Technology Update
Moisture monitoring
 Jaguar fighter-bombers: Michell Instruments has developed portable hygrometers for the RAF. |
Accurate monitoring of moisture content in aerospace systems is an essential safety element. Michell Instruments, a European manufacturer of industrial hygrometers, is supplying the UK Royal Air Force (RAF) with specially modified portable devices.
Based on the company's ceramic moisture sensor technology, the Cermax portable hygrometer has been designed to meet the RAF's performance, reliability, and accuracy requirements. The instruments are capable of operating to an accuracy of ±1°C from -60 to +20°C dew point and ±2°C from -100 to -60°C dew point, with a resolution of 0.1°C dew point across the entire range.
The Cermax will be used to measure the moisture content of nitrogen and oxygen used in RAF systems, nitrogen primarily in weapons systems, and oxygen for onboard systems, including life support. The hygrometers have a drop-down menu system with recorded dew point data displayed on a multifunctional LCD display. Each has been configured with a complete sample conditioning system to suit the RAF's needs.
- Stuart Birch
Collision avoidance for UAVs
 To demonstrate UAV collision-avoidance capability, engineers conducted a series of flight tests using a piloted NASA FIA-18 and the Proteus UAV equipped with new sensors. |
Test pilots and engineers at NASA have reached a milestone that they hope will help bring uninhabited aircraft safely into the national airspace. During tests in New Mexico, an airplane remotely piloted from the ground detected another approaching airplane, enabling the ground controller to successfully maneuver the remote aircraft away from a collision course. NASA, New Mexico State University, the U.S. Navy, Scaled Composites, and MTSI, Inc. ran the tests as part of the Environmental Research Aircraft and Sensor Technology (ERAST) program, which was started to further develop UAV technologies that could one day provide low-cost telecommunications relay services, environmental monitoring, and remote border surveillance.
The test flights used the Proteus UAV, as several other test airplanes, including a high-speed NASA F/A-18 jet, approached from various angles to give sensors on the UAV the opportunity to detect the presence of aircraft on collision courses. Proteus relayed information to the ground controller at the Las Cruces, NM, airport, who had sufficient data displayed on a computer screen to select a safe new course for the UAV.
"We believe this is the first time a remotely piloted airplane has been maneuvered away from a collision course based on onboard sensors detecting a collision potential," said NASA Project Manager Jeff Bauer.
During the New Mexico tests, all the aircraft carried pilots for an additional safety margin, but Proteus was operated remotely via a ground station. In about 18 scenarios, airplanes approached Proteus from a variety of angles and altitudes, providing the ground controller with complex situations to solve to keep the aircraft out of harm's way. However, the approaches had a built-in safety margin of separation, with the sensors on Proteus calibrated to treat these as genuine airspace threats to validate the equipment.
 The Proteus was operated via a ground control station in New Mexico. |
The primary sensor used by Proteus is the Skywatch HP traffic advisory system, a radio-based device that relies on common transponder radio signals from other aircraft to detect collision potential. Other sensors on Proteus used infrared or radar technology to pick out aircraft without transponder signals. According to Bauer, an optimized detect, see, and avoid (DSA) suite for operational UAVs would probably rely on a combination of radio and non-radio sensors.
Another expected benefit of this research is a reduction in the cost of DSA equipment to make it practical to use in more aircraft, whether piloted or remote, Bauer said.
The introduction of the technology to UAVs represents the first step toward gaining acceptance of these vehicles in the national airspace. However, for that to happen, UAV technology will need to go even further to satisfy the concerns of the Federal Aviation Administration, which will have final approval of its integration into the national airspace.
- Frank Bokulich
