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In order to improve the adaptability of GNSS receivers in weak signal circumstances,this paper designed an acquisition scheme,which could be applied to all GNSS signals,and implemented it on the FPGA platform.Code-phases and carrier frequencies were searched partial-parallel in the scheme,and the searching origin could be configured flexibly.In the phase of pre-detection integration,the signal-noise ratio of detection was enhanced by extending the non-coherent integration time.Since the autocorrelation function of pseudo-code would distort due to the code Doppler while the integration time was extended,two compensation methods were adopted during the procedures of down-sampling and non-coherent integration,respectively.In the phase of detection,a two-stage detector with immediate-rejection was employed,in which a modified location constraint scheme was proposed to suit the lengthened integration time.After an analysis of the detection performance of the acquisition scheme,its implementation principles on FPGA were introduced.In the last part,a hardware test platform was built based on a signal simulator and the acquisition sensitivity of the scheme was tested.The test result showed that the acquisition sensitivity was about -145dBm when the detection probability was not less than 90% and the false-alarm probability was not more than 1e-6.