V2V Ranging Protocol for Fast Centimeter-Level Vehicle Positioning
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Solution Overview
Problem
Existing vehicle location determination methods, such as GNSS and hybrid positioning, struggle to achieve sub-meter accuracy quickly enough for collision avoidance and autonomous driving due to limitations in time and infrastructure requirements.
Innovation Solution
Implement a ranging protocol that concentrates ranging signals in a short period to achieve highly accurate vehicle positioning, compensating for clock drifts and reducing the number of signals needed, thereby improving efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS and hybrid positioning methods are used for vehicle location determination, then positioning coverage is provided, but sub-meter accuracy cannot be achieved quickly enough for collision avoidance and autonomous driving
Solution Approach 1:
The positioning system is segmented into multiple independent ranging pairs, where each pair independently measures distance between vehicles. This segmentation allows parallel processing of multiple ranging measurements, achieving sub-meter accuracy quickly without requiring complex centralized computation, thus resolving the contradiction between positioning accuracy and positioning time.
Solution Approach 2:
The system performs preliminary synchronization and signal exchange between vehicle pairs before final position calculation. By pre-establishing time references and exchanging ranging signals in advance, the system can rapidly compute accurate positions when needed, reducing the time penalty while maintaining sub-meter accuracy for collision avoidance applications.
2Measurement precision
If traditional ranging protocols are used, then vehicle positioning can be achieved, but clock drifts affect measurement accuracy and require more signals to be transmitted
Solution Approach 1:
The patent changes the time reference parameter from absolute time to relative time between transmitting and receiving vehicles. By measuring time difference of arrival (TDOA) or time of flight (TOF) as a relative parameter rather than absolute time, the system becomes inherently immune to clock drifts. This parameter transformation eliminates the need for frequent synchronization signals, reducing energy consumption while maintaining ranging accuracy.
Solution Approach 2:
The system uses reciprocal signal exchange where each vehicle copies the ranging measurement approach and applies it to the other vehicle. This symmetric copying of the ranging protocol allows both vehicles to independently verify measurements and compensate for any residual timing errors without requiring additional correction signals, thereby reducing overall energy consumption while maintaining precision.
3Reliability
If more ranging signals are transmitted to compensate for clock drifts, then positioning accuracy can be maintained, but energy and resource usage increase
Solution Approach 1:
Each vehicle independently performs ranging measurements and calculations using its own receiver and processor. The system is self-sufficient and does not require external correction signals or additional infrastructure to compensate for timing errors. This self-service approach maintains positioning reliability through distributed redundancy while minimizing energy loss by eliminating unnecessary signal transmissions.
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
The proposed ranging protocol enables centimeter-level vehicle positioning with reduced energy and resource usage, suitable for real-time applications like collision avoidance and autonomous driving.
Implementation Method 1
a transceiver of the first vehicle determines a first time-of-arrival (ToA) for a ranging signal transmitted by a transceiver of a second vehicle
Data Source
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AI summary
Aspects of the present disclosure are directed to device-to-device (D2D) and, more particularly, vehicle-to-vehicle (V2V) communication in which an efficient ranging protocol allows efficient ranging-assisted vehicle positioning. A vehicle transmits a first slot ID in a first control period, to indicate a first time slot for transmitting a first ranging signal in a ranging cycle including a plurality of time slots. The vehicle transmits the first ranging signal in the first time slot in the ranging cycle. From a second vehicle, the first vehicle receives a second ranging signal in a second time slot that is different from the first time slot in the ranging cycle. The first vehicle determines a first time-of-arrival (ToA) of the second ranging signal when received by the first vehicle, and transmits the first ToA in a second control period.