The UHARS Non-GPS Based Positioning System

The Ultra High Accuracy Reference System (UHARS) is the 746th Test Squadron's next generation reference system, currently under development to meet test and evaluation reference requirements for future navigation and guidance systems. Consisting of a rack mounted, tightly integrated system of navigation sensors/subsystems, data acquisition system, and a post-mission reference trajectory algorithm, UHARS will provide a highly accurate reference solution for airborne and land-based test vehicles in electronic warfare environments where modernized and legacy GPS signals are jammed from friendly or hostile systems. The system will be appropriately sized and constructed for use on-board multiple test-beds including current and future test aircraft and ground vehicles. Achieving these accurate reference solutions requires a Non-GPS Based Positioning System (NGBPS) subsystem capable of providing sub-meter position accuracy in a GPS-denied (jamming) environment. The NGBPS portion of the UHARS program plans to employ a network of ground transceivers and test vehicle rover receivers, manufactured by the Locata Corporation. The NGBPS uses Locata's standard commercial transceiver and rover devices, but meeting the demanding UHARS accuracy and distance requirements necessitated major improvement of Locata's normal antennas, amplification and navigational software. To this end, the 746th Test Squadron awarded Locata a contract to re-design these components and demonstrate a system delivering longer ranges (both for acquisition and tracking), higher power transmission levels, new antenna designs for aircraft use, and higher aircraft dynamics than previously envisaged. The 746th Test Squadron and Locata completed a technical demonstration of this improved capability on October 2011 on White Sands Missile Range. The demonstration (including set-up, flight trials and check-out time) spanned a 3-week period. This paper details the NGBPS demonstration to include the following: technical challenges, conduct details such as flight profiles and ground station set-up, and the results.