Stepped-Chirp Radar Sensor with Sub-Band Receivers for Fine Ranging
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Solution Overview
Problem
Conventional frequency modulated continuous wave (FMCW) based active sensors are unable to meet the stringent requirements of covering up to a range of 50 meters with sub-centimeter-level range resolution and capturing mobile objects at an angular resolution less than 2° due to limitations in power generation, phase noise, and receiver sensitivity at high frequencies.
Innovation Solution
A stepped chirp radar system utilizing dual-voltage control oscillators, phase-locked loops, and narrowband receivers to achieve a wideband operating bandwidth with sub-centimeter-level range resolution and angular resolution, employing a synthetic stepped chirp waveform generation and a cooperative sub-band receiver array to enhance power efficiency and noise figure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional FMCW radar systems operate at high frequencies to achieve wide bandwidth, then bandwidth is improved, but power generation capability deteriorates and phase noise increases
Solution Approach 1:
The system divides the wideband frequency range into multiple sub-bands, with each sub-band processed by a separate receiver channel. This segmentation allows each oscillator to operate at lower frequencies within its sub-band where power generation is more efficient, while collectively achieving wide bandwidth through the combination of multiple sub-bands.
Solution Approach 2:
The patent transitions from a single-frequency-dimensional approach to a multi-dimensional approach by using multiple oscillators operating at different frequency sub-bands simultaneously. This dimensional expansion in frequency space allows the system to achieve wide overall bandwidth while each individual oscillator maintains efficient power generation at its lower operating frequency.
2Measurement precision
If conventional FMCW radar systems operate at high frequencies to achieve wide bandwidth, then bandwidth is improved, but phase noise deteriorates
Solution Approach 1:
The frequency spectrum is segmented into multiple sub-bands, each handled by a dedicated oscillator operating at lower frequencies. This segmentation reduces phase noise because each oscillator operates in a lower frequency range where phase noise is inherently lower, and the segmented sub-bands are then combined to form the complete wideband signal.
3Measurement precision
If conventional FMCW radar systems operate at high frequencies to achieve wide bandwidth, then bandwidth is improved, but receiver sensitivity deteriorates
Solution Approach 1:
The receiver is divided into multiple narrowband receiver channels, each optimized for a specific frequency sub-band. Each narrowband receiver can be optimized for maximum sensitivity within its designated sub-band, achieving better overall system sensitivity across the wide bandwidth compared to a single wideband receiver.
4Measurement precision
If conventional FMCW radar systems use single wideband oscillators to achieve wide bandwidth, then bandwidth is improved, but device complexity increases
Solution Approach 1:
Instead of designing a single complex wideband oscillator, the system segments the frequency range and uses multiple simpler narrowband oscillators. Each oscillator is designed to operate within a limited frequency sub-band, reducing individual oscillator complexity while the collective system achieves the desired wide bandwidth through frequency multiplication and combination.
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 achieves high range and angular resolution with improved power efficiency and reduced noise figure, enabling accurate estimation of object location and velocity within local-area sensing zones, overcoming limitations of conventional FMCW radar systems.
Implementation Method 1
a first phase-lock loop coupled to the first voltage-controlled oscillator, the first phase-lock loop configured to control an oscillation frequency of the first voltage-controlled oscillator
Implementation Method 2
a first mixing phase-lock loop (PLL) configured to receive outputs from the first and the second d-VCOs
Data Source
AI summary
The disclosed FMCW radar system is configured to achieve a wide synthetic bandwidth of operation and a high range resolution. The disclosed FMCW radar system includes a receiver that combines the intermediate frequency (IF) components of multiple narrowband receivers to achieve the millimeter-scale range resolution. The disclosed FMCW radar system can be easily scaled, which enables it to be deployed in large arrays of antennas in order to attain high angular resolution. Additionally, the operation frequency of the disclosed FMCW radar system enables millimeter level cross-range resolution. In this manner, accurate estimation of the location and/or velocity of the objects within the local-sensing range (and potentially beyond) can be achieved.