Following Apple’s Google’s leap into 3D mapping technologies, Amazon has acquired a 3D mapping startup of its own. The online retail giant today sealed a deal to purchase UpNext in a move that could signal the company’s intentions to bring 3D maps to its Kindle Fire slate without any assistance from Google.

As things currently stand, for Kindle Fire users to access maps on their device, they must download third-party Android apps like Google Maps, or access similar services using a web browser. However, Amazon’s acquisition of UpNext suggests that the company is following in Apple’s footsteps and taking mapping matters into its own hands.

Of course, it’s unlikely the service will make its way onto the existing Kindle Fire anytime soon — especially given that the device doesn’t pack a GPS radio — but it could well be a selling point for its second-generation Kindle Fire. And with Google’s new Nexus 7 now shipping, the Kindle Fire 2 is going to need all the selling points it can get its hands on.

Like both Apple’s and Google’s new 3D maps services, UpNext, which was founded in 2007 by a group of high school friends, offers highly-detailed, interactive 3D maps of major cities and venues. Although the price of Amazon’s purchase has not been disclosed, GigaOM reports that each investor will see a 5x return on the investment they made just 16 months ago:

While the price of the acquisition is undisclosed, we’ve heard that investors are getting a 5x return on the investment from 16 months ago. As part of the deal, the four-person company will be shipping off to Seattle to lead the company’s core mapping effort, according to a source familiar with the matter.

Right now, UpNext can be found on both iOS and Android devices via the official UpNext apps, with support for 50 cities across the U.S. It has also partnered with the NFL to include Super Bowl guides with 3D stadium maps. It’s unclear, however, whether these apps will stick around now that UpNext is owned by Amazon.

• SourceGigaOM