Acrossair produced a video (embedded below) showing a side-by-side comparison of the app running on an iPhone 4 and a previous model without the gyroscope. The gyro on the iPhone does a much better job of picking up subtle motion than the early model does. The difference is a small one, but the increased realism produced by the gyroscope is just another step toward making the overall AR experience more immersive.

The company also has swapped business models for its previously paid U.S. "Nearest" line of apps that help people find public transit stations. People in New York, Chicago, San Francisco and Washington D.C. can now make use of these apps for free as Acrossair has incorporated Apple's iAd platform into the apps - another first for a major augmented reality app maker.

Users can use the Layar AR viewfinder to find nearby Foursquare locations and by linking the app to their account can check in without leaving Layar. There is also a feature in each layer to view entries on a map, or in list view. The map is especially handy for Foursquare integration because Foursquare's own app disappointingly doesn't support a map view. An equally interesting layer to investigate is the Recovery.org layer which shows you which U.S. organizations in your area received funding (and the amount they received) from the Recovery Act.

"The new Layar Reality Browser has a re-engineered engine under the hood. This new engine makes the application light, stable and very quick," the company said on its blog. "It is ready to handle all the current layers and it is a good base to realize all of our exciting future plans."

Layar's return to the iPhone platform comes just in time for the company's new layer marketplace which will allow developers to charge users for their content; in other words, an App Store for mobile AR. If Subway wants to create a layer with all of their locations and charge $.99 for it's use, they or any other company will easily be able to do that. One could assume that Layar will make use of Apple's in-app purchase functionality on the iPhone, but it would be sad to see Layar lose a percentage of their cut on the purchases to Apple. If anything, that could raise prices on the layers themselves, but that's a whole other argument.

This could be a huge step forward for the mobile AR space. As these applications become more useful, more refined and more popular, companies will be excited to participate in providing branded content in an AR experience. Expect an announcement from Layar in the next few weeks about the launch of this exciting new platform, but in the meantime, iPhone users (3GS only) can go snag Layar's free app (iTunes link) in the App Store.

This new verison of Wikitude also marks the browser's first commercial entries as users can find the nearest Startbucks, Walmart, Harley Davidson or BestBuy locations using the various World filters found on the applications new "Overview" home screen. Some of the Worlds, such as Last.fm events, Meetup Events and Outside.in content, are unique to Wikitude and are innovative inclusions for AR browsing.

First released for Android phones in October of 2008, Wikitude was the very first mobile augmented reality browser to hit the market. Since then Layar, acrossair and hundreds of other mobile AR apps have upped the ante in the mobile AR space, and the latest iteration of Wikitude is in direct response to this competition.

Wikitude's updated features follow a continuing trend in mobile AR to consolidate a group of applications into a single AR browser-like experience. Mobilizy previously produced the AR application C2 YouTube for the iPhone, but has moved that functionality into Wikitude.

Additionally, acrossair's AR browser now includes features like Twitter and Wikipedia entries, which were previously features in their own independent applications. French iPhone app development house Presselite, which made waves with its Metro Paris Subway app, and other transit applications, has since rolled its applications together into the Bionic Eye application. It's only a matter of time before these companies begin rolling games and entertainment, a growing AR sector, into their browsers for one-stop augmented reality experiences.

Mobilizy, Layar, acrossair, and Presselite now have comparable AR browsing applications with Tonchidot not far behind with its more social app, Sekai Camera, the most popular AR app in Japan. Competition is certainly a good thing when it comes to mobile AR, and the deal-breaker in the coming months and years for most users will likely be the commercial content found on the applications.

Which mobile AR application do you like best? Let us know what you think in the comments.

Layar has quickly become of the most popular mobile AR browsing applications across the globe thanks to its impressive set of features, but the company's choice to provide an open API may have been the decision which fueled them to success. Companies that wish to jump on the augmented reality bandwagon have several choices for getting their content on Layar quickly and easily. Layar provides documentation on its website for how to use and interpret their API, but those looking for an easier method of geo-data input can use any of a number of third party tools. Thanks in no small part to tools like buildAR, Muzar and Winvolve, Layar's database of geo-data has rapidly expanded to include over 300 content layers including anything from restaurants to Twitter results, to even the locations of nearby heart defibrillators.

