Abstract: The traditional global positioning system (GPS) L1C/A code signal and the new L1C signal are both in L1 band (1 575.42 MHz), which makes full use of the limited frequency band resources. A new combined acquisition based on unit correlation is proposed, for the multiple peaks in the combined acquisition of GPS L1C/A and L1C signal. Local L1C/A code and L1C sequence are divided into an odd unit signal and an even unit signal respectively. Then, the unit correlation functions of unit signals and the received signal are reconstructed, so that nine subpeaks caused by L1C/A code signal are completely eliminated, and the main peak value is improved to obtain a sharp narrow correlation peak. Simulation results show that, the span of correlation peak with the proposed method is 0.5 chip, which greatly improves the acquisition accuracy, and the acquisition sensitivity is about 2 dB higher than that of the combined acquisition with the single channel. Besides, this algorithm has a lower complexity and can be applied to engineering practice.