Conical Scanning Spacecraft Sun Pointing with Cant Sensor
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Solution Overview
Problem
Conventional spacecraft Sun search and pointing processes require complex sensors, which are not suitable for volume-constrained, mass-constrained, or budget-constrained satellite programs, and existing methods do not efficiently align the spacecraft with the Sun using limited sensor suites.
Innovation Solution
A conical scanning system that uses a spacecraft with a principal moment of inertia axis, an incidence angle sensor with a canted boresight, and processors to control actuators, allowing the spacecraft to rotate and align the axis with the Sun direction using incidence angle and presence sensors, simplifying the control architecture and achieving stable Sun pointing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional two-axis sensors with eigenaxis slew or spin maneuvers are used for Sun search and pointing, then Sun pointing capability is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the essential Sun pointing function from complex two-axis sensors and implements it using a simplified single-axis gimbal mechanism combined with a basic incidence angle sensor. This removes unnecessary sensor complexity while retaining the core capability to determine Sun direction and control spacecraft attitude.
Solution Approach 2:
The patent uses a simplified sensor model that copies only the essential measurement capability (incidence angle) needed for Sun pointing, rather than implementing full two-axis sensor functionality. The gimbal mechanism copies the directional sensing function in a mechanically simpler way.
2Measurement precision
If complex sensors are used for Sun search and pointing, then accurate Sun direction measurement is achieved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, complex two-axis sensors with inexpensive single-axis incidence angle sensors and simple gimbal mechanisms. These simpler components are cheaper to manufacture and replace, reducing overall system cost while maintaining adequate measurement precision for Sun pointing operations.
3Device complexity
If simple sensor suites are used in spacecraft, then mission cost is reduced, but ability to align with Sun efficiently is worsened
Solution Approach 1:
The patent introduces dynamic conical scanning motion of the gimbal-mounted sensor to compensate for the simplicity of the sensor suite. By rotating the sensor in a cone pattern, the system efficiently samples Sun direction from multiple angles, achieving rapid and accurate Sun alignment despite using simple, low-cost sensors.
Solution Approach 2:
The conical scanning mechanism performs periodic rotational motion to sweep the incidence angle sensor through a cone of directions. This periodic scanning enables the simple sensor to gather sufficient directional information efficiently, maintaining high Sun alignment productivity despite sensor simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enables efficient Sun pointing with limited sensor suites, reducing mission costs and complexity, and is applicable to small satellites like CubeSats and microsatellite constellations, such as CYGNSS, by aligning the spacecraft's principal moment of inertia axis with the Sun direction using conical scanning and incidence angle measurements.
Implementation Method 1
a spacecraft having a principal moment of inertia axis, the spacecraft being configured to rotate about the principal moment of inertia axis
Implementation Method 2
An incidence angle sensor is secured to the spacecraft, and has a boresight that is canted with respect to the principal moment of inertia axis
Data Source
AI summary
A conical scanning method and system is provided for orienting a spacecraft with respect to a source. The system includes a spacecraft and an incidence angle sensor secured to the spacecraft to sense a signal from a source. The incidence angle sensor has a boresight that is canted with respect to the principal axis. A processor communicates with actuators on the spacecraft to adjust an attitude of the spacecraft based on information received from the incidence angle sensor and to thereby align a principal axis of the spacecraft with a direction from the spacecraft to the source. The method and system can also rely on information received from source presence sensors. The source may be the Sun, or a non-solar signal source.