Method of validating the detection of a correlation peak by a satellite positioning system receiver
View Patent ↗The present invention relates to a method of validating the detection of a correlation peak between a signal transmitted by a plurality of navigation satellites and received by an RNSS satellite radio navigation receiver, said signal corresponding to a sum of signals each sent by a satellite and each modulated by a spread spectrum signal characteristic of said satellite and a local replica generated by said receiver of a spread spectrum signal characteristic of a satellite that is being looked for. Said method includes a step of determining the correlation function 3 as a function of time between said received signal and said local replica and further includes a step of comparing said correlation function 3 with the theoretical autocorrelation function 2 as a function of time of said spread spectrum signal characteristic of said satellite that is being looked for.
1. A method comprising:
validating the detection of a correlation peak between:
a signal transmitted by a plurality of navigation satellites and received by a radio navigation satellite system (RNSS) satellite radio navigation receiver, said signal corresponding to a sum of signals each sent by a satellite and each modulated by a spread spectrum signal characteristic of said satellite,
a local replica generated by said RNSS satellite radio navigation receiver, said replica being the replica of a spread spectrum signal characteristic of a satellite that is being looked for,
said method including a step of determining a correlation function ( 3 ) as a function of time between said received signal and said local replica,
said method being characterized in that it further includes a step of comparing said correlation function ( 3 ) with a theoretical autocorrelation function ( 2 ) as a function of time of said spread spectrum signal characteristic of said satellite that is being looked for over the whole of a vector of the correlation function wherein comparing said correlation function ( 3 ) with the theoretical autocorrelation function ( 2 ) includes a step of comparing secondary peaks ( 5 , 7 ) of each of said correlation and theoretical autocorrelation functions.
2. The method according to claim 1 characterized in that it includes a step of determining said theoretical autocorrelation function as a function of time of said spread spectrum signal characteristic of said satellite that is being looked for.
3. The method according to claim 1 characterized in that said comparison step includes a step of calculating the correlation between said correlation function and said autocorrelation function.
4. The method according to claim 1 characterized in that said spread spectrum signal is a signal modulating said signal with a known pseudorandom sequence replacing each bit of said signal.
5. The method according to claim 1 characterized in that, in the event of non-validation of the detection of said correlation peak, said method includes the following steps:
a step of determining theoretical intercorrelation functions as a function of time between said spread spectrum signal characteristic of said satellite that is being looked for and each of the satellites other than said satellite that is being looked for, and
a step of comparing said correlation function with each of said theoretical intercorrelation functions.
6. The method according to claim 5 characterized in that each of said spread spectrum signals associated with a particular satellite is selected so that said theoretical autocorrelation function and each of said theoretical intercorrelation functions are different.
7. The method according to claim 5 characterized in that each of said spread spectrum signals associated with a particular satellite is selected so that each of said theoretical intercorrelation functions is decorrelated.
8. An apparatus comprising:
a device for validating the detection of a correlation peak between:
a signal transmitted by a plurality of navigation satellites and received by a radio navigation satellite (RNSS) satellite radio navigation receiver, said signal corresponding to a sum of signals each sent by a satellite and each modulated by a spread spectrum signal characteristic of said satellite, and
a local replica generated by said RNSS satellite radio navigation receiver of a spread spectrum signal characteristic of a satellite that is being looked for,
said device including means for determining a correlation function ( 3 ) as a function of time between said received signal and said local replica,
said device being characterized in that it further includes means for comparing said correlation function ( 3 ) with a theoretical autocorrelation function ( 2 ) as a function of time of said spread spectrum signal characteristic of said satellite that is being looked for over the whole of a vector of the correlation function wherein comparing said correlation function ( 3 ) with the theoretical autocorrelation function ( 2 ) includes a step of comparing secondary peaks ( 5 , 7 ) of each of said correlation and theoretical autocorrelation functions.