Radar Chirp Timing With Multi-Clock Ghost Target Filtering
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Solution Overview
Problem
Radar systems using multiple clock frequencies face issues with ghost targets due to frequency mismatches, leading to inaccurate object detection, and the need to avoid restricted frequency bands while conserving energy.
Innovation Solution
Adjusting the frequency of the RF phase-locked loop (PLL) to generate clock signals outside restricted bands and adjusting the chirp signal period to move ghost targets to predefined doppler bins for filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple clock frequencies are used in radar systems, then energy consumption is reduced and restricted frequency bands can be avoided, but ghost targets appear due to frequency mismatches between clock signals
Solution Approach 1:
The patent changes the frequency parameter of the chirp signal to be synchronized with the microcontroller clock frequency. By adjusting the chirp signal frequency to match the microcontroller clock (e.g., setting chirp frequency = N × f_mcuk where N is an integer), the system eliminates ghost targets while maintaining multiple clock frequency operation for energy efficiency and frequency band compliance.
Solution Approach 2:
The patent implements a feedback mechanism where the chirp signal generation is synchronized with the microcontroller clock cycles. The system uses the microcontroller clock as a reference to generate chirp signals at frequencies that are integer multiples of the microcontroller clock, ensuring phase coherence and eliminating the frequency mismatch that causes ghost targets.
2Reliability
If clock frequency synchronization is implemented to eliminate ghost targets, then detection accuracy is improved, but system complexity increases due to additional frequency coordination requirements
Solution Approach 1:
The patent makes the microcontroller clock serve multiple functions: it drives the microcontroller operations and simultaneously serves as the reference frequency for generating chirp signals. By using the same clock source (microcontroller clock) for both control operations and radar signal generation, the system eliminates the need for separate frequency synchronization mechanisms, reducing overall system complexity.
Solution Approach 2:
The patent merges the clock generation functions by using the microcontroller clock as the common reference for both the microcontroller operations and the chirp signal generation. This consolidation eliminates the need for separate clock synchronization circuits and simplifies the frequency coordination between different system components.
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
Effectively removes ghost targets by filtering them out, ensuring accurate object detection and energy conservation.
Implementation Method 1
an RF phase-locked loop (PLL) to generate an output signal at a first frequency; a microcontroller to operate at a second frequency, the first frequency being a multiple of the second frequency
Implementation Method 2
a filter to filter out a doppler bin corresponding to the reflected signal based on the chirp period
Data Source
AI summary
Methods, apparatus, systems, and articles of manufacture are described corresponding to a sensor system operating with multiple clock frequencies. An example system includes a radio frequency (RF) phase-locked loop (PLL) to generate an output signal at a first frequency; a microcontroller to operate at a second frequency, the first frequency being a multiple of the second frequency; a transmitter to output a chirp signal with a chirp period selected based on the second frequency; a receiver to receive a reflected signal corresponding to the chirp signal; and a filter to filter out a doppler bin corresponding to the reflected signal based on the chirp period.