Three-Satellite TDOA Positioning Model Based on Calibration Point Constraint

Three-satellite Time Difference of Arrival (TDOA) positioning is an important method of passive location. However, because the positioning equations are nonlinear equations, when the satellite configuration is unreasonable and the measurement error is large, the solution is prone to pseudo-solution. In view of this situation, this paper proposes a constrained optimization model based on movable calibration point. By deploying the calibration points with known coordinates, the constraint model is constructed by using the time difference between the arrival of the calibration signal and the arrival of the target source signal to the satellite. The solution of the nonlinear equations is transformed into an optimization problem under the constraint condition, which effectively simplifies the positioning model and suppresses the pseudo solution. The simulation results show that the calibration constraint algorithm can effectively eliminate the pseudo solution of the sub-satellite point area and improve the positioning accuracy.