GP&C hybrid landing system

This working paper has been submitted by the Swedish Civil Aviation Administration to ICAO.

Special European Regional

Air Navigation Meeting

Vienna (Austria), 5-16 September 1994

 

Agenda Item 3: Formulation of the European CNS/ATM Plan, including consideration of VHF congestion and ILS/MLS transition.

AND LANDING SYSTEMS

(Presented by Sweden)

Introduction.

The EANPG proposed strategy for a coordinated transition from ILS to new precision approach and landing systems, as presented in WP 9, declares that current minima for low visibility operations must be maintained at least their current levels. This may not be possible with ILS alone at some locations due to interference problems, primarily on the Localizer frequency.

Discussion

Although an ILS facility itself may have a number of yeas after 1998 to perform its service, a degradation of Category or total decommissioning my be required due to frequency interference. As GNSS still have some time to go before the system will be certified as stand-alone precision approach system, the EANPG proposes that MLS will be installed at such locations.

With an integration of GNSS and ILS, a so called hybrid system, the associated site shortcomings of the systems may be overcome in a cost effective way. This combination will also improve the integrity of both the ILS and the GNSS. To validate hybrid concept SCAA (Swedish Civil Aviation Administration) is currently conducting a test program (at attachment A) for an integrated GPS and ILS Glide slope Category I and II approach. The test results so far achieved shows that the accuracy is within the requirement of Category II (and III) limits. A certification activity is initiated with the scope of having the system approved initially as a supplement system by 1995.

With a hybrid system as an option the transition strategy, as proposed by EANPG, may need to take this into consideration as an intermediate step into new approach and landing environment. This would be of great value for many providers since an ILS with a remains lifetime do not have to be replaced earlier than necessary, taking full benefit of its technical lifetime. With regard to the ILS systems, currently operational in Sweden this solution would allow continuous precision approach service from most of the 54 facilities beyond 1998 without major investments in.

It is recognized that some runways in the Region, for several reasons, urgently need to replace ILS with MLS to ensure continued Category III operations. The hybrid system may not be a suitable solution for those runways as multipath effects and airport capacity (eg critical and sensitive areas) related to ILS most certainly will remain even with a hybrid system. However, a hybrid system may be an interesting option for those airports that do not suffer from such limitations. To that end it should be noted that the needs for low visibility operation varies within the Region and any proposed strategy should reflect that situation.

Proposal

It is proposed that the Implementation Working Group take the discussion above into consideration when elaborating on the proposed ILS transition strategy and;

- include the hybrid system as an option

- recognize the variations in low visibility requirements within the Region.

- support a postponement of the current protection date for ILS in Annex 10

Test site

The flight testing has been performed at Norrkoeping Airport runway 27. A Normarc NM 3533B ILS installed 1990 with CAT II capability is used Equipment

Aircraft

The aircraft used were Grumman Gulfstream G1 and Beech King Air 200,

Avionics

The GPS-transponder includes a six or twelve channel, carrier aided differential receiver. The update frequency is 1 Hz. The navigation information is PC based software an ARINC 429 interface to the FIS. The two systems are, fully compatible.

Calibration equipment

A fully computerized FFV Aerotech Flight Information System approved for calibration of ILS CAT II facilities. The FIS has a modular structure allowing implementation of GPS information for these tests.

GPS Reference station

The reference station is situated 600 metres from the ILS threshold. It is composed of a 12-chamel GPS-receiver and is transmitting DGPS pseudorange messages in compressed RTCM Ver. II format, The station is monitored from the test base. The reference site is surveyed according to the WGS 84 triangular network (Euref 89)

Data link

A time-division multiplex TDMA VHF data link was used for the, differential corrections and transmitted on 136.95 MHz. Integrity messages were also transmitted on the, data link.

Test result in accordance with ICAO DOC 8071

Attached

Return to GP&C hybrid landing system

Seach words: GPC Systems International AB, GNSS-Transponder, GNSS Transponder, GP&C Transponder, GPS-Transponder, STDMA data link, SOTDMA, ICAO VDL Mode 2, ICAO VDL Mode 3, ICAO VDL Mode 4, ADS-B broadcast, Surveillance, Mode S Squitter, GPS-Squitter, AMASS, ASDE, TCAS, CDTI, DGPS, DGNSS, GBAS, LAAS, ICAO/AMCP, RTCA Task Force 3, Free Flight Steering Committee, Flight 2000, CNS/ATM, NEAN, NEAP, NAAN, FARAWAY, SUPRA, MAGNET-B, FREER, PETALII, 4S Transponder, AIS transponder, Håkan Lans, Hakan Lans, http://www.gpc.se, http://www.gpc.se