I have got the A-GPS option enabled through KaiserTweak and it does make a big difference on Google Maps. My only concern is- what does it cost? Where is it connecting to to get a fix?
I am on T-Mobile UK Web n Walk (unlimited data plan) so if it is connecting through that then there is no issue. I am just always a bit wary about things that I don't understand (quite a lot to be wary about then!) and couldn't find a straight answer anywhere.
Thanks to anyone who can enlighten me!
THe GPS itself is free, the google maps you pay for the data as it downloads the map info. if you use tomtom then you dont pay for anything other than the initial cost of the maps and software if the software didnt already come with the phone
The GPS signal is courtesy of the huge sums spent on military defense over the past couple decades
For real, there is no charge for the GPS tracking proper. What does not come for free are the maps. so Google maps come over the air, meaning you pay via a data plan. If you purchase navigation software, you will pay for maps as well, but you can load them onto a storage card so there would then be no data charges. so esentially a Nav program like Tom Tom/ Garmin/ iGo, once you pay upfront, it is free thereafter (relatively speaking as you will still need to pay for the cost of charging your device battery)
Thanks for your reply. i understand that the GPS itself is free as it is just receiving satellite signals, however the Kaiser also has assisted GPS as an option in KaiserTweaks. From what I understand, this uses info from network masts to give an approximation of where you are. My question is how does this work, or more precisely are there any cost implications that should make me disable the A-GPS option?
A-GPS in terms of the updates that occur from the network are short bursts of data about every 6 days (or almost never if you use active sync regularly as the updates will occur thru the PC's internet connection). If you have any sort of data plan this is a non issue.
The phone just gets some sattellite data to speed up the startup fix when using the built-in GPS.
RemE said:
A-GPS in terms of the updates that occur from the network are short bursts of data about every 6 days (or almost never if you use active sync regularly as the updates will occur thru the PC's internet connection). If you have any sort of data plan this is a non issue.
The phone just gets some sattellite data to speed up the startup fix when using the built-in GPS.
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You are confusing A-GPS with QuickGPS. QuickGPS simply downloads satellite location data via the internet as opposed to getting it directly from the satellites. It's faster to get it from the internet. A-GPS uses cell tower triangulation, though I'm not sure how (or even if) that integrates with the satellite based triangulation when that feature is enabled. Regardless, I wouldn't think A-GPS would cost anything... it doesn't use data, and doesn't use talk time.
No, A-GPS = Assisted GPS = QuickGPS. It's free if you connects by active synch or a wifi connection. It downloads ephemerides of satellites for next 7 days (position of satellites for 6 days and 23 hours exactly) which helps your GPS for the first fix (or cold fix). So with QuickGPS (or A-GPS) you can do the fix in 15-30 seconds max instead of 2-3 minutes without . It's just an help for your GPS ( more informations on http://www.gpspassion.com)
Or you could say that QuickGPS uses A-GPS technology to assist in obtaining quicker GPS fixes. Either way mickey is right.
If you don't use Active Sync or WiFi very much you will use a small amount of data but it is a negligible amount.
mickeydeplage said:
No, A-GPS = Assisted GPS = QuickGPS. It's free if you connects by active synch or a wifi connection. It downloads ephemerides of satellites for next 7 days (position of satellites for 6 days and 23 hours exactly) which helps your GPS for the first fix (or cold fix). So with QuickGPS (or A-GPS) you can do the fix in 15-30 seconds max instead of 2-3 minutes without . It's just an help for your GPS ( more informations on http://www.gpspassion.com)
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Pretty close: The diffference in layman terms: The A-GPS allows your device to remember the last location when you hit a dead spot. This allows the selected GPS program to continue an estimated tracking based on the last recieved location, direction & speed data.
A(ssited) GPS uses no internet data. So there is no charge period. It just uses satelite data.
mickeydeplage said:
No, A-GPS = Assisted GPS = QuickGPS.
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Ok what is the system used by the latest Googlemaps application, and no doubt others, which gives a rough location purely on cell tower data? I understood this to be AGPS.
Shamelessly ripped from Wikipedia...
Assisted GPS
GPS is a satellite based positioning system. Assisted GPS, or A-GPS was introduced to enhance performance. The development of A-GPS was accelerated by the U.S. FCC's E911 mandate requiring the position of a cell phone to be available to emergency call dispatchers. [1]
Conventional GPS then had difficulty providing reliable positions in poor signal conditions. For example when surrounded by tall buildings (as a result of multipath), or when the satellite signals are weakened by being indoors or under trees. Some newer receivers fare better.
