Patent ID: 7257153
Filing Date: 2007-08-14
Classification: G01S,H04B,H04L

Abstract:
1. A method for synchronizing a receiver with a transmitted code-modulated spread spectrum signal, the method comprising performing a search in frequency versus code-phase space to determine a carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and a code phase of a code used in modulation of the code-modulated spread spectrum signal, the search including: 1). performing a correlation between a set of sample vectors formed from the received code-modulated spread spectrum signal and a reference code to produce a set of correlation results, the reference code corresponding to the code used in modulation of the code-modulated spread spectrum signal; 2). forming a correlation function matrix from said set of correlation results said correlation function matrix comprising the correlation results of a correlation between the set of sample vectors and the reference code with different phase differences for each sample vector; 3). performing a time-to-frequency domain transformation on a basis of a transpose of said correlation function matrix to form a coherent search matrix; and 4). determining the carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and the code phase of the code used in modulation of the code-modulated spread spectrum signal by examining values of elements of said coherent search matrix.