Detection And Parameter Estimation Of Space Maneuvering Targets Based On Space-borne Radar

With human beings' constant development and utilization of resources in the geospace,the number of the target in the space is increasing rapidly. The space targets are the great menace to spacecrafts, satellites and air defence of the homeland. Therefore, various countries in the world pay high attention to the space targets detection technology. The radar targets detection and tracking technology which takes spacecrafts as platforms becomes the frontier fields of the current study. The space targets detected by space-borne radar usually have the higher speed and the larger acceleration. At this moment, the echo signals have the Range Cell Migration(RCM) effect and the Doppler Frequency Migration(RFM) effect, and the energy of the targets can not be accumulated in the same range cell and the Doppler frequency cell, which makes it difficult to effectively detect the targets and get the corresponding parameter estimation results. When the radar has a short observation time on space targets and receives the weak echo signals, which makes it more difficult to detect the targets and get the targets parameter estimation results.Based on the above-mentioned problems, the basic problems of space maneuvering targets detection and parameter estimation based on space-borne radar are studied. The main contents are as following.Firstly, the RCM effect and the DFM effect are discussed. With the simulation experiments, the factors that influence the RCM effect and the DFM effect are analysed in detail.Secondly, the space-borne radar carries out the single scanning on space maneuvering target and the problem is the detection and parameter estimation of the target. The method called The Single Scanning Processing Method Based on Radon-Modified Discrete Chirp Fourier Transform(Radon-MDCFT) is proposed. The proposed method accumulates the energy of the echo along the motion trail of the target in range cell-slow time domain, and then it uses the energy accumulation result of the target for target detection and parameter estimation.Thirdly, the space-borne radar carries out the multiple scanning on space maneuvering target, based on this, a method called The Multi-Scanning Coherent Integration TrackBefore Detect(TBD) Method Based on Modified Range Frequency Compensation and Fractional Fourier Transform(FRFT) is proposed. The RCM effect and the DFM effect can be corrected by Modified Range Frequency Compensation and FRFT, respectively, then the energy of the target can be accumulated and the target detection and parameter estimation can be obtained by proposed method effectively.Fourthly, for the problem of large computational load or necessarily known Doppler ambiguity integer existing in the current maneuvering target detection and parameter estimation methods, the method called The Fast Method Based on Range Frequency Polynomial-Phase Transform(RFPPT) is proposed. These method uses the RFPPT to correct the RCM effect and the DFM effect in range frequency-slow time domain, and it can obtain the better target detection and parameter estimation performance under relatively low computational load.