Northrop Grumman Inertial System and Relative Navigation Software Contribute to Automated Aerial Refueling Flight Tests
WOODLAND HILLS, Calif., Nov. 15, 2007 (PRIME NEWSWIRE) -- Northrop Grumman Corporation's (NYSE:NOC) relative navigation software and highly accurate fiber-optic inertial navigation system provided the precise positioning information used to successfully complete the positions and pathways flight test of Air Force Research Laboratory's (AFRL) Automated Aerial Refueling (AAR) program.
"Northrop Grumman's relative navigation algorithms were the key to the positions and pathways flight test," said Jacob Hinchman, AAR program manager at the Air Force Research Laboratory. "These algorithms provided a new level of accuracy in fused precision global positioning system/inertial navigation system relative positioning."
The AFRL's Air Vehicle Directorate AAR flight tests, completed in Sept. 2007, were performed using a Learjet, which acted as a surrogate for an unmanned refueling receiver aircraft. The purpose of the AAR program is to demonstrate the capability of refueling unmanned aerial vehicles with the existing Air Force tanker fleet. The flight tests demonstrated the ability of the AAR system to autonomously execute aerial refueling maneuvers in close proximity to a tanker and to practice breakaways.
During one of the flights, the AAR system was engaged and flew transitions for a total of 75 minutes. It also held at a precise contact position for 20 consecutive minutes, allowing the Learjet to follow the KC-135 through multiple refueling orbits -- all without pilot inputs. During these tests, Northrop Grumman's relative navigation software fused raw GPS measurement data and inertial navigation data from both the tanker and Learjet to provide the Learjet with the required relative motion information.
"Northrop Grumman has been involved with the AAR program since its inception and has supplied hardware, program analyses and support for all the test flights so far," said Ike Song, director of strategic programs at Northrop Grumman Navigation Systems Division. "We are proud to contribute our relative navigation capabilities to these successful flights."
Northrop Grumman worked closely with a national team that included the Air Vehicles Directorate of the Air Force Research Laboratory, the Naval Air Systems Command and the Boeing Phantom Works to integrate its relative navigation software and LN-251 inertial navigation systems into the flight system of the surrogate aircraft. The LN-251 was equipped with the highly precise 24-channel Global Rockwell Collins ASR-24 dual frequency selective availability/anti-spoofing module receivers that decrypted the precision GPS coordinates used for these flights.
"Relative navigation, the ability to accurately and reliably measure the relative three-dimensional motions of two moving vehicles, is a key enabler for capabilities that involve vehicles that must move in close proximity," said Dr. Alex Fax, manager of network navigation systems at the company's Navigation Systems Division and principal investigator for this effort. "A relative navigation capability dramatically extends the operational effectiveness of unmanned aerial vehicles by enabling aerial refueling and carrier landings."
The LN-251 units utilized for this demonstration are the smallest, lightest navigation-grade embedded global positioning system/inertial navigation systems available. These units contain a high performance navigation-grade fiber optic gyro-based inertial measurement unit, providing a compact and low noise precision navigation solution for the relative navigation applications. The LN-251, with its digital interface, is easy to incorporate into new aircraft and avionics systems of existing aircraft. Its modular open architecture supports additional applications and evolving requirements.
Northrop Grumman Corporation is a $30 billion global defense and technology company whose 120,000 employees provide innovative systems, products, and solutions in information and services, electronics, aerospace and shipbuilding to government and commercial customers worldwide.
CONTACT: Don Barteld
Northrop Grumman Electronic Systems
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