Boc signal acquisition and tracking method and apparatus

Abstract

A BOC signal acquisition and tracking apparatus and method. In the present invention, at least a BOC signal, a BOC-cos signal and a PRN coded signal are generated for a received signal. Depending on application condition (e.g. acquisition mode or tracking mode), autocorrelation of the BOC signal is combined with cross-correlation of the BOC signal and one of the BOC-cos signal and the PRN coded signal to generate a proper combined correlation result.

1 . A BOC signal acquisition and tracking apparatus comprising
 a carrier unit generating a carrier;   a code unit generating a plurality of BOC subcarriers and a code, and outputting a specific one of the BOC subcarriers, and also outputting at least one of the remaining BOC subcarrier and said code; and   a code delay estimator receiving a signal, removing a carrier component from said signal by using said carrier from the carrier unit, generating a plurality of BOC signals for the received signal by using the outputs from the code unit, calculating an autocorrelation of a specific one of the BOC signals and a cross-correlation of each remaining BOC signal with the specific BOC signal, and combining said autocorrelation and each cross-correlation to generate a combined correlation.   
     
     
         2 . The apparatus of  claim 1 , wherein said specific one of the BOC subcarriers comprises a BOC subcarrier. 
     
     
         3 . The apparatus of  claim 2 , wherein the other BOC subcarrier comprises a BOC-cos subcarrier with respect to the BOC subcarrier. 
     
     
         4 . The apparatus of  claim 2 , wherein the remaining BOC subcarrier comprises a harmonic of the BOC subcarrier. 
     
     
         5 . The apparatus of  claim 2 , wherein the remaining BOC subcarrier comprises a harmonic of a BOC-cos subcarrier with respect to the BOC subcarrier. 
     
     
         6 . The apparatus of  claim 1 , wherein said code is PRN code. 
     
     
         7 . The apparatus of  claim 1 , further comprising a controller controlling said code unit to output one of the remaining BOC subcarrier and said code. 
     
     
         8 . The apparatus of  claim 1 , wherein said code unit comprises a code generator for generating said code, a subcarrier generator for generating the BOC subcarriers, and a multiplexer receiving said remaining BOC subcarrier and said code, and outputting one of said remaining BOC subcarrier and said code. 
     
     
         9 . The apparatus of  claim 1 , wherein said code estimator comprises a combination unit, said combination unit generates said combined correlation by squaring said autocorrelation of said specific BOC signal, squaring said cross-correlation of said specific BOC signal and said code, and subtracting the cross-correlation square multiplied by a coefficient from the autocorrelation square when the code estimator outputs said code. 
     
     
         10 . The apparatus of  claim 1 , wherein said code estimator comprises a combination unit, said combination unit generates said combined correlation by squaring said autocorrelation of said specific BOC signal, squaring said cross-correlation of said specific BOC signal and said remaining BOC signal, and adding the cross-correlation square multiplied by a coefficient to the autocorrelation square when the code estimator outputs said remaining BOC signal. 
     
     
         11 . A BOC signal acquisition and tracking method comprising steps of:
 receiving a signal;   generating a carrier;   generating a plurality of BOC subcarriers and a code;   outputting a specific one of said BOC subcarriers and also said code;   removing a carrier component from said signal by using said carrier;   generating a plurality of BOC signals for said signal by using said outputs of the outputting step;   calculating an autocorrelation of a specific one of the BOC signals;   calculating a cross-correlation of each remaining BOC signal with the specific BOC signal; and   combining said autocorrelation and each cross-correlation to generate a combined correlation.   
     
     
         12 . The method of  claim 11 , wherein said specific BOC subcarrier comprises a BOC subcarrier. 
     
     
         13 . The method of  claim 12 , wherein said remaining BOC subcarrier comprises a BOC-cos subcarrier with respect to the BOC subcarrier. 
     
     
         14 . The method of  claim 12 , wherein said remaining BOC subcarrier comprises a harmonic of the BOC subcarrier. 
     
     
         15 . The apparatus of  claim 12 , wherein said remaining BOC subcarrier comprises a harmonic of a BOC-cos subcarrier with respect to the BOC subcarrier. 
     
     
         16 . The method of  claim 11 , wherein said combined correlation is generated by squaring said autocorrelation of said specific BOC signal, squaring said cross-correlation of said specific BOC signal and said code, and subtracting the cross-correlation square multiplied by a coefficient from the autocorrelation square when the code estimator outputs said code. 
     
     
         17 . The method of  claim 11 , wherein said combined correlation is generated by squaring said autocorrelation of said specific BOC signal, squaring said cross-correlation of said specific BOC signal and said remaining BOC signal, and adding the cross-correlation square multiplied by a coefficient to the autocorrelation square when the code estimator outputs said remaining BOC signal.