OpenSignal, which allows mobile phone users to find the best signal providers in their area, has raised $4m in a Qualcomm and O'Reilly Media-backed series A round.

UK-based mobile signal mapper OpenSignal has raised $4m in series A funding from investors including the corporate venturing arms of chipmaker Qualcomm and publisher O’Reilly Media. 

Venture capital firm Passion Capital also participated in the round, investing alongside Qualcomm Ventures and O’Reilly AlphaTech Ventures.

OpenSignal offers mobile signal maps it claims are independent, unbiased and accurate, and  will use the capital to hire new staff.  Founded in 2010, the company raised $1.3m in a seed round led by O’Reilly AlphaTech Ventures in 2012.