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GNSS components

Low Earth Orbit (LEO)

Holds substantial potential for enhancing PNT


Low Earth Orbit (LEO) presents a significant opportunity for Positioning, Navigation and Timing (PNT)

LEO’s proximity to Earth, in contrast to satellites in Medium Earth Orbit (MEO) or Geostationary Orbit (GEO), offers several distinct advantages. It enables LEO satellites to receive stronger signals with higher power levels, facilitating more robust communication and data transmission. Additionally, the shorter distance means lower signal propagation delays, resulting in faster data transfer rates—essential for real-time applications. LEO’s proximity further translates into cost savings, as launching payloads into this orbit is generally more economical than reaching higher orbits like MEO or GEO. This affordability can make LEO-based Positioning, Navigation, and Timing (PNT) solutions a financially viable choice. Furthermore, LEO’s proximity to Earth makes it ideal for Earth imaging missions, as satellites can capture detailed and high-resolution imagery for various Earth-monitoring and observation purposes.

The PNT challenges in LEO

Challenges and complexity of PNT in Low Earth Orbit

PNT in LEO present a unique set of challenges. The proximity of LEO satellites to Earth offers advantages like reduced signal propagation delay, but it also introduces complications. Ionospheric delay, resulting from the charged particles in the upper atmosphere, affects signal accuracy. Scintillation phenomena, causing rapid signal fluctuations, can disrupt precise PNT measurements. Keplerian modeling, which relies on simplified orbits, may not fully capture the complex dynamics of LEO satellites subject to atmospheric drag and perturbations from Earth’s gravitational field. Moreover, the high dynamics of LEO satellites, characterised by fast orbital changes and frequent passes, demand sophisticated algorithms and corrections to ensure accurate and reliable PNT solutions in this dynamic environment.

GNSS Components -Low Earth Orbit (LEO) -graphic