Updating your location in the background on mobile apps is gaining momentum as a use-case, most recently with an app allowing you to Check-In On Foursquare Without Taking Your Phone Out Of Your Pocket.
Problem is—though this sounds really amazing—such uses of background location services are bound by hardware / software limitations and aren’t quite ready for primetime. The Future Checkin app (which is obviously an innovative example of using Foursquare’s API) reveals why: this app specifies a 300 meter check-in radius, which is equivalent to about four city blocks.
Imagine being in Union Square in New York and the app deciding to “check in”—to where exactly? You could be close to 10-20 places you’ve already checked into in the past. Not only could you have tons of previous check-ins within a small radius, but you may just be walking (or in a taxi) with no plans to stop anywhere. The Future Checkin app intelligently uses “favorites” to mitigate this, which are locations that you or it tags automatically when you frequent them enough, as well as recent-check-ins.
For me, this reduced “nearby” locations to around eight when I opened the app in Union Square. In less-populated areas which people frequent occasionally, this could help, but in cites like New York the technology feels like it’s not yet ready for primetime.
The main issue preventing these types of great ideas (granular geofencing, passive check-ins, pushed coupons) from becoming reality is the fact that GPS radios consume incredible amounts of power. For this reason Apple precluded use of GPS on iOS 4 location backgrounding. Instead, cell towers are used to approximate a subscriber’s location.
Cell tower triangulation has long been considered a joke. Though it’s been really useful for safety features such as 911 call-locating and for applications like geo-tagging photos within a city radius, the inaccuracy and infrequency of updates really mitigate the promise of broader applicability.
Also, 300 meters is overly-optimistic. Accuracy of background location on iOS 4 depends on how quickly you’re moving, the relative frequency of cell tower updates, and hardware (iPhone 4 makes better use of triangulation than iPhone 3GS). In non-optimal conditions, one kilometer accuracy is about all a person could expect (a 12 city block radius!).
The truth is that as much as Apple wanted to provide granular LBS with iOS 4, there’s a disconnect between the maturity of the technology and the goals of the people who dream up product ideas. This passage from Apple’s iOS reference library shows where Apple hopes developers will go:
“You might use region monitoring to alert the user to approaching landmarks or to provide other relevant information. For example, upon approaching a dry cleaners, an application could notify the user to pick up any clothes that had been dropped off and are now ready”
But it’s kind of comical when you see Apple product people pushing ideas that almost certainly won’t produce an “Apple experience”. Unless they think that you’ll want to be alerted to pick up your dry cleaning when you are 12 blocks away, this isn’t going to fly.
This problem isn’t limited to Apple however. Android has issues as well because successful background location depends on GPS. And today it’s simply not feasible to leave the radio connected or your phone will die within several hours. Issues such as poor indoor reception and time to first fix (TTFF) complicate this further.
So what’s the solution? Eventually the GPS radios inside phones will become more sensitive to location and will consume less power. Broadcom recently won the iPhone 4 GPS design (from Infineon), and it is producing highly integrated chips and multi-function radios that will do wonders to enable low power background updates.
Modes like assisted GPS will allow the GPS chip to turn on and get a fix within seconds (instead of the standard 40 seconds for a cold start) even without any satellite information. They do this with aid from the cellular network (time and frequency data). In between updates, the chips will go into a “sleep” state, consuming up to 1000 times less power, but can still wake within seconds, since after the initial fix the receiver can predict where the satellites will be a certain time later.
But these advancements are still a minimum of one year out, so don’t get excited too soon—it’s unlikely that even next year’s iPhone will solve all of the hardware and software issues around checking-in with your phone in your pocket.
Photo credit: Flickr/ Roanish.
Contributor Steve Cheney is an entrepreneur and formerly an engineer & programmer specializing in web and mobile technologies.