Radar Velocity Sensor Using Dual Notch Filters
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Solution Overview
Problem
Radar systems face challenges in distinguishing between target returns and clutter from intermediate velocity objects, which can lead to false alarms and resource depletion, especially when these objects have similar radar cross-sections to targets.
Innovation Solution
A sensor system utilizing a narrow-band notch filter and a wide-band notch filter, along with a comparator, to generate flag signals indicating the presence of objects moving at lesser velocities, thereby reducing clutter processing and conserving radar resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single band-stop filter is used to filter out near-zero velocity clutter, then static and near-zero velocity clutter is effectively removed, but intermediate velocity object returns are not distinguished from target returns
Solution Approach 1:
The invention divides the clutter filtering function into two separate band-stop filters: a first filter for near-zero velocity clutter and a second filter for intermediate velocity clutter. This segmentation allows each filter to be optimized for its specific velocity range, improving both clutter rejection and velocity discrimination precision simultaneously
Solution Approach 2:
The invention adds a new dimension to the filtering approach by introducing a second filtering path with a different bandwidth characteristic. Instead of relying on a single filter, the system processes signals through multiple filtering dimensions (narrow-band and wide-band notches) and combines the results, enabling differentiation of intermediate velocity objects that a single filter cannot resolve
2Reliability
If the band stop filter is tuned to discard signals from intermediate velocity objects, then false alarms from intermediate velocity objects are reduced, but the chance of failing to detect valid targets increases
Solution Approach 1:
The system dynamically adapts the filtering strategy by using two different filter bandwidths that can be selectively applied. The narrow-band notch filter handles cases where intermediate velocity objects are the primary concern, while the wide-band notch filter ensures target detection is maintained. This dynamic approach allows the system to adjust its sensitivity based on the operational context
Solution Approach 2:
The invention introduces an intermediary processing stage that combines outputs from both narrow-band and wide-band filter paths. This intermediary stage allows the system to weigh evidence from both filtering approaches, reducing false alarms from intermediate velocity objects while maintaining sensitivity to valid targets through the complementary information provided by the second filter path
3Reliability
If multiple filters are used to discard intermediate velocity object returns, then clutter processing is improved, but device complexity increases
Solution Approach 1:
The invention merges the functionality of multiple filters into a coordinated dual-filter system where the narrow-band and wide-band notch filters work together. By combining these filters in a structured manner with a unified output combination stage, the system achieves improved clutter discrimination without the complexity of fully independent multiple filter systems, as the filters share common input and output processing infrastructure
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
The system effectively discriminates between target returns and intermediate velocity object returns, minimizing false alarms and optimizing resource allocation in radar systems by providing clear outputs for further processing.
Implementation Method 1
The target returns may hence be distinguished from the clutter based upon the relative Doppler shifts of the respective returned signals
Data Source
AI summary
There is provided a sensor for use generally within the signal processing unit of a radar system. The sensor enables entity returns to be classified according to the velocity of the entity and thus allows returns to be processed according to classification. In particular, the sensor comprises a first processing means that filters an input signal using a narrow-band notch filter to output a wideband output. In particular, the sensor comprises a second processing means that filters an input signal using a wide-band notch filter to output a narrowband output. The invention provides for the comparison of the outputs to determine how the entity return is to be classified.