This paper describes the bit error rate (BER) charcteristics for data transfer on 4.8 kbps aviation-quadrature-phase-shift-keying (AQPSK) signals measured in a laboratory test and in an experiment using Engineering Test Satellite V (ETS-V). AQPSK is expected to be used for the transmission of 2.4 kbps or 4.8 kbps voice or data between an aircraft and an air traffic control (ATC) center via a geostationary satellite for oceanic ATC. Flight experiments were conducted using both Japan Airlines' B747 and Beechcraft B99 aircraft.

The result showed the followings. The BER characteristics for an eastbound flight show larger degradations than those for a westbound flight in the experiments using the B747 aircraft. The BER characteristics for a B99 aircraft almost equal to those for the westbound flight of B747. In general, it is found that the BER characteristics of AQPSK equal to or are better than those of BPSK for a transmission rate of 4.8 kbps.

The International Civil Aviation Organization (ICAO) investigates the Global Navigation Satellite System (GNSS) as a new navigation system in civil aviation. In GNSS, the position and time can be determined globally using satellites. The Global Positioning System (GPS) of the United States is considered as one of candidates for the GNSS. It is pointed out that GPS has some faults if this system is adopted as the GNSS. One of these faults is deterioration of positioning accuracy. The ICAO suggests those faults of GPS should be improved if GPS is used as the GNSS.

The system for Geostationary Augmentation of GPS is considered as one of means to resolve the faults of GPS. A geostationary satellite is addid to GPS in the System for Geostationary Augmentation of GPS. A GPS-like signal is generated at a ground station and transmitted to users via the geostationary satelite. Users can use this GPS-like signal in positioning calculation. The use of GPS-like signal in positioning calculation is expected to improve positioning accuracy which is obtained when only GPS satellites are used.

This improvement of positioning accuracy in the System for Geostationary Augmentation of GPS is cofirmed in this report by a computer simulation.

Especially, it is found the use of all satellites in view is very effective in the calculation of dilution of precision (DOP) and a user position.

In order to increase an air traffic capacity in oceanic areas, the introduction of a new surveillance system which enables reduced separations is needed. Automatic Dependent Surveillance (ADS) is a system whereby aircraft automatically transmit, via a data link, data derived from on board navigation system. The ICAO/FANS committee recommended its early development and implementation in the scenario of CNS (Communications, Navigation and Surveillance) required for Air Traffic Services (ATS) for the next two decades. Currently, the ADS panel of ICAO is working out the Standard and Recommended Practices (SARPs) for ADS.

We carried out the ADS Pacific Engineering Trial (ADS/PET) for evaluation of ADS, a trilateral cooperative program by Australia, USA and Japan. In case of Japan, the ADS data are sent from the aircraft to the Ground Earth Station (GES) via INMARSAT satellite in the pacific ocean region or indian ocean region and relayed to the ENRI (Electronic Navigation Research Institute) through the data link computer at AVICOM JAPAN. Those data are processed, displayed and stored by ADS Data Processing & Display System. The trials were carried out using a JAL's (Japan Air line's) B747-400 aircraft from May 1991 to March 1993. This paper describes the concept of ADS PET program, and development of the ADS Data Processing & Display System.