Geopositioning method using assistance data

A computer program product comprising non-transitory computer readable medium containing a computer program code for implementing geopositioning operations, by at least one radio navigation signal receiver of a reference network, using radio-navigation signals from a set of satellites of the reference network, each satellite of the set broadcasting at least a first radio-navigation signal on a first frequency and a second navigation signal on a second frequency distinct from the first frequency, the computer program code for implementing the geopositioning operations enabling the at least one radio navigation signal receiver to remove phase ambiguities, the computer program code executable by a processing unit to cause the processing unit to perform:

• receiving, by the at least one radio navigation signal receiver, for each satellite of the set that is visible from a receiver, at least the said first radio-navigation signal;
• performing, by the at least one radio navigation signal receiver, for each visible satellite, code measurements and phase measurements of the first radio-navigation signal received, said phase measurements presenting the phase ambiguities, the phase ambiguities including an ambiguity of an a priori unknown integer number of cycles;
• receiving, by the at least one radio navigation signal receiver, a set of assistance data, wherein the set of assistance data comprises, for each satellite of the set of satellites, data sufficient for reconstructing a transmitter clock value associated with a carrier code shift combination, derived in a same manner across all the satellites and receivers of the reference network;
• determining, by the at least one radio navigation signal receiver, for each satellite, a carrier code shift combination value from the code measurement and the phase measurement of the first radio-navigation signal, the phase ambiguities being removed as a result of the determining of the carrier code shift combination value;
• determining, by the at least one radio navigation signal receiver, from said carrier code shift combination value the transmitter clock value associated with the carrier code shift combination, to obtain an unambiguous carrier code shift observable;
• and
• utilizing, by the at least one radio navigation signal receiver, the unambiguous carrier code shift observables to determine a precise receiver position of the at least one radio navigation signal receiver.

A global navigation satellite system receiver configured to implement geopositioning operations using radio-navigation signals from a set of satellites of a reference network, each satellite of the set broadcasting at least a first radio-navigation signal on a first frequency and a second navigation signal on a second frequency distinct from the first frequency, the geopositioning operations enabling the global navigation satellite system receiver to remove phase ambiguities, the operations comprising:

• receiving, by the global navigation satellite system receiver, for each satellite of the set that is visible from the global navigation satellite system receiver, at least the said first radio-navigation signal;
• performing, by the global navigation satellite system receiver, for each visible satellite, the code measurements and the phase measurements of the first radio-navigation signal received, said phase measurements presenting the phase ambiguities, the phase ambiguities including an ambiguity of an a priori unknown integer number of cycles;
• receiving, by the global navigation satellite system receiver, a set of assistance data, wherein the set of assistance data comprises, for each satellite of the set of satellites, data sufficient for reconstructing a transmitter clock value associated with a carrier code shift combination, derived in a same manner across for all the satellites and receivers of the reference network;
• determining, by the global navigation satellite system receiver, for each satellite, a carrier code shift combination value from the code measurement and the phase measurement of the first radio-navigation signal, the phase ambiguities being removed as a result of the determining of the carrier code shift combination value;
• determining, by the at least one radio navigation signal receiver, from said carrier code shift combination value the transmitter clock value associated with the carrier code shift combination, to obtain an unambiguous carrier code shift observable;
• and
• utilizing, by the global navigation satellite system receiver, the unambiguous carrier code shift observables to determine a precise global navigation satellite system receiver position.