Android finds the Corrupted Jammers

JLOC Android Application for GPS Interference Detection and Effects Situational Awareness
A. Brown, D. Vollmer and R. Edwards, NAVSYS Corporation

GPS signal interference, both intentional and unintentional, exists today and continues to be problematic for both military and civilian applications. Rapidly detecting, characterizing and locating GPS interference sources is, therefore, a high priority task to counter the evolving GPS jamming threat. Under contract to the U.S. Government, NAVSYS Corporation developed the GPS Jammer Detection and Location System (JLOC) as an operational capability supporting joint warfighters at all levels (theater to tactical). The system currently provides GPS jammer alerts and products depicting GPS effectiveness to users in a selected area.

With the advent of Google´s open Android development environment, it is now possible to inexpensively and rapidly develop new applications (apps) for operation on Android mobile devices such as cell phones and tablet PCs. Google maintains an open marketplace where developers can post their applications for customer download. DARPA has engaged in the development of a similar apps marketplace which could be used for rapid distribution of military and government applications directly to warfighters and first responders.

This presentation will detail the implementation of a DARPA-sponsored JLOC Android Application that can be downloaded to any Android device for the purpose of detecting, reporting and displaying GPS interference events. The JLOC Android app is designed to use the Android phone´s GPS unit as a sensor to the JLOC system to provide early detection of GPS jamming and provide the existing JLOC situational awareness displays on the effect of known GPS jammers directly to the user for display on their handheld device. This is possible because the Android development environment allows client software access to the device´s Signal-to-Noise (C/N0) ratio data for each tracked GPS satellite. As the GPS User Equipment (UE) approaches the area where the jammer is in operation, the C/N0 sensed by the UE drops.

In a collaborative environment, JLOC participants can view the real-time sensor reports through the Android app indicating GPS current status as red/yellow/green positions. The red points indicate locations where GPS was not able to be acquired and cellular positioning was used (or the last GPS location), the yellow points indicate degraded GPS reception and the green points indicate locations where no degradation is observed on the GPS signal.

Initial testing of the Android application was conducted near the White Sands Missile Range during a jamming test. During this presentation, we will present results of these tests and show the sensor results detected and the JLOC displays generated. We will also discuss how the JLOC system could be used for geo-location of interference sources when combined with data collected from multiple sensors using the JLOC Server. Finally, we will identify other systems that could integrate the app such as the Army´s Tactical Ground Reporting System (TIGR) or a civil version of JLOC, for use within the United States.

The JLOC Android Application will provide a simple GPS interference alerting and awareness tool that will benefit the individual user, his network partners, command decision makers and the larger intelligence community. By designing this capability around the National Geospatial-Intelligence Agency´s existing, proven JLOC system, the application can be integrated quickly into both contingency and domestic environments producing immediate synergies.