Printed headline: Radar Renaissance
For onboard weather radar, there are changes in the air. Reacting to customer demands, the OEMs are pushing the technology to generate a wider range of data, greater durability and a more user-friendly experience for pilots of commercial and business aircraft.
Newer radar systems have longer-range capability, are calibration-free and have a mean time between failure (MTBF) north of 30,000 hr., compared with legacy systems where MTBF was 7,000-15,000 hr., explains Paul Hart, chief technology officer at the Defense Solutions, Aerospace Electronics and Motion Control business unit of Curtiss-Wright Defense Solutions. This is the result of getting away from magnetron-based radar, which uses high voltages and cavity-tuning mechanisms to change frequency, which inherently reduces reliability.
Hart points out that the latest radar technology also incorporates gallium arsenide (GaS), the semiconductor doping compound used within the transistors that provides the amplification stages for transmission from the slotted grid antenna typical of weather radars. “At the moment, GaS is being superseded by gallium nitride (GaN) technology, which can operate at much higher junction temperatures. This increases amplifier efficiency to generate much higher radiated powers from the antenna,” he says.
According to Vipul Gupta, senior product marketing director of radar and safety systems at Honeywell Aerospace, modern radar “identifies and differentiates critical weather conditions from normal precipitation,” enabling pilots to avoid hazardous weather, including hail, lightning and wind shear. “At the same time, lower weight, smaller size and improved reliability are also in demand,” he says. “We are also considering touch-screen interactivity for the radar and are working on touch-screen controllers.”
Gupta notes that Honeywell’s new radar system, the IntuVue RDR-4000, as well as its newest iteration—now in development—provide complete weather coverage from both a lateral and vertical perspective, with detection extending 320 nm ahead of the aircraft and from ground level to 60,000 ft. “Our newest IntuVue radar will bring predictive wind shear to the regional jet and business aviation market,” he says. “We expect that radar will evolve from just being a weather sensor to being able to sense multiple items simultaneously. In the future, it will recommend options to the pilot for an optimized and comfortable journey to destination.”
Michael McDowell, Collins Aerospace’s commercial avionics product marketing manager for communication, navigation and surveillance, also predicts that weather depiction “will eventually go beyond tactical information,” providing more data for the entire flight regime to enable the flight crew to make more efficient decisions pertaining to weather and routes. “This will happen through the integration of radar-detected weather depictions and uplinked weather data combined,” he explains.
Given the fast pace of technology developments with avionics, McDowell was asked about the degree of scalability of new radar systems. The goal, he replies, is to “always have robust hardware” that will accommodate increased capabilities through software-only upgrades. “This allows avionics manufacturers to be more efficient and flexible with the introduction of new features,” he says. “However, this is not always achievable, depending on the capability being introduced.”
McDowell says Collins Aerospace’s MultiScan ThreatTrack Weather Radar system provides a more complete view of weather and that it highlights inferred threats through “Core Threat Analysis” of each weather cell. The ability to infer lightning, for instance, has resulted in a 60% reduction in lightning strikes on aircraft that use Collins’ Multi-Scan ThreatTrack products.
Other radar products McDowell cites include the RTA-4200 MultiScan for business aircraft and regional airliners, as well as the ISS-2100 Integrated Surveillance System. “The ISS-2100 includes the MultiScan weather radar, and is certified on the [Boeing] 787, with availability on the new 777X upon its entry into service,” he points out.
But while these weather radar systems represent the state of the art in threat evaluation, with a 320-nm forward detection range, McDowell stresses that the avionics OEM continues to pursue product improvement.
“We are looking at high-altitude ice crystal detection, volcanic ash detection and the vertical profile of weather cells,” he says. “We are also employing connected weather solutions, which provide the capability to download and upload weather data to provide a more complete weather depiction.”
As for any plans to add touch-screen interaction with radar, McDowell notes that while Collins Aerospace has touch-screen capabilities in display systems for business and commercial aircraft, there is no touch-screen capability specifically related to weather radar. However, he stresses that as the aircraft OEMs continue to determine how best to use the touch-screen capability, this will likely be considered. “It is likely that touch-screen capability will begin to emerge as [automatic dependent surveillance-boradcast] ‘In’ applications are introduced with more crew interface requirements, such as cockpit display of traffic information (CDTI), assisted visual separation (CAVS) and flight deck interval management (FIM).”
For the retrofit market, Collins Aerospace holds supplemental type certificates (STC) for the MultiScan ThreatTrack on multiple platforms. Boeing and Airbus, McDowell reports, have service bulletins to upgrade to MultiScan ThreatTrack. “We see a growing market for retrofits to take advantage of the advanced features of MultiScan ThreatTrack. As more airlines get these [modern radar] capabilities on forward-fit aircraft, it is likely that they will want to upgrade their existing fleet to be consistent,” says McDowell.
According to Joel Andrews, team leader of design engineering for Garmin in Olathe, Kansas, weather radar “has traditionally involved a high degree of pilot workload and considerable experience” to interpret the data displayed onscreen. He reports that Garmin is taking major steps to address this issue with its new GWX 80, which he calls the company’s “major focus.”
Currently, the GWX 80’s primary market is business aircraft, with line fit on Cessna’s new Citation Longitude jet. “But it is also available under a Garmin STC, for line fit on the King Air twin turboprop family,” he notes, adding that a derivative for commercial airliner application is also under study.
“Automated weather-threat detection is behind a lot of the technology that Garmin has put into the GWX 80,” Andrews says. With a conventional radar system, he explains, pilots need to use multiple tilt angles to determine what is being displayed as weather or ground clutter, then differentiate between the two.
“But with the GWX 80, there is less need for the pilot to interact with it to provide the correct tilt settings,” he says. “In fact, the pilot can look at the screen quickly to get a better feel for the weather and the degree of threat the weather indicates.”
In addition to a simplified interface, says Andrews, customers also want the highest-quality information—on an as-requested basis.
“Basically, pilots want to do with radar what they are already doing with smartphones,” he remarks. “They want a smart radar that will be totally automated, displaying what the weather will look like over the course of a flight plan—and they only want to be alerted if the weather predicts a threat.”
Andrews describes the GWX 80 as a software-defined radar for control of the waveforms and tailoring of the signals to what the pilot is specifically trying to view. “It also provides improved resolution, which allows the pilot to see farther out, and is as flexible as possible,” he explains. “The software itself has been designed to be upgradeable in the future.”
In addition to the software, Andrews stresses that “a considerable amount of engineering” has been put into the GWX 80’s hardware. “We have installed a larger, dual-core processor for expandability and to accommodate more memory,” he says. “This allows for future growth for new, more powerful signaling display, as well as how that information can be generated and passed to the pilot.”
In addition to weather threats, the GWX 80 has been designed to support predictive wind-shear standards as defined by the FAA, through the use of a 12 in. antenna, which Andrews says is the smallest antenna certified for wind-shear detection. “As we move into larger antennas, predictive wind-shear will get even better,” he remarks.
While weather detection is the main focus of civil airborne radar, Andrews says there is a push for multimission radars normally associated with military aircraft.
“We are looking at being able to present some of this technology to commercial pilots as well,” he reports. “Terrain avoidance is definitely a potential function, as well as noncooperative traffic such as balloons, drones or birds, for example. The software, in fact, has the flexibility to accommodate multimission tasks.”
As for coming technology developments to watch, Andrews says that Garmin is improving internal monitoring and fault recording systems to provide better data analytics and enhanced capabilities to predict potential failure at specific points in the radar’s service life. “The obvious advantage is that if you have a pretty good idea of when the system will fail, you can plan for it and not find yourself in a situation with unplanned down time.”