Two-Tone Radar Gesture Detection System
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Solution Overview
Problem
Existing gesture detection systems face challenges in compactness, affordability, and integration into portable devices due to the complexity and size of wideband radar detection systems, making them unsuitable for use in devices like smart watches or mobile phones.
Innovation Solution
A two-tone radar detection system that alternates between transmitting two radar tones to concurrently detect absolute distance and relative movement of a target object, using a simplified signal source and direct-conversion homodyne receiver to generate digital samples for processing, enabling accurate gesture recognition without the need for complex hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FMCW radar detection is used for gesture detection, then detection accuracy is improved, but device complexity and size increase
Solution Approach 1:
The patent divides the radar detection function into two separate single-tone radar systems operating at different frequencies (e.g., 2.4 GHz and 5 GHz). Each system independently detects specific aspects of gesture (one for absolute distance, another for relative movement), avoiding the need for a complex wideband FMCW radar system while maintaining detection accuracy through frequency diversity.
Solution Approach 2:
The patent makes each single-tone radar system serve multiple purposes by using them to detect both absolute distance and relative movement through frequency comparison. The same hardware components (antenna, signal generator, receiver) are reused across different frequencies, achieving multi-functional detection capability without proportionally increasing hardware complexity.
2Measurement precision
If FMCW radar detection is used for gesture detection, then detection accuracy is improved, but device size increases
Solution Approach 1:
The patent segments the detection function across two separate single-tone radar systems rather than using one large FMCW radar system. Each system uses standard, compact components suitable for portable devices, and the overall form factor is reduced by using established radar modules rather than custom wideband radar hardware.
Solution Approach 2:
The patent changes the operating frequency parameters between the two radar systems (e.g., 2.4 GHz and 5 GHz) to achieve the detection capabilities previously requiring wideband FMCW radar. This parameter approach allows the use of smaller, more compact single-frequency radar components instead of a larger wideband system.
3Measurement precision
If FMCW radar detection is used for gesture detection, then detection accuracy is improved, but cost increases
Solution Approach 1:
The patent segments the detection function into two independent single-tone radar systems that can be manufactured using standard, off-the-shelf radar modules. This approach avoids the need for expensive custom FMCW radar hardware and allows each system to be produced using established supply chains and manufacturing processes, reducing overall cost.
Solution Approach 2:
The patent uses inexpensive single-tone radar modules that are easier and cheaper to manufacture than FMCW radar systems. These modules can be produced using standard electronic components and assembly processes, significantly reducing the manufacturing cost while achieving the required detection accuracy through the two-frequency approach.
Data Source
AI summary
A gesture detection system uses two radar tones to concurrently detect absolute distance and relative movement of a target object. A radar-based detection device alternates transmitting a first radar tone and a second radar tone via a radar-emitting device, and then captures a first return signal and a second return signal that are generated by the first radar tone and second radar tone reflecting off the target object. The radar-based detection device demodulates the return signals into a first set of quadrature signals and a second set of quadrature signals and, in some cases, generates a first set of digital samples and second set of digital samples from the respective quadrature signals. Various aspects process the first set of digital samples and second set of digital samples to concurrently identify absolute distance and relative movement and, at times, determine an in-the-air gesture performed by the target object.