Directional Radar Sensing for Short-Range Vehicle Detection
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Solution Overview
Problem
Current time-of-flight ranging technologies face challenges in accurately detecting and measuring objects at short distances due to the need for extremely short transmit pulses, which results in broad spectral emission and regulatory compliance issues, making it difficult to detect slow-moving or stationary objects in outdoor environments like parking spaces or near traffic signals.
Innovation Solution
A directional sensor using a true time-of-flight radar with a transmit pulse train of 1-3 nanoseconds and an adjustable receive window, integrated with a camera and capable of low-power communication, to effectively detect and measure objects by optimizing pulse repetition frequency and receive window timing, allowing for precise range measurement and vehicle identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transmit pulse of 1-3 nanoseconds duration is used for time-of-flight ranging at short distances, then adequate separation between transmit and receive windows is achieved, but the emitted spectrum becomes very broad up to or above 1 GHz causing regulatory compliance issues
Solution Approach 1:
The patent uses periodic pulse transmission with carefully controlled pulse repetition frequency to achieve adequate separation between transmit and receive windows while maintaining regulatory compliance. The periodic action allows the system to use shorter pulse widths (1-3 nanoseconds) for precise ranging while managing spectral emissions through controlled transmission timing.
Solution Approach 2:
The patent adjusts multiple parameters including pulse width, pulse repetition frequency, and receive window timing to resolve the contradiction. By optimizing these parameters together, the system achieves both precise short-range measurement and regulatory compliance, rather than relying on a single parameter adjustment.
2Object-generated harmful factors
If aircraft radar's pulse widths are used in the microseconds range, then regulatory compliance is easier to achieve, but there will not be a separation between the transmit pulse and receive pulse for nearby objects
Solution Approach 1:
The patent implements dynamic adjustment of receive window timing based on the detected object's distance. The receive window is positioned to follow the transmit pulse by a time corresponding to the round-trip distance, allowing the system to adapt to different ranging distances and maintain both regulatory compliance and measurement precision.
Solution Approach 2:
The system performs preliminary calibration to determine the relationship between pulse transmission and echo reception timing. This preliminary action establishes the basis for subsequent dynamic receive window positioning, enabling the system to handle both close and distant objects effectively.
3Productivity
If the pulse repetition frequency is increased to improve detection rate, then productivity increases, but the spectral emission and interference with other systems increases
Solution Approach 1:
The patent employs feedback mechanisms where the system monitors the detection environment and adjusts the pulse repetition frequency accordingly. This feedback allows the system to optimize detection rate while maintaining spectral emissions within regulatory limits by reducing frequency when interference risks are detected.
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 reliable detection and measurement of objects at short distances while complying with regulatory frequency limits, providing precise range data and vehicle identification, enhancing applications such as parking space management and traffic enforcement.
Implementation Method 1
a directional sensor for the purposes of detecting the presence of a vehicle or an object within a zone of interest on a roadway or in a parking space by transmitting a microwave transmit pulse such that a total distance occupied by the pulse in air is less than 5 feet
Implementation Method 2
radiating the transmitted pulse by a directional antenna system to enable the transmit pulse to be radiated preferentially towards a detection area
Data Source
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AI summary
A method of using a directional sensor for the purposes of detecting the presence of a vehicle or an object within a zone of interest on a roadway or in a parking space. The method comprises the following steps: transmitting a microwave transmit pulse of less than 5 feet; radiating the transmitted pulse by a directional antenna system; receiving received pulses by an adjustable receive window; integrating or combining signals from multiple received pulses; amplifying and filtering the integrated receive signal; digitizing the combined signal; comparing the digitized signal to at least one preset or dynamically computed threshold values to determine the presence or absence of an object in the field of view of the sensor; and providing at least one pulse generator with rise and fall times of less than 3 ns each and capable of generating pulses less than 10 ns in duration.