The integer ambiguity resolution is the key to precise attitude determination.In case of single frequency single epoch

this paper presents a fast integer ambiguity resolution method based on nonlinear constrained integer least-squares solved with the quadratic eigenvalue problem

and applies it to BDS attitude determination system.The method will integrate the baseline length called the priori information into objective function

and construct new objective function to improve the accuracy of integer ambiguity solution.The effectiveness of the proposed method is verified by experiments on the BDS attitude determination platform.The results show that

in the single frequency single epoch BDS attitude determination

the method has highly improved the success rate of integer ambiguity and attitude determination resolution.