Synthetic-vision systems developed for civil aviation to improve safety in reduced visibility are moving into the military arena, with tests of systems to help helicopter pilots land in rotor-blown dust and other degraded visual environments.

Under a U.S. Defense Advanced Research Projects Agency (Darpa) program, Honeywell has completed flight tests that fused a stored terrain database with real-time sensor data to provide the pilot with a three-dimensional view of the outside word in poor visibility.

The tests, in a U.S. Army Sikorsky UH-60, combined a millimeter-wave (MMW) radar developed under Darpa's Multi-Function Radio-Frequency project with a processing system from the Synthetic Vision Avionics Backbone (SVAB) project and based on Honeywell's commercial SmartView synthetic vision system.

Used in business jets, SmartView combines computer-generated terrain with infrared-camera imagery so pilots can see obstacles that may not be in the database. “We go one step further and fuse in radar,” says Bob Olson, product line director for military avionics. “Infrared provides better situational awareness; radar lets the system understand where [an obstacle] is.”

The demonstration goal was to provide an out-the-window view in a degraded visual environment (DVE) using synthetic vision as a vehicle to take a priori terrain and navigation data and add real-time sensing with MMW radar. “We demonstrated the ability to fuse information into a view the pilot could use in all phases of flying, en route and landing,” says Howard Wiebold, business development manager.

“The system accurately detected obstacles, terrain and power lines, and displayed them in a realistic 3-D view on the current cockpit displays,” he says. “We also demonstrated through an interface control document on the ground that we could take a number of different sensors and fuse them.”

Rather than display hard-to-interpret raw imagery, Honeywell's approach uses an “evidence grid” to take objects detected by radar and fuse them into the 3-D terrain model. “It's a layered approach. There is the digital terrain elevation database, and the MMW data is another layer,” says Wiebold.

Rockwell Collins, meanwhile, has won an Army contract to design a DVE pilotage system (DVEPS) for special-operations helicopters, based on its SVAB system. Boeing and Sierra Nevada Corp. also received contracts for Phase 1 of the DVEPS program.

In the first phase, companies will demonstrate anti-brownout sensors on the ground. In the late second quarter of 2014, one or two competitors will be chosen to fly their sensor. One system will then proceed to development, integration and qualification testing to prepare for fielding by 2018. The initial application is the Boeing MH-47G, followed by the Sikorsky MH-60M.

“We have proposed a lidar sensor, in a system based around the SVAB developed with Darpa,” says Dan Toy, principal rotary-wing marketing manager at Rockwell Collins. Arete Associates is supplying the imaging laser radar and signal processing.

Lidar provides high resolution but can have difficulty seeing though dust. MMW is lower-resolution but more penetrating. “Lidar is challenged to see through very heavy dust, but we have worked with Arete in that area and lidar offers the advantage over radar of very high resolution, which helps significantly in meeting the challenging requirements,” Toy says.

Feature extraction finds landing-zone hazards and obstacles in the lidar imagery and fuses them with the terrain database in the synthetic-vision system. “We completed a lab demo for Darpa last spring and are getting ready for flight test,” says Toy. Flights on an Army UH-60 under the SVAB project will involve BAE Systems' Blast MMW radar, but Rockwell Collins hopes to fly both sensors. “We've done a lot of lab work on integrating data from both Blast and lidar,” he says.

“SVAB is sensor-agnostic. It georegisters the imagery from lidar or radar, extracts features such as small rocks, depressions, power lines and bushes and fuses them with the synthetic vision,” Toy says. DVEPS will feed existing Rockwell Collins-developed Common Avionics Architecture System displays in the MH-47G and MH-60M and use anti-brownout symbology already fielded by the Army.