Later this month, an inconspicuous 150-kilogram satellite is set to launch into space aboard the SpaceX Transporter 14 mission. Once in orbit, it will test super-accurate next-generation satnav technology designed to make up for the shortcomings of the US Global Positioning System (GPS).  The satellite is the first of a planned constellation called Pulsar, which is being developed by California-based Xona Space Systems. The company ultimately plans to have a constellation of 258 satellites in l...