The Research Based On Passive Bearing-only And Time Difference Of Arrival Location Technology

Passive location technology is paid more and more attention due to the passivesystem and strong concealment. In recent years, the passive bearing-only and the timedifference of arrival (TDOA) location technology cause widespread attention andintensive study. The source localization faces new challenges because of the newobservation platforms and a variety of complex localization scenarios. How to improvethe accuracy of location effectively is a problem that urgently needs to be resolved.This paper discusses the passive bearing-only and TDOA location method. Byimproving the reasonable observation station layout and selecting the suitable locationestimation algorithm to improve the location accurancy. The specific work is asfollows.First of all, the principles of bearing-only passive location by single station andmulti-station and TDOA location by multi-station are introduced. For analyzing thelocation accuracy, the concept of Geometric Dilution of Precision (GDOP) andCramer-Rao lower bound (CRB) are presented. Discuss the factors which influence onlocation accuracy by changing different parameters. Meanwhile, by comparing thelocation error of single positioning and joint positioning system, we discuss whetherthe joint positioning system has ability to improve the location accurancy.Secondly, we discuss the bearing-only passive location by single station andmulti-station in detail. The location error in bearing-only location is discussed and theuncertainty of observers’ positions can lead to significantly degrading in sourcelocalization accuracy is proved. A method which calibrates the error of observers’positions by using calibration source in bearing-only location is proposed. Thetraditional location estimation is unbiased, but the studies have shown that theunbiased estimator is not the essential condition that leads to a small MSE. We proposea biased estimator by minimizing the estimation error instead of data error. It is shownthat the MSE of the proposed scheme is not only lower than that of LS, TLS and WLS,but also lower than the CRB of unbiased estimator. We introduce the basic principles of extended kalman filter (EKF) and its improved algorithms in detail and apply to thebearing-only locatioin by single station and multi-station.Finally, the TDOA passive location by multi-station is discussed in detail. Thereduction of the position errors in the traditional methods is suffering the loss of extracalibration sources and the performance is related to calibration sources’ positions to agreat extent. We propose a more effective way to reduce the estimation errors ofobservers’ positions and improve localization accuracy in the source localization byusing range finding technology. By way of using the range finding technology tomeasure the relative distance of the two coordinative observers, the extra observedinformation can be obtained. Later on, the model of TDOA is set up and theobservation information of the primary station and the auxiliary stations is proved. Atlast, the Chan estimation algorithm is performed in three dimensional positioning, lateron EKF and improved algorithm are applied in TDOA location.