Minutes of the Washington Section November 2003

The November meeting of the Institute of Navigation Washington Section was held at Patuxent River Naval Air Station. It was attended by 15 people, 8 were members of the Section and 7 were visitors. The following is a summary of the meeting events:

JPALS Briefing at Patuxent River Naval Air Museum

3:00-3:45
Bus tour of the Naval Air Station. The meeting began at the Patuxent River Naval Air Museum. Ray Breslau and Diane O’Brien organized three activities for the group. The first event was a bus tour of the Air Station. Tammy Richmond was the guide for the tour which took about 45 minutes. The group learned that more than 19000 people work at the Air Station, which is the home for the V22 Osprey Tilt Rotor Aircraft Program. A third of the military astronauts are graduates of the test pilot school at Patuxent River.

3:45-4:30
Tour of the Naval Air Museum.


Chuck Kerr Describing Ejection Seat Technology

Following the bus tour, the group returned to the Naval Air Museum. Chuck Kerr was the host and gave an informative tour of the museum. People were able to sit in the cockpit of several aircraft simulators. On display were various sonar buoys used by P-3 Orion aircraft in their anti-submarine warfare mission. An array of ejection seats provided a visual example of how technology changes: Early systems were designed to only get the flyer out of the aircraft. Newer systems have the ability eject while on the aircraft is sitting on the ground. Recent designs call for guided ejection seats that can carry a flyer to safety even when the plane is inverted. Mr. Kerr’s discussion and tour also described the changes in the design of aircraft carriers, airplanes, and aircraft engines.

4:30-5:30
JPALS Lecture by Frank Allen. Jim Doherty introduced CDR Phil Beachy who is the Deputy Program Manager for the Navy Joint Precision Approach and Landing System (JPALS). Eventhough, the Air Force is the lead service for JPALS, naval carrier operations are a unique application of the system. Therefore, CDR Beachy leads a group whose job is to develop the Navy’s specific requirements and to harmonize those requirements with the Air Force. Frank Allen was introduced to give a detailed presentation of on the Navy’s JPALS program.


Frank Allen Next to a P3 Sonar Buoy Display

For the Navy, the JPALS program is focused on using GPS carrier phase range measurements for providing precise relative positioning for landing aircraft. The system provides 5-10 cm positioning accuracy at the time of landing. It has 15 cm accuracy at 10 nautical miles from the ship. The system integrity risk (i.e. the probability that the position error is greater than the system alert limit without the pilot being warned) is 10-7 per hour. The alert limit for vertical position errors is expected to be less than 1 meter at the time that the aircraft lands. JPALS is designed to be highly resistant to GPS jamming. This is accomplished by using Controlled Radiation Pattern Antennas (CRPA), the GPS Precise Positioning Service, inertial integration, and high data rate GPS correction messages. All of this is achieved while operating in an environment where strength of the signals radiated from the aircraft carrier must be minimized.

5:30
Meeting adjourned.