In addition, when first turned on in these conditions, some non-A-GPS units may not be able to download the almanac and ephemeris information from the GPS satellites, rendering them unable to function until a clear signal can be received continuously for up to one minute.
An A-GPS receiver can address these problems in several ways, using an Assistance Server:
The Assistance Server can locate the phone roughly by what cell site it is connected to on the cellular network.
The Assistance Server has a good satellite signal, and lots of computation power, so it can compare fragmentary signals relayed to it by cell phones, with the satellite signal it receives directly, and then inform the cell phone or emergency services of the cell phone's position.
It can supply orbital data for the GPS satellites to the cell phone, enabling the cell phone to lock to the satellites when it otherwise could not, and autonomously calculate its position.
It can have better knowledge of ionospheric conditions and other errors affecting the GPS signal than the cell phone alone, enabling more precise calculation of position. (See also Wide Area Augmentation System)
Some A-GPS solutions require an active connection to a cell phone (or other data) network to function, in others [2] [3] it simply makes positioning faster and more accurate, but is not required.
As an additional benefit, it can reduce both the amount of CPU and programming required for a GPS Phone by offloading most of the work onto the assistance server. (This is not a large amount for a basic GPS - many early GPSs ran on 386/16 or similar hardware).
High Sensitivity GPS is an allied technology, that addresses some of the same issues in a way that does not require additional infrastructure. It notably cannot provide instant fixes when the phone has been off for some time, that some forms of A-GPS can.
Coorect. There are several types of Assisted GPS. The native A-GPS on the Kaiser is only for using the data recieved before hitting a dead spot, so your track can continue as estimated.
The recent cell tower & CID assisted GPS programs can take that a step further & in stead of guessing your track based on last known heading & coordinates can also use information from cell towers. Some process this data through servers which keep track of cell tower locations & then provide an estimated fix based on tower triangulation.
GSLEON3 said:
Pretty close: The diffference in layman terms: The A-GPS allows your device to remember the last location when you hit a dead spot. This allows the selected GPS program to continue an estimated tracking based on the last recieved location, direction & speed data.
A(ssited) GPS uses no internet data. So there is no charge period. It just uses satelite data.
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Click to collapse
Yep, correct! A-GPS is only a vector forwarding, short intergration of previous data. Only works whilst GPS gives out 'No Sat Data'
It also depends on if you unit is in mode 1 or mode 2 (only ref'd to WM6 GPSmode reg key as it has the handler)...
DTR Control Flow Values.
GPS_NMEA_0183 = 1
GPS_RTCM_104 = 2
Mode 2 (which is default) processes all data through the WM6 handler, Mode 1 will give you RAW data (which should solve the Navigon 'Destination Reached' problem!!!)
A-GPS costs nothing as it is only a calculation, QuickGPS costs only your Internet acces time for its own download and if you have it setup for Activesync, will only use your comps link....
Wow! glad im not the only one who is confused! I get what you're saying about it just calculating position based on last available data, but that doesn't fit with my experience with googlemaps after a hard reset where it came up with a circle of my location despite no gps fix being available.
Thanks to everyone for their help!
The excellent test of the Kaiser here : http://www.gpspassion.com/fr/articles.asp?id=237&page=1 gives a link for the QuickGPS of the Kaiser here : http://www.cdmatech.com/download_library/pdf/gpsonextra_assistance.pdf
mickeydeplage said:
The excellent test of the Kaiser here : http://www.gpspassion.com/fr/articles.asp?id=237&page=1 gives a link for the QuickGPS of the Kaiser here : http://www.cdmatech.com/download_library/pdf/gpsonextra_assistance.pdf
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Brilliant! Thanks for clearing that one up!
mickeydeplage said:
The excellent test of the Kaiser here : http://www.gpspassion.com/fr/articles.asp?id=237&page=1 gives a link for the QuickGPS of the Kaiser here : http://www.cdmatech.com/download_library/pdf/gpsonextra_assistance.pdf
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Now come on!! Where were you hiding when we needed you for reference many threads back??
Good info input...
Assisted GPS or A-GPS uses the mobile phone network to assist the GPS receiver in the mobile phone to overcome the problems associated with TTFF (time to first fix) and the low signal levels that are encountered under some situations.
