Target Tracking Initialization Using Body-Frame Coordinate Smoothing
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Solution Overview
Problem
Existing target tracking devices suffer from deteriorated prediction accuracy due to a large deviation of the initial value of a smoothed value from the original smoothed value, leading to ineffective target tracking.
Innovation Solution
The target tracking device calculates an initial value of a smoothed value based on position observation information from a sensor, performs estimation processing using a transformed coordinate system, and predicts future states in a body coordinate system before transforming back to a north-east-up coordinate system for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an initial value of a smoothed value is set in the tracking filter to predict target position, then the prediction process can be performed, but when the initial value greatly deviates from the original smoothed value, the prediction accuracy deteriorates
Solution Approach 1:
The patent performs preliminary coordinate transformation of the initial value of the smoothed value from the north-east-up coordinate system to the body coordinate system before using it in the tracking filter. This preliminary action ensures that the initial value is properly aligned with the target's orientation, preventing accuracy deterioration even when the initial value deviates from the original smoothed value.
Solution Approach 2:
The patent changes the coordinate system parameter from the north-east-up coordinate system to the body coordinate system for the initial value of the smoothed value. This parameter change adapts the initial value to match the target's body-fixed reference frame, resolving the contradiction between enabling prediction and maintaining accuracy.
2Measurement precision
If coordinate transformation is performed to align the initial value with the target's body coordinate system, then prediction accuracy is maintained, but additional processing steps are required
Solution Approach 1:
The coordinate transformation is performed as a preliminary action during the initialization phase before the tracking filter begins operation. By completing the transformation upfront, the patent avoids the need for continuous transformations during tracking, thereby maintaining accuracy while minimizing overall processing complexity.
Data Source
AI summary
This target tracking device includes an initial value calculating unit that acquires position observation information at two different sampling times from a sensor, and calculates an initial value of a smoothed value including a position vector of the target and a velocity vector of the target as an initial value of the smoothed value. In addition, the target tracking device includes a smoothing unit that performs estimation processing of estimating a smoothed value and a prediction value, and a prediction unit that predicts a future state of the target by using an initial value of the smoothed value calculated or a smoothed value and outputs a prediction value to the smoothing unit as a prediction value to be used by the smoothing unit for next estimation processing.