Long Baseline Accelerometer Triad for GNSS Navigation
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Solution Overview
Problem
Conventional MEMS gyroscopes are expensive and lack accuracy due to biases and poor stability, making them unsuitable for modern navigation systems, while accelerometers in inertial motion units (IMUs) have limited accuracy and a short baseline, which is inadequate for precise navigation.
Innovation Solution
Combining an accelerometer triad with a GNSS antenna using a long baseline system to increase angular rate sensitivity, allowing for better rate stability and performance, enabling the determination of full position, velocity, and attitude navigation solutions by integrating accelerometer and GNSS data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MEMS gyroscopes are used, then the system can provide rotational rate measurements, but the cost increases and accuracy decreases due to biases and poor stability
Solution Approach 1:
The patent replaces expensive MEMS gyroscopes with inexpensive accelerometers that can be mass-produced. The accelerometers are placed in a triad configuration with a long baseline between them, allowing the system to derive rotational rate information from the accelerometer measurements rather than relying on costly gyroscopic sensors.
Solution Approach 2:
The patent substitutes the mechanical gyroscopic sensing system with an accelerometer-based system. Instead of using mechanical spinning elements to measure rotation, the system uses accelerometers to measure linear acceleration and derives rotational information through the long baseline geometry and signal processing.
2Measurement precision
If accelerometers are used in a compact IMU unit, then the system can measure linear acceleration, but the baseline length is short which limits angular rate sensitivity
Solution Approach 1:
The patent transitions from a compact three-dimensional IMU unit to a distributed linear arrangement of accelerometers along a long baseline. This dimensional change from compact volumetric placement to extended linear placement increases the baseline length, thereby improving angular rate sensitivity through the long baseline GNSS vector system.
3Measurement precision
If a long baseline accelerometer triad is combined with GNSS antenna, then angular rate sensitivity and navigation accuracy improve, but the device complexity increases
Solution Approach 1:
The patent divides the navigation system into separate functional modules: an accelerometer triad for measuring linear acceleration, a GNSS antenna for satellite signal reception, and a processing system that integrates the data. This segmentation allows each component to be optimized independently while working together to provide accurate navigation solutions.
Solution Approach 2:
The long baseline accelerometer triad system serves multiple functions: it measures linear acceleration, determines angular rate through the long baseline geometry, provides navigation position, velocity, and attitude information. This multi-functionality reduces the need for separate dedicated sensors for each navigation parameter.
Data Source
AI summary
A system and method for providing location information using a long baseline accelerometer/GNSS system. A first set of accelerometers is operatively associated with the first GNSS antenna while a second set of accelerometers is operatively associated with a second (or more) GNSS antenna. The multiple assemblies are separated by predefined distances and held rigid to each other. Accelerometer data is combined with the GNSS data to provide improved navigation and location information.