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Global ADSB Tracking about to go live

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Global ADSB Tracking about to go live

Old 18th Jan 2017, 16:34
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Global ADSB Tracking about to go live

SpaceX began launching Iridium’s NEXT satellites, equipped with Aireon’s ADS-B receivers, from Vandenberg Air Force Base in California on January 14th, 2017. By May 2017, FlightAware will begin providing services fusing Aireon’s space-based ADS-B with FlightAware’s existing flight tracking systems. By early 2018, Iridium and spaceX will have launched all 72 satellites (66 in-service and 6 on-orbit spares) and global ADS-B coverage will be available 24/7.
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Old 18th Jan 2017, 17:21
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Who pays for it and how much does it cost?
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Old 18th Jan 2017, 20:32
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ANSPs pay for the service, how much is negotiable. FAA have a "letter of intent" with Aireon, annual fee is in the region of $100 million.
Several ANSPs are part of the Aireon consortium, I guess they get cheap rates.
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Old 18th Jan 2017, 22:04
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Interesting, I wasn't aware of this development.

Does it require new hardware on the aircrafts? Any reference / tech information (tried to google it but did not find much)?
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Old 18th Jan 2017, 22:11
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Originally Posted by atakacs View Post
Does it require new hardware on the aircrafts?
No. That's the whole point.

This will allow for 100 percent global surveillance using the same ADS-B signal that aircraft already transmit.
It's Just ADS-B
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Old 18th Jan 2017, 23:50
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ANSPs pay for the service, how much is negotiable. FAA have a "letter of intent" with Aireon, annual fee is in the region of $100 million.
Along with ANSPs the bulk of Aireon's customers will be airlines and airports. (There are many more of them than ANSPs).

Airlines in particular use position data to monitor routes and continuously improve operational efficiency. In the future global flight tracking may also be mandated by regulators. Airlines currently source position data from aggregators like FR24 and Flightaware which blend ADS-B sources with real-time ANSP data, or from service providers using ACARS (ADS-C) feeds.

As ve3id mentioned, Flightaware is an Aireon partner so they will have first mover advantage of this new service, with Qatar Airways set to become their launch customer.

By the way Aireon is majority owned by NAV CANADA.
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Old 19th Jan 2017, 01:58
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I'm interested in the mechanics of how ten satellites are launched into presumably different orbits.

Can anyone point me to a link ?
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Old 19th Jan 2017, 02:50
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All of the satellites were launched to the same temporary orbit (parking orbit) via a special dispensers which released one satellite every 100 seconds.

Over the next several weeks, the satellites will undergo qualifications at the temporary orbit. Afterwards each satellite will be moved higher to various final orbits -- replacing existing Iridium satellites on a one-to-one basis. There's enough propulsion in the satellites to move them in and out of (and maintain position at) various orbital positions.

Eventually they will also place spare satellites at parking orbits.
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Old 19th Jan 2017, 06:03
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Space based ADS-B tracking was already demonstrated in the fall of 2015 by a small Danish company on a very modest Cubesat called GOMX-3 launched from the International Space Station. It worked pretty darned well and returned good data until it reentered about a year later. Expect global ADS-B coverage to be a commodity in very short time, and costs to be very reasonable.

As a curve ball broadly inline with the same topic, folks are also experimenting with very small floating solar powered ADS-B receivers with similar goals.
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Old 19th Jan 2017, 06:35
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peekay4,

Thanks very much for that useful information. When the satellites are boosted out of the parking orbit, is the orbital inclination changed at the same time?
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Old 19th Jan 2017, 07:17
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No they were placed in the correct inclination (86.4 degrees for all Iridium satellites). Changing the inclination would require too much propulsion. Right now all the satellites would be close together in the same orbital plane -- one following another -- in a lower orbit than final.

The ascending node of satellites in prograde orbit drift westward. Boosting one satellite to a higher orbit also means it will drift slower, i.e., it "slows down" vs. the rest. In this way they can start evenly "spacing out" the satellites around the earth (although they still will be in the same orbital plane).

The next bunch of satellites will be on the same 86.4 degree inclination but on a different orbital plane. By repeating this process they can create a mesh of satellites spaced out in different orbital planes.
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Old 19th Jan 2017, 11:12
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Iridium Orbits

Almost, but not quite. They can also move satellites to different orbital planes.