On the opposite end the spectrum, the accrossair browser, a similar mobile AR browser available on the iPhone, has decided to keep its API private and helps with the input of geo-data themselves for companies that wish to participate on their platform. Instead of allowing anyone to upload location data onto their platform, acrossair has reached out to corporations like McDonalds and FedEx to provide them with their own POIs in their browser. The one disadvantage this places on their product is a significantly lower number of POI sets that a user can access. With just over a dozen different options, acrossair has a fraction of the curated POI sets that Layar does. Founder Chetan Damani says that while their closed API certainly limits the amount of data on their browser, it enhances the overall stability of the browser - a factor which may play heavily for the company as they expand beyond the iPhone to Android and Symbian devices.

"We are keeping [the API] closed right now because we will be in a period of evolution and multiple iteration," Damani told ReadWriteWeb. "We want to move to Android, and we want to make sure that the APIs are the right APIs and that they won't limit our development. We only get one opportunity to get this right."

Damani and acrossair are playing it safe until they are able to expand their presence to more platforms before opening their API - a step Damani says they do plan on taking. When acrossair moves their browser to Android, Symbian and possibly even Windows Mobile devices, having a closed API will make the transition much smoother. Opening the API after they set up shop on each mobile OS will be a lot easier without loads of independently developed geo-data on their system.

So is it better to limit one's API early on for the sake of stability while simultaneously hampering the possible reach of one's product? The acrossair browser seems to be taking that chance, while Layar, on the other hand, is welcoming third party developers with open arms. However, acrossair has one thing going for them that Layar currently doesn't - a working iPhone application.

How much of a role Layar's open API played in the demise of their iPhone application is unknown, but all that could be moot when Layar relaunches on the iPhone "by the end of February". However, if augmented reality is the supposed "future of web browsing" as some believe it to be, having closed browsing platforms is not a viable long-term solution.

The company says its API "represents the emergence of an open AR development platform which could further drive the adoption of Wikitude as a potential standard for developers who want to create their own mobile AR experience." Get ready to see Augmented Reality come to far more mobile applications and for Wikitude's competitors to respond.

Wikitude says it worked with more than 100 developers from 25 countries in building its API. Both commercial and non-commercial API keys are available to remove the watermark placed over non-keyed implementations. The API allows developers to customize the actions that occur when info-balloon overlays are clicked on and change the menu options for the AR browser.

Will competitors like Layar, AcrossAir, Tochnidot, RobotVision and others release APIs soon as well? They have to be working on it, but Wikitude appears to have the most open disposition, one of the broadest developer communities and thus may be the best suited to become the AR platform of choice.

There are enough players in the AR field already that the competition will likely come down to two things: usability of interfaces and developer-friendliness. May the games begin!

RobotVision is a new Augmented Reality (AR) app for the iPhone 3Gs. It's not available yet, but it will be as soon as AR apps are formally welcomed into the App Store by Apple, probably sometime next month. AR browsers "turn the world inside out" by exposing latent online information about your surroundings; there will soon be enough of them that they will compete based on user experience. RobotVision looks like it could be a good one.

Does that mean that AR browsers will be commodities? "I hope not, for my sake!" Sears says, "But I do think there's going to be a lot of them. I look at it just like building a website. You have your data source and you're just trying to parse and present your data in a meaningful way, just like you would on the web."

Layar, Wikitude, Yelp, PresseLite, AcrossAir - the Augmented Reality market is heating up fast and there's not even official support for AR on the iPhone yet. (Android welcomes AR apps already.) Sears guesses that once that support comes, as many as half a dozen other competitors may pop up. It may be far more than that. Sears says he plans on building one-off white label implementations of RobotVision as his business model; Universities might want a version for campus locations, for example.

What is Sears bringing to market product-wise to try to differentiate? User experience development is what he's spending the majority of his time on right now.

