Apple has bought the indoor GPS mapping firm wifiSLAM for 20 million dollars, The Wall Street Journal reported on Monday, in a move seen as a challenge to Google’s dominance of mobile mapping software.

WifSLAM’s technology could allow Apple to pinpoint the location of users inside buildings to within 2.5 metres — an asset that could be valuable to advertisers wishing to target mall shoppers.

Google already has an extensive catalogue of public floor plans which it used to map the interior of public buildings for users of its Google Maps service.

Apple tried to challenge the dominance of Google Maps when it released its own mapping software with the launch of the iPhone 5 and iOS 6 last year. However the software was widely criticized for being inaccurate and confusing and Apple was forced to issue an apology to users and recommend using third-party products.