Abstract: Based on the special relationship of dual-frequency carrier phase observations,GNSS dual-frequency integer relationship constrained ambiguity resolution(FirCAR) is proposed,which enlarges the equivalent wavelength of carrier phase in local integer rang,to achieve a fast integer ambiguity resolution.With the code pseudorange and dual-frequency carrier phase observations,the proposed method resolves integer ambiguities satellite by satellite independently.The correctness and effectiveness of this method have been tested by two baselines of different lengths;and the influence of cut-off angle is also analyzed.