| dc.description.abstract | The use of Global Navigation Satellite Systems (GNSS) had increased over the past few decades and had been widely applied to navigation, surveying and geo-physics. Accompanied by the increasing demand, however, the requirements on its accuracy, precision, reliability, and availability had also been raised. The carrier phase measurements were extremely precise but there still was an ambiguity caused by an unknown number of cycles; this was the so-called integer-value.
To solve the problem, the integer ambiguity resolution algorithms had been developed. The main idea of integer estimation process consisted of three steps. First, use standard least-squares method was applied with the integer property of the ambiguities disregarded, and the float solutions were obtained. In the second step, the integer constraint of the ambiguities was considered. In the final step, the integer constraint of the ambiguities was considered. In other words, the float ambiguities were mapped to integer values. Normally, a
decorrelation technique would be used in this step to reduce the number of candidates reliably but the number were still too much. Of course, in the final step, the still-remained unknown parameters of the estimated integer-valued ambiguities were calculated by their correlations, and the solution was fixed.
A new technique could reduce the number of candidates by using float transformation and threshold domain. We proposed the method to reduce the number of candidates and keep the quality of so-called Zero-correlation Transformation for Ambiguity-resolution (ZETA). However, there exists no-candidate-passed problem in ZETA algorithm, and that cause significant errors. Therefore, in this thesis, a new method called Approximation ZEro-correlation Transformation for Ambiguity-resolution (AZETA) using eigenvalue and eigenvector in float transformation step and other methods in verified integer step was propose. In 23.1 km baseline, the mean number of candidates of three methods, traditional LLL method, ZETA and AZETA algorithm, are 8.95, 0.83 and 1.06 respectively. The final results on east-west direction are 0.1458 m, 0.6994 m, and 0.2792m; north-south direction are 0.2119 m, 1.2254 m and 0.2865 m; height direction are 0.9572 m, 5.5558 m, and 1.5489 m. These results really prove AZETA algorithm that can achieve the balance of accuracy and efficiency simultaneously.
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