To further expedite L2C signal acquisition, in the correspondence a double-chipwise correlation technique is developed. Inspired by the L2C signal structure that a CM chip before multiplexing indeed represents the CM chip itself and a multiplexed CL chip after the multiplexing, the new technique accumulates the samples across a CM and a CL chip periods together. Compared with the recently proposed chipwise correlation technique, the new technique further reduces the correlation complexity of testing cells to half and decreases the code phases to test to half, at the expense of about 1:3dB detection performance loss on average. In addition, no extra operations are needed to deal with local CM code. Numerical results show that the new technique saves acquisition time significantly and especially for L2C signal received at clear sky conditions the saving is about 75%.