Geopositioning method using assistance data

A computer program product comprising a non-transitory computer readable medium storing computer program code for determining assistance data to facilitate processing of radio-navigation signals from a set of radio-navigational satellites of a reference network, each radio-navigational satellite broadcasting at least a first radio-navigation signal on a first frequency and a second radio-navigation signal on a second frequency, the second frequency being distinct from the first frequency, the computer program code being executable by a processor of at least one signal receiver of the reference network to cause the processor to perform:

• recording as radio-navigation signals any first radio-navigation signal and second radio-navigation signal broadcasted by each radio-navigational satellite;
• deriving code and phase measurements from the said radio-navigation signals recorded, the phase measurements having ambiguities, each of which is an a priori unknown integer number of cycles;
• resolving the ambiguities in the phase measurements on the first frequency in a same manner for all the satellites and reference receivers of the reference network to produce a resolution;
• deducing a set of iono-free transmitter phase clock values arising from the resolution and a set of iono-free receiver phase clock values arising from the resolution;
• calculating for each satellite-reference receiver pair, a carrier code shift combination value from the code and phase measurements for each respective satellite on the first frequency;
• calculating plurality of measurement residues based on the carrier code shift combination value, a modelled geometric contribution, a contribution of the iono-free receiver phase clock value, an iono-free transmitter phase clock value, and a contribution of the carrier code shift combination value;
• separating in a same manner for all the satellites and receivers of the reference network, each of measurement residues into a transmitter part and a receiver part, and
• smoothing the transmitter part of the plurality of measurement residues.

A system comprising radio-navigational satellites and at least one signal receiver, the at least one signal receiver configured to determine assistance data to facilitate processing of radio-navigation signals from a set of radio-navigational satellites of a reference network, each radio-navigational satellite broadcasting at least a first radio-navigation signal on a first frequency and a second radio-navigation signal on a second frequency, the second frequency being distinct from the first frequency, the at least one signal receiver configured to:

• record as radio-navigation signals any first radio-navigation signal and second radio-navigation signal broadcasted by each radio-navigational satellite;
• derive code and phase measurements from the said radio-navigation signals recorded, the phase measurements having ambiguities, each of which is an a priori unknown integer number of cycles;
• resolve the ambiguities in the phase measurements on the first frequency in a same manner for all the satellites and reference receivers of the reference network to produce a resolution;
• deduce a set of iono-free transmitter phase clock values arising from the resolution and a set of iono-free receiver phase clock values arising from the resolution;
• calculate for each satellite-reference receiver pair, a carrier code shift combination value from the code and phase measurements for each respective satellite on the first frequency;
• calculate plurality of measurement residues based on the carrier code shift combination value, a modelled geometric contribution, a contribution of the iono-free receiver phase clock value, an iono-free transmitter phase clock value, and a contribution of the carrier code shift combination value;
• separate in a same manner for all the satellites and receivers of the reference network, each of measurement residues into a transmitter part and a receiver part, and
• smooth the transmitter part of the plurality of measurement residues.