LAAS could end up being overtaken by a combination of the FAA’s WAAS and Europe’s GPS equivalent, Galileo. While official speakers at last month’s U.S.
Satellite navigation systems
The FAA’s decision to relegate the GPS Cat 1 local-area augmentation system (LAAS) to a mere R&D program (AIN, March 2004, page 1) came as little surprise to either administration officials or industry.
Arinc has flight tested a new differential-GPS precision approach and landing system designed to withstand electronic jamming. Conducted on April 5 at Holloman Air Force Base in New Mexico in an Air Force C-12J (the military version of the Beech 1900C), the tests evaluated the performance of Arinc’s developmental local-area differential GPS (LDGPS) landing aid.
A study commissioned by the NGATS Institute on behalf of the FAA’s JPDO and prepared by the advanced engineering and sciences division of ITT determined that eLoran (for enhanced) has “the highest overall preference rating…particularly in the U.S.” as a backup for satnav receivers in the event of failure or interference.
This summer a Eurocopter EC 155 all-weather demonstrator performed satellite-guided precision approach tests in Lausanne, Switzerland, as part of a research program aimed at developing approach and departure IFR procedures suited to helicopters using the European geostationary navigation overlay service (egnos) Skyguide, the Swiss air navigation service provider, coordinated the program. Swiss medical air rescue agency Rega was also involved.
The DOD’s Navstar GPS reached a new performance level this year, with 30 satellites in orbit versus its minimum required civil complement of 24. Four more satellites add signal coverage and reduce the number of occasional “holes,” or gaps where fix geometry can sometimes fall below navigation standards.
A satellite navigation backup study commissioned by the JPDO has given eLoran “the highest overall preference rating...particularly in the U.S.” Not yet publicly released, the 180-page document was prepared by ITT’s advanced engineering and sciences division and assessed seven candidates against a series of essential requirements. The candidates include DME/DME/INS; GNSS/INS; eLoran; VOR; “hardened” GNSS; terrain mapping; and multilateration.
The U.S. Air Force last month reiterated its intention to choose a single contractor for a new constellation of global positioning satellites known as GPS III. Teams led by Lockheed Martin and Boeing are competing for the contract to launch eight Block A GPS III satellites by 2013. The Air Force invited bids last month for these first satellites, the foundation for an enhanced system scheduled to start operating in 2018.
Occasionally, GPS satellites are spread across the sky in configurations that prevent a receiver from calculating a good position fix. When that happens, the unit’s receiver autonomous integrity monitor (RAIM) will generate an alert to the pilot to use an alternative navigation source.
Members of the Transport, Telecommunication and Energy Council of the European Union have accepted a proposal by the European Commission to assume control of Galileo, the European satellite-based navigation program.