Patent ID: 7679554

Claim:
A differential navigation system using time transfer to improve accuracy comprising: a first navigation receiver configured to: receive and process navigation signals to determine position and provide a first navigation time mark; a first communications device configured to: provide a first communications time mark, and compare the first communications time mark to the first navigation time mark to compute a first time offset; a two-way communications link over which the first communications device communicates messages and computes time offset via two-way time transfer; a second navigation receiver configured to: receive and process navigation signals to determine position, which position is compared with a known position of the second navigation receiver and used to determine differential correction signals to be transmitted to said first navigation receiver, and provide a second navigation time mark; and a second communications device, which is time offset with respect to said first communications device by a second time offset, said second communications device being configured to: receive messages from the two-way communications link, provide a second communications time mark, and compare the second navigation time mark to the second communications time mark to obtain a third time offset, and for transmitting the third time offset over the two-way communications link to the first communications device; the first communications device is further configured to: receive the third time offset from the two-way communications link, compute the second time offset, and compute a first navigation receiver to second navigation receiver time offset to provide clock aiding to the first navigation receiver.