Method for providing differential code bias (DCB) correction for a global navigation satellite system (GNSS)

A plurality of reference stations and a central computation unit including a microprocessor, configured to calculate primary differential code biases and secondary differential code biases, in a global navigation satellite system using satellites communicating by using at least:

• a common signal;
• a first signal and an additional first signal both having a first carrier frequency;
• and
• a second signal and an additional second signal both having a second carrier frequency;
• wherein primary differential code biases for the first signal and the second signal are determined by the central computation unit using the common signal;
• wherein primary differential code biases are used to calculate, and providing, secondary differential code biases for the additional first signal and the additional second signal;
• wherein the primary differential code biases concern the differential code bias between the first signal and the second signal to the common signal, and the secondary differential code biases concern the relation between the first additional signal and the first signal and/or the differential code bias between the second signal and the additional second signal;
• wherein the primary differential codes are determined for the first signal and the second signal and provided for determining the secondary differential code biases of the additional first signal and the additional second signal, by using further primary differential codes concerning the differential code bias between the first additional signal and the second additional signal to the common signal;
• wherein the common signal is used to calculate both the primary code bias and the secondary differential code bias;
• wherein the common signal is used to determine at least two primary differential code biases, namely DCB1-First (first signal−common signal) and DCB1-Second (second signal−common signal) and further primary differential code biases DCB1-First-Additional (first additional signal−common signal) and DCB1-Second-Additional (second additional signal−common signal);
• wherein two dependent secondary differential codes biases (DCB2s) are provided based on the four independent primary differential code biases (DCB1-First, DCB1-Second, DCB1-First-Additional, and DCB1-Second-Additional)
• wherein the primary differential code biases and the secondary differential code biases are provided to the receiver for being used to determine the precise position of the receiver;
• characterized in that:
• the information for differential code bias of the additional first signal and the additional second signal are limited due to a limited number of reference stations which are used for providing data for calculating the necessary information, and the first signal and the additional first signal are tracked by a first receiver;
• wherein the second signal and the additional second signal are tracked by a second receiver;
• wherein the additional first signal and the additional second signal are handled by first reference stations among the reference stations, whereas the first signal and the second signal are handled by different reference stations from the first reference stations, the different reference stations which only handle the first signal and the second signal but not the additional first signal and/or the additional second signal;
• wherein the common signal is tracked by the first receiver and the second receiver;
• wherein the first receiver and the second receiver are different types of receivers;
• wherein the first receiver and the second receiver differ in the ability to observe and/or analyze specific signals;
• wherein while the first receiver can observe and/or analyze the first signal and the second signal, the first receiver cannot observe and/or analyze the additional first signal and the additional second signal;
• wherein the first receiver and the second receiver have different public regulated service (PRS) certifications;
• and
• wherein the central computation unit is further configured to:
• determine correction information based on raw data provided from different reference stations;
• and
• transmit the correction information via at least one satellite to a mobile receiver for determining a position of the mobile receiver.