National carrier South African Airways (SAA) is deploying a locally developed satellite payment system, which is also able to track the aircraft anywhere in the world, across its fleet of airliners.

The system, developed by satellite authorisation company SatAuth, had to determine in which territory a transaction was concluded to determine the foreign exchange implications of the transaction.

This requirement meant that the system could also pinpoint an aircraft to within two nautical miles of the last transmission of the system, if the frequency of transmissions were set to 15 seconds.

The system used the military global positioning system (GPS) satellite services provided by US military spin-off company Iridium to determine the latitude, longitude, altitude and airspeed of an aircraft using four satellites to calculate the information. The system also had licences to use the Russian Glonass and Chinese GPS-equivalent satellites to derive position, if necessary.

Inventor and SatAuth MD Paul Roux noted that the system was not designed as an aircraft tracking system and current uses only saw the system sending information every 30 minutes or when a transaction was logged. However, the SatAuth system could send information every 15 seconds, which would enable the aircraft to be located to within two nautical miles of the last transmitted position.

International Civil Aviation Organization regulations required tracking systems to be accurate to within four nautical miles of the last transmission of such systems, placing the SatAuth system well within this requirement, he said.

The data from the SatAuth system had a latency (the time lapse from transmission from the aircraft to reception by the company) of four to seven seconds.

“The SatAuth system is portable and uses the identification code of the server rack of the aircraft in which it is placed to identify and verify the aircraft it is tracking. Further, the SatAuth system can be installed on an aircraft during a routine eight-hour “A-check” maintenance procedure, which is done every 200 to 400 cycles of the aircraft. This makes the system quick to install and is a potential boon to SatAuth in future.”

Roux stressed that the system was not originally intended as a tracking system, but to enable card payments on aircraft during flight.

UK aerospace engineering company Cranfield Aerospace, under head designer Pete Howarth, developed the supplemental type certificate over six months of tests, which determined that the system did not place significant stresses or fatigue on the aircraft over its life of service, for the system to be safely used on commercial airliners.

The SatAuth system was certified with the European Aviation Safety Agency and US Federal Aviation Administration.

The tracking capabilities of the SatAuth system have risen to prominence following the disappearance of Malaysia Airlines Flight 370 and the crash of Indonesia AirAsia Flight 8501 during bad weather.