Abstract: Disclosed is a method which synchronizes a slave time with a master time. The master time is derived from a received signal. The master time is compared to the slave time to detect any offset of the slave time relative to the master time. If an offset is detected, the slave time is adjusted to correct the offset. Also disclosed is a method of synchronizing a pseudolite transmitter time with GNSS time. The transmitter time is compared to GNSS time to detect any offset of the transmitter time. The transmitter time is adjusted to correct the offset if an offset is detected. Also disclosed is an improved pseudolite. The pseudolite has a pseudolite transmitter and GNSS receiver. The pseudolite transmitter time is synchronized with GNSS time.

Abstract: Disclosed are methods of transferring satellite ephemeris data for a first GNSS satellite from a pseudolite to a GNSS receiver. Also disclosed are pseudolites and GNSS receivers implementing the same. A first satellite global positioning signal transmitted by the first GNSS satellite is received at the pseudolite. The pseudolite transmits a pseudolite global positioning signal containing the satellite ephemeris data for the first GNSS satellite. The GNSS receiver receives the pseudolite global positioning signal and retrieves from the pseudolite signal the satellite ephemeris data.

Abstract: Disclosed are systems, pseudolite transmitters, receivers, and methods of using the same to navigate. An airborne pseudolite transmitter transmits a first spread spectrum signal indicative of a first fixed location spaced apart from a current actual position of the transmitter. The airborne pseudolite transmitter also transmits a corrections signal indicative of a vector error correction between the first fixed location and the current actual position of the transmitter. A receiver receiving the first spread spectrum signal and the corrections signal calculates its location in response thereto.