This accessor uses the dump1090 driver to access a Software-Defined Radio such as the NooElec R820T (http://www.nooelec.com/store/sdr/sdr-receivers/nesdr-mini-rtl2832-r820t.html) in order to receive and parse ADS-B messages. ADS-B is a cooperative surveillance technology in which an aircraft periodically broadcasts its state such as location, altitude, heading, etc. In order to run this accessor you need to compile the dump1090 driver from https://github.com/MalcolmRobb/dump1090, plug your SDR USB dongle, and run ./dump1090 --net --interactive One can also feed the accessor with a reference location (e.g. from an autopilot) and a threshold parameter. If a reference location is provided, the accessor retrieves all the aircrafts within the threshold distance in the output "traffic"
||double||Latitude of the reference location|
||double||Longitude of the reference location|
||double||Altitude of the reference location|
||object||An object mapping aircraft flight IDs to aircraft state|
||object||Aircrafts within a threshold distance of the reference location|
||string||The address of the web server created by dump1090|
||int||The port of the web server created by dump1090|
||int||The time interval in millisecond after which an aircraft is removed from the list in case an update is not received from the SDR device|
||double||Threshold distance in kilometers|
Filter the response, extracting the aircrat information. The full response is produced on the 'response' output.
Set up the accessor by defining the inputs and outputs.