US Patent 7142159 Pseudolite navigation system

The pseudolite includes a communication (COM) satellite receiver for receiving a communication satellite specific RF signal from a communication satellite and providing communication satellite navigation and position data. A GNSS receiver receives a GNSS signal from a GNSS satellite and provides GNSS timing information. A pseudolite transmitter receives the communication satellite navigation and position data and the GNSS timing information. The pseudolite transmitter includes at least one digital signal generator for utilizing the communication satellite navigation and position data and the GNSS timing information for providing a digital signal generator output having an intermediate frequency and navigation message data which are suitable for up-conversion to a desired communication channel RF frequency. At least one communication satellite RF module of the pseudolite transmitter receives the digital signal generator intermediate frequency output from an associated signal generator and converts the intermediate frequency output to a communication satellite transmit RF signal having the desired communication channel RF frequency. The communication channel RF frequency is preferably adjustable and may cover a range of potential communication frequencies.