Jammer and Interference Location System – Design and Initial Test Results

Conventional jammer location equipment consists of dedicated electronic intelligence (ELINT) equipment installed in an aircraft pod. This is effective against small numbers of high power jammers but is less effective when the threat is large numbers of low power, low cost jammers. The low power of GPS satellite signals makes it particularly susceptible to jamming or interference. NAVSYS has solved this more difficult jammer detection and location problem through a network centric approach where data is collected from both specialized GPS receiver equipment and conventional GPS user equipment acting as jammer sensors. The data from these sensors is relayed over a data link or network to a JLOC Master Station that can use the data to derive the various jammer locations. To determine the accuracy that this technique can achieve, NAVSYS is building three types of sensors. The first uses the diagnostic data generated from conventional GPS user equipment to allow it to act as a jammer sensor. With this data from multiple sensors, jammer or interference locations can be derived. The second sensor identifies the Angle-of Arrival (AOA) of the jammer signals at the sensor. This unit is not based on an ELINT equipment design, so it is less expensive than existing jammer location hardware. With the data from one moving AOA sensor collected over a period of time, the jammer or interference positions can be found. The third sensor collects data snapshots of the jammer’s RF spectrum at multiple locations. By correlating this data at the Master Station, the jammer or interference sources can be located. The design of this system will be presented. To demonstrate the capability of a network centric jammer location system, the Air Force Space Battlelab has developed the GPS Availability To Overcome Resistance (GATOR) initiative. Under this effort, the applicability of a network based jammer location system to battlefield conditions will be evaluated and its data timeliness will be measured. In addition, alternative navigation technologies (ANT) will be evaluated for use when GPS is not available on the battlefield. A description of this effort as well as initial test results will be presented.