Covering the skies

Two radar makers combine forces to make air travel safer

Two are stronger than one. Especially with these radars.

Raytheon Technologies is combining its secondary airport surveillance radar with a primary airport surveillance radar made by the German company HENSOLDT. The companies have teamed to market the result, an airport surveillance radar that can detect and display the presence and position of aircraft in the terminal area and the airspace around airports. The two companies bring more than 100 years of defense, radar and sensor technology under one roof.

Airports need a combination of two radars to handle air traffic. A primary surveillance radar sends out a radar pulse, then listens for echoes that will bounce off any flying aircraft, typically reporting back just the distance and bearing of the aircraft. A secondary surveillance radar is an interrogation system that sends a ping out to aircraft transponders to get additional information such as identification code, distance, bearing and altitude. Without a secondary surveillance radar, aircraft would go unidentified. 

“HENSOLDT has invested in the next-generation primary side, while we’ve invested in the next-generation secondary side,” said Matt Gilligan, vice president of Navigation, Weather and Services at Raytheon Intelligence & Space, a Raytheon Technologies business. “So what we bring to market is the co-mounting of our two radars which are very, very complementary.”

Raytheon Technologies radar sensors and air traffic management systems help control more than 60 percent of the world’s airspace, including locations in 60 countries. It has installed more all-solid-state air traffic radars than all other manufacturers combined. HENSOLDT was part of the electronic business at the defense division of aerospace giant Airbus. It traces its corporate heritage to leading European defense and radar companies.

The team has installed a new co-mounted radar at a Royal Netherlands Air Force Base, and it's working on the first phases of upgrading radars at three major airports in Germany – Munich, Frankfurt and Hamburg – for the Deutsche Flugsicherung, or German Air Navigation Services, as the first part of its nationwide surveillance upgrade.

HENSOLDT’s ASR-NG® primary radar consists of a rotating parabolic dish with three beams and a range of 120 nautical miles in the S-Band frequency range. It can detect position and distance of aircraft, along with special processing to establish an aircraft’s 3-D position. Additionally, the radar contains signal processing algorithms to enhance detection in challenging settings, such as wind farms and high clutter environments.

“The ASR-NG’s 3D capability allows it to determine altitude when an aircraft’s transponder is off or malfunctioning,” said Erwin Paulus, HENSOLDT executive committee member and head of Radar, IFF and COMMS. “It’s also very useful when trying to see through the clutter of wind farms, which many primary radars mistake for aircraft. Our radar is able to tell controllers the difference between the rotating blades of wind turbines and aircraft. No more blank spots.”

Raytheon Technologies’ Condor third-generation MK3 monopulse, secondary surveillance radar interrogates aircraft transponders, which transmit a signal back with the aircraft's identification, altitude and an emergency status code, which is displayed on the radar screen next to the return from the primary radar. The MK3 uses gallium nitride for the transmitter, reducing the number of circuit cards, improving reliability and reducing cost. The MK3 also has built-in ADS-B, or Automatic Dependent Surveillance-Broadcast, that determines an aircraft’s position via GPS, which then periodically broadcasts it back to the radar so the aircraft can be better tracked.

“The MK2 came in two large racks," said Gilligan. "Through advancements in technology, we’ve taken that down to a single rack with virtually no maintenance required.”

The partnership is looking to both upgrade aging systems and install new systems worldwide.