# GPS transmission from Aircraft [closed]

At the risk of being marked as a duplicate question, i am raising my first ever question in aviation.

I have always wondered how/why of aircrafts positioning, ever since the "lost" plane of Malaysian airline. Here are few things that are still unclear to me -

1. We have fairly precise GPS service available to cars/phones etc. why cant the same be availale to planes? And more importantly, why cant the planes reciprocate with their own coordinates ? Better if it can be shared in real time ? What are the challenges?

I have read some about ADS-B a little and understand that it has its limitations. owever, when we have so many human lives at stake, why is a better solution looked into/implemented?

The limitations that have been described for ADS-B systmes is pretty serious, given that many of the aircraft today travel through horizon boundaries.

1. How exactly do "people" get to know of a aircraft and/or its position in order to "potentially" strike it using a missile etc? Is any of ADS-B data available publicly allowing a plane to be tracked by "anyone"? if so, why also, isnt that encrypted, and if not, why not?

My thought process is mostly around "how can someone track a plane without being part of the ATS system/network"?

1. What are the areas of our planet not covered by navigational satellites ? There are references to lack of navigational satellite coverage in many areas on earth. For that reason, I want to understand more on that topic. For an aeroplane, flying on a given route, transmitting its position to a satellite above, what are the potential challenges?
• Why do you think ADS-B needs to be secret/encrypted? What incidents have occurred that could have been prevented? The only recent incident of a downed airliner almost certainly occurred because the groups in question thought it was military - something that could have been ironically avoided by the use of some kind of flight tracking.
– Dan
Nov 2 '15 at 11:38
• This is really three questions, of which the first is a duplicate, the second doesn't make a huge amount of sense, and the last is unclear. If you have multiple questions, please could you put them into separate threads with one clear, non-duplicate question in each? Nov 2 '15 at 11:50
• Possible duplicate of Why don't all commercial aircraft transmit GPS data in real time? Nov 2 '15 at 11:57
• @Raghav You're GROSSLY misunderstanding how GPS and Satellite Navigation work. GPS is one way only - no ifs and buts, all you get from GPS is a Latitude / Longitude location and an estimate of accuracy depending on the amount of satellites involved. Everything else relies on 3rd party propriety systems - that's everything from the map you see to route planning, traffic data and so on. For your domestic sat nav, that either relies on radio transmissions to tell you about traffic (Again,one way only) or internet based communications.
– Dan
Nov 2 '15 at 12:17
• the data is provided anonymously. No data is provided. GPS satellites do not receive data. They only transmit data. The GPS in your car, or on an aircraft, can only receive data. They might send data to another system, but that is not GPS. You should carefully read the duplicate and linked questions and answers and also read some basic articles on how GPS works. You cannot track anything with GPS. Nov 2 '15 at 12:32