Proposed Orbital Products for Positioning Using Mega-Constellation LEO Satellites

Area of Science:

• Satellite dynamics and orbital mechanics
• Geodesy and positioning systems
• Space-based navigation and surveillance

Background:

• The proliferation of Low Earth Orbit (LEO) mega-constellations presents new opportunities and challenges for satellite-based positioning and navigation.
• Existing positioning systems may require adaptation to effectively utilize data from LEO constellations.
• Accurate orbital products are crucial for reliable positioning services.

Purpose of the Study:

• To propose and assess the feasibility of generating LEO orbital products at two distinct accuracy levels.
• To provide meter-level accuracy orbits (Level A) as broadcast ephemerides for LEO-specific applications.
• To generate centimeter-level accuracy orbits (Level B) as polynomial corrections based on Level A orbits.

Main Methods:

• Analysis of real data from the LEO satellite GRACE FO-1 to evaluate error budgets.
• Development of procedures for generating Level A (meter-level) and Level B (centimeter-level) orbital products.
• Investigation of orbital prediction errors and ephemeris fitting for accuracy assessment.

Main Results:

• Orbital prediction errors are the dominant factor in Level A product accuracy, reaching up to 1 meter for 6-hour prediction intervals.
• Ephemeris fitting for Level A products introduces orbital user range errors (OUREs) of a few centimeters.
• Level B products achieve centimeter-level OUREs for short prediction periods, with polynomial fitting reducing errors to millimeters.

Conclusions:

• The proposed two-level accuracy approach for LEO orbital products is feasible.
• Orbital prediction accuracy is critical for meter-level LEO ephemerides.
• Centimeter-level accuracy for LEO positioning can be achieved through polynomial corrections, especially for short-term predictions.