For A-GPS, the network provides the Ephemeris data to the cell phone GPS receiver and this improves the TTFF. This can be achieved by incorporating a GPS receiver into the base station itself, and as this is sufficiently close in position to the mobile the data received by the base station is sufficiently accurate to be transmitted on to the mobiles. The base station receiver is obviously on all the time, and will be located in a position where it can "see" the satellites.
The information provided can be either the Ephemeris data for visible satellites or, more helpfully the code phase and Doppler ranges over which the mobile has to search, i.e. 'acquisition data'. These ranges can be estimated as the position of the mobile is bounded because it must be within the cell served by the particular base station. This technique is able to improve the TTFF by many orders of magnitude.
Assisted GPS or A-GPS is also used to improve the performance within buildings where the GPS signals are by 20 dB or possibly more. Again by providing information to the GPS receiver in the mobile it is able to better correlate the signal being received from the satellite when the signal is low in strength. Using this technique it is possible to gain considerable increases in sensitivity and some manufacturers have claimed it is possible to receive signals down to power levels of around -159dBm. The base station supplies the receiver with navigation message bits - 'sensitivity data'.
Summary: A-GPS is designed to help get the first fix, but does not improve GPS accuracy; Therefore QuickGPS is a form of A-GPS
To improve the accuracy of the GPS fix, you need Differential GPS (DGPS) - see below
There are many sources of possible errors that will degrade the accuracy of positions computed by a GPS receiver. The travel time of GPS satellite signals can be altered by atmospheric effects; when a GPS signal passes through the ionosphere and troposphere it is refracted, causing the speed of the signal to be different from the speed of a GPS signal in space. Sunspot activity also causes interference with GPS signals. Another source of error is measurement noise, or distortion of the signal caused by electrical interference or errors inherent in the GPS receiver itself. Errors in the ephemeris data (the information about satellite orbits) will also cause errors in computed positions, because the satellites weren't really where the GPS receiver "thought" they were (based on the information it received) when it computed the positions. Small variations in the atomic clocks (clock drift) on board the satellites can translate to large position errors; a clock error of 1 nanosecond translates to 1 foot or .3 meters user error on the ground. Multipath effects arise when signals transmitted from the satellites bounce off a reflective surface before getting to the receiver antenna. When this happens, the receiver gets the signal in straight line path as well as delayed path (multiple paths). The effect is similar to a ghost or double image on a TV set.
Satellite geometry can also affect the accuracy of GPS positioning. This effect is called Geometric Dilution of Precision (GDOP). GDOP refers to where the satellites are in relation to one another, and is a measure of the quality of the satellite configuration. It can magnify or lessen other GPS errors. In general, the wider the angle between satellites, the better the measurement (see GPS Basics slide show for an illustration). Most GPS receivers select the satellite constellation that will give the least uncertainty, the best satellite geometry.
GPS receivers usually report the quality of satellite geometry in terms of Position Dilution of Precision, or PDOP. PDOP refers to horizontal (HDOP) and vertical (VDOP) measurements (latitude, longitude and altitude). You can check the quality of the satellite configuration your receiver is currently using by looking at the PDOP value. A low DOP indicates a higher probability of accuracy, and a high DOP indicates a lower probability of accuracy. A PDOP of 4 or less is excellent, a PDOP between 5 AND 8 is acceptable, and a PDOP of 9 or greater is poor. Another term you may encounter is TDOP, or Time Dilution of Precision. TDOP refers to satellite clock offset. On a GPS receiver you can set a parameter known as the PDOP mask. This will cause the receiver to ignore satellite configurations that have a PDOP higher than the limit you specify.
The nett result of all these error can amount to 10 metres. To provide corrections, Assisted GPS uses data taken from a series on "Known" fixed locations to provide some estimation of the GPS error at a particular location and thus correct it. How this error correction data gets to your PDA depends on the hardware and software involved. Some GPS hardware vendors offer a web/GPRS based service. Differential GPS (DGPS) uses long-wave radio, requiring an additional radio receiver & many transmitting beacons.
