This paper proposes a simple and practical threshold adaptive estimating method for PN code acquisition.After analyzing the statistical property of the decision variable

we use the Maximum Likelihood (ML) criterion to adaptively estimate the variance of the Gaussian noise.Thus

we get the decision threshold.The performance of the acquisition method using estimated threshold got by computer simulation is very close to the theoretical one's

which shows that the proposed method is useful.Furthermore

for the threshold's estimation method is very simple and fast

it is very fit for practical application.