Honeywell has been testing alternative navigation technologies that could enable accurate navigation in GPS-denied environments, all without relying on a ground-based backup system such as eLoran. The three technologies are vision-, celestial-, and magnetic anomaly-aided navigation.
Vision-aided navigation uses cameras to gather live visual feeds and compare the position of the aircraft to mapping information. This technology has also been tested for drone navigation, as well as an autoland system tested by Germany’s Technical University of Munich in a Diamond DA42. In Honeywell testing in a Leonardo AW139 helicopter and Embraer E170 airliner, engineers were able to create GPS-like performance, including a 67 percent performance improvement over earlier tests.
Celestial-aided navigation has a long history and, in modern times, star tracking is a principal navigation method for spacecraft. Honeywell tested the celestial-nav system in the E170, reaching an accuracy of 25 meters circular error probability of 50 percent, a 38 percent improvement over earlier testing.
According to Honeywell, “This is the first time a resident space objects-based (RSOs) navigation solution was demonstrated on an airborne platform, as most competing solutions rely only on star-based navigation.” RSOs are satellites orbiting earth, and Honeywell’s system tracks RSOs with a star tracker “to provide a passive, not jammable solution with GPS-like accuracy in GPS-denied or spoofed conditions.”
Finally, Honeywell said it “conducted the world’s first real-time magnetic anomaly-aided navigation on an airborne platform—the Embraer E170.” This method "measures earth’s magnetic strength and compares it with magnetic maps to accurately identify the position of the vehicle.” The tests were done on an embedded platform, not in “special environments to mitigate electromagnetic noise,” the company said, which is “a historic milestone.”