I recently got my hands on a copy of Maps Booster from Skyhook Wireless and I must say that I ws impressed. Instead of using satellite signals like GPS, Maps Booster uses local Wi-Fi signals to determine your location. Maps Booster searches for Wi-Fi hotspots and compares signals to the Skyhook Wireless Wi-Fi database to triangulate your position.

Once installed you will see a new application icon for Maps Booster and if you go to "Location" / "Positioning" / "Positioning Methods" you will find a new item at the top of the list of Assisted GPS, Integrated GPS, Bluetooth GPS and Network Based positioning, namely Maps Booster providing Wi-Fi based positioning. The location manager/server then picks the best available positioning method based on some criteria defined by Nokia and switches between the positioning methods as conditions change. Worldwide there are about 150 million Wi-Fi access points mapped in the Skyhook Wireless positioning system and is receiving about 250 million new location requests per day.

The Maps Booster "application" enables the user to choose the network connection and verify that Wi-Fi positioning works. The app does not need to run for Maps Booster to be active, and you can go to "Location," "Positioning," "Positioning Methods" to enable/disable Maps Booster or GPS. Wi-Fi positioning is available in most built-up areas where GPS struggles, and in general, you get the best location available. If no app is requesting location then no power is consumed by the Wi-Fi positioning service.

Maps Booster does require a data connection, either via 3G/GPRS or a Wi-Fi access point. The reason is that the application scans Wi-Fi access points and their signal strengths, and then downloads a subset of the Skyhook Wireless' Wi-Fi access point location database to the device, so that no data has to be transmitted for subsequent location requests in the same general area. If you choose your carrier's data connection, then you do not have to be connected (or attached) to a local Wi-Fi network. As an aside, the time it takes to establish a data connection can be improved if you go to "packed data" in the Symbian settings and change the connection from "when requested" to "when available," and key in your access point.

The main thing I need location based information on my phone is Navigation, but you shouldn't forget geo-blogging, geo-tagging and other location-aware applications, like Gravity, OVI Lifecasting, Location Tagger, many of which you may want to use indoors.

Reading the initial blogs around the ether many have warned of possible battery issues based on the power drain you see from a constant WiFi connection or leaving WiFi searching on. The truth is that the power you use is related to the positioning method and the time it takes to acquire a fix. Wi-Fi positioning provides a very quick fix indoors, whereas, GPS keeps searching for GPS. GPS is relatively energy efficient when in "tracking mode", after aquiring a stable satellite fix, quite power intensive whilts trying to acquire a new fix.

If you are in an area that has poor GPS reception, the phone will keep trying to acquire a fix and consume power. In comparison, if you have an application that is looking for "a fix" indoors, or in "urban canyons," then Wi-Fi positioning is fantastic. If, in comparison, you have more sky visibility in more suburban areas with lower level buildings or in country side, then GPS is the best positioning method and it may be best to disable Wi-Fi positioning, as it isn't as useful in that scenario.

An interesting aside is that you can add Wi-Fi positioning to phones that don't have intgrated GPS, but do have built-in Wi-Fi built (e.g. the E51). This greatly improves the experience when compared to pure cell tower based positioning.

My conclusion on this app is that it is worth the small pricetag over at the OVI Store for indoor usage and positioning where GPS fix is not attainable.