You can’t just download a GPS app from the App Store and hit the road. In order to take full advantage of using the iPhone as a navigational aid, you’ll need two key accessories.
Charging cable. Using the GPS sucks power like nobody’s business, draining a full battery in a couple of hours. You will want a car-power adapter, likely one that also provides audio output; or if your car stereo lacks iPod integration with USB charging, you may want to upgrade to a model that supports that. If you use an integrated iPod stereo, consider which apps talk over music and which pause playback.
Windshield mount. Oh, yes, you will want some kind of mount. It’s critical that the iPhone has a line of sight as good as possible to the sky, and resting your iPhone somewhere or hoping it works in the passenger seat isn’t a real option for regular navigation use. I recommend the Kensington windshield mount, which has a long positionable arm, making it possible to move the phone to a better viewing angle that was more reachable when stopped at traffic lights or pulled over. The arm can vibrate while driving. (Kensington Windshield Mount for iPod and iPhone, $30.)
GPS Car Kits. Both TomTom and Magellan sell combination charger and mounting kits with a difference—they also include GPS receivers that improve on the iPhone’s built-in GPS features and even enable second-generation iPod touch models to work as navigation devices.
In my testing of the $120 TomTom Car Kit ( ), I found that GPS reception definitely improved. The kit incorporates hands-free calling using the built-in microphone and either the integral speaker or audio output through the iPhone’s stereo jack. Hands-free calling uses Bluetooth, because Apple doesn’t allow audio support for calls via the dock. The TomTom dock also offers music output via an audio output jack, although that requires an auxiliary stereo input on your car stereo system. (If you have a USB-based car system with direct iPod control, you can’t use it with this dock.)
I didn’t have a chance to test Magellan’s $130 Premium Car Kit (magellangps.com), but it offers more or less the same features as the TomTom Car Kit, including speakerphone, Bluetooth hands-free calling, and its own GPS receiver with iPod touch support.
Neither car kit requires the use of the app made by the company who manufactures the kit, though of course the manufacturers encourage the use of those apps.
For me, the big stumbling block with these products is their cost. Add in the cost of an app, and you’ve spent more than a decent mid-range dedicated GPS device. If you really want to use your iPhone—or more notably, your iPod touch—with one of these devices, it’ll definitely improve performance. In the end, I didn’t feel the TomTom kit improved performance enough to justify its additional cost.
Mobile Navigation Devices vs. the iPhone
GPS navigation devices have dropped considerably in price in the last couple of years, and it’s possible to find hardware for $120 to $200 that has most or all the features present in iPhone GPS applications that cost from $30 to $100 or $3 to $10 per month.
This doesn't seem like much more than some of the apps or subscription prices, and you may be tempted to opt for a dedicated device. However, there are tradeoffs. First off, standalone devices include only the map they shipped with; some manufacturers offer a free update if new maps are released within 60 days of purchase. But if you want to keep the device up to date with the latest maps, you can spend $40 to $100 per year (more with factory-installed car GPS units) for map updates. iPhone GPS apps with a fixed price will likely also charge for updates, too, although it’s unclear just how and when that might happen.
Second, the user interface and interaction on the more affordable navigators is quite poor compared to the best of the iPhone GPS apps. Data entry is tedious, touchscreen behavior slow, and displays seem coarse and blocky. iPhone apps use Apple’s or a company’s rendering modules or libraries for typically smooth animation, along with quick and simple shifts among 2D and 3D views.
On the flip side, in testing with an inexpensive and recently released Garmin GPS, the rate of refresh—the frequency at which the map was updated to reflect the current position—was better than all the iPhone software tested. That’s a function of a device optimized for GPS antenna position and accuracy.
Most of the iPhone software we tested didn’t lag much, although at times could be several to a few dozen feet behind in the worse cases; the TomTom car kit with the TomTom app created a refresh rate seemingly as perfect as the Garmin device.
Standalone GPS units are also larger: the screen resolution may be poorer than an iPhone (the absolute number of pixels), but the larger size can make the display easier to read.
The competition: Google Navigation for Android
What if you could get a full package of GPS-based navigation at no cost: no upfront rate, no monthly cost, live over the network? Google wants to oblige with Google Navigation.
I tested this service, available initially on the Verizon Droid phone that uses the Google-backed Android 2.0 operating system. Google also released a version compatible with phones running or upgradable to Android 1.6.
In areas where most navigation systems—standalone and iPhone-based—shine, such as entering a destination address or changing settings, Google Navigation was horrible. You must enter a destination or select from contacts using the Maps directions feature, which works nearly the same as in iPhone Maps.
After plotting a direction, Navigate appears as an option at the top of a list of turn-by-turn directions. This launches what appears to be a separate application. Changing the destination requires tapping the back arrow button, which jumps you back into Maps.
Once you’re in the Navigation app, however, the display and operation is as good or better than all the iPhone apps I tested—possibly because Google has top-to-bottom access to all the functions of the phone and operating system. Animation is smoother than any iPhone app, and the view continuously changes as is needed for context. Sometimes, it’s presented as a flat 2D overview for a confusing set of turns; other times, it’s a receding 3D view that resizes based on speed and direction. The design and presentation is lovely.
When you near a destination, the program switches to Google Street View (if available) showing you what you’ll see from the same perspective.
Google could release Navigation for the iPhone, as there’s no particular aspect of the service that would appear to violate Apple’s terms. Like Google Voice, Navigation would compete with an AT&T subscription offering, but that seems even less likely to matter in this case.
Two iPhone GPS power tips
While all the software tested can work in portrait or landscape mode, I found myself continually reverted back to portrait mode. It’s the orientation I’m most used to reading in. Polarized sunglasses interfere with a rotated iPhone 3GS screen, rendering the display nearly invisible, too.
If you use the iPod function on your iPhone constantly while driving, pay close attention to our discussion of iPod integration within the GPS applications. While you can exit a GPS app, change iPod settings, and launch the app again without any of the applications we tested losing your destination, that’s a lot of fuss. Some apps also handle voice-over speaking poorly when the iPod is playing. Some applications don’t allow you to select podcasts, although they will continue to play and control them if selected in the iPod app.
[Updated 12/16 11:15 a.m. to correct statement that Sygic's app doesn't offer itinterary management. Updated 12/16 11:31 p.m. to correct statement that MotionX doesn't do traffic. Updated 2/2/2010 to add three new reviews.]