The CanX-7 Automatic Dependent Surveillance-Broadcast
(ADS-B) nanosatellite mission collected more than four million ADS-B messages
between October 2016 and April 2017. An analysis of data collected over the
north Atlantic Ocean from 05 to 28 Oct included 20,707 position messages in
which the angle from satellite nadir to aircraft was determined. The proximity
of the received signal strength to the noise floor of the sensor allowed for an
analysis of optimal aircraft-satellite orientation for ADS-B transmission
detection. The results showed a significant disparity between descending and
ascending passes of the satellite. For descending passes, the
average nadir angle was 50.1°？with 90% of the contacts greater than 40°. The ascending passes had an average nadir angle of 31.6°？with only 24.8% of the contacts exceeding 40°. The evidence suggests that the satellite
magnetic torquer may not have been fully aligned with the north magnetic pole
as the satellite moved northward, resulting in ascending pass nadir angles that
were not reflective of the full range of values. Further analysis of the
descending passes showed agreement with an ADS-B signal propagation model with
peak reception at nadir angles of 51°？± 8°. For space-based
ADS-B operations, the results support the replacement of the current aircraft upper
quarter-wave monopole to an antenna that will transmit more energy directly
above the airframe.
References
[1]
RTCA DO-260B (2009) Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Services-Broadcast (TIS-B). Radio Technical Commission for Aeronautics.
[2]
Aerion Press Release (2019) Aireon System Goes Live—Trial Operations Begin Over the North Atlantic Marking New Chapter in Aviation History.
https://aireon.com/2019/04/02/aireon-system-goes-live-trial-operations-begin-north-atlantic-marking-new-chapter-aviation-history/
[3]
Francis, R., Vincent, R. Noel, J.M., Tremblay, P., Desjardins, D., Cushley, A. and Wallace, M. (2011) The Flying Laboratory for the Observation of ADS-B Signals. International Journal of Navigation and Observation, 2011, Article ID: 973656.
https://doi.org/10.1155/2011/973656
[4]
Vincent, R.F. (2011) The FLOAT Mission: Promoting Teamwork in the Classroom. Physics in Canada, 67, No. 4.
[5]
Cushley, A. and Noel, J.M. (2014) Ionospheric Tomography Using ADS-B Signals. Radio Science, 49, 549-563.
[6]
Cushley, A.C., Kabin, K. and Noel, J.M. (2017) Faraday Rotation of Automatic Dependent Surveillance-Broadcast (ADS-B) Signals as a Method of Ionospheric Characterization. Radio Science, 52, 1293-1300. https://doi.org/10.1002/2017RS006319
[7]
Cushley, A.C., Kabin, K. and Noel, J.M. (2018) Faraday Rotation, Total Electron Content, and Their Sensitivity to the Average Parallel Component of the Magnetic Field. Radio Science, 53, 1075-1088. https://doi.org/10.1029/2018RS006667
[8]
Francis, R. Noel, J. and Vincent, R. (2011) Orbital Monitoring of Automatic Dependent Surveillance-Broadcast (ADS-B) Signals for Improved Air Traffic Surveillance in Remote and Oceanic Airspace. Proceedings of the 62nd International Astronautical Congress, Cape Town, 3-7 October 2011.
[9]
Van Der Pryt, R. and Vincent, R. (2015) A Simulation of Signal Collisions over the North Atlantic for a Spaceborne ADS-B Using Aloha Protocol. Positioning, 6, 23-31. https://doi.org/10.4236/pos.2015.63003
[10]
Van Der Pryt, R. and Vincent, R. (2015) A Simulation of the Reception of Automatic Dependent Surveillance-Broadcast (ADS-B) Signals in Low Earth Orbit. International Journal of Navigation and Observation, 2015, Article ID: 567604.
https://doi.org/10.1155/2015/567604
[11]
Van Der Pryt, R. and Vincent, R. (2016) A Simulation of Reflected ADS-B Signals over the North Atlantic for a Space-Borne Receiver. Positioning, 7, 51-62.
https://doi.org/10.4236/pos.2016.71005
[12]
Vincent, R. (2015) The CanX-7 ADS-B Mission: Tracking Aircraft from Space. Canadian Space Society: Canadian Space Summit, Vancouver, 19-20 November 2015, 1-12.
[13]
Vincent, R. and Van Der Pryt, R. (2015) The CanX-7 Nanosatellite ADS-B Mission: A Preliminary Assessment. Positioning, 8, 1-11.
https://doi.org/10.4236/pos.2017.81001
[14]
University of Toronto Institute of Aerospace Studies—Space Flight Laboratory, Nanosatellites: CanX-7. https://www.utias-sfl.net/?page_id=210
[15]
Freitag. K. (2017) An Analysis of Automatic Dependent Surveillance-Broadcast Signals Received by the Canx-7 Nanosatellite: Examining the North Atlantic Oceanic Airspace Control Area. M.Sc. Thesis, Royal Military College of Canada.
[16]
Bennett, I., Paris, A., Cotton, B. and Zee, R. (2016) Nanosatellite Aircraft Tracking: Simulation and Design of the CanX-7 ADS-B. The Canadian SmallSat Conference, Toronto, 2-3 February 2016.
