Patent ID: 9036683
Filing Date: 2015-05-19
Classification: G01S,H04B

Abstract:
1. A receiver for signals of different signal strengths and modulated with respective pseudorandom noise (PN) codes, the receiver comprising: a correlator circuit operable to correlate the signals with a selectable locally-issued PN code having a Doppler and a code lag to produce a power peak, the correlator circuit being subject to cross correlation with a distinct PN code carried by least one of the signals that can produce cross correlation; and cross correlation circuitry including: i. processor circuitry having first outputs for Doppler difference between two received signals, second outputs for code phase difference between the two received signals, and an input for a variable comparison value; ii. cross correlation mitigation circuitry having inputs for the Doppler difference between two received signals coupled to the first outputs of the processor circuitry, inputs for the code phase difference between the two received signals coupled to the second outputs of the processor circuitry, and an output for the variable comparison value coupled to the input of the processor circuitry, the mitigation circuitry generating the variable comparison value related to the cross correlation as a function of values representing the Doppler difference and the code lag difference between the locally-issued PN code and the distinct PN code; and iii. the processor circuitry using the variable comparison value to reject a power peak as invalid from cross correlation if the peak does not exceed the variable comparison value or to pass a power peak as a valid received peak if the peak exceeds the variable comparison value.