amplitude-frequency characteristics and modulation cycle stability of the laser modulation, which affects the system performance, through theory, experiments, and simulations; 4) proposed the demodulation scheme of DFDMDL system in fiber optics, free-space optical path, analyzed the implementation feasibility of real-time wideband signal processing in hardware and software, and studied the key technologies of ultra highspeed FFT implementation; 5) experimental verification and analysised the key points to improve DFDMDL laser radar performance; 6) developed the DFDMDL modulation module, built the DFDMDL signal processing system, developed the optical quadrature Doppler velocimetry signal processing board, developed several sets of broadband data acquisition and signal processing systems.The innovation of this paper is mainly reflected in the following aspects:1. The first proposed and and verified " dual-frequency dual-modulation dual-LO(DFDMDL) symmetrical triangular linear frequency modulation coherent range and range-rate detection ladar mechanism ", which has greatly expanded the range of ranging of Symmetrical Triangular Linear Frequency Modulation(STLFM) range and range-rate detection system, and the system can work under a high repetition frequency, and can take advantage of pulses accumulation to reduce the demand of emission energy.2. The first proposed using optical I / Q quadrature detection system to get the beat frequencies difference and the plus-minus, and a coherent experiments to detect the range-rate was carried out with good results.