Abstract:Fast and effective resolution of GNSS carrier phase ambiguity is a crucial precondition for attitude measurement. This paper discusses and analyzes the least square algorithm with a baseline length constraint (CLAMBDA). For practical applications, the general calculation procedure of CLAMBDA method is given. In view of the inadequate searching efficiency in processing high dimensional ambiguity by the CLAMBDA method, an improved CLAMBDA method based on partial ambiguities searching strategy is proposed. The searching efficiency can be improved because the new algorithm reduces the dimension of ambiguity and gets a better searching space by optimizing partial ambiguity. The results of three examples show the new algorithm consumed less time with a high success rate than the original method, and the search efficiency is increased. Meanwhile, the new method is more suitable for real time GNSS attitude measurement.