Satellite Deorbiting Using Magnetometer and Sun Sensor Attitude Estimation

The patent replaces expensive, complex attitude measurement equipment (stellar sensors, gyrometers) with inexpensive, simple sensors (magnetometers, sun sensors) that are already available on survival-mode satellites. This principle of using cheap, readily available components instead of expensive specialized equipment directly resolves the contradiction between measurement precision and device complexity.

The patent substitutes optical/mechanical attitude measurement systems (stellar sensors requiring star field detection, gyrometers requiring mechanical rotation) with electromagnetic field-based sensors (magnetometers detecting Earth's magnetic field, sun sensors detecting solar radiation). This substitution eliminates complex mechanical and optical systems while achieving sufficient attitude determination for deorbiting maneuvers.

The patent makes the basic sensors serve multiple functions: magnetometers and sun sensors, originally designed for sun-pointing attitude control in survival mode, are repurposed to determine orbit-plane alignment and velocity vector orientation for deorbiting maneuvers. This multi-functionality allows the same simple sensors to achieve both survival mode operation and precise deorbiting alignment.

The patent changes the operational parameters and measurement interpretation of the basic sensors. Instead of using them for traditional sun-pointing control, the system utilizes magnetic field direction data and sun vector data in a novel coordinate transformation framework to derive orbit-plane alignment information and trigger deorbiting maneuvers at precise orbital positions.

The patent performs preliminary calculations and predictions of the optimal deorbiting maneuver时机 (timing) based on orbital parameters before execution. The system pre-determines when the satellite will be in the correct orbital position and attitude configuration for efficient deorbiting, allowing simple sensors to trigger precisely timed thruster activations without requiring complex real-time control during the maneuver.

The patent employs a simplified control architecture where the basic sensors and onboard computer automatically determine alignment conditions and trigger deorbiting maneuvers without requiring complex external guidance or manual intervention. The system uses the Earth's magnetic field and sun position as natural reference frames that the satellite can autonomously exploit for alignment, eliminating the need for complex artificial reference systems.