Birthday Present -Sat Nav
Join Date: Feb 2006
Location: Uk
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I use an air box aware plus as my primary-cheap and excellent
I then have an iPad 2,air nav pro with Bluetooth gps which I have on my passengers lap as back up -works well.
I then have an iPad 2,air nav pro with Bluetooth gps which I have on my passengers lap as back up -works well.
Join Date: Oct 2003
Location: UK
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Luddite Warning!!
I'm afraid I can't offer a recommendation for a particular GPS, as I fly with a commercial airliner type Flight Management System. But flying with a GPS is dull in my opinion. I have to use one pretty much all the time but it is nice to be able to do things the old fashioned way from time to time. I still look at the sun, the ADF needle and ground features to confirm the GPS isn't lying (it doesn't lie very often I admit). But navigating by map and compass is so much more satisfying and so much more fulfilling. I definitely think having a GPS is a great idea, particularly if the weather is not looking good, or you need to divert to the nearest airfield, but don't miss out on the fun to be had by using your eyes and brain, and developing a hard won, but immensely satisfying skill.
I'm afraid I can't offer a recommendation for a particular GPS, as I fly with a commercial airliner type Flight Management System. But flying with a GPS is dull in my opinion. I have to use one pretty much all the time but it is nice to be able to do things the old fashioned way from time to time. I still look at the sun, the ADF needle and ground features to confirm the GPS isn't lying (it doesn't lie very often I admit). But navigating by map and compass is so much more satisfying and so much more fulfilling. I definitely think having a GPS is a great idea, particularly if the weather is not looking good, or you need to divert to the nearest airfield, but don't miss out on the fun to be had by using your eyes and brain, and developing a hard won, but immensely satisfying skill.
Join Date: Nov 2010
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"...it doesn't lie very often, I admit..."
Question for you all: apart from hardware failure or problems with GPS reception, daylight viewing etc, does a GPS unit ever give a wrong result? Does it fail safe?
My understanding is that accuracy is defined in terms of % probability of the stated position being within a specified distance of the actual position, but the device will keep refreshing so I'm assuming that it's unlikely to sustain an incorrect reading.
Question for you all: apart from hardware failure or problems with GPS reception, daylight viewing etc, does a GPS unit ever give a wrong result? Does it fail safe?
My understanding is that accuracy is defined in terms of % probability of the stated position being within a specified distance of the actual position, but the device will keep refreshing so I'm assuming that it's unlikely to sustain an incorrect reading.
Join Date: Sep 2006
Location: 23, Railway Cuttings, East Cheam
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I'm afraid I can't offer a recommendation for a particular GPS, as I fly with a commercial airliner type Flight Management System. But flying with a GPS is dull in my opinion. I have to use one pretty much all the time but it is nice to be able to do things the old fashioned way from time to time. I still look at the sun, the ADF needle and ground features to confirm the GPS isn't lying (it doesn't lie very often I admit). But navigating by map and compass is so much more satisfying and so much more fulfilling. I definitely think having a GPS is a great idea, particularly if the weather is not looking good, or you need to divert to the nearest airfield, but don't miss out on the fun to be had by using your eyes and brain, and developing a hard won, but immensely satisfying skill.
I use all of the navigational facilities I have all of the time, I don't rely just on GPS, it's there as an AID, like the map and the stopwatch, ADF and VOR. I still draw lines on maps, the lines still have track times on them, I still use a plog, I also use the GPS.
As it happens I did a flight over the Peak District for a friend a couple of weeks ago, which as anyone who flies that area will know is pretty tight for airspace around the top of Derwent/Holmfirth area. I climbed in, looked in my bag for the GPS and remembered it was on charge at home. No problems, I didn't bust any airspace, I didn't get lost and we had a good flight.
Hovering AND talking
Join Date: Feb 2003
Location: Propping up bars in the Lands of D H Lawrence and Bishop Bonner
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You see this is what I can't understand, why is it that GPS users have no other skills and people who use pine cones for weather forecasting and lodestones for navigating are superior?
Cheers
Whirls
Join Date: Sep 2006
Location: 23, Railway Cuttings, East Cheam
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Probably wasn't, I only half read posts at the best of times. Sometimes I just pitch in without reading anything at all, like a pot luck type thing.
"...it doesn't lie very often, I admit..."
Question for you all: apart from hardware failure or problems with GPS reception, daylight viewing etc, does a GPS unit ever give a wrong result? Does it fail safe?
My understanding is that accuracy is defined in terms of % probability of the stated position being within a specified distance of the actual position, but the device will keep refreshing so I'm assuming that it's unlikely to sustain an incorrect reading.
Question for you all: apart from hardware failure or problems with GPS reception, daylight viewing etc, does a GPS unit ever give a wrong result? Does it fail safe?
My understanding is that accuracy is defined in terms of % probability of the stated position being within a specified distance of the actual position, but the device will keep refreshing so I'm assuming that it's unlikely to sustain an incorrect reading.
About the time I passed Liverpool, I got refused an airspace crossing I'd hoped for and vectored about 15 miles off route, and my GPS lost consistent satellite view - for the next 100 miles.
I *could* if required have sorted myself out using VOR/ADF, but it was a classic case of why we learn to fly accurate VFR/DR diversions, which is exactly what I did.
