Soft Landing

When landing a SA-400 Jackal—a compact helicopter that can operate as an Unmanned Aerial Vehicle (UAV) or optionally piloted vehicle—on a moving ship, there’s little room for error.

If this 1,200-pound helicopter misses the landing site, it could end up in the water, damage the ship with its blades, or even injure people on board. These landings must be precisely executed, which is why Steen Mogensen, the CEO of Fort Collins, Colorado–based Scion UAS, and his team rely on NovAtel’s OEM615 multi-constellation GNSS receivers for the precision positioning that make such operations less hazardous.fig1

The ability to land on a moving ship makes this helicopter well suited for military applications and is part of the reason Scion UAS received a $3 million contract from the Naval Research Laboratory (NRL) to deliver multiple SA-400 Jackal turbine-powered Vertical Take Off and Landing (VTOL) aircraft. The NRL will use the systems to develop, demonstrate and test emerging sensor systems. The Colorado-based company has already delivered two Jackals to the NRL.

Mogensen and his team have tested the Jackal’s landing capabilities more than 100 times, using a computer to land the aircraft on a large trailer pulled behind an instrument-laden truck—the company’s simulator platform for a maritime vessel.
During an August 2014 test flight, the SA-400 Jackal landed smoothly on the 16 x 20-foot trailer being towed along a runway at speeds up to 10 knots. The Jackal successfully completed 10 landings and takeoffs during this test, including straight-line approaches and 45-degree approaches to simulate ship-based operations. The company completed the final test flight in October 2014, where the NRL took delivery of the first system.

Without the precision that the OEM615 receivers provide, these successful platform landings and takeoffs wouldn’t have been possible. 

“Most people think of GPS as something you have in a car that tells you how to get to the store,” Mogensen said. “All you need to know is roughly where the store is, and the GPS tells you whether to go left or right at the next intersection.”

However, Mogensen added, “If you want the GPS to tell you how to park your car in one parking spot in front of the store, you need to make sure you’re not hitting the cars next to you or hitting the store. Now the precision needs to be down to a few inches. Imagine trying to do that with your eyes closed and listening to the GPS direct you left or right. That’s what our aircraft needs when it lands on a ship. The precision must be within a foot or so of hitting the landing deck we need to be on.”