Initial Test Results for a New PPS GPS Timing Receiver

Abstract : A new Global Positioning System (GPS) timing receiver has been built for the U.S. Naval Observatory (USNO). The new receiver is a 12-channel Precise Positioning Service (PPS) unit capable of tracking GPS Y-Code signals and internally removing the effects of Selective Availability. It is based on the receiver being used in the GPS Monitor Stations by the GPS Control Segment. Testing is being done at the Naval Research Laboratory (NRL) using the GPS signal simulator. The NRL simulator is capable of producing 10 simultaneous signals with Selective Availability and Y-Code. Initial test results show that prior problems with timing calibration due to uncertainties in the initial conditions in the receiver have been shown to be stable to less than one nanosecond with small bias. Additional data will be presented showing the measured effects of temperature on the receiver.