Stanford University

GPS WAAS Laboratory

Anti-Jam GPS Aircraft Antenna

Flight Trials

Date: September 16 & 18, 2002

Location: NASA AMES/Moffett Field

Air Crew:
   Frank N. Bauregger - Lead Engineer
    Dr. Sharon Houck - Air Captain
    Ben Hovelman - Pilot in Command
    Geary Tiffany - Pilot
    Terry Reager - Pilot

Ground Crew:
    Logi Vidarsson - Transmitter Operator
    Claude Hammond - Transmitter Operator/Ground Communications
    Yolanta Lubos - Transmitter Operator
    Dr. Stewart Cobb - Spectral Monitoring

The purpose of this flight test was to demonstrate a novel anti-jam GPS antenna. The antenna has two modes of operation: a wide-angle mode which allows reception of all GPS satellites in view, and an anti-jam mode which has increased resistance to jamming from the ground. Pilots may switch manually between the two modes depending on the jamming environment. Alternately, a smart GPS receiver can be programmed to switch to anti-jam mode in the presence of jamming.

Read more about the antenna here:

A Novel Dual-Patch Anti-Jam GPS Antenna
Presented June 2002 at 58th ION Annual Meeting, Albuquerque, New Mexico

A Novel Dual-Patch Anti-Jam GPS Antenna
Presented to Stanford GPS Lab October 3, 2002

Photographs:
    Air Crew
    Ground Crew
    Caravan
    Equipment
    Pictures from the ground
    Pictures from the Caravan
    Other aircraft

Selected Results:

    JPEGs:
    Realtime AJ - Plot of simulated jammer power during final approach
    Relative AJ - Plot of signal-to-interference ratio (S/I) during final approach for a high elevation satellite
    Landing - Protecting the aircraft during a landing
    Powerplot - Plot of GPS satellite and jammer power levels during an approach
    UTD vs. Measured - Received jammer power based on UTD theory, vs. measured power
    Skyplot - A snapshot of the GPS satellite constellation during the flight trials
    Roll - Theoretical roll plane pattern of antenna on the Caravan
    Pitch - Theoretical elevation plane pattern of antenna on the Caravan

    MPEGs: (Cool!)
    GPS RX Status - Movie showing GPS RX tracking status & other parameters during final approach
    Constellation Parameters - Movie of GPS constellation parameters during final approach
    General - General airborne navigation performance in the presence of jamming

Last update: December 9, 2002

frankb@stanford.edu