Team tests EMI treatments on next generation Global Hawk

Published July 31, 2006
By Airman 1st Class Julius Delos Reyes
95th Air Base Wing Public Affairs

EDWARDS AIR FORCE BASE, Calif. -- Northrop-Grumman engineers, in conjunction with the 452nd Flight Test Squadron, recently teamed up with the 412th Electronics Warfare Group in the Benefield Anechoic Facility to verify the effectiveness of production level electromagnetic interference mitigation treatments installed on the Global Hawk RQ-4, Block 30, unmanned aerial vehicle.

The test article analyzed in the BAF is comprised of the main fuselage of the next generation Global Hawk UAV. In the nose section of the fuselage, it includes the avionics suite containing a high power satellite communication transmitter and a payload of extremely sensitive signals intelligence receiver processor systems known as the Advanced Signals Intelligence Payload. Because these systems are positioned very close to each other in the front of the vehicle, the potential to cause EMI between the two systems is high.

Only the BAF is ideally suited for this type of testing because it provides an extremely quiet and no-reflective radio frequency environment so that sensitive measurements of interfering signals can be made. The Benefield Anechoic Facility is the largest facility of its type in the world, capable of testing the largest aerial weapon systems in the U.S. inventory.

The BAF test team, led by 2nd Lt. Michael Stackhouse, 772nd Test Squadron electronics warfare test engineer, designed and implemented an antenna isolation measurement system that controls the Global Hawk SATCOM transmit antenna while simultaneously collecting RF data from the ASIP receiver to verify the effectiveness of EMI mitigation treatments installed on the vehicle.

The measurement system, created by Dave Mulvey and Justin Cobbs, is capable of a multitude of RF measurements in a short amount of time, allowing Northrop-Grumman test engineers to have graphic plots available to them to immediately analyze the data and make real-time decisions on the effectiveness of the EMI treatments.

“Without this antenna isolation measurement system and people like Mr. Mulvey and Mr. Cobbs, we’d really have a difficult time supporting customers coming to our facility for EMI troubles,” said Lieutenant Stackhouse. “We have an outstanding EMI team here at the BAF ... they’re highly competent at what they do and they’re continuously working towards improving the unique capability of the BAF to help defend this nation.”

Northrop-Grumman senior EMI engineer, Dick Hohol, is supporting the test with engineers Monty Hall and Chuck Wilkerson from the Unmanned Systems Operation in Rancho Bernardo, Calif. The team also received technical support from Rocky Furton of the Northrop Grumman Antelope Valley Manufacturing Facility.

“The BAF enables us to perform highly accurate and repeatable measurements of antenna to antenna RF coupling in an environment representative of flight,” Mr. Hohol said. “Without a facility like the BAF, it would be necessary to conduct extensive flight testing on the Global Hawk to identify EMI issues and even further testing to verify the performance of any mitigation treatments.”

This test of the Global Hawk unmanned aerial vehicle is one of a series of evaluations of this major intelligence gathering weapon system at the BAF. Tests, such as this one on the Global Hawk, enhance overall warfighter capability by minimizing the EMI effects on the vehicle and help maximize the reliability and accuracy of data provided to combatant commanders in the field by the ASIP SIGINT system so they’re able to make better decisions in real time.