In this thesis, carrier phase prediction method was investigated for improving real time kinematic (RTK) positioning when signals experience temporary loss of lock. The prediction method is developed and tested using GPS vector-based and GPS/IMU ultra-tight software receivers to generate predicted phase measurements. The main error sources and characteristics of the predicted phase are analyzed and tested using simulated data. Effort is then focused on evaluating the RTK positioning accuracy applying the predicted measurements.
Positioning with and without using the prediction method is compared for the GPS vector-based receiver, and ultra-tightly coupled GPS/IMU receiver, and for an RTK/IMU loosely coupled system. Tests were carried out including simulated and foliage attenuation data. The tests’ outputs were analyzed in measurement and position domain separately, and it was verified that using predicted carrier phase measurements without an IMU do not provide significant benefits, but including the IMU provides considerable benefits.