نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناسی ارشد، دانشگاه جامع امام حسین (ع)، تهران ، ایران
2 استادیار، دانشگاه جامع امام حسین (ع)، تهران، ایران
3 دانشیار دانشگاه جامع امام حسین (ع)، تهران ،ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Knowing the location of the emitter is essential in almost all electronic warfare systems. This article studies and investigates methods of emitter localization using satellites. In emitter localization based on combined TDOA-FDOA measurements, Linear Least Squares (LLS) estimation is widely used due to its computational efficiency. Two-stage weighted least squares and constrained weighted least squares are common LLS methods, but their performance decreases significantly under Large Equal Radius (LER) scenarios, which is a common geometry in satellite-based localization. In this scenario, conventional localization methods often face ill-conditioned matrix problems. In addition, these methods suffer from problems such as high complexity or complex root selection strategy. In the LER scenario, the equations of the combined TDOA-FDOA measurements are linearized using a geometric approach. Linear equations provide the possibility of using weighted least squares estimation to obtain a closed-form solution for the emitter location. This technique does not require initial guess, auxiliary variable, two-stage estimation and complex root selection strategies. In this method, the estimation bias caused by LER modeling is significant in the absence of measurement noise and in weak LER conditions; which it can be compensated and by establishing a strong LER condition, an unbiased estimator can be obtained, ultimately. By analyzing and evaluating the performance of the proposed estimator theoretically, it is shown that the covariance matrix of the emitter location error reaches the Cramér-Rao Lower Bound (CRLB) in strong LER conditions. The simulation results show that the proposed algorithm reaches CRLB in a wider range of measurement noise range with lower run time and complexity compared to other conventional methods.
کلیدواژهها [English]