Doppler Group Radar Frequency Synchronization
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Solution Overview
Problem
Doppler radars and sonars operating in the same frequency band often experience errors due to interference, where the frequency difference between devices is misinterpreted as Doppler shift, leading to incorrect relative speed detection, especially when multiple devices are in close proximity.
Innovation Solution
Implementing a system where Doppler group radars, sonars, or sensors synchronize their frequency properties using a shared frequency reference signal, ensuring that all devices within the system generate identical frequency signals, thereby avoiding interference and accurately detecting relative speeds and ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple Doppler radars operate in the same frequency band, then the productivity and coverage of the system is improved, but detecting errors occur due to frequency interference between devices
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the frequency properties of radar signals. Specifically, the system modifies the frequency of transmitted signals and local oscillator signals in a coordinated manner between master and slave radars. This allows multiple radars to operate simultaneously in the same frequency band without interference, as each radar's frequency parameters are changed to maintain a consistent frequency relationship, eliminating false Doppler shifts while preserving system coverage.
2Measurement precision
If frequency division, time division, code division, or beam division techniques are used to mitigate interference, then measurement precision is improved, but device complexity and coordination difficulty increase
Solution Approach 1:
The patent merges the frequency control functions of multiple independent radars into a coordinated system. A master radar generates reference frequency signals that are distributed to slave radars, combining their operations into a unified frequency framework. This merging approach eliminates the need for complex individual frequency management at each radar, reducing overall system complexity while maintaining detection accuracy through centralized frequency coordination.
Solution Approach 2:
The system implements feedback mechanisms where slave radars receive frequency reference signals from the master radar and adjust their local oscillator frequencies accordingly. This feedback loop ensures that all radars maintain synchronized frequency properties, automatically correcting any frequency deviations and eliminating the need for complex manual coordination while preserving measurement precision.
3Measurement precision
If pre-assignment of unique frequency, time, or code to each radar is implemented, then measurement precision is improved, but adaptability and ease of operation deteriorate due to limited resources and random vehicle encounters
Solution Approach 1:
The patent applies dynamics by transitioning from static frequency assignment to dynamic frequency coordination. Instead of pre-assigning fixed frequencies to specific radars, the system dynamically adjusts frequency parameters based on real-time operational conditions. The master radar continuously manages frequency allocation, and slave radars adapt their frequencies dynamically through feedback, allowing the system to accommodate any number of radars in any location without requiring pre-planned frequency assignments, thus improving both adaptability and maintaining precision.
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 synchronization allows for effective coexistence of multiple Doppler devices without interference, ensuring accurate detection of relative speeds and ranges by eliminating false Doppler shifts caused by frequency differences between devices.
Implementation Method 1
a radio receiver, for receiving broadcasted signal(s) and based on the signal(s) to generate frequency reference signal and timing signal
Implementation Method 2
signal generator(s) for generating a first signal of continuous wave(s) (CW) and/or a second signal of frequency modulated (FM) CW(s) based on the frequency reference signal
Implementation Method 3
wave transmitter(s) for transmitting a linear combination of the first and second signals as waves for object sensing
Implementation Method 4
Doppler effect has been used in Doppler radar, Doppler sonar and generally Doppler sensors to detect moving objects in many applications, including detecting relative speed thereof
Implementation Method 5
wave receiver(s) for receiving waves associated with objects under detection, mixing received wave signals with local replica signal(s)
Implementation Method 6
a wave antenna or a wave transducer for converting the transmitting signal into waves and sending the waves into propagation media
Implementation Method 7
one of a wave antenna or a wave transducer, for receiving waves associated with objects under sensing and converting the waves into a wave signal
Data Source
AI summary
In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.