I have had GPS drop-outs before, and every system I've yet seen is pretty good at telling you it isn't getting a signal. I think it's the longest I've yet seen, and the first from about 6 months / 60 hours use of the Aera.
I've never seen a GPS wrong - they either work or they don't in my experience.
G
Join Date: May 2001
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Flying over the Yorkshire dales using an early Skyforce1 GPS which suffered an "engine failure," I twigged something was not right when it showed me somewhere over Germany.
Never had a dropout on my Aera, but my Garmin 96 likes to turn itself off when ever its feeling like a rest, poor thing.
Never had a dropout on my Aera, but my Garmin 96 likes to turn itself off when ever its feeling like a rest, poor thing.
Join Date: Jun 2003
Location: EuroGA.org
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Flying over the Yorkshire dales using an early Skyforce1 GPS which suffered an "engine failure," I twigged something was not right when it showed me somewhere over Germany.
A loss of signal should be obvious, with a big message across the screen.
Skyforce have not designed anything (GA) for about 10-15 years.
I fly 100% on GPS. I can navigate using VOR/DME/ADF but such a fallback is extremely rare. I lost a signal (on all 3 GPSs) for some minutes flying down the middle of the Adriatic in 2004 at about 1000ft, and that was obviously jamming. On another occassion I could not get the KLN94 (the main GPS I have, panel mounted) to get a fix for about half an hour after departure from Padova, Italy, back to the UK. It picked it up somewhere over the Alps. This was an IFR flight and ATC gave me a VOR-based route, albeit at a higher MEA (FL160 instead of FL140 as filed). That is about all that I recall. The Ipad2 GPS has proved to be very unreliable and moreover (running Memory Map) the app does not show when it has lost a fix; you just get a map which is no longer moving. I read something on the net suggesting that the IOS GPS API does not return satellite status (which is why the IOS version of MM does not give a clue about the sats) which if true is totally outrageous but I can imagine the arrogant Church of Jobs politburo making such a decision "for the simplest [dumb] user experience"...
Join Date: Jun 2007
Location: Swindon, Wiltshire
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The reason it does this is that the device caches the last location. On a phone, when you open a location based service, you are more interested in roughly where you are. You're going to want Google Maps to open in approximately the right place, and you're going to want your 'house hunting' app to show you houses near where you are. It is after all what a smartphone is used for 99% of the time.
The first thing that any developer making a navigation application should do is set the desired accuracy filter to two kilometres or so. This will by definition block the cell tower / WiFi location stuff and force the device to use GPS.
The workaround to the caching feature is so stupidly simple that anyone who didn't figure it out shouldn't be working as a programmer.
When you retrieve a location event, one of the members is 'timestamp' which shows when the location data was last valid. All the humble programmer needs to do is check the timestamps. If they aren't changing, then it isn't working.
In summary, iOS does give you the horizontal and vertical accuracy figures, and it also tells you how old they are. It's up to the programmer to decide if he wants to use figures that are 'old'.
Join Date: Jun 2003
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I wonder why Apple crippled it like that.
OK; it's a "phone" but if it has a GPS then it can be reasonably expected to be used for "serious" GPS apps, whose pre-existence Apple cannot possibly be unaware of.
OK; it's a "phone" but if it has a GPS then it can be reasonably expected to be used for "serious" GPS apps, whose pre-existence Apple cannot possibly be unaware of.
Join Date: Jun 2007
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What is crippling about not being able to see the satellite constellation? What practical use is it apart from looking pretty?
Surely all that matters is the precision of the fix?
Surely all that matters is the precision of the fix?
Join Date: Jun 2007
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Quite - which is exactly what I covered in my earlier post. I would question the quality of any data more than a few seconds old in an aviation application.
Join Date: Jun 2003
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Does the app gets a precise time?
The only time against which the timestamp of a GPS fix could be judged is the GPS time. The Iphone time could be way off.
Actually the constellation data (or at least the traditional individual satellite signal strength histogram) can be very useful. You can e.g. see if there is interference which knocks the signals down when you do something. This is very important in testing for interference from e.g. VHF (11th and 13th harmonic).
I can see Apple would not be bothered because they know where 99% of their sales are coming from, but here we are talking about fairly critical applications.
The only time against which the timestamp of a GPS fix could be judged is the GPS time. The Iphone time could be way off.
Actually the constellation data (or at least the traditional individual satellite signal strength histogram) can be very useful. You can e.g. see if there is interference which knocks the signals down when you do something. This is very important in testing for interference from e.g. VHF (11th and 13th harmonic).
I can see Apple would not be bothered because they know where 99% of their sales are coming from, but here we are talking about fairly critical applications.
Join Date: Jun 2007
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It doesn't matter what the reference for the timestamp is - all it is showing is the time between subsequent GPS fixes. What is important is the delta between the two times. It comes from the system clock.
Fair point about the visibility of the signal strength indications.
Fair point about the visibility of the signal strength indications.
Join Date: Dec 2010
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I use Skydemon with my HTC HD2 smartphone, and have been very impressed with it.
Thanks for that Bob. Do you use the inbuilt GPS receiver or external with blue tooth? Any problem with signal dropouts? Perspex canopy or metal roof ? where do you locate the unit?
Does the phone work satisfactorily as a modem for a laptop?
Does the phone work satisfactorily as a modem for a laptop?
