NextNav, a California-based location services provider, announced today that it has concluded a $70 million Series D round of financing.

The company specializes in location services indoors and in dense urban environments, where using GPS is not always possible. Anyone with a mobile device can use NextNav’s positioning technology to chart their location when a GPS signal isn’t available.

NextNav’s services are especially critical in medical emergencies. Safety-of-life applications like E911 can use the service to specify the location of an emergency. This may enable medical professionals to get to patients faster.

The company will use the new funding to improve its Metropolitan Beacon System (“MBS”) positioning network. The MBS network works similar to cellular phone networks, covering a wide area.

Venture capital firms New Enterprise Associates and Oak Investment Partners led the round. Existing investors Columbia Capital, Telcom Ventures, and Goldman Sachs Investment Partners also participated.

“We are delighted to have the support of top-tier venture partners and the deep domain and industry expertise of our new board members as we bring this powerful new technology to market,” NextNav CEO Gary Parsons said in a statement.

NextNav is currently working with Public Safety organizations and technology companies to equip more mobile devices with its product.