WAAS (Wide Area Augmentation System) is a satellite based differential GPS system (DGPS ). A set of satellites constantly transmit correction data for s et of known points. The simplicity of the system is the error correction data is transmitted in the sand frequency spectrum as the GPS data, so not extra radio gear is needed. http://www8.garmin.com/aboutGPS/waas.html gives a reasonable overview of how WAAS works
WAAS is a US based system first tested in 1999; Europe has an equivalent system called EGNOS (European Geostationary Navigation Overlay Service ) operational since July 2005
PS: the Kaiser's GPS receiver has no DGPS functions
Related
Is this function in our Kaiser? I've enable it from the Kaiser Tweak but today i tested it when i was in a tunnel....it did not work at all and the tunnel was 4 KM long....it should have had enough time to get a fix if it was working.
Is the Assisted GPS what i think it is?
How do you expect to get a GPS fix in a tunnel???
AGPS is basically what the QuickGPS app. does: it downloads sat. data (satellite locations) via a network connection from a server, so that TTF (time to fix) is reduced, since the device doesn´t have to download above data from the satellites themselves - which is slow....
Hope I was not too unclear, doing a search will give you much more and detailed info about how GPS works......and it doesn´t in tunnles....
As mentioned above, the AGPS uses server information (via cellular network) to locate the GPS satellite for a quicker fix and hash conditions. For a 4KM tunnel, I'm sure that your phone would have lost both GPS and network signal.
michi123 said:
How do you expect to get a GPS fix in a tunnel???
AGPS is basically what the QuickGPS app. does: it downloads sat. data (satellite locations) via a network connection from a server, so that TTF (time to fix) is reduced, since the device doesn´t have to download above data from the satellites themselves - which is slow....
Hope I was not too unclear, doing a search will give you much more and detailed info about how GPS works......and it doesn´t in tunnles....
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Click to collapse
Thats correct, there are som applications that tries to estimate where in the tunnel you are when the fix is gone. But I suppose this is a function of the application and not the GPS hardware
I stand partially corrected........ http://en.wikipedia.org/wiki/Assisted_GPS
michi123 said:
How do you expect to get a GPS fix in a tunnel???
AGPS is basically what the QuickGPS app. does: it downloads sat. data (satellite locations) via a network connection from a server, so that TTF (time to fix) is reduced, since the device doesn´t have to download above data from the satellites themselves - which is slow....
Hope I was not too unclear, doing a search will give you much more and detailed info about how GPS works......and it doesn´t in tunnles....
Click to expand...
Click to collapse
Which is why the title is "Assisted GPS".....I've done some search on AGPS and it's suppose to use the cellular to still get a fix when in the tunnel. Well....i read it sometime ago way before Kaiser was out and this was actually one of it's talked about feature in Kaiser. Using the Kaiser Tweak, one can enable this feature but i've tested it today in the tunnel with strong cellular signal, the GPS is dead until i came out of the tunnel.
I guess it also has to be supported by the particular program. Many TomTom PNAs have a dead reckoning mode which shows your position in a tunnel based on your "entry" speed for about 30 seconds, than the position freezes in the tunnel. Now that of course has nothing to do with AGPS, but it´s a way of overcoming temporary signal loss.
Best way would be to have an inertial sensor built into the phone like in fix-mounted car-navs......but then again, that would be overkill....
You have to remember that the Assisted GPS (Cellular network mode) relies on the fact the network itself supports the feature. I know most in the UK don't have it turned on in general use. They only allow it to be used by emergency services and the likes.
Perhaps that's the same in your country?
the_ape said:
You have to remember that the Assisted GPS (Cellular network mode) relies on the fact the network itself supports the feature. I know most in the UK don't have it turned on in general use. They only allow it to be used by emergency services and the likes.
Perhaps that's the same in your country?
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Click to collapse
Probably so.....oh well....it was worth a try
Thanks guys for the input.
Hi all,
I am using Navigon6 for navigation but while driving in a tunnel navigon says "you have reached the destination" after the tunnel it starts navigating as usual. I now activated "assisted GPS" with the Kaiser Tweak but now? How does it work now? What do I have to do?
Thanks
Michael
micha2802 said:
Hi all,
I am using Navigon6 for navigation but while driving in a tunnel navigon says "you have reached the destination" after the tunnel it starts navigating as usual. I now activated "assisted GPS" with the Kaiser Tweak but now? How does it work now? What do I have to do?
Thanks
Michael
Click to expand...
Click to collapse
You do nothing! Some people say the tweak works and some don't. It seems to have worked for me. I don't lose signal at this road will lots of trees now (I used to lose signal before I had this tweak applied).
