Tightly coupled precise point positioning and attitude determination

A method is described for joint precise point positioning and attitude determination with tight coupling of two single-frequency low-cost global navigation satellite system receivers and an inertial sensor. The sensor fusion is performed with an extended Kalman filter. The carrier phase ambiguities are determined in a constrained tree search using soft a priori information on the antenna distance. A code multipath parameter is determined for each satellite to improve the accuracy. Ionospheric corrections are estimated also by single-frequency receivers.