Suspicious GPS behaviour Sometimes, when I wake my Acer Iconia Tab A500 up, I see blinking searching for GPS icon near the clock, which disappears quickly. I already noticed something like this on other devices. The questions is: what is it?
It's impossible to pin-point such app without closer information. But there are several helpers available to narrow down the list of candidates. Easiest way is if
Your device is rooted
and running Android &lt; 4.1 (i.e. up to 4.0.x). In this case take a look at LBE Privacy Guard: Set GPS to &quot;always ask&quot; for all apps and see which one is touching it. LBE would then pop-up a dialog box and ask you to confirm/deny, optionally also to remember this decision. For all legitimate candidates, simply confirm and let it remember; for unwanted candidates reject and remember. If unsure, just don't let it remember. Along these lines, your candidate should reveal its presence.

With Android 4.1+, don't even try to install that app (your device would be locked into a boot-loop). Instead, head to XDA, where they have localized versions of its companion (e.g in this thread). It's quite bloated, but might help in your case.
Your device is not rooted
This makes it a little more tricky. No fancy popups helping you out here (to my knowledge). But you could use a permission scanner to narrow down the list of candidates. One possible candidate would be AppBrain Ad Detector – with the side-effect to also detect apps with dangerous ad modules in installed apps (SpyWare and the like):
 
In the first example screenshot (just click the image for a larger variant) you can see &quot;May share your location&quot; listed in &quot;concerns&quot;. Which means the app displayed uses location and network. To not have to open each app separately: the second screenshot shows you can list apps by permission.
Alternative helpful candidates include Guardian Droid and Permission Explorer:
 
With some luck, your investigation leaves you with only a few candiates (with great luck it's just one, and you've found the culprit). Now you can see if you can (temporarily) disable those, and whether the problem is gone this way. If so, enable them one-by-one until the problem re-appears – which is after you've re-enabled the app you're looking for.
PostScriptum
Above described steps can similarly be applied to other permissions as well :)