3D Localization for Launch Vehicle Using Virtual TOA and AOA of Ground Stations

Abstract

Generally, a ground telemetry station for a launch vehicle (LV) includes a tracking function only; therefore, position measurements for LV depend on received navigation data from on-board systems of LV or depend on estimated position from ground radar system in real time. Time of arrival (TOA) and angle of arrival (AOA) are typical location techniques for emitting targets. In this study, we propose a virtual on-board timer to estimate TOA for LV and verify its localization performance using Combined TOA and AOA localization method. For real time processing, the proposed virtual on-board timer should be created at space center and distributed to remote stations before lift-off of LV. By comparing the time stamp of the virtual on-board timer and received time, TOA and its corresponding slant range can be estimated. In order to combine the estimated TOA and AOA, we create sphere equations with the estimated range radius and vertical plane equations, to include unit vectors for the AOA direction. By solving these equations, a three-dimensional (3D) target point can be obtained. We confirm localization performance of the estimated TOA by comparing with an on-board GPS of 3rd KSLV-1 mission in January 2013.