Precision-Aided Partial Ambiguity Resolution Scheme for GNSS Attitude Determination

Abstract

The use of carrier phase data play an important role for high-precision Global Navigation Satellite Systems (GNSS) positioning solutions, such as Real-Time Kinematic (RTK). Similarly, precise orientation information can be obtained with multi-antenna setups which exploit carrier phase observables. The availability of high precision navigation solutions is, however, subject to the Integer Ambiguity Resolution (IAR) performance. IAR is the process of mapping the real-valued carrier ambiguities to integer ones, enhancing the attitude solution by virtue of the cross-correlation with the estimated integer ambiguities. Unfortunately, IAR is known to suffer from dimensionality course or, in other words, the chances for finding the correct vector of integers reduces with the number of ambiguities. This work focuses on improving the availability of high precision attitude estimates by means of using a Partial Ambiguity Resolution (PAR) scheme. PAR relaxes the condition of estimating the complete vector of ambiguities and, instead and finds a subset of them to maximize the availability. A new formulation for attitude determination using quaternion rotation within a precision-driven PAR scheme is proposed. Numerical simulations are used to showcase the attitude determination performance with a conventional Full Ambiguity Resolution (FAR) and a precision-aided PAR approach.