Dismount Inertial Alignment via Vehicle Reference
Solution Overview
Problem
Dismount localization systems face challenges in maintaining accurate position solutions due to the absence of wheel encoders and lower quality inertial sensors, leading to prolonged initialization times and reduced accuracy, especially when transitioning from a vehicle to performing a mission.
Innovation Solution
The Vehicle Localization Augmentation for Dismounts (VLAD) system enhances dismount localization by aligning inertial systems with vehicle sensors using ranging radios and algorithms, allowing for quicker initialization and maintaining accurate position solutions during vehicle rides and transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dismount localization systems use lower quality inertial sensors to reduce size and cost, then the system becomes more portable and affordable, but initialization time increases and accuracy decreases
Solution Approach 1:
The patent combines multiple sensors (accelerometers, gyroscopes, magnetometers) into an integrated inertial measurement unit (IMU) for dismounts. By merging these sensors and processing their data together through sensor fusion algorithms, the system compensates for individual sensor limitations and achieves acceptable localization accuracy without requiring expensive high-quality sensors.
Solution Approach 2:
The patent introduces vehicle localization data as an intermediary reference frame. By aligning the dismount's inertial sensors to the vehicle's known accurate localization system, the dismount benefits from the vehicle's higher quality sensors indirectly, improving initialization speed and accuracy without carrying expensive sensors.
2Device complexity
If dismount localization systems omit wheel encoders to reduce complexity, then the system becomes simpler and lighter, but accelerometer error correction is lost reducing accuracy
Solution Approach 1:
The patent makes the vehicle's localization system multi-functional by having it serve both the vehicle's navigation needs and the dismount's alignment needs. The vehicle's accurate localization data is used not only for vehicle positioning but also as a reference frame for aligning and calibrating the dismount's inertial sensors, eliminating the need for wheel encoders on the dismount.
Solution Approach 2:
The system uses the vehicle's own localization capabilities to service the dismount's alignment needs. The vehicle's localization system provides reference data that automatically aligns the dismount's sensors without requiring additional sensors or complex calibration procedures on the dismount itself.
3Measurement precision
If dismounts require prolonged initialization time to achieve accurate localization, then sensor alignment can be more precise, but the system becomes less responsive and harder to deploy quickly
Solution Approach 1:
The patent performs preliminary alignment of the dismount's inertial sensors to the vehicle's reference frame while the dismount is still in the vehicle. This preliminary action uses the vehicle's stable platform and accurate localization during the ride to pre-align sensors before the dismount exits, reducing the additional initialization time needed after deployment.
Solution Approach 2:
The patent maintains continuous sensor alignment and calibration throughout the vehicle ride rather than requiring a separate initialization phase after exiting. The localization system continuously processes data from inertial sensors and vehicle reference data during transit, so the alignment process is ongoing and ready when the dismount needs to deploy.
Data Source
AI summary
A Vehicle Localization Augmentation for Dismounts (VLAD), which extends the technology used by dismount localization systems to include the capability of riding and aligning inertial systems to a vehicle. VLAD takes the proven Warfighter's Integrated Navigation System (WINS) and, when appropriate, increases capabilities by investigating aiding sensors, algorithms, and frameworks to align dismount inertial sensors to vehicle inertial sensors. The two focuses of this effort are initialization and maintaining the solution quality. Initialization is the process where an inertial unit calculates sensor biases in an effort to minimize systemic errors in the localization solution. This process is highly related to the sensor being used. High quality sensors, for example, perform a gyrocompassing operation on initialization. Gyrocompassing measures the Earth's rotation and gives the absolute heading relative to the Earth. On man-portable inertial systems, this process can take 15 minutes.