Navigation With Differential Carrier Phase Measurements From Megaconstellation LEO Satellites

An opportunistic framework to navigate with differential carrier phase measurements from megaconstellation low Earth orbit (LEO) satellite signals is proposed. A computationally efficient integer ambiguity resolution algorithm is proposed to reduce the size of the integer least-squares (ILS) problem, whose complexity grows exponentially with the number of satellites. The Starlink constellation is used as a specific megaconstellation example to demonstrate the efficacity of the proposed algorithm, showing a 60% reduction in the size of the ILS problem. The joint probability density function of the megaconstellation LEO satellites' azimuth and elevation angles is derived for efficient and accurate performance characterization of navigation frameworks with LEO satellites, and to facilitate system parameter design to meet desired performance requirements. Experimental results are presented showing an unmanned aerial vehicle (UAV) navigating for 2.28 km exclusively using signals from only two Orbcomm LEO satellites via the proposed framework, achieving an unprecedented position root mean squared error of 14.8 m over a period of 2 minutes.