This repository contains the Buoy example application we use to evaluate Celestial. Check out the main repository to learn more about Celestial!
There are three types of components that make up this distributed application.
The sensor buoys are the data source for the application.
Sensors located on the sea send data and imagery to the application.
The locations of these sensors is based on real NOAA stations.
See stations.csv for the full list of locations.
The processors process the data from sensors. This can happen in a ground station computers or in the LEO edge.
NOAA Dart processing location: Pacific Tsunami Warning Center Building 176 1845 Wasp Boulevard 21.366315122964277, -157.96262184972477
Processed data generates events that are read by the data sinks.
These can be island ground stations, e.g., for tsunami warnings, or ships, e.g., for weather warnings.
Ground station locations are located in the groundstations.csv file and based on real locations.
Vessel locations from MarineTraffic. Pacific island locations from United Nations Environment Programme Island Directory.
DART buoys use the Iridium constellation for communication. The current Iridium constellation has six planes of eleven satellites each. There are spaced along a 180 degree arc (i.e., only ascending above one half of the globe, descending above the other). They have a 780km altitude and 90 degree inclination (polar orbit).
Iridium offers different "plans" for subscribers, from a few bps bandwidth up to 704Kbps receive (352Kbps transmit, Certus 700 product). Iridium recommends their Certus 100 product for "vehicles, vessels, and aircraft all over the world" as well as "portable operations like workforce communications, remote monitoring, and real-time asset control". Certus 100 is capable of 88Kbps TX/RX, so we use that for our clients.
ISLs in NEXT are in the 22.18-22.38 GHz band (Ka band), with 21.6MHz necessary bandwidth for each transponder according to p.16 of this FCC filing. I have no idea what that means for data rate.