FMCW Radar Zoom Detection Segmented Ramp Signals
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Solution Overview
Problem
Ultrasonic parking sensors are cost-intensive, time-consuming, and sensitive to environmental conditions, with limited distance coverage and safety concerns in high-speed vehicles, while existing radar technologies face challenges in achieving high resolution and processing efficiency with limited IF bandwidth.
Innovation Solution
A radar apparatus that generates a first ramp segment with a specific slope, allowing for coarse and zoom-in detection processes to estimate obstacle distances with high resolution, using a local oscillator, frequency shifter, mixer, and digital signal processor to process intermediate frequency signals, thereby mitigating image foldback and maintaining low processing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FMCW radar uses a large bandwidth to achieve high distance resolution and large detection range, then the distance resolution and detection range are improved, but the IF bandwidth and ADC sampling rate requirements increase significantly
Solution Approach 1:
The patent divides the detection process into two segments: a first detection process using a first ramp signal for coarse detection of obstacles at various distances, and a second detection process using a second ramp signal with higher slope for zoom-in detection of specific target objects. This segmentation allows the system to achieve high distance resolution for specific targets without requiring the entire system to operate at high bandwidth continuously.
Solution Approach 2:
The patent dynamically adjusts the ramp signal slope based on detection needs. The first ramp signal has a lower slope for general detection, while the second ramp signal has a higher slope for detailed inspection of specific targets. This dynamic adjustment allows the radar to optimize between detection range and resolution based on the current operational requirements.
2Measurement precision
If FMCW radar increases the ramp signal slope to improve distance resolution, then the distance resolution is improved, but the maximum detection range decreases
Solution Approach 1:
The patent segments the detection process into two phases: first detection using a ramp signal with lower slope to maintain adequate detection range, and second detection using a ramp signal with higher slope to achieve high distance resolution for specific targets. This allows the system to overcome the inverse relationship between slope and detection range.
Solution Approach 2:
The patent performs preliminary detection with the first ramp signal to identify target objects and their approximate distances before initiating the second detection process. This preliminary action allows the system to then focus resources on high-resolution detection of specific targets without needing to maintain high resolution across all possible ranges simultaneously.
3Area of stationary object
If multiple parking sensors are used to cover the entire rear of the vehicle, then the detection coverage is improved, but the system cost increases
Solution Approach 1:
The patent implements a multi-functional radar system that can perform both coarse detection of multiple obstacles and detailed inspection of specific targets using the same hardware infrastructure. The single radar apparatus can dynamically adjust its detection parameters to cover different areas and provide different levels of detail, replacing the need for multiple specialized sensors.
Solution Approach 2:
The patent uses periodic detection cycles where the radar alternates between broad-area scanning using the first ramp signal and focused high-resolution detection using the second ramp signal. This periodic action allows a single sensor to effectively cover multiple areas over time, reducing the need for simultaneous multiple sensors.
4Device complexity
If ultrasonic sensors operate in time division mode to detect obstacles, then the system complexity is reduced, but the detection time increases
Solution Approach 1:
The patent uses continuous wave FMCW radar that transmits continuous modulated signals rather than periodic pulses. This allows for continuous detection without the dead time between pulses, enabling real-time monitoring of obstacles while maintaining relatively simple system architecture. The continuous transmission provides uninterrupted detection capability.
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
Enables efficient detection of obstacles with high resolution and range, even with lower IF filter bandwidth, reducing the need for high sampling rates and processing power, thus providing a cost-effective and reliable radar system.
Implementation Method 1
A transmit signal is frequency modulated to generate a ramp segment
Implementation Method 2
The transmitted pulse is scattered by the obstacle. The scattered pulse is received by the radar
Implementation Method 3
A signal obtained by mixing the ramp segment and the scattered signal is termed as an IF (intermediate frequency) signal. The frequency (f) of the IF signal is proportional to the distance (d) of the obstacle from the FMCW radar
Data Source
AI summary
The disclosure provides a radar apparatus fur estimating a distance of the one or more obstacles in a range of interest. The radar apparatus includes a local oscillator that generates a first ramp segment having a first start frequency. A frequency shifter receives the first ramp segment and generates a transmit signal and a mixer signal. The transmit signal is scattered by a one or more obstacles in the range of interest to generate the scattered signal. A mixer mixes the scattered signal and the mixer signal to generate a non-zero IF signal which is filtered to generate a filtered non-zero IF signal. An ADC (analog to digital converter) samples the filtered non-zero IF signal to generate a valid data. A DSP (digital signal processor) processes the valid data for estimating the distance of the one or more obstacles.