By using Bing Local search to glean location and business review data, RobotVision gets access to some key Bing features like aggregated reviews from CitySearch, Judy's Book and Yelp. Bing looks at the reviews of restaurants and tells you how they stack up in aggregate for a business' food, ambience, service and more. (That's a feature we've seen at BooRah, though that service doesn't have access to Yelp reviews.)

If you've seen the new Yelp iPhone AR (it just launched yesterday), you probably noticed that all the pushpin markers for sites in the direction you're facing are lined up top to bottom. RobotVision layers its presentation based on proximity and then paginates the windows that appear when you click on a marker, so it's easy to browse nearby spots.

RobotVision's options to view local Tweets and Flickr photos bring more richness to the places you're looking at.

When you point your phone at the ground with RobotVision running, it switches to map mode and displays pushpin markers for all the nearby spots in that format.

UX and AR

There are a lot of possible ways RobotVision could integrate the map and the AR camera view in this app. AR is hot, but a good AR app in the future will probably defer to other ways of displaying data when appropriate. AR should complement other ways of seeing the world around us, not be expected to replace maps, lists or the naked eye.

These are the very early days of Augmented Reality apps, and current implementations are very simple. Even in their simplicity, though, there will be a lot of variance in the ways that different parts of a UI work together on each respective AR app.

Putting geo-tagged data on top of a mobile phone's camera viewer is not difficult. How an AR platform goes about collecting, displaying and interacting with those layers of data will probably make the difference in a crowded market. (For more on the UX of AR, see this long post by Joe Lamantia.)

Problems With RobotVision and AR Apps in General

AR apps are at the mercy of the publishers of the data they display. RobotVision's comprehension of its surroundings was pretty good in our tests, but not perfect. One restaurant we walked past didn't show up when we pointed a phone at it - but its information did appear when we pointed away from the building and down the street.

Sears says that GPS on mobiles still takes some time to calibrate each time you turn it on. It's often not that accurate anyway, and many places are mapped to their nearest street intersection instead of their exact location. Likewise, if a phone doesn't have a clear line of sight to a GPS satellite, then further inaccuracies can occur. Inaccuracies in location-based Augmented Reality mean that you could be shown things that aren't really there and miss things that you ought to see.

We suspect that just as GPS data providers historically didn't want to make GPS data available in real-time until the killer turn-by-turn driving apps that required it arrived, so too could a new economy of GPS users seeking greater location accuracy for Augmented Reality help usher in a more accurate level of service.

These are very early days for the world of commercially available Augmented Reality, but its utility and value are clear to many people. Bring on the competition and best software to win the hearts and handsets of users!

Tim Sears expects to launch RobotVision next month. He'll launch his AR browser at the same time that many other people launch theirs.

Wikitude is one of the most high-profile augmented reality services on the market. It's a market that's getting crowded fast, and everyone wants to know if interoperability will be a priority or if we're looking at the next browser war.

Last week, what looks like the first AR app to do so snuck into the iPhone app store. Yesterday a red hot app for road conditions in major US cities made an appearance. And now Wikitude quietly let AR bloggers know today about its new release.

Wikitude's application appears to be more user-centric than its competitors. By enabling content creators to add points of interest by simply logging in with their Google, Twitter, Yahoo or OpenID accounts, there will be a lower barrier to entry than there is for creating a Wikipedia entry for a location with proper location markup that can be viewed through other AR browsers.

Hopefully, just like with desktop and other mobile browsers, we'll be able to see all the AR content someday through any AR browser. Probably the market leader right now, Layar told us this week that interoperability is something they are big proponents of, though they haven't done any legal work in that direction yet and seemed to us most interested in their own technology becoming the agreed-upon standard.

Interoperability is a technical, business and legal challenge that's much easier said than done. That work is being done by data portability, identity and open-web advocates on the web at large, but augmented reality appears set to be the new way in which people around the world will view the web of data. We'll be watching eagerly for movement towards a single AR web that browser providers compete on by trying to offer the best user experience.