Distributed Radar Clock Synchronization via Communications Bus
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Solution Overview
Problem
Current automotive radar systems face challenges in synchronizing multiple transceivers due to high-frequency local oscillator signals (10-100 GHz) experiencing substantial transmission losses over distances greater than a few cm without the use of waveguides.
Innovation Solution
A radar system that includes a control module, a processing module, and multiple radar transceivers connected via a communications bus. The control module generates a first clock signal and transmits it to the transceivers, which generate a second clock signal for transmitting and receiving frequency-synchronized radar signals. The processing module calculates and compensates for phase differences between the transceivers to process received radar signals coherently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high frequency local oscillator signal is distributed from a master transceiver to slave transceivers, then frequency synchronization is achieved, but substantial transmission losses occur over distances greater than a few cm without waveguides
Solution Approach 1:
The patent introduces a clock signal as an intermediary carrier that transports timing information from the master transceiver to slave transceivers through a communications bus. This clock signal acts as a mediator that enables frequency synchronization without requiring direct transmission of the high-frequency local oscillator signal, thereby avoiding substantial transmission losses while maintaining reliable synchronization across multiple transceivers
Solution Approach 2:
The patent replaces the physical transmission of high-frequency electromagnetic signals (which suffers from transmission losses) with a digital clock signal transmission system. By substituting the direct RF signal distribution with a clock-synchronized digital communication approach, the system eliminates the need for waveguides and reduces transmission losses while achieving the same synchronization objective
2Measurement precision
If multiple transceivers are cascaded to increase the radar aperture, then angular resolution is improved, but phase synchronization becomes difficult to maintain
Solution Approach 1:
The patent implements a feedback mechanism where the master transceiver transmits a clock signal to slave transceivers, and the system measures phase differences between transceivers. The measured phase differences are then compensated by adjusting the clock signal distribution, creating a closed-loop feedback system that maintains phase synchronization across cascaded transceivers, thereby preserving angular resolution improvement while ensuring reliable phase coherence
Solution Approach 2:
The patent changes the approach from directly transmitting and maintaining high-frequency signal phase relationships to using a lower-frequency clock signal for synchronization. By transforming the synchronization problem from the RF domain to the clock domain, the system can maintain phase synchronization across multiple transceivers more reliably while still achieving the desired angular resolution through aperture expansion
Data Source
AI summary
The disclosure relates to a radar system in which multiple radar transceivers are synchronised with a common clock signal. In example embodiments a radar system (200) comprises: a control module (205); a processing module (206); a plurality of radar transceivers (2011-n); and a communications bus (211) connecting the control module (205) to one or more of the plurality of radar transceivers (2011-n), wherein the control module (205) is configured to generate a first clock signal and transmit the first clock signal via the communications bus (211) to one or more of the plurality of transceivers (2011-n) and to receive radar data from the plurality of transceivers (2011-n) via the communications bus (211), wherein each of the plurality of transceivers (2011-n) is configured to generate a second clock signal extracted from the first clock signal and to transmit and receive frequency synchronized radar signals based on the second clock signal, and wherein the processing module (206) is configured to: calculate a phase difference between the frequency synchronized radar signals; compensate for the measured phase difference; and process received radar signals from the plurality of transceivers (2011-n).