Hi, so I tried the Kaiser with activated A-GPS and Navigon6. As I said I had the problem that Navigon gave the message "Destination reached" while driving through a tunnel. I expected that Navigon, because of a signal from A-GPS, won't bring these message. In the first moment I was happy because the Icon didn't turn to red in a tunnel but then there was the message again. But there is another problem, with activated A-GPS there seems to be some kind of signal (icon doesn't turn red) and because of this Navigon doesn't start routing after the tunnel. So it seems that A-GPS doesn't work together at least with Navigon6. Any ideas?
Cheers
Michael
Hi
I expected that Navigon, because of a signal from A-GPS, won't bring these message.
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Click to collapse
As far as I know A-GPS (QuickGPS on Kaiser) is just for getting initial fix for GPS applications. This helps avoid the initial delay in getting your location, after that it will perform exactly the same.
Regards
Phil
Hi Phil,
OK, I understood what A-GPS does but Navigon should proceed navigation after a tunnel (when GPS signal is back) again even A-GPS is turned on or not?
Cheers
Michael
PhilipL said:
Hi
As far as I know A-GPS (QuickGPS on Kaiser) is just for getting initial fix for GPS applications. This helps avoid the initial delay in getting your location, after that it will perform exactly the same.
Regards
Phil
Click to expand...
Click to collapse
PhilipL said:
Hi
As far as I know A-GPS (QuickGPS on Kaiser) is just for getting initial fix for GPS applications. This helps avoid the initial delay in getting your location, after that it will perform exactly the same.
Regards
Phil
Click to expand...
Click to collapse
QuickGPS is indeed a form of Assisted GPS used to quick the initial fix. However, he is talking about the Assisted GPS tweak for use _while_ navigating. It already requires a fix and lets your phone keep on tracking when going through tunnels or when satellite reception is too low. If it works by simple extrapolating direction and speed or uses some sort of GSM tower triangulation technique nobody seems to know. All we know is that the signal doesn't get lost so quickly with it As always with stuff like that, YMMV.
Are we all sure about the definition of "Assisted GPS" - 'cos QuickGPS is not my understanding of it and neither is extrapolating position using GSM tricks when the GPS signal fails.
As far as I am concerned, Assisted GPS is the term to cover a variety of techniques aimed at improving the accuracy of a fix over and above what is possible from just the received satellite signal. WAAS (EGNOS in Europe) is the most common way of doing this but on a device with a built in data connection there are other options. The basic idea is that a variety of factors including interference to the satellite signals as they come through the ionosphere and GPS satellites being out of adjustment can reduce the accuracy of the calculated location. With Assisted GPS, there are a number of base stations dotted around the world at locations which have been very accurately determined by traditional surveying techniques. GPS receivers at each of these locations are continuously calculating their GPS based locations, comparing them with the known, correct location and generating hints in a defined format which other GPS receivers can use to improve the accuracy of their calculations.
The issue then is how to get these hints out in near real-time to the remote GPS receivers. WAAS and EGNOS use dedicated satellites to transmit them back to earth, but these only cover the US and parts of Europe. With a GPS in a mobile phone, you obviously have the possibility of using the data channel to distribute the correction data - a lot cheaper than launching satellites. The EGNOS correction data is already published on their web site - not sure about WAAS - I tend to assume that enabling Assisted GPS on a Kaiser just sets the receiver to downloading the correction data stream off the internet...
Martin
No, that's not Assisted GPS. That's Differential GPS.
Assisted GPS is designed to allow GPS to perform in areas with poor satellite reception, augmenting the fix with information on nearby cell towers (which have known locations and ranges). Also, in most situations, A-GPS also means that the GPS pseudorange processing is offloaded from the phone to the tower (to allow for E911 on phones with insufficient CPU to calculate a GPS fix on their own), but I'm assuming this part of A-GPS is not coming into play here.
Some users from the pocketnavigation forum have the same Problem with the Kaiser/GPS-Chip. It seems to be a really big software/hardware bug.
By loosing the signal in the tunnel the gps chip stops to send any information to the Navigon-software. That's the problem: The required systemtime for further navigation is missing.
So Navigon tells you: You've reached your destination.
Any Firmwareupdates for this Problem?
