RMC student experiment monitors air traffic from near-space
An experiment developed by a student team at the Royal Military College of Canada (RMC) observed aircraft transponder signals from the upper atmosphere last week, delivering scientific results which are the first of their kind and opening new possibilities for aviation safety and security.
The near-space mission, called FLOAT (Flying Laboratory for Observation of ADS-B Transmissions), was a project of the Department of Physics (Space Science), with sponsorship from Defence Research and Development Canada (DRDC) and support from Transport Canada, Nav Canada, AirNav Systems and Huron County. FLOAT’s goal was to observe ADS-B signals from commercial aircraft from high altitudes, to characterize the signal strength and accuracy from far above the aircraft. ADS-B (Automatic Dependent Surveillance – Broadcast) is a navigational transponder system used by aircraft to share their position, velocity, and identity with each other. Nav Canada, the provider of air traffic services in Canadian airspace, has recently begun using ADS-B for air traffic control, and expansion of this service is planned in the coming years.
The high-altitude research balloon carrying FLOAT was launched from Wingham airport in mid-western Ontario at 11:31 EDT on Friday, 12 June 2009. At its highest point, FLOAT rose 92,950 feet – 28.3 kilometers – over southern Ontario. For comparison, the aircraft being monitored were mostly large airliners which cruise at altitudes between 25,000 and 40,000 ft (7.6 – 12.2 km). 112 minutes into the flight, the balloon burst as planned, and the payload descended by parachute, continuing to collect data until it came to rest in a tree 90 km east of the launch site at 13:56 EDT, after a flight of 2 hours, 25 minutes. It was recovered shortly thereafter by members of the student team. Throughout the flight, the team kept in close co-ordination with air traffic authorities to ensure safety to aviation.
The primary payload was a commercial ADS-B receiver provided by AirNav Systems LLC. The ADS-B data, along with information from GPS, environmental, and housekeeping sensors, was transmitted to a ground station located at the launch site, as well as being stored on-board for later recovery.
This was the second flight of the FLOAT payload. The first, conducted three weeks earlier, validated the mission concept and qualified key systems. With this launch, the system completed its science mission, meeting all of its observational goals. The turn-around between the launches was only two-and-a-half weeks, long enough for a rapid and thorough analysis of the performance during the first flight, allowing systems to be adjusted for the second launch.
The entire mission was designed, built, and operated by graduate and undergraduate students in the Space Mission Design courses taught in RMC’s Physics department (PH 549 and PH 448), under the supervision of their professor Captain Ron Vincent. The mission was developed in a very short time frame – only five months from kick-off to launch, including design, procurement, integration and operation of both balloon flights. In addition to the scientific data, the experience provided valuable education and operational experience to the students, who learned a great deal about the development, management, and operation of a space mission from their five months of hard work.
The successful conclusion of the mission has delivered the first-ever ADS-B observations from the stratosphere. The payload system returned a complete data set, meeting all of its experimental goals. ADS-B data was collected during the entire ascent profile, including several samples from altitudes greater than 90,000 ft. GPS position data allows correlation of the locations and relative geometries of the payload sensors and the observed aircraft. Additionally, environmental sensors carried on-board will give a profile of the atmospheric conditions and health of the sensor equipment, allowing further refinement of the data. The data set will now be analyzed at RMC, to determine the feasibility of monitoring air traffic from platforms high in the Earth’s atmosphere – or above it. The results may inform the design of future sensing equipment.
FLOAT’s success shows the strength of the Space Science program offered by RMC, and opens the way for future developments in air traffic management based on ADS-B. For example, data from FLOAT could be used in the development of a satellite-based ADS-B surveillance system, which would provide both experimental and operational data to air traffic controllers, further enhancing the safety and security of air traffic in Canada. Meanwhile, new high-altitude balloon missions are already being planned by researchers both in Physics and other departments at RMC to make use of the new research capability established by the successful FLOAT project.
Capt Vincent and the members of the student team wish to thank staff in the Physics and Electrical Engineering departments at RMC, as well as personnel from the supporting agencies for their assistance. In particular, Transport Canada and Nav Canada, Air Nav Systems, DRDC Ottawa, Huron County and Wingham Airport are thanked for their direct contribution to the success of the mission.
Graduate students
Pascal Tremblay – Team Leader
Raymond Francis – Operation Officer
Undergraduate students
Daniel Desjardins – Telemetry, Tracking and Communication Officer
Matthew Wallace – Payload and Power Officer
Alex Cushley – Integration and Thermal Officer