They just launched their 10 satellites into the one orbit which is in the worst shape ("orbital plane 6"): it already has a small gap, and no spares left. In this case, eight are supposed to stay there and will be spread out by boosting them out of their current lower orbit into the higher one at appropriate times. Two will be moved to the adjacent orbital plane 5.

In the end, I think eleven satellites each (plus spares) are supposed to go into each of the six orbits (planes), so with seven launches lifting chunks of 10, that wouldn't work if they could not move between orbits.
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Old 19th Jan 2017, 13:45
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Almost, but not quite. They can also move satellites to different orbital planes.
Yes, of course. The question was about changing the orbital inclination between the parking orbit and the final one. Both orbits will have the same inclination.

Significant changes to the inclination require a huge amount of propellant (unless we're willing to wait forever) so it's best to place the satellites in the correct inclination to start with.

Changing the orbital plane can be done by making only a tiny, temporary change to the inclination. Changing the inclination isn't the aim -- typically the change is only a fraction of a degree -- just enough to very slowly drift the satellite towards the new plane. It can take a year before the satellite arrives at an adjacent plane.

Two will be moved to the adjacent orbital plane 5.
Thanks, I hadn't read that. Looks like the next launch will go for plane 3. Do you know how many drifters will be on the next launch?
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Old 19th Jan 2017, 14:31
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Space based ADS-B tracking was already demonstrated in the fall of 2015 by a small Danish company on a very modest Cubesat called GOMX-3 launched from the International Space Station.
It was actually demonstrated prior to that using a German Space Agency (DLR) sensor aboard PROBA-V (mid-2013).
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Old 20th Jan 2017, 01:45
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Grumpi and peekay4,

Thanks a lot for the detailed information. I was aware of the energy implications of changing inclinations, which is why I asked the question. Where can I find more information about launches and orbits?
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Old 20th Jan 2017, 03:19
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Depending on your interests there are some great online courses (all free!) on edX:

1. MITx 16.00x Introduction to Aerospace Engineering is a great introductory course by MIT professor and NASA veteran astronaut Jeff Hoffman. The course has ended but you can still enroll and access all of the course content. Hard math parts optional; many students / enthusiasts simply skip them, and you can freely jump around to topics which interest you (e.g., Orbital Mechanics).

2. UC3M The Conquest of Space is another free intro course blending the history of spaceflight (from the V2, sputnik, Apollo to present day) along with more technical topics. The next class starts Feb 28.

3. EPFL Space Mission Design and Operations is a more rigorous course taught by veteran ESA astronaut Claude Nicollier. Orbital mechanics are explored at length. If you still remember your undergrad level physics & calculus, this may be the course to take. The next running of the course starts Feb 22.
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Old 20th Jan 2017, 06:11
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Great stuff. I'll review Number 1 and signup for Number 3. I use physics and calculus in my day job, so I think I can cope.
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Old 20th Jan 2017, 11:00
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What has not yet been demonstrated is the discrimination of ADS-B transmissions when congested areas are in the hosted payload footprint. As the ADS-B mandates apply to more aircraft and GA move to 1090MHz from DUAT, frequency congestion that is a problem now even at aircraft levels will become worse. In a 3000 mile footprint there can be a lot of transmissions to discriminate.
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Old 20th Jan 2017, 11:34
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The Aireon system is really designed for remote / oceanic routes where the traffic density will always be relatively low, as compared to high density terminal areas like ORD or ATL. So I don't think discrimination will be an issue for the satellites over these routes.

A bigger issue than density is total system capacity -- I believe Aireon can track about 10,000 aircraft simultaneously. But these days (on a busy day) we already have more than 10,000 aircraft flying at one time, and it's increasing every day. So that tells me Aireon will not try to track all aircraft world-wide, but will function as a supplement to existing & future ADS-B ground receiver infrastructure.

Mind you ADS-B congestion is a big issue, just not for these satellites over remote / oceanic areas.
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Old 20th Jan 2017, 11:47
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Interesting stuff. I assume they have a way of bringing the old Iridium satellites down to burn up ?
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