Patent ID: 6810072
Filing Date: 2004-10-26
Classification: G01S,H04B,H04L

Abstract:
An apparatus for acquiring a spread spectrum signal, the signal having a carrier component at a carrier frequency, a code component, and a data component, the acquiring including matching the phase of a replica of the code component to the phase of the received code component and also determining the carrier frequency including any shifting of the carrier frequency, the apparatus comprising:a) a multi-section matched filter having a plurality of sections, the multi-section matched filter being responsive to a signal derived from the spread spectrum signal by a sequence of processing steps including mixing the spread spectrum signal with a first frequency, for providing successive section outputs for each section, each section output of each section including elements corresponding to a different replica code phase; and b) a compensated acquisition module, responsive to each section output of each of the sections, for providing a sequence of second frequency indicators, each second frequency indicator corresponding to a different frequency offset in a group of frequency offsets from the first frequency, and each section output having elements each of which corresponds to a particular value of replica code phase, wherein each second frequency indicator is based on a combining, phase element-wise, of the section outputs using compensating factors that depend on the corresponding frequency offset.