Turret Landmark Calibration for Vehicle Inertial Alignment
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Solution Overview
Problem
Existing inertial navigation systems in land vehicles require disruptive recalibration methods that immobilize the vehicle and involve specialized personnel or equipment, and existing methods are not suitable for recalibrating without predefined reference points or when GPS is unavailable.
Innovation Solution
A method and device for recalibrating inertial navigation systems using a vehicle's turret to point at known landmarks, combining angular measurements with cartographic databases and GPS or rangefinder data to calculate a transformation matrix for aligning the inertial unit, allowing recalibration without specialized tools or skills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated teams with measurement tools are used to align the inertial measurement unit, then alignment accuracy is improved, but the platform is immobilized for a certain period and additional qualified personnel are required
Solution Approach 1:
The system enables the vehicle to perform its own alignment automatically using its existing turret and angular measurement means, without requiring external dedicated teams or specialized measurement tools. The vehicle points the turret at three known landmarks and uses the angular measurements combined with GPS position and cartographic data to calculate and update the transformation matrix, thereby aligning the inertial measurement unit independently.
2Ease of operation
If GPS signals are used for alignment, then alignment can be performed without specialized personnel, but GPS information is insufficient when the vehicle must remain stationary and signals are disrupted
Solution Approach 1:
The system combines multiple data sources and methods into a unified alignment approach. It integrates GPS positioning data, cartographic database information, and angular measurements from the turret to calculate the transformation matrix. This multi-functional approach ensures that alignment can be performed reliably whether GPS is available or not, and whether the vehicle is stationary or mobile, by cross-validating and complementing different data sources.
3Measurement precision
If radar images and predefined reference points are used for recalibration, then inertial navigation system can be recalibrated, but the system is not suitable for land vehicles without well-defined reference points known beforehand
Solution Approach 1:
The system transitions from using fixed, predefined reference points to using dynamic, selectable landmarks that can be identified in real-time during the alignment process. The vehicle can point the turret at any three recognizable landmarks on the terrain whose coordinates are available in the cartographic database, making the system adaptable to various land vehicle operations without requiring pre-surveyed reference points or specialized radar equipment.
Data Source
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AI summary
The invention relates to a method for calibrating an inertial unit provided on a terrestrial platform (1) such as a vehicle, the vehicle being equipped with at least one turret (2) which can be oriented in elevation and bearing to determine at least one pointing direction (di) of at least one object present on the ground and being provided with a cartographic database. According to the method, at least three landmarks (P1, P2, P3), present on the ground and whose geographical coordinates in the terrestrial coordinate system (RT) are known, are pointed at from the turret of the stationary vehicle; the elevation (β) and bearing angles (α) of each pointing direction (d1, d2, d3) are recorded in the vehicle coordinate system (RV); finally, coefficients of a matrix MTV for passing from the terrestrial coordinate system (RT) to the vehicle coordinate system (RV) are determined by calculating the direction of the landmarks (P1, P2, P3) in the vehicle coordinate system (RV) using the measurements of the angles of the pointing directions and the knowledge of the coordinates of the landmarks in the terrestrial coordinate system (RT). The invention also relates to a calibration device carrying out said method.