Xona, which plans to deploy a 258-satellite low-Earth orbit constellation as a commercial alternative to GPS, raised a $250M Series D at a $2.45B valuation (Monica Hunter-Hart/Forbes)

Monica Hunter-Hart / Forbes : Xona, which plans to deploy a 258-satellite low-Earth orbit constellation as a commercial alternative to GPS, raised a $250M Series D at a $2.45B valuation, The U.S. government built GPS. Now Silicon Valley is funding a rival developed by the startup Xona, which just raised $250 million in venture funding.