Design a Hybrid Extended Kalman Filter for the Entire LISA Constellation

Abstract

The hybrid-extended Kalman filter is briefly derived. The three types of inter-spacecraft measurements of LISA are simulated, whose properties are then discussed. The clock errors have been simulated in the measurements, but ignored in the time stamps of the samples. A 24-dimensional state vector is used to describe the system. Accordingly, the measurement equation and dynamic equation are formulated. Then, the hybrid-extend Kalman filter is applied to the simulated data. According to the simulation, the algorithm has significantly improved the ranging accuracy and synchronized the clocks, hence it makes the phasemeter raw measurements usable for time-delay interferometry algorithms.