Satellite Orientation Blended Filter System
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Solution Overview
Problem
Current satellite orientation systems face challenges in achieving precise boresight-to-target knowledge and high-frequency jitter motion due to a mismatch between inertial reference unit (IRU) and gimbal encoder bandwidths, leading to limited disturbance rejection and increased payload size, weight, and power consumption.
Innovation Solution
A dual-sensor, two-stage blended filter system that combines signals from a Coriolis vibratory gyro and a magneto-hydro dynamometer, using lowpass and highpass filters respectively, and an H-infinity filter to generate a unified signal for the flight controller, allowing for accurate satellite orientation and high-bandwidth disturbance rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sensor (IRU) is used for inertial reference, then the system structure is simple, but the measurement bandwidth is insufficient (DC to 100 Hz) and cannot achieve high-frequency jitter rejection
Solution Approach 1:
The measurement bandwidth is segmented across two sensors: the IRU handles low-frequency measurements (DC to 100 Hz) while the MHD handles high-frequency measurements (3 Hz to 1000 Hz). This segmentation allows each sensor to operate within its optimal bandwidth range, achieving comprehensive coverage from DC to 1000 Hz without requiring a single complex high-bandwidth sensor.
Solution Approach 2:
The patent combines outputs from two different sensors (IRU and MHD) through a multi-stage filter system. The filtered outputs are merged to create a unified high-bandwidth measurement signal that leverages the strengths of both sensors, achieving 1000 Hz effective bandwidth while maintaining system reliability through redundancy.
2Reliability
If passive isolation mechanisms such as D-struts are used to roll off high frequency disturbances, then disturbance rejection is improved, but the payload size, weight, and power consumption increase
Solution Approach 1:
The patent replaces passive mechanical isolation mechanisms (D-struts) with an active signal processing system consisting of two sensors and a multi-stage filter. This substitution eliminates the need for heavy mechanical isolation structures while achieving superior disturbance rejection through high-bandwidth measurement and active control, reducing payload weight and power consumption.
Solution Approach 2:
The system changes the approach from mechanical parameter adjustment (physical isolation) to signal parameter processing (filtering and blending). By processing measurement signals through multiple filter stages and combining sensor outputs, the system achieves disturbance rejection without requiring physical isolation mechanisms, thereby reducing payload mass and power requirements.
3Measurement precision
If the IRU bandwidth is increased to match gimbal encoder bandwidth, then disturbance rejection bandwidth is improved, but the IRU size, weight, and power consumption increase
Solution Approach 1:
The MHD sensor serves multiple functions: it provides high-frequency measurement capability (extending bandwidth to 1000 Hz), acts as a complementary sensor to the IRU, and enables the system to achieve high-bandwidth disturbance rejection without modifying the IRU. This multi-functionality allows a single sensor to address bandwidth limitations while keeping power consumption low.
Solution Approach 2:
The patent creates a composite sensor system combining two different sensor technologies (IRU and MHD) with complementary bandwidth characteristics. This composite approach achieves high effective bandwidth (1000 Hz) by leveraging the strengths of each sensor type, avoiding the need to increase power consumption of the IRU while maintaining disturbance rejection capability.
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 achieves a unified bandwidth of 500 Hz with minimal passband ripples, enabling precise satellite pointing and orientation, while reducing the size, weight, and power requirements of the satellite system.
Implementation Method 1
a first sensor including or defining a first measurement bandwidth... the first sensor can include a Coriolis vibratory gyro
Implementation Method 2
a second sensor including or defining a second measurement bandwidth... the second sensor includes a magneto-hydro dynamometer
Data Source
AI summary
Embodiments of the present invention include a two-stage blending filter that blends the measurements from two angular sensors to form a single superior high bandwidth measurement for improved disturbance rejection in a satellite systems for increased accuracy in satellite pointing, orientation, and attitude control. Embodiments of the present invention can include a satellite system including a first sensor including or defining a first measurement bandwidth; a first filter connected to the first sensor; a second sensor including or defining a second measurement bandwidth; a second filter connected to the second sensor; and a third filter connected to the first filter and the second filter. The third filter blend the first signal and the second signal into a third signal; and transmit the third signal to a flight controller configured to adjust an orientation of the satellite, a satellite subsystem, or both, relative to a target in response to the third signal.