Patent ID: 7286594

Claim:
Method for determining a correlation phase between a signal received from a satellite at a receiver and an available replica sequence comprising using a matched filter to check various correlation phases, said matched filter multiplying samples of said received signal with samples of said replica sequence and summing the resulting products to obtain a correlation value for a specific correlation phase, said method further comprising shifting samples of said received signal and of said available replica sequence relative to each other for each correlation phase which is checked, and using results obtained in the calculations for one correlation phase by said matched filter for calculating a subsequent correlation phase, and determining a current position of said receiver, wherein said received signal comprises a binary sequence, wherein possible values of said binary sequence are +1 and −1, wherein C i constitutes a determined correlation value for an i th checked correlation phase, wherein N is a length of said binary sequence, wherein x j+i constitutes a j th sample of said received signal for said i th correlation phase, wherein the samples of said replica sequence are not shifted for different correlation phases which are to be checked, wherein r i constitutes a j th sample of said replica sequence, wherein a set J + comprises the indices j for which (r j =1 & r j−1 =1) OR (r j =−1 & r j−1 =−1), and wherein a correlation value C i+1 for the (i+1) th correlation phase is calculated as: C i + 1 = - C i - r 0 ⁢ x i + r N - 1 ⁢ x i + N + ∑ j ∈ J + ⁢ ⁢ 2 * r j ⁢ x j + i .