Would TomTom work in an airliner?
Discussion
Dunk76 said:
Just out of curiousity more than anything else.
If I turned my TomTom on at 30,000ft - would it find the satellites? would the plane fall out of the sky?
On the flight from Male to the island we were staying on in the Maldives, the plane's navigation system was the same Garmin GPS that we had on our boat - just a small, portable inexpensive one. We were probably flying in excess of 10,000 ft at a guess, so on that basis, it works. Not sure about airliner heights and speeds though. If I turned my TomTom on at 30,000ft - would it find the satellites? would the plane fall out of the sky?
Presumably the airliner uses GPS as well as Radar to work out it's own position? So if the question is 'does GPS work on planes?' I think the answer is 'yes'.
Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
mrmr96 said:
Presumably the airliner uses GPS as well as Radar to work out it's own position? So if the question is 'does GPS work on planes?' I think the answer is 'yes'.
Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners do not use GPS as their primary navigation aid and they do not use radar as a navigation aid at all, at least, not the radar on board the aircraft itself.Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners use two main methods of finding their way around - the first one is to use ground based radio beacons. There are two main types of these, NDBs (Non Directional Beacons ) and VORs (VHF Omnidirectional Range). These are generally used over land masses as there are no beacons in the ocean.
A radio receiver on the aircraft can detect the direction in which a particular beacon lies and, witha VOR, can also detect the distance the beacon is from the aircraft. Air traffic control instruct the pilot to fly towards each beacon on the route and to report overhead each beacon. Once a beacon has been passed, ATC will then instruct the pilot to head for another beacon - and so on.
For long oceanic crossings, Inertial Guidamce Navigation (INS) is used. This is based on onboard accelerometers (gyroscopes) linked to a navigation computer. The aircraft's geographical position is entered into the computer before take off and any changes in direction and speed are detected by the gyroscopes and translated into positional information by the computer.
At the moment, GPS is mainly used as a back up to these older established systems.
Ground based radar systems allow the controllers to see where the aircraft they are controlling actually are in relation to each other.
The radar set on the aircraft itself is used for detecting rain and clouds. It is essentially a weather radar, not a navigational radar.
Thanks for that info Eric. Very interesting.
I was initilly surprised at the use of the INS you describe, however it was presumably developed before GPS was brought into service. Do you know why the planes have not been adapted to use GPS now? Is it a case of 'aint broke dont fix it?' Or do you think that there would be a risk of relying on something outside the aircraft? (Or at least something outside the aircraft which the USA could decide to turn off at any point.)
I was initilly surprised at the use of the INS you describe, however it was presumably developed before GPS was brought into service. Do you know why the planes have not been adapted to use GPS now? Is it a case of 'aint broke dont fix it?' Or do you think that there would be a risk of relying on something outside the aircraft? (Or at least something outside the aircraft which the USA could decide to turn off at any point.)
INS has been around for a long time, IIRC the V-2 rocket used early implementations. Modern aircraft use all the data available to them e.g. INS, GPS, VOR/DME etc. Usually there are three INS units and it uses the average.
They don't just rely on one source - eg GPS is inherently unreliable and at the mercy of the US government; INS units drift over time and need to be 'refixed'; there is no VOR/DME over the Atlantic etc etc.
They don't just rely on one source - eg GPS is inherently unreliable and at the mercy of the US government; INS units drift over time and need to be 'refixed'; there is no VOR/DME over the Atlantic etc etc.
Edited by john_p on Friday 10th July 12:06
Gyroscope technology began to be used in aircraft before WW1. The Sperry company were pioneers in using gyros as the control mecahnism for automtaic pilot systems.
Sperry autopilots became standard fitment in larger aeroplanes in the 1930s.
With the advent of analogue and later digital computers, the ability of the gyros to "inform" the aircraft as to its location relative to its starting point became feasible. This is where the INS technology evolved from.
It was also developed for medium and long range missiles and spacecraft.
GPS is relatively new and is not standtardised throughout the aviation industry. Many airacft are now fitted but, as I said, it is really
only for backup purposes.
Sperry autopilots became standard fitment in larger aeroplanes in the 1930s.
With the advent of analogue and later digital computers, the ability of the gyros to "inform" the aircraft as to its location relative to its starting point became feasible. This is where the INS technology evolved from.
It was also developed for medium and long range missiles and spacecraft.
GPS is relatively new and is not standtardised throughout the aviation industry. Many airacft are now fitted but, as I said, it is really
only for backup purposes.
Dunk76 said:
Just out of curiousity more than anything else.
If I turned my TomTom on at 30,000ft - would it find the satellites? would the plane fall out of the sky?
Yes, it'll find the satellites and no, it won't fall out of the sky.If I turned my TomTom on at 30,000ft - would it find the satellites? would the plane fall out of the sky?
