For almost 40 years, Western armed forces have relied upon the U.S. NavStar Global Positioning System (GPS) constellation to guide them both on and off the battlefield.
Initially, GPS was fairly rudimentary and user equipment was large, unwieldy, and too power-hungry for combat operations; however, some 1,400 early man-portable GPS receivers were fielded during Operation Desert Storm, bringing an invaluable improvement in navigational accuracy to U.S. and Coalition forces in the nearly featureless desert and proving the value of the new technology.
Since then, the major powers have become all but reliant upon GPS in military operations – from dismounted troops’ point-to-point navigation to precision weapon guidance. This reliance is recognised by our adversaries who constantly work to counter the effectiveness of GPS on the battlefield.
The most important challenges are GPS jamming and spoofing. Jamming denies access to GPS signals whilst spoofing provides false locational information. Both aim to disrupt GPS-based navigation and positioning, and the accuracy of precision-guided munitions (PGMs). Military Y-Code receivers are extremely well protected from spoofing by their Selective Availability Anti-spoofing Modules (SAASMs), which leaves GPS Jamming.
Recently, the volume of GPS jamming incidents has increased across the globe. There has been extremely aggressive Electronic Warfare in the area of Ukraine and in the Baltic region. In the Middle East, jamming incidents of both civil and military platforms are equally common in the region. In South East Asia, in the South China Sea, there have also been GPS Jamming activities.
Many platforms now bear some form of GPS anti-jamming (AJ) system, but in the cyclic technology race, many are now inferior to the jamming systems they face. Whilst many forces state that they have GPS AJ systems in place on their platforms, many systems are aged and use older and less effective nulling solutions to provide critical GPS AJ protection.
Currently, the most effective defence against GPS Jamming is “digital beamforming,” where nulling of the jamming signal still takes place, but reception lobes are locked onto good satellite signals and remain locked even when the platform is aggressively manoeuvring.
BAE Systems has recently seen huge success in fielding its new Digital GPS Anti-Jamming Receiver (DIGAR), an antenna electronics unit that can be fitted to all types of military platforms, from unmanned aerial vehicles to ships, ground platforms, and air tankers.
The highly effective DIGAR System has been selected for numerous U.S. platforms to harden their onboard GPS systems against the growing jamming threat and until next-generation M-Code GPS technology becomes available. With 125+ dB J/S performance*, DIGAR is unrivalled in the levels of protection provided, as it delivers significant hardening to include direction finding against the highest levels of GPS jamming when coupled with a digital receiver and controlled reception pattern antenna (CRPA).
Internationally, DIGAR has been selected for the F-16 Fighting Falcon as well as other U.S. military aircraft, and is under consideration for other aircraft within European NATO forces.
Due to the open architecture of DIGAR, installation on many existing platforms is simple and low-risk. DIGAR can be fitted into an existing mount and easily connected to the existing GPS receiver and CRPA. Normally, changes to the platform Operational Flight Program or airframe are not necessary.
For additional information about BAE Systems military GPS products, visit: https://www.baesystems.com/en-us/product/gps-products.
Phil Froom is International Business Development Director for the Navigation and Sensor Systems business at BAE Systems.