GPS receiving system

A global positioning system (GPS) receiving system having a first GPS receiver mounted on a first moving object and a second GPS receiver mounted on a second moving object, the first and second GPS receivers calculating relative positions and relative velocities of the first and second moving objects by selecting GPS data with a common GPS satellite identification number from first GPS data yielded by the first GPS receiver and second GPS data yielded by the second GPS receiver, at least one of the first moving object and the second moving object comprising:

• a time tag error correction unit for correcting a time tag of the GPS data selected for a clock bias, which is clock inaccuracy of the GPS receiver producing the GPS data selected;
• a time tag commonizing unit for commonizing a time tag of the GPS data selected and which has been corrected by the time tag error correction unit;
• and
• a differential computation unit for calculating a difference between a first pseudorange and a second pseudorange having time tags that have been commonized by the time tag commonizing unit.

A global positioning system (GPS) receiving system comprising:

• a first GPS receiver obtaining GPS data from a plurality of GPS satellites and communicating with a second GPS receiver;
• a common GPS satellite selection unit for selecting GPS data required for determining a relative distance between the first GPS receiver and the second GPS receiver from a plurality of GPS data obtained by the first GPS receiver from the plurality of satellites;
• a time tag commonizing unit for commonizing time tags of the first GPS receiver and the second GPS receiver with regard to the GPS data selected;
• a differential computation unit for calculating a difference between commonized GPS data of the first GPS receiver and commonized GPS data of the second GPS receiver;
• a time tag error correction unit for correcting the difference calculated with an error based on clock inaccuracy between the first GPS receiver and the second GPS receiver;
• and
• a relative navigation unit for determining relative positions of the first GPS receiver with respect to the second GPS receiver based on the calculated difference after correction.

A global positioning system (GPS) receiving system comprising:

• a first GPS receiver obtaining GPS data from a plurality of GPS satellites and communicating with a second GPS receiver;
• a common GPS satellite selection unit for selecting GPS data required for determining a relative distance between the first GPS receiver and the second GPS receiver from a plurality of items of GPS data obtained by the first GPS receiver from the plurality of satellites;
• a time tag error correction unit for correcting time tags of the GPS data selected using clock inaccuracy between the first GPS receiver and the second GPS receiver;
• a time tag commonizing unit for commonizing corrected time tags of the first GPS receiver and the second GPS receiver, after correction, for each item of the GPS data selected;
• a differential computation unit for calculating a difference between commonized GPS data of the first GPS receiver and commonized GPS data of the second GPS receiver;
• and
• a relative navigation unit for determining relative positions of the first GPS receiver with respect to the second GPS receiver based on the calculated difference.