Utilization of modified spherical coordinates for satellite to satellite bearings-only tracking

A new satellite to satellite passive tracking method using Bearings-Only measurements in Modified Spherical Coordinates (MSC) is proposed. The system dynamics and measurement process are presented in three-dimensional MSC, and then the tracking method is deduced in details based on the Cartesian method. Performance of the new method is validated through computer simulations, which proved that the proposed method is effective in terms of the estimation accuracy and convergence time compared with the Cartesian method no matter the Initial State Errors (ISE) and measurement errors are large or small.