TPMS Tire Localization Using RSSI Signatures and ABS Wheel Angles
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Solution Overview
Problem
Current tire localization methods in vehicle tire pressure monitoring systems (TPMS) are costly and unreliable, particularly due to the need for multiple host devices and accelerometers, and are susceptible to environmental variations, which affects the accurate identification of tire positions and corrective measures.
Innovation Solution
A single or multiple wireless host devices use received signal strength indicator (RSSI) signatures, matched with wheel angles derived from anti-lock braking system (ABS) data, to uniquely identify TPMS sensor locations by generating and correlating RSSI signatures over wheel rotations, reducing the need for multiple devices and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are placed in each TPMS sensor to measure wheel rotation, then tire localization accuracy is improved, but device cost and power consumption increase
Solution Approach 1:
The patent replaces the mechanical accelerometer-based rotation measurement system with a wireless signal-based system. The host device uses RSSI measurements of wireless communications from TPMS sensors, combined with ABS wheel speed data, to determine wheel positions and perform tire localization without requiring accelerometers in each sensor.
Solution Approach 2:
The patent makes the existing TPMS sensors multi-functional by enabling them to serve both their original pressure/temperature monitoring function and a new localization function. The sensors continue to transmit pressure data wirelessly, and this same wireless communication channel is now used for RSSI-based position determination, eliminating the need for separate localization hardware.
2Reliability
If multiple wireless host devices are used to measure signal strength from different TPMS sensors, then tire localization reliability is improved, but device cost increases
Solution Approach 1:
The patent merges the functions of multiple host devices into a single host device. By combining RSSI measurements from a single host device with ABS wheel speed data from the vehicle's existing anti-lock braking system, the system achieves reliable tire localization without requiring multiple separate host devices for each wheel.
Solution Approach 2:
The patent introduces ABS wheel speed data as an intermediary element that bridges the gap between a single host device and multi-wheel localization. The ABS data provides wheel rotation information that, when combined with RSSI measurements, enables the single host device to accurately determine which sensor corresponds to which wheel position.
3Ease of operation
If signal strength measurements are used to differentiate wheel locations, then tire localization is achieved, but measurement precision deteriorates due to environmental variations
Solution Approach 1:
The patent uses ABS wheel speed data as an intermediary to compensate for environmental variations in RSSI measurements. By correlating RSSI signal strength changes with wheel rotation data from the ABS system, the method creates a more stable and accurate localization signal that is less susceptible to environmental interference.
Solution Approach 2:
The patent changes the parameter used for localization from absolute signal strength to signal strength variations correlated with wheel rotation. By focusing on the dynamic changes in RSSI as wheels rotate rather than static signal levels, the system becomes more resilient to environmental variations while maintaining measurement simplicity.
Data Source
AI summary
Techniques are described for using one or more wireless host devices to perform tire localization of TPMS sensor data by determining received signal strength indicator (RSSI) signatures that are unique to the wireless communication channel between a host device and each TPMS sensor. RSSI signatures represents a periodic variation of the wireless communication channel between a host device on the car body and a TPMS sensor in a rotating tire. Characteristics of the communication channel is a function of the wheel angle and is periodic with wheel rotations. The RSSI signatures may be created by matching RSSI measurements of packets received by the host device from a TPMS sensor with wheel angles derived from wheel speed sensor (WSS) data of the anti-lock braking system (ABS). The RSSI signatures are a unique marker of each wheel that may be used to identify the locations of the TPMS sensors for tire localization.