Radar Device Pulse Repetition Frequency Variation for Echo Removal
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Solution Overview
Problem
Conventional radar systems face challenges in effectively removing multi-order echoes and interference from other radar apparatuses due to complex configurations, large processing circuits, uncertainty in detection speed, and potential removal of genuine target signals, especially when dealing with similar pulse repetition frequencies.
Innovation Solution
A radar apparatus that transmits pulse signals at varying repetition cycles, allowing for the detection and removal of multi-order echoes and interference by setting different repetition cycles and maintaining a constant sampling cycle, thereby preventing uncertainty in speed and ensuring accurate target object detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-order echo clutter is specified and deleted based on a difference between reception signals by transmission pulse cycles of a short distance range and a long distance range, then multi-order echo can be removed, but the processing circuit size becomes large
Solution Approach 1:
The patent changes the parameter of pulse repetition frequency (PRF) over time, using a sequence of different PRFs. This allows multi-order echoes to be identified and removed by comparing target positions across different PRF cycles, without requiring complex simultaneous processing of multiple reception signals, thus reducing circuit size while maintaining removal accuracy.
Solution Approach 2:
The patent employs periodic variation of pulse repetition frequencies in a predetermined sequence. By periodically changing PRF and comparing target detections across these periodic cycles, the system can identify and remove multi-order echoes through temporal pattern recognition rather than complex spatial signal differentiation, simplifying the processing circuit.
2Reliability
If a transmission frequency signal which is set to a frequency which increases or decreases by a predetermined frequency every pulse repetition cycle is used, then primary echo and multi-order echo can be discriminated based on speed, but the transmission means capable of frequency modulation at a high speed is necessary
Solution Approach 1:
Instead of changing frequency, the patent changes the pulse repetition frequency parameter. This achieves echo discrimination through temporal sampling at different PRFs, which is simpler to implement than high-speed frequency modulation while still enabling primary and multi-order echo discrimination through position comparison across cycles.
3Reliability
If the radar apparatus itself and another radar apparatus which becomes an interference source are similar radar apparatuses, then mutual interference avoidance becomes difficult, but interference can be prevented by controlling a cycle, transmission interval, or modulation gradient
Solution Approach 1:
The patent dynamically adjusts the pulse repetition frequency over time using a predetermined sequence. This dynamic PRF variation creates temporal separation between transmissions from similar radar apparatuses, enabling interference avoidance through time-domain differentiation rather than requiring complex frequency or phase modulation control mechanisms.
4Reliability
If a pulse repetition frequency (PRF) is varied and asynchronous signal removal processing is performed, then target reflection reception signals appearing at a different time position every repetition time period can be removed, but the circuit configuration becomes complex
Solution Approach 1:
The patent systematically varies PRF according to a predetermined sequence and uses this known variation pattern to identify and remove asynchronous signals. By using a predetermined, repeatable PRF sequence rather than random or complex variations, the system can use simple correlation-based detection to identify clutter signals, reducing the complexity of the removal processing circuit.
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 solution enables the simple and effective removal of multi-order echoes and interference from other radar systems, ensuring accurate target object detection without increasing circuit complexity or size, and preventing the removal of genuine target signals.
Implementation Method 1
transmits pulse signals... receiving and analyzing the pulse signals reflected by a target object
Implementation Method 2
a primary echo and a multi-order echo can be discriminated based on a speed
Data Source
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AI summary
[OBJECT] To surely remove a multi-order echo or interference from another radar apparatus [ORGANIZATION] A radar apparatus transmitting pulse signals at predetermined repetition cycles and receiving and analyzing the pulse signals reflected by a target object to thereby detect the target object has: a setting means (control unit 11) setting so that at least a part of the repetition cycles of the pulse signals is different; a detection means (speed detection/object detection unit 16) detecting a distance to the target object specified by the pulse signal; and a removal means (clutter removal unit 17) removing the target object as clutter when the distance to the target object detected in the different repetition cycle or in a period subsequent to the different repetition cycle by the detection means and the distance to the target object detected in the period other than that by the detection means are different.