Guangtongxin yanjiu (Jun 2024)
Satellite Search and Rescue Localization Technology based on Windowed CAF Estimation
Abstract
【Objective】With the continuous development of satellite technology, the application of satellites to low coverage areas of ground information networks for personnel search and rescue is becoming increasingly popular. As an effective means of indicating the location of personnel and facilities, satellite search and rescue positioning technology is widely used in maritime, aviation, and personal distress rescue operations. Therefore, in the continuous development and research of global satellite search and res-cue systems, achieving high-precision and rapid positioning of search and rescue sources is the main goal.【Methods】In view of the sudden characteristics of satellite search and rescue signals, dual-satellite Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) positioning are adopted as the satellite search and rescue positioning methods. The estimation of the required TDOA and FDOA parameters is the key to improve the positioning accuracy. In order to improve the parameter estimation performance and positioning accuracy of dual-satellite TDOA and FDOA positioning technology, this paper proposes a search and rescue positioning technology scheme based on time-frequency difference estimation of windowed Cross Ambiguity Function (CAF). The method of filtering redundant noise by adding windows in time domain is introduced, and the accuracy of time-frequency difference estimation is improved by adding windows in time domain and CAF. The estimated value is substituted into dual-satellite TDOA and FDOA positioning equations to calculate the location of the search and rescue signal source. It means that the purpose of improving the positioning accuracy is to efficiently and accurately find the search/rescue source by improving the estimation accuracy of TDOA/FDOA parameters.【Results】The simulation results show that the method of estimating the TDOA/FDOA parameters of CAF with windows can be applied to search and rescue positioning, and the accurate time-frequency difference estimation value can be obtained through this method. The method proposed in this paper can effectively improve the accuracy of time-frequency difference parameter estimation, and add Fourier transform to reduce the time of parameter estimation, thus optimizing the positioning performance. When the TDOA error is controlled within 4 μs and the FDOA error is controlled within 0.2 Hz, the positioning accuracy can reach the kilometers.【Conclusion】The time-domain windowed time-frequency difference parameter estimation scheme proposed in this paper has improved the positioning performance after being incorporated into the satellite search and rescue positioning technology, which can support the application of the satellite search and rescue positioning technology in the satellite search and rescue system. The algorithm has the advantages of simple structure, low complexity and practical feasibility.
