Patent ID: 7023381

Claim:
A positioning system comprising: a plurality of pseudolite transmitters, each pseudolite transmitter capable of transmitting a plurality of GNSS-like radio-frequency (RF) signals, each signal including a carrier signal and a spreading code modulating said carrier signal; and a receiver system, the receiver system capable of: a) receiving said plurality of GNSS-like radio-frequency (RF) signals; b) determining a plurality of measurements including: a carrier phase measurement of each said carrier signal; and a code phase measurement of each said spreading code; and c) calculating a range between at least one of the plurality of pseudolite transmitters and the receiver system from said carrier phase and code phase measurements where the range is accurate to within one wave length of a highest frequency of the carrier signal in the absence of relative motion between the pseudolite transmitters and the receiver system; wherein the plurality of GNSS-like radio-frequency (RF) signals includes signals whose frequencies fall within at least two different continuous ISM bands.