The second function is extending the battery life of the iPod Touch. The XGPS300's shell also holds a 1,100mAh rechargeable battery that can extend and charge the iPod's battery.
However, the XGPS300 cannot perform both of these functions at the same time. A switch on the backside of the shell allows users to choose between the battery or GPS functions, or disable both. This isn't too much of a hassle until you place the shelled iPod into the cradle, settle in for a drive, and fire up your navigation app only to realize that you've forgotten to flip the mode select switch to GPS. This sort of thing happened to us a lot during testing. It's a minor inconvenience, but we don't think it's too much to ask for automatic mode switching.
Performance and the NavAtlas app
The XGPS300 adds universal location awareness to the iPod Touch, so it should work with any app that requires GPS. However, because the iPod lacks the "always on" data connection of the iPhone, said app will need to store its maps locally to be of much use with this setup. Because the XGPS300 is designed to work with the NavAtlas app, this is what we used for the duration of our testing.
NavAtlas is a free download that only works when the Dual XGPS300 is connected and in GPS mode. It includes North American maps and points of interest, all of which is stored locally on the iPod and can take about 4GB of the device's storage space. The app is a very rudimentary navigation app that features text-to-speech turn-by-turn directions, but no pedestrian mode and no advanced features. It does have a route editor that allows users to create and manage multidestination trips. Although the XGPS300 can be used outside of the car, the NavAtlas app does not include a pedestrian mode for navigating on foot.
Satellite lock was almost instantaneous, possibly because of the receiver beginning its search before the app booted. Testing turn-by-turn directions in downtown San Francisco, the XGPS300 did merely an OK job of tracking our movements. Occasionally, as we passed between tall buildings, the receiver would lose track of our position or think that we'd taken a turn that we hadn't and began rerouting. Fortunately, once we'd cleared the obstruction, satellite lock was quickly re-established and we were back on our way. In less densely packed skies, such as on the open highway or in the suburbs, we experience fewer tracking issues. To be fair, this is mostly a limitation of the GPS technology, but it is one that other manufacturers have worked around using improved tracking algorithms or gyroscopic/accelerometer techs.
For users who want to add turn-by-turn directions to their iPod Touch without making the jump to a full-blown iPhone and the wireless contract it requires, the XGPS300 is a possible solution. That it comes with an integrated battery extender and access to a free navigation app and map data are icing on the cake. It's not the best GPS receiver that we've tested, but with a bit of patience within city limits it will get you were you need to go. And though there are a few issues we'd like to see worked out if there ever is a second revision, such as automatic mode switching, the XGPS300 performed exactly as advertised.
The biggest objection that we have to the XGPS300 is the MSRP. With a $200 sticker on this kit, adding GPS location to your iPod Touch is as expensive as buying your iPod Touch. The XGPS300 shares a market with devices such as the TomTom Car Kit for iPod Touch or the Magellan Premium Car Kit for iPhone or iPod Touch, both of which live in the $120 to $130 range. Comparatively, the Dual kit is almost prohibitively expensive, particularly for users who don't intend to do much navigating outside of their cars. However, neither of these devices can be used outside of a car and neither includes any turn-by-turn application, so take about $50 to $60 out of their price advantages. If you're still interested at this point and you like the idea of also having an iPod battery backup, then perhaps the XGPS300 is the device for you. However, we're willing to bet that's a pretty small niche that this kit is filling.