MEMS On-Chip Inertial Navigation Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inertial navigation systems are bulky and lack accuracy due to separate components for quartz oscillators and MEMS accelerometers, with no on-chip integration of GPS, temperature monitors, or inertial sensors, leading to compromised compensation and limited navigational capabilities in harsh environments.
Innovation Solution
An on-chip inertial navigation system is developed using MEMS fabrication techniques to integrate a disk resonator gyroscope and quartz resonator oscillator on a single chip, with low-temperature bonding and selective etching, allowing for close proximity and error correction among sensors, including GPS and optical sensors, to enhance accuracy and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quartz oscillator and MEMS accelerometer are packaged separately in multiple boxes, then mechanical and thermal decoupling is achieved, but compensation accuracy is compromised and device size increases
Solution Approach 1:
The patent integrates the quartz oscillator, MEMS accelerometer, and other INS components onto a single common substrate. This merging of previously separate components enables them to share a common environment and provides the proximity needed for accurate error compensation while significantly reducing device size from multiple boxes to a single chip-scale package.
Solution Approach 2:
The common substrate serves multiple functions: it mechanically supports all INS components, provides thermal pathways for temperature monitoring and compensation, and enables environmental sensing for error correction. This multi-functional substrate replaces the need for separate packaging and support structures for each component.
2Measurement precision
If GPS, temperature monitors, and inertial sensors are not integrated on-chip, then component fabrication is simpler, but navigation accuracy and compactness are limited
Solution Approach 1:
The patent combines GPS receivers, temperature monitors, disk resonator gyroscopes, and MEMS accelerometers onto a single chip using MEMS fabrication techniques. This integration enables all sensors to monitor the common environment and provides the proximity needed for real-time error correction, significantly improving navigation accuracy despite the increased fabrication complexity.
3Reliability
If sensors are placed in close proximity on a single chip, then error correction capability is enhanced, but fabrication processes may endanger fragile oscillator resonators
Solution Approach 1:
The patent employs low-temperature bonding processes and selective etching techniques that are gentler on fragile quartz resonators compared to conventional high-temperature fabrication. By changing the temperature parameter and selecting appropriate etching chemistry, the fragile oscillator resonators can be integrated on-chip without damage while still enabling close proximity sensing for error correction.
4Object-affected harmful factors
If conventional INS components are used without on-chip integration, then device robustness in harsh environments is reduced, but sensor proximity for environmental monitoring is compromised
Solution Approach 1:
The patent integrates all INS sensors onto a single chip, placing them in close proximity so they all experience the same harsh environmental conditions (temperature, vibration, shock). This common environmental exposure enables the sensors to monitor each other and perform real-time error correction, significantly improving robustness in harsh environments compared to separately packaged components.
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 solution provides a compact, high-accuracy inertial navigation system capable of real-time error correction in harsh environments, maintaining navigation data integrity under high temperatures, physical impacts, and vibrations by utilizing sensors as error-correction monitors.
Implementation Method 1
a gyroscope on the semiconductor substrate, the gyroscope including a first material
Implementation Method 2
an oscillator on the semiconductor substrate, the oscillator including a resonator, the resonator including a second material different from the first material
Data Source
AI summary
An on-chip navigation system, optionally combined with GPS (Global Positioning System) and/or an imaging array, which incorporates MEMS (MicroElectroMechanical Systems) components is possible by the use of careful material selection and novel bonding techniques used during fabrication. The use of MEMS components permits many of the components of a typical inertial navigation system to reside on a single chip. Because the components are in close proximity, the components can then be used to monitor the environmental changes of the chip, such as temperature and vibration, and correct for the resulting offsets of other components. This allows improved system performance even if the individual sensor components are not ideal.