Digital Time-of-Flight Sensing for Close-Range Distance Measurement
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Solution Overview
Problem
Existing radar systems face limitations in accuracy for measuring distances to targets due to large resolution, energy leakage, and switch-over time between transmission and reception, which can interfere with close-range measurements and obscure target detection.
Innovation Solution
A method and system that transmit digital electromagnetic signals with specific patterns, receive and digitize echoes, and use correlator devices to determine time of flight by comparing receive patterns to echo signals, employing coarse, fine, and ultrafine stage determinations to enhance measurement precision and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transmit/receive switch is used to control transmission and reception timing, then the system can manage wave transmission and echo reception, but the switch requires non-zero switching time that prevents accurate measurement of close-range targets
Solution Approach 1:
The patent extracts and removes the transmit/receive switch from the system architecture. By using separate transmitting and receiving antennas without a switching mechanism, the system eliminates the switching time delay that prevented close-range target measurement, while maintaining reliable target detection through the antenna array configuration
Solution Approach 2:
The patent combines the transmitting and receiving functions into a unified radar system architecture where both functions operate simultaneously through different antennas. This merging eliminates the need for time-sequential switching while maintaining the ability to perform both transmission and reception operations
2Device complexity
If energy leakage occurs from transmitting antenna to receiving antenna, then the system can maintain simple antenna configuration, but the leakage interferes with and obscures target distance measurement and motion detection
Solution Approach 1:
The patent applies local quality by assigning different functional characteristics to different antennas in the array. Each antenna element has optimized properties for its specific role (transmitting or receiving), and the spatial distribution of antennas creates directional radiation patterns that minimize mutual interference while maintaining measurement precision
Solution Approach 2:
The patent introduces signal processing techniques as intermediaries that separate the transmitted signal from received echoes. Through correlation processing and pattern matching, the system distinguishes between direct leakage signals and genuine target reflections, thereby maintaining measurement accuracy despite the presence of energy leakage
3Productivity
If analog electromagnetic waves are transmitted and echo strength/frequency is measured, then the system can detect target presence, but the resolution for calculating target distance is relatively large and accuracy is limited
Solution Approach 1:
The patent replaces traditional analog signal measurement methods with digital signal processing. By converting received echoes to digital form and applying correlation algorithms with known transmit patterns, the system achieves higher resolution distance measurement through precise temporal and spectral analysis of the digital signal data
Solution Approach 2:
The patent employs periodic transmission of coded waveforms with specific patterns. By transmitting repetitive signal sequences and correlating received echoes with these known patterns, the system achieves enhanced measurement resolution through the accumulation of multiple measurement cycles and precise timing of signal features
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
This approach allows for precise measurement of separation distances and detection of target motion, overcoming the limitations of existing systems by improving resolution and reducing interference, enabling accurate distance calculation even for close-range targets.
Implementation Method 1
transmitting an electromagnetic first transmitted signal from a transmitting antenna toward a target object
Implementation Method 2
receiving a first echo of the first transmitted signal that is reflected off the target object
Data Source
AI summary
A method (e.g., a method for measuring a separation distance to a target object) includes transmitting an electromagnetic first transmitted signal from a transmitting antenna toward a target object that is a separated from the transmitting antenna by a separation distance. The first transmitted signal includes a first transmit pattern representative of a first sequence of digital bits. The method also includes receiving a first echo of the first transmitted signal that is reflected off the target object, converting the first echo into a first digitized echo signal, and comparing a first receive pattern representative of a second sequence of digital bits to the first digitized echo signal to determine a time of flight of the first transmitted signal and the echo.