Constrained Wrapped Least Squares: A Tool for High Accuracy GNSS Attitude Determination

TL;DR

This paper introduces a constrained wrapped least-squares (C-WLS) method for high-accuracy GNSS attitude determination, leveraging prior information and an efficient search strategy to directly estimate attitude parameters from carrier-phase data.

Contribution

The paper presents a novel C-WLS approach that improves attitude estimation accuracy by integrating prior information and handling ambiguities without fixed ambiguity resolution.

Findings

Outperforms existing methods like LAMBDA and ambiguity function in accuracy

Demonstrates high performance through simulations and real data experiments

Achieves better results without prior ambiguity fixing

Abstract

Attitude determination is a popular application of Global Navigation Satellite Systems (GNSS). Many methods have been developed to solve the attitude determination problem with different performance offerings. We develop a constrained wrapped least-squares (C-WLS) method for high-accuracy attitude determination. This approach is built on an optimization model that leverages prior information related to the antenna array and the integer nature of the carrier-phase ambiguities in an innovative way. The proposed approach adopts an efficient search strategy to estimate the vehicle's attitude parameters using ambiguous carrier-phase observations directly, without requiring prior carrier-phase ambiguity fixing. The performance of the proposed method is evaluated via simulations and experimentally utilizing data collected using multiple GNSS receivers. The simulation and experimental results demonstrate excellent performance, with the proposed method outperforming the ambiguity function method, the constrained LAMBDA and multivariate constrained LAMBDA methods, three prominent attitude determination algorithms.