The Importance of GPS-Denied Navigation
Extensively used throughout the globe, the GPS (Global Positioning System) is a big support system for both civilian needs and military operations. It is a system of 30+ satellites orbiting the earth which broadcast signals and codes. These codes are then translated into accurate time and position on the receiver’s navigation device. In the field of defence, the GPS helps aircraft navigate safely through unchartered territories, and conduct surveillance and reconnaissance missions. It also helps in precise combat power by assisting GPS-guided missiles in tracking and targeting the enemies.
So, when an enemy jams or spoofs your GPS signal, it can affect both your navigation and deployment and targeting of weapons, resulting in a totally adverse battle outcome. “This gets worse when a group of aircraft is flying. Every aircraft in your unit needs to have the exact, same information. Even if one aircraft loses GPS, it will not be able to share information like position, potential threat or weapon deployment with the others. Imagine multiple pilots firing a missile in different directions while aiming at the same target! This can lead to a compromised mission,” Kent-Åke Molin, Sales and Marketing Director at Saab says.
Currently, navigation in a non-GPS environment is a manual and cumbersome process where all the pilot’s attention usually is diverted to safe navigation, hence missing out on tactical awareness. Giving the control back to a fighter pilot while flying amidst GNSS-independent skies, Saab, in collaboration with Maxar, has designed an anti-GPS navigation system. The first component of this revolutionary system is odometry, an image mapping technology that uses onboard electro-optical sensors to map the landscape features while an algorithm helps derive the aircraft's velocity vector.
"It’s like going back to basics, the old ways of flight navigation, but more effective, of course. Odometry identifies pixels in your image that have rich terrain information. These pixels are then constantly tracked by the algorithm using onboard sensors," Kent-Åke says.
Odometry works in association with the next important part of the system- terrain navigation system or TERNAV. Saab uses its decades of experience working on fighters and UAVs to constantly update this in-house Inertial Navigation System’s substitute that assists in fixing any drift the fighter might have faced during its flight.
Then comes the third part of this anti-GPS system called 3D mapping, a technology that uses machine vision to aid in profiling objects in three dimensions to map them in the real world. Combining odometry, terrain navigation, and Maxar's 3D database (which offers a resolution of 50 cm or better and 3 m accuracy in all dimensions), this new navigation system helps the Gripen pilot to safely navigate without the help of any GPS signal.
“Gripen E's game-changing capability to safely navigate through unchartered terrains would give the Indian Air Force’s fighter pilots a protective layer from the threats of jamming and spoofing. We now will take the next step to implement this technology in solutions for our customers. This would further add to our already really strong offer for India, especially considering the IAF’s demanding mountainous and high-threat operational environment,” says Kent-Åke.