Baidu has begun the rollout of indoor location services powered by indoor mapping provider IndoorAtlas to the 270 million monthly active users of its Baidu Maps service.

IndoorAtlas had been in beta testing, with the company saying it can pinpoint a location inside a building within 6.5 feet. IndoorAtlas-developed software lets the compass contained in smartphones pinpoint a person’s indoor location by analyzing the variations that buildings cause in the Earth’s magnetic fields.  Now in its early stages, the technology could eventually cover shopping malls, airports and other buildings.

Described as “indoor GPS,” the IndoorAtlas technology lets shoppers use their cellphones to navigate store aisles to the products that they want to buy. A dot moves across a map on the phone’s screen to indicate where a person is in relation to the desired items.  Once paired with another technology that delivers individually tailored deals, the IndoorAtlas system also can beam opt-in advertising, discounts and rewards to shoppers’ smartphones, based on their precise location inside the store.  Baidu made a $10 million investment in IndoorAtlas in September and obtained exclusive rights to use the company’s technology in China.

The IndoorAtlas software competes with, among others, Apple‘s iBeacon. That technology, which Apple rolled out in late 2013, uses Bluetooth to let electronic devices wirelessly exchange data over short distances using radio transmissions.