Passive Coherent Location Signal Prediction and Selection
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Solution Overview
Problem
Passive coherent location systems face accuracy degradation due to noise and atmospheric interference, as they rely on non-cooperative signals of opportunity, which can vary in quality and availability.
Innovation Solution
An apparatus comprising a forecaster, evaluator, and correlator that predicts radio-frequency signals, generates an effectiveness metric, and determines the position and velocity of objects using a radio-frequency signal with the highest accuracy, thereby selecting the most effective signal and reducing noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-cooperative signals of opportunity are used for passive coherent location, then the system can operate without active transmitters, but the accuracy is degraded due to noise and atmospheric interference
Solution Approach 1:
The forecaster generates predictions of the direct path signal in advance before the actual signal reception. This preliminary action allows the system to have a reference signal available for correlation processing, enabling accurate location measurements even when the reflected signal is weak or buried in noise.
Solution Approach 2:
The predicted direct path signal acts as an intermediary reference that mediates between the noisy received signal and the location calculation. By correlating the received signal with the predicted reference, the system can extract accurate location information while rejecting noise and interference.
2Adaptability or versatility
If multiple non-cooperative signals are available, then signal availability increases, but selecting the optimal signal becomes complex
Solution Approach 1:
The manual or complex algorithmic signal selection process is replaced by an effectiveness metric calculation that automatically evaluates and ranks available signals. The metric quantifies signal quality based on forecast accuracy, allowing the system to automatically select the best signal without complex decision logic.
Solution Approach 2:
The system changes the parameter used for signal selection from simple signal strength to an effectiveness metric that incorporates forecast accuracy and signal characteristics. This parameter transformation enables automatic optimization of signal selection based on the specific operational context.
3Measurement precision
If the receiver continuously monitors all available signals, then signal quality can be optimized, but energy consumption increases
Solution Approach 1:
The forecaster performs preliminary evaluation of available signals and their effectiveness metrics before the receiver begins full monitoring. This advance preparation allows the system to identify and focus on only the most promising signals, reducing the receiver's monitoring burden and energy consumption.
Solution Approach 2:
Instead of continuously monitoring all available signals at full capacity, the system applies partial monitoring by focusing resources on signals that exceed a certain effectiveness threshold. This selective approach maintains signal quality optimization while significantly reducing energy consumption.
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
Improves the accuracy and sensitivity of passive coherent location by predicting and selecting the best available radio-frequency signals, reducing reliance on suboptimal signals and enhancing noise reduction.
Implementation Method 1
The correlator determines, from the radio-frequency signal reflected from the object as received at the receiver, an ambiguity function having a maximum at a temporal offset and a Doppler shift
Data Source
AI summary
An apparatus for passive coherent location includes a forecaster, an evaluator, a receiver, and a correlator. The forecaster generates a prediction of a radio-frequency signal transmitted from an antenna of a broadcasting service. The evaluator generates an effectiveness metric from the prediction of the radio-frequency signal. The receiver receives the radio-frequency signal that an object reflects from the antenna to the receiver. The correlator determines, from the radio-frequency signal reflected from the object as received at the receiver, an ambiguity function having a maximum at a temporal offset and a Doppler shift. The temporal offset and the Doppler shift at the maximum partially determine at least a position of the object. The apparatus optionally includes a selector for tuning the receiver to the radio-frequency signal in response to the effectiveness metric.