Broadband LEO Constellations for Navigation

There has been resurgent interest in building low Earth orbiting (LEO) constellations of satellites on a new scale. Their aim is Internet for the world with plans for potentially thousands of satellites. Here, we explore how these LEO constellations can be utilized for navigation. Closer to Earth, LEO offers stronger signals, strengthening us against jamming and aiding in indoor and urban environments. Proximity is also its weakness, where satellites have a small Earth footprint requiring many to provide global coverage. We show that the strength of the Broadband LEO constellations is their numbers, where they offer threefold improvement in satellite geometry compared to navigation core-constellations today. This allows for relaxation of the signal-in-space user range error, while still matching the position accuracy of GPS. Coupled with the more benign radiation environment in LEO compared to GPS in medium Earth orbit, this enables a navigation payload designed using commercial-off-the-shelf components.

[1]  Peter Cash,et al.  Space CSAC: Chip- Scale Atomic Clock for Low Earth Orbit Applications , 2013 .

[2]  Per Enge,et al.  GNSS Integrity in The Arctic: GNSS Integrity in The Arctic , 2016 .

[3]  Robert Lutwak.  The SA.45s Chip-Scale Atomic Clock – Early Production Statistics , 2011 .

[4]  J. Allen,et al.  Radiation Around the Earth to a Radial Distance of 107,400 km. , 1959, Nature.

[5]  E. J. Marian.  Standard for Environmental Specifications for Spaceborne Computer Modules , 1995 .

[6]  Jan Stupl,et al.  A Compact Optical Time Transfer Instrument for Ground-to-Space Synchronization of Clocks , 2017 .

[7]  Daniel Heynderickx,et al.  ESA's Space Environment Information System (SPENVIS) - A WWW interface to models of the space environment and its effects , 2000 .

[8]  A HansonWard,et al.  In Their Own Words: OneWeb's Internet Constellation as Described in Their FCC Form 312 Application , 2016 .

[9]  J. Walker.  Some circular orbit patterns providing continuous whole earth coverage. , 1970 .

[10]  A.H. Ballard,et al.  Rosette Constellations of Earth Satellites , 1980, IEEE Transactions on Aerospace and Electronic Systems.

[11]  K. Senior,et al.  Characterization of periodic variations in the GPS satellite clocks , 2008 .

[12]  John C. Ries,et al.  Precise orbit determination for GRACE using accelerometer data , 2006 .

[13]  Zhigang Hu,et al.  Study on Signal-In-Space Errors Calculation Method and Statistical Characterization of BeiDou Navigation Satellite System , 2013 .

[14]  P. Touboul,et al.  Accelerometers for CHAMP, GRACE and GOCE space missions: synergy and evolution , 1999 .

[15]  Naofal Al-Dhahir,et al.  Doppler characterization for LEO satellites , 1998, IEEE Trans. Commun..

[16]  Steven P. Hughes,et al.  Verification and Validation of the General Mission Analysis Tool (GMAT) , 2014 .

[17]  F. J. Dietrich,et al.  The Globalstar cellular satellite system , 1998 .

[18]  E. Groten,et al.  Relativistic effects in GPS , 1988 .

[19]  M. Watkins,et al.  The gravity recovery and climate experiment: Mission overview and early results , 2004 .

[20]  Per Enge,et al.  Orbital representations for the next generation of satellite-based augmentation systems , 2015, GPS Solutions.

[21]  M. Birnbaum,et al.  The GPS Navigation Message , 1978 .

[22]  N. W. Rhodus,et al.  The GPS 21 primary satellite constellation , 1988 .

[23]  Stephen Horan,et al.  Commercially hosted government payloads: Lessons from recent programs , 2011, 2011 Aerospace Conference.

[24]  Miguel M. Romay-Merino,et al.  Galileo Constellation Design , 2001, GPS Solutions.

[25]  Per Enge,et al.  Orbital Diversity for Satellite Navigation , 2012 .

[26]  C. Reigber,et al.  CHAMP mission status , 2002 .

[27]  David G. Lawrence,et al.  Test Results from a LEO-Satellite-Based Assured Time and Location Solution , 2016 .

[28]  Peter Steigenberger,et al.  Broadcast versus precise ephemerides: a multi-GNSS perspective , 2015, GPS Solutions.

[29]  R. J. Danchik,et al.  An Overview of Transit Development , 1998 .