Train Intrinsic Speed Estimation from Stationary Radar Reflections
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Solution Overview
Problem
Existing methods for estimating airspeed using Doppler radar are prone to inaccuracies due to the inclusion of reflections from both stationary and moving objects, leading to unreliable speed estimates, particularly in complex traffic scenarios.
Innovation Solution
A method that filters received beams to distinguish between reflections from stationary and moving objects using geographical and temporal matching, spatial filtering, and additional techniques such as RANSAC, RCS, and µ-Doppler filtering to improve airspeed estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If all received beams are used for airspeed estimation, then the quantity of data for estimation is increased, but the measurement precision deteriorates due to inclusion of reflections from moving objects
Solution Approach 1:
The patent extracts and separates reflections from stationary objects from the total received beams by analyzing Doppler shift characteristics. Beams reflected from stationary objects exhibit specific Doppler shift patterns that differ from those reflected from moving objects, allowing the system to isolate and use only the stationary object reflections for airspeed estimation, thereby maintaining measurement precision while utilizing available data.
Solution Approach 2:
The patent applies different processing qualities to different subsets of received beams based on their origin. Reflections from stationary objects are processed with one level of detail for airspeed estimation, while reflections from moving objects are either excluded or processed differently. This local differentiation in data quality ensures that the critical airspeed measurement is not contaminated by irrelevant moving object reflections.
2Measurement precision
If filtering methods are applied to distinguish stationary and moving objects, then the measurement precision of airspeed estimation is improved, but the device complexity increases
Solution Approach 1:
The patent changes the parameter used for differentiation from spatial position to Doppler shift characteristics. By analyzing the Doppler shift of received beams, the system can identify reflections from stationary objects versus moving objects without requiring complex spatial filtering or additional sensors. This parameter change simplifies the processing while maintaining high measurement precision.
Solution Approach 2:
The patent replaces complex mechanical or spatial filtering systems with signal processing based on Doppler effect analysis. Instead of using physical filters or complex antenna arrangements to separate stationary and moving object reflections, the system uses computational methods to analyze Doppler shift patterns, thereby reducing device complexity while achieving the same filtering objective.
3Reliability
If spatial regions are defined to exclude certain areas, then the reliability of airspeed estimation is improved by avoiding moving objects, but the quantity of usable beams is reduced
Solution Approach 1:
Instead of excluding spatial regions to avoid moving objects, the patent inverts the approach by selecting beams based on their Doppler shift characteristics that indicate reflection from stationary objects. This inversion allows the system to positively identify and select reliable beams from stationary objects regardless of their spatial origin, thereby maintaining reliability while maximizing the quantity of usable beams.
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
Enhances the accuracy of airspeed estimation by selectively using reflections from stationary objects, reducing computational effort and minimizing errors from moving objects, thus providing a more reliable airspeed measurement.
Implementation Method 1
For each received beam, a reflection angle with respect to an orientation of the sensor is recorded. In addition, at least two received beams, relative velocities of the beams, and reflection angles are determined. The relative velocity is determined based on a Doppler shift of the received beam.
Data Source
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AI summary
The invention relates to a method for estimating an intrinsic speed of an ego object, in particular a train, wherein beams of the ego object are emitted, wherein reflected beams are received by the ego object, wherein the received beams are checked to the extent as to whether the beams were reflected from a stationary or moving object, and wherein the beams, which were reflected from stationary objects, are used for estimating the intrinsic speed.