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How to get accurate positioning without satellites

3 min read

To be able to navigate with confidence and accuracy when GPS is unavailable for a long time is a game-changing capability for a fighter pilot. It sounds like a challenge - for others. Saab have studied and tested image-based and terrain navigation techniques and now propose new technology for powerful tactical navigation capability in GPS-denied environments.

Last year, Saab performed successful flight tests with Gripen E using new algorithms providing real-time and highly accurate positioning based on image mapping, known as 3D-mapping. The tests, conducted in collaboration with Maxar, successfully proved the concept where data from on-board electro-optical sensors and geo-registration algorithms is compared with a 3D surface model database in the aircraft.

Odometry and terrain navigation

The use of image mapping technology of odometry has also been tested previously with good results. Here an on-board sensor observes landscape features ahead and the algorithms generate a more accurate velocity vector and assist the inertial navigation system.

Terrain navigation, in which Saab has a long history, for instance TERNAV, has also been tested previously in different demonstrations and this technology has evolved in-house with new algorithms and database-handling technologies.

Robust positioning with high accuracy

By combining these three technologies (3D-mapping, odometry and terrain navigation), the navigation system will provide the Gripen pilot with a disruptive and unique capability to operate in Global Navigation Satellite System (GNSS-)/GPS-denied environments with highly accurate positioning maintained.

“In the world of modern war fighting and amongst others its requirements for zero collateral damage a high precision and robust positioning is key. The tactical navigation technology in GNSS denied environments that Saab now start to conclude will lead to a true game-changer capability in the operational arena,” says Jonas Jakobsson, Gripen Experimental Test Pilot, Saab.

Leading the industry

The capability to perform long range or long duration operations in a GNSS denied environment with robust, highly accurate position data, is needed especially when operating against high-end opponents, and Saab is now planning a solution for current and future users of Gripen.

“We believe that we are ahead of others in this area since we already now have demonstrated major parts of this robust, fused, real-time navigation capability with flight tests. We now take the next step to implement this technology in solutions for our customers. Based on the test results we have decided to include this solution as part of our Gripen offer for Finland,” says Tobias Jansson, Product manager Gripen.

Other derived benefits

In addition to support the navigation, there are other potential derived benefits of this technology, such as building and executing targeting functions, and facilitating aircraft landings in challenging environmental conditions where normal landing aids are compromised.