Tire Pressure Monitoring System Sensor Radio Frequency Measurements for Privacy Concerns

Since the National Highway Traffic Safety Administration mandated the incorporation of tire pressure monitoring systems (TPMSs) in all newly produced passenger vehicles, most vehicle manufacturers have adopted direct pressure measurement. Direct TPMS sensors embedded in each tire require a wireless radio frequency (RF) communications link that broadcasts tire status to the vehicle once per minute from each tire when at speed. Each TPMS message communicates benign information that includes pressure and temperature as well as a static unique identifier that may be exploited, which raises concerns about privacy and spoofing. To focus on concerns related to the TPMS-RF interface, vehicle motion simulations were integrated with live propagation modeling measurements from three classes of passenger vehicles: subcompact car, full-size sedan, and full-size pickup. The RF link and channel models for this TPMS interface with the vehicle resulted in surprisingly long ranges away from the vehicle for the radiation of the unique identifiers. A TPMS sensor redesign could use the proposed RF channel propagation measurements to change the directions of signal propagation while reducing battery consumption by the TPMS sensor (which is affected primarily by RF transmission).