Dead Reckoning Altimeter Yaw Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dead reckoning systems face challenges in accurately measuring altitude and inclination angles, especially when continuous GNSS fixes are unavailable or noisy, and tend to be less accurate for vertical positions compared to horizontal ones.
Innovation Solution
A dead reckoning altimeter and inclinometer apparatus using a speedometer, forward-looking accelerometer, yaw rate sensor, and a Kalman filter to calculate altitude changes and inclination angles by compensating acceleration measurements for yaw angle rates and biases, allowing for precise determination of altitude and inclination without continuous GNSS data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dead reckoning systems use traditional methods (GNSS, barometric pressure) for altitude measurement, then they can obtain altitude data, but the accuracy is poor and noisy especially when continuous GNSS fixes are unavailable
Solution Approach 1:
The patent replaces traditional mechanical/barometric altitude measurement systems with an optical-based dead reckoning system. It uses a forward-looking camera to capture images of the ground, extracts feature points, and calculates altitude through photogrammetric methods. This substitution eliminates reliance on barometric pressure (which is noisy) and continuous GNSS fixes (which are unavailable in obstructed views), providing continuous and accurate altitude measurement through visual feature matching and geometric calculations.
2Measurement precision
If dead reckoning systems integrate multiple sensors (speedometer, accelerometer, yaw rate sensor), then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges multiple measurement functions (altitude detection, inclination angle measurement, speed measurement, acceleration detection, and yaw rate sensing) into a single integrated dead reckoning system. By combining these sensors and processing them through unified algorithms (including coordinate transformations and compensation mechanisms), the system achieves high measurement precision while managing complexity through integrated architecture rather than separate independent systems.
Solution Approach 2:
The system employs feedback mechanisms where the yaw rate sensor provides real-time rotational information that is used to compensate accelerometer measurements. The calculated altitude and inclination data are continuously refined through feedback loops that adjust for sensor biases and environmental variations, improving overall measurement precision while using the existing sensor suite efficiently.
3Measurement precision
If the system compensates acceleration measurements for yaw angle rates and biases, then altitude measurement accuracy improves to within a meter or two, but processing complexity and computational requirements increase
Solution Approach 1:
The system performs preliminary compensation of accelerometer measurements for yaw angle rates and sensor biases before using these measurements for altitude calculation. By pre-correcting the acceleration data through coordinate transformations and bias compensation algorithms, the system reduces computational complexity in subsequent altitude integration steps while achieving high precision results within 1-2 meters accuracy.
Solution Approach 2:
The system transforms acceleration measurements from the sensor's coordinate system to the navigation coordinate system through parameter changes (coordinate transformations). It also dynamically adjusts for yaw rate variations and sensor biases by changing the compensation parameters based on real-time sensor inputs, enabling high-precision altitude measurement while adapting to varying operational conditions.
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 accurate and continuous measurement of altitude and inclination angles, improving navigation precision to within a meter or two, even in obstructed views or without continuous GPS, by integrating speed, acceleration, and yaw rate data with external positioning information.
Implementation Method 1
a forward direction linear accelerometer for measuring acceleration in the forward direction
Implementation Method 2
a yaw rate sensor to measure yaw angle rate
Data Source
AI summary
An altitude dead reckoning system using a measured forward speed and a measured forward-looking acceleration in a dead reckoning (DR) altitude calculator to calculate an altitude change. The DR altitude calculator may also use a measured yaw angle rate to provide compensation to improve the accuracy of the altitude change calculation.