Evaluation of TDOA based air target localization algorithm using GNSS-based passive radar

The effectiveness of the air target localization method based on time difference of arrival (TDOA) is assessed using passive radar based on the global navigation satellite system (GNSS). The equations of localization and their weighted least squares solution are derived. To determine the weight matrix, an elevation-dependent model and a signal to noise ratio(SNR)-dependent model are introduced. Simulation and outdoor experiment results show that the elevation-dependent model and SNR-dependent model can effectively reduce the position error of the TDOA based air target localization algorithm compared with the unweighted model. When the number of satellites used for localization is fewer than seven, the position performance improves quickly as the number of satellites used increases. However, the improvement trend slows down if more than seven satellites are employed. The evaluation of geometric dilution of precision shows that there is a positive linear correlation between the geometric dilution of precision and position error. In outdoor experiment, the maximum position error of airliners is 206.30 m, and the minimum position error is 13.85 m.