Optomechanical Lorentz Velocity Sensing for GPS-Denied Navigation
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Solution Overview
Problem
Existing navigational systems face challenges in accurately determining velocity without GPS, particularly in environments where satellite signals are unreliable, and struggle to decouple sensor platform velocity from environmental factors like wind or water flow.
Innovation Solution
A velocity-sensing system utilizing a charged optomechanical resonator in an optical cavity that measures displacement through a magnetic field, combined with a Lorentz force sensor and magnetometer, to calculate velocity by detecting the Lorentz force experienced by the charged object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS is used for position detection, then position accuracy is improved, but the system becomes unreliable in urban canyons or environments where satellite signals cannot be received
Solution Approach 1:
The patent introduces an intermediary measurement system (accelerometer, magnetometer, barometer) that indirectly measures position by detecting physical quantities (acceleration, magnetic field, pressure) rather than directly receiving satellite signals. This intermediary approach allows position estimation to continue functioning in GPS-denied environments by using alternative physical measurement pathways.
Solution Approach 2:
The navigation system is segmented into multiple independent measurement components (velocity sensor, heading sensor, barometric sensor) that can function independently. When GPS is unavailable, the system segments the position determination task into smaller sub-tasks handled by different sensors, allowing continued operation without a single point of failure.
2Measurement precision
If velocity is measured relative to environmental references, then velocity can be detected, but the measurement becomes affected by external noise and environmental factors such as wind or water flow
Solution Approach 1:
The patent replaces mechanical/external reference-based velocity measurement with an inertial measurement system using accelerometers and integration algorithms. Instead of mechanically comparing motion against environmental references (which introduces environmental noise), the system uses internal inertial sensors to measure acceleration and computationally derives velocity, substituting a cleaner physical measurement mechanism that is not directly affected by environmental factors like wind or water flow.
3Reliability
If inertial sensors are used for velocity measurement, then GPS independence is achieved, but measurement drift and accumulated error increase over time
Solution Approach 1:
The system implements feedback by continuously monitoring measurements from multiple sensors (accelerometer, magnetometer, barometer, GPS when available) and using sensor fusion algorithms to correct drift. When GPS is available, it provides feedback to reset accumulated errors. When GPS is unavailable, the system uses feedback from complementary sensors (e.g., barometric pressure for vertical velocity, magnetometer for heading) to constrain and correct inertial measurement drift, preventing error accumulation.
Solution Approach 2:
The patent merges multiple measurement systems (inertial measurement unit, magnetometer, barometer, GPS receiver) into a unified navigation solution. By combining these diverse measurement sources, the system compensates for the weaknesses of individual sensors—the inertial sensors provide GPS independence while the other sensors provide reference points to correct drift, achieving both autonomy and accuracy.
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
Enables precise velocity measurement even in low magnetic fields and low velocities, effectively resolving ambiguity in velocity calculations and accounting for additional magnetic fields, thus enhancing navigational accuracy.
Implementation Method 1
sensing a displacement of a charged optomechanical resonator disposed in an optical cavity as the optical cavity moves through a magnetic field
Implementation Method 2
an optical measurement system configured to sense optical output of the cavity
Data Source
AI summary
Systems and methods for sensing velocity based on the Lorentz force experienced by a charged object moving in a magnetic field (e.g., Earth's magnetic field) are described. In some examples, methods for sensing velocity may include sensing a displacement of a charged optomechanical resonator disposed in an optical cavity as the optical cavity moves through a magnetic field. A velocity associated with the movement of the optical cavity through the magnetic field is determined based at least on the sensed displacement of the resonator.