I often use my GPS to find out how fast we're flying.
strudel said:
Keeping to this thread for tidyness - why won't my gps work on the train? It doesn't get a sniff of a single satellite yet will happily pick them up through double glazing at home! Would sitting on the south side help?
Mine is the same .. I think its the laminated windows... I can get a fix and plot my speed when in a plane no problems, but on a train ... No chance. very hard to get a lock.Managed it with an external reciever placed near an open window, attached to a laptop , but as for hand helds ... Havnt managed it yet
Eric Mc said:
mrmr96 said:
Presumably the airliner uses GPS as well as Radar to work out it's own position? So if the question is 'does GPS work on planes?' I think the answer is 'yes'.
Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners do not use GPS as their primary navigation aid and they do not use radar as a navigation aid at all, at least, not the radar on board the aircraft itself.Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners use two main methods of finding their way around - the first one is to use ground based radio beacons. There are two main types of these, NDBs (Non Directional Beacons ) and VORs (VHF Omnidirectional Range). These are generally used over land masses as there are no beacons in the ocean.
A radio receiver on the aircraft can detect the direction in which a particular beacon lies and, witha VOR, can also detect the distance the beacon is from the aircraft. Air traffic control instruct the pilot to fly towards each beacon on the route and to report overhead each beacon. Once a beacon has been passed, ATC will then instruct the pilot to head for another beacon - and so on.
For long oceanic crossings, Inertial Guidamce Navigation (INS) is used. This is based on onboard accelerometers (gyroscopes) linked to a navigation computer. The aircraft's geographical position is entered into the computer before take off and any changes in direction and speed are detected by the gyroscopes and translated into positional information by the computer.
At the moment, GPS is mainly used as a back up to these older established systems.
Ground based radar systems allow the controllers to see where the aircraft they are controlling actually are in relation to each other.
The radar set on the aircraft itself is used for detecting rain and clouds. It is essentially a weather radar, not a navigational radar.
Better still, there is a Local Area Aug. System (LAAS), which is brilliantly accurate, apparently moreso than a Cat 3C ILS, and as its RNAV (GPS), the approach is 'bendable', brilliant for approaches through mountainous areas like Innsbruck. Again, its just a matter of waiting for LAAS approaches to be certified.
Conventional VOR/DME/NDB is still very prevalent, particularly because jet airliners aren't as modern as the racing GPS technology, but RNAV is definately the future. It's more prevalent here in the US, as here is where the technology is pioneered and tested. I was a sceptic before, but the more I use it, the more I see the benefits in its versatility.
Eric Mc said:
mrmr96 said:
Presumably the airliner uses GPS as well as Radar to work out it's own position? So if the question is 'does GPS work on planes?' I think the answer is 'yes'.
Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners do not use GPS as their primary navigation aid and they do not use radar as a navigation aid at all, at least, not the radar on board the aircraft itself.Regards the TomTom getting a lock, I presume (as mentioned above) that the metal box which is the plane may block the signal. I suggest that you try opening a window and hold the device outside at arms length.
Let me know how that goes. HTH.
Airliners use two main methods of finding their way around - the first one is to use ground based radio beacons. There are two main types of these, NDBs (Non Directional Beacons ) and VORs (VHF Omnidirectional Range). These are generally used over land masses as there are no beacons in the ocean.
A radio receiver on the aircraft can detect the direction in which a particular beacon lies and, witha VOR, can also detect the distance the beacon is from the aircraft. Air traffic control instruct the pilot to fly towards each beacon on the route and to report overhead each beacon. Once a beacon has been passed, ATC will then instruct the pilot to head for another beacon - and so on.
For long oceanic crossings, Inertial Guidamce Navigation (INS) is used. This is based on onboard accelerometers (gyroscopes) linked to a navigation computer. The aircraft's geographical position is entered into the computer before take off and any changes in direction and speed are detected by the gyroscopes and translated into positional information by the computer.
At the moment, GPS is mainly used as a back up to these older established systems.
Ground based radar systems allow the controllers to see where the aircraft they are controlling actually are in relation to each other.
The radar set on the aircraft itself is used for detecting rain and clouds. It is essentially a weather radar, not a navigational radar.
You are correct that most flights are flight planned as VOR-VOR (at least in cruise), but most VORs are not very accurate, so GPS is used since it is far more accurate and reliable, although again, the FMS does look at VOR signals as a cross-check to GPS. On the rare occasions when the GPS is deferred and we do actually fly using VORs there is a big difference and you really notice the reduction in accuracy (as do the controllers, who are used to the accuracy of GPS and ask why you are off course and all you can say is that you show 'dead-on').
As for INS, it is for sure still used on many airliners, but on the smaller and newer airliners it is sometimes not even present - GPS, VOR, etc is enough.
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