Greetings
As far as I understood it, QuickGPS is downloading the satellite almanac from the internet, instead of getting it through the GPS. A GPS which has not been turned on for a while will get this almanac even without internet connection, but it takes about 15 minutes to download it (happens automatically in any GPS unit). Getting it from the internet saves you these 15 minutes, but if you have used your GPS recently for more than a 15 minutes period, QuickGPS should not make any difference.
The almananac for the GPS satellites is like a sun or moon almanac, just for satellites instead. This means that if you have a current almanac, and your GPS knows your rough position, then the almanac will tell the GPS where it should expect to see the satellites. This includes which of the satellites are visible on a given position on the earth (roughly around a third of them), and at what azimuth and elevation. GPS satellites are orbiting the Earth in intervals of just under 12 hours in certain orbits, intercepting the Equator at 55 degree angles (which means that they will cross 55 deg North/South when they are closest to either pole). Since they are more than 20000 km out, this is not a problem if you are actually on or close to either pole, but it means that you will not see satellites right above you at either pole. WAAS satellites are geostationary (which means they can only be somewhere over Equator at about 36000 km orbit), and these satellites do not transmit normal position and time information like the other satellites (SVs) in the GPS system, but precision and integrity information. Put in other words, they tell the GPS receiver 1) Is the signal in your area good or bad and 2) What vector to correct your measured position in whatever area your GPS says you are in. Similar for LAAS units, although they differ in being local area only but on the other hand, more precise. LAAS units are called pseudolites, because they act almost like satellites, though they are really not. For aviation, LAAS enables precision auto-landings in "zero weather" for the same reason, but since the LAAS station is on or close to the surface of the Earth, it only works when in line-of-sight of it.
The problem I am experiencing is if I turn my GPS off and move it a couple of hundred of miles and then turn it on again. This is usually when I am flying, and as we all know, the battery of the Kaiser is not really built for powering the unit for very long! When I turn the GPS on after for intance an hour or so, it still assumes the original position, and it will sometimes get a lock on on or two satellites only, trying desparately to maintain that position. Knowing how the GPS satellites interpolates via a time-shifting technique, I can see why this happens, as it gets a false fix. Aviation grade GPS systems will never lock on to anything less than 3 satellites for a 2D fix, and prefers 5 or 6 satellites minimum for integrity reasons (called RAIM).
What I think is the real problem is that these end user GPS systems for road use have to be more sensitive, so they can be used behind shielded windows and poor reception areas in buildings etc. Trees with many leaves can be an issue also, although clouds are no factor in this equation. Sunspots can blind the system completely if they are strong enough, and that is why eLORAN is an update to the LORAN-C system which is currently being considered for backup purposes mainly.
So, my Kaiser and other end user GPS units will be less restrictive for a good quality fix, and accept second guessing the position, where as aviation and other critical uses of GPS have to have a good position.
We need a GPS utility for the Kaiser GPS to carry out a position reset so it can do a new fix.
Hi guys,
OK I understood what A-GPS is but there is still the issue that Navigon really stops Navigation if the signal is lost when A-GPS is turned on.
If A-GPS is turned of there is also the message "destination reached" but after the tunnel it starts navigating again. Any idea on this?
Cheers
Michael
micha2802 said:
Hi guys,
OK I understood what A-GPS is but there is still the issue that Navigon really stops Navigation if the signal is lost when A-GPS is turned on.
If A-GPS is turned of there is also the message "destination reached" but after the tunnel it starts navigating again. Any idea on this?
Cheers
Michael
Click to expand...
Click to collapse
It sounds more like a bug in Navigon more than anything, check for updates on their site.
A-GPS for Mobile devices as said by some in this thread, extrapolates from the last vector information of the GPS using also information of cell location (in some countries this info is not available due to Gov restrictions) and inserts new data available for any app when signal loss is present from the GPS unit, thus reducing the 'Lost satellite reception' on your app. On WM devices, we are not looking directly at the GPS output but at a 'handler' at com4 able to supply GPS information to more than one app at a time. This is where A-GPS and QuickGPS insert their data when needed. A-GPS just directly inserts nomal NMEA data stream whereas QuickGPS sends the latest Ephemeris data it has downloaded for satellites saving the GPS unit wasting time downloading it from the sats themselves at turn on.
