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There are at least a dozen "Faster GPS Fix" apps in the Play Store -- one is even a $5 paid app -- and they remind me of those RAM Booster/Optimizer utilities of the 1990s.

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What do they do -- and the better question is: why doesn't Android do this by itself?

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2 Answers 2

up vote 10 down vote accepted

One of the apps you have a picture of, the venerable GPS Status & Toolbox, describes this claim in the app description:

Keep your GPS fast: reset it or download A-GPS data regularly for faster fixes

Wikipedia does a great job defining the basic concepts behind Assisted-GPS:

Standalone GPS provides first position in approximately 30–40 seconds. A Standalone GPS system needs orbital information of the satellites to calculate the current position. The data rate of the satellite signal is only 50 bit/s, so downloading orbital information like ephemeris and almanac directly from satellites typically takes a long time, and if the satellite signals are lost during the acquisition of this information, it is discarded and the standalone system has to start from scratch. In AGPS, the Network Operator deploys an AGPS server. These AGPS servers download the orbital information from the satellite and store it in the database. An AGPS capable device can connect to these servers and download this information using Mobile Network radio bearers such as GSM, CDMA, WCDMA, LTE or even using other wireless radio bearers such as Wi-Fi. Usually the data rate of these bearers is high, hence downloading orbital information takes less time.

If your phone's A-GPS cache is corrupt or stale, forcing a refresh can be beneficial. Normally, Android does in fact take care of maintaining this cache automatically. I've personally only used this app to help diagnose and solve GPS problems, something it does very well. In normal usage I wouldn't bother with the A-GPS cache until you find it needs intervention.

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One of the advantages of the A-GPS download feature in these apps is that you can download the A-GPS data when you want to, whereas Android only (attempts to) download it when it needs it. I've used this a few times to pre-download the A-GPS data to ensure I've got a recent copy of it, when I know I'm going to be using the GPS later in the day/week in an area with poor/no data signal. –  GAThrawn Aug 31 '12 at 9:41

There is another style of app that simply keeps the gps working non-stop or more regularly.

The android system, unlike CE and systems used in various GPS only units, has a feature of letting the GPS go back to sleep until needed. Or we could reverse that and say that it only wakes it up as needed. This can save a lot of power (a lot more in the early years of these devices).

If you can keep the GPS reciever awake and continually polling the sattalites, any time you actually need this data , it will be working, it will be gathering data from many sattalites and the accuracy of a single quick poll of the location will be much better.
Again only because the GPS receiver is running non-stop. (not too special, but it is a method)

One app of this style is "tracker booster" , also "gps status" (a real status program) has both methods possible (AGPS and Keep alive). Many Car Dock and Car Home type apps, will apply the "keep polling" the gps method. Plus any app that simply needs to use the GPS data, speed widgets, speedometers, location tools.
Anything that keeps the gps awake and going.

When is a Location not a good location :-)
Quick polls of the sat data from the gps only expect there to be a "lock" which only requires 2 sats for 2D and 3 sats for 3D positioning. But this position is not hugely accurate. Given enough time running, the GPS can lock onto more like 8-20 sats (in the US) and aquire a positioning that is within 9 Meters (thats about max from what I have seen). Add in some averaging (multiple polls same location) a full fix, clear view of the sky I can confirm my location within about a 10 feet area.

The claims of this style of apps to be more accurate, and faster fixes, is achieved by keeping the gps awake, that is all.
When Hiking, GPS tracking, GPS cache hunting, or car navigating, most applications already Keep the GPS running non-stop, but not all of them, and not for all situations.
If an app is pushed to the background and has no settings for keeping the GPS alive, when it comes back on the accuracy will suffer some for a while.
Serious GPSers will employ such a method to . . . Keep the gps alive, which does help.

In this different method, AGPS assistance can still be employed to gain a faster first fix. If your device has no data connection of any sort, And the GPS software does not fail when AGPS is not loaded, Keeping the GPS going will keep a good fix on the sats going, AGPS at that point is unnessisary.

Both types of programs show up in the store , often with very poor explaination of the functions, so it helps to know what method(s) is employed.

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