Dangerous space debris detection via spaceborne ladar based on intensity modulation and coherent optical processing

For the detection and recognition of dangerous space debris, a novel detection scheme with space-based or spaceborne ladar is presented in this paper. In the scheme, the semiconductor laser of 1.55 micron is adopted as the emitter source and a chirped intensity modulation waveform is utilized to obtain the range and radial speed of dangerous space debris. To improve the SNR and further the maximum detectable range, the simplified coherent optical processing (i.e. heterodyne processing) is proposed. The proposed ladar system has the advantage of low cost, low complexity and high flexibility and can meet the requirement of spaceborne detection. This paper is mainly comprised of three parts. In the first part, the schematic diagram of the proposed laser radar system is shown and the main components are introduced in brief; and then the operation principle and processing flow are formulated in detail. In the second part, some operating parameters (such as transmitting power, modulation bandwidth and duration time) and system performance (such as SNR, detection range and resolution) are analyzed. In the final part, the detection of the typical dangerous space debris is simulated numerically, and some conclusions are made as well. The theoretic analysis and numerical simulation prove that the proposed detection scheme is effective and feasible.