It does seem that Navigon can not resume from the handover back to normal data as other apps can. The fact that it even says 'Destination reached' in a tunnel without A-GPS shows an inherent problem!
when reading the forum i think people are confusing the two
our diamond has quick-gps standard. this means that it will download a list of sattelites from the internet and use this to get a faster lock.
a-gps is also available, but with adanced config only.
a-gps helps you inpositioning your device with the help of your phone network.
turning on a-gps has a negative impact on tom-tom. (reported on this forum) quick gps works very good with tomtom.
a-GPS is a logical extention to GPS if a wireless (not wifi) signal is present it allows the phone to maintain a GPS signal indoors, or areas of low gps signal.
It is NOT what some phones have reported as GPS by giving you the Cell area you are located in which may be accurate to > 100meters
It uses the cell phone to pin point the rough area it is in, then using incomplete GPS signal at the phone and / or the strong GPS signal at the A-GPS trasmitter to work out your location, it is possible for a trasmitter to be stationed indoors which will allow you to maintain a GPS lock indoors.
there is no reason it should have any effect on tomtom or anything else because its still getting accurate GPS signals all be it relayed from an earth based trasmitter.
quick GPS is a system that lets you lock on to sats quicker by giving the GPS reciever a list of information that "should" be in that area, by having this info it doesnt have to fart about to much getting GPS locks on sats that are not totally available.
I'm a bit confused about AGPS and data transfer. I was previously using TT6 and had AGPS disabled. However, it took about 5-7 minutes to get a position lock (if I was lucky). So I read that AGPS could improve that at the cost of a few KB. I enabled AGPS, updated with QuickGPS and also installed Franson GpsGate.
When I launch TT6, the position lock is indeed much faster. However, the data connection stays open. I was thinking that AGPS would download what it needed from the network and then close the data connection once it got a position lock. Like I said though, the data connection stays open.
The plan I have right now (I believe) allows no data whatsoever, every byte costs me extra. If the connection would be closed after position lock, that would be fine (like a $0.50 fee every time I use GPS) but I'm not willing to rack up a huge charge for a longer trip...
So....how to get the data connection to close after position lock?
AGPS uses constant data, that's how it works. Your phone is constantly leveraging off the towers, either sending them raw timing data to crunch (since the assistance servers are far more powerful and faster then your phone), or receiving timing data to fill in fragmented signals it got directly (since the towers have much better line-of-sight with the satellites and have precisely known and stable positions themselves).
Even if you were not moving, your phone is constantly getting fresh satellite data and handing it off to the tower servers for a crunch of the fix - happens numerous times per second and never stops, not as long as you are using a GPS application on your phone.
You will rack up data charges if using aGPS, no way around that. So without a data plan, best to leave it off.
Interesting...most sources say that AGPS primarily enhances the startup time of the GPS (Wikipedia: "...A-GPS, enhances the startup performance of a GPS satellite-based positioning..."). Also, most people say that it's "only a few KB" of data transfer though I have nothing to back this up.
What you say makes sense though, since it offloads a lot of processing to the tower computers, saves battery life, makes more money for the carriers...
However, what I want should still technically be possible, right? The AGPS would be used to speed up the initial positioning at which point it would be shut off and only the GPS data stream would be used. I've never had any problems with keeping a position lock (w/o AGPS), the only issue was that the startup time was too long.
Hi,
I know (for example) the HTC Diamond, the internal GPS does an GPS Assist (send data packet to network to help GPS do triangulation, speeding GPS location. The obvious problem, is that I have to paid to my service provider that (one) data packet (in my case, 0.33€).
What I really dont know, if this is a software or hardware specification. I want to sincronyze my Niki with an Holux 236 (I'm searching for one), and I dont know I will have to paid anything to navigate around my country.
Anyone can help me?
Hi, I think we all need some clarification on the GPS vs. aGPS.
Here is a good article to read:
http://wmexperts.com/articles/gps_vs_agps_a_quick_tutorial.html
In conclusion you need a receiver in order to have any type of GPS on your phone. In most cases aGPS doesn’t require the maps to be present on your phone as they are been downloaded in real time.
If you have a GPS receiver on your phone you can use other software (like Garmin or TomTom) with maps loaded on you card. In this case there is no need for data communication and you can use it without paying aGPS fees. I confirm that as I use it on my Neon400.
The location identification through tower triangulation cannot be done with good accuracy and not in “real time”. It is not reliable for car navigation but it is used for police, etc to find your approx. location.