Comparison of MEO, LEO, and Terrestrial IoT Configurations in Terms of GDOP and Achievable Positioning Accuracies

Complementary solutions to the Medium Earth
Orbit (MEO) Global Navigation Satellite Systems (GNSS) are
more and more in demand to be able to achieve seamless positioning worldwide, in outdoor as well as in indoor scenarios,
and to cope with increased interference threats in GNSS bands.
Two of such complementary systems can rely on the emerging
Low Earth Orbit (LEO) constellations and on the terrestrial
long-range Internet of Things (IoT) systems, both under rapid
developments nowadays. Standalone positioning solutions based
on such systems complementary to GNSS can be beneficial in
situations where GNSS signal is highly affected by interferences,
such as jammers and spoofers, while hybrid GNSS and nonGNSS solutions making use of LEO and terrestrial IoT signals
as signals of opportunity can improve the achievable positioning
accuracy in a wide variety of scenarios. Comparative research
of performance bounds achievable through MEO, LEO, and terrestrial IoT signals are still hard to find in the current literature.
It is the goal of this paper to introduce a unified framework to
compare these three system types, based on geometry matrices
and error modeling, and to present a performance analysis in
terms of Geometric Dilution of Precision (GDOP) and positioning
accuracy bounds.