Passive Entry Controller Latency Reduction via Flag State
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Solution Overview
Problem
In automotive passive entry systems, determining the location of a remote transmitter fob inside or outside a vehicle is time-consuming, leading to increased latency and unfavorable user experiences, as existing methods require sequential activation of multiple antennas to accurately locate fobs, which can result in delayed actuation of passive functions.
Innovation Solution
A method utilizing interior and exterior antennas to transmit encoded signals to fobs, with the passive entry controller determining the fob's location based on signal strength thresholds and last known flag states, allowing for low-latency execution of passive unlock and lock functions without the need for an interior search when the fob is confirmed outside, and ensuring security by verifying the fob's presence before unlocking or locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential antenna activation is used to determine fob location, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary actions by maintaining flag states that record the last known interior/exterior status of each fob. When a passive entry function is requested, the system first checks these pre-established flags to quickly determine if a full sequential antenna search is necessary, or if the decision can be made immediately based on previously stored location information.
Solution Approach 2:
Instead of always performing the complete sequential antenna activation process, the system applies partial action by using only the flag state check when sufficient. The full antenna sequence is reserved for cases where the flag information is insufficient or ambiguous, thus reducing average activation latency while maintaining adequate location determination precision.
2Productivity
If low-latency determination is implemented without interior search, then productivity is improved, but reliability decreases
Solution Approach 1:
The system implements feedback by continuously updating flag states based on antenna search results and using these flags to guide subsequent decisions. The flag acts as a feedback mechanism that captures the outcome of location determination, allowing the system to make informed security decisions without repeating the full search process, thus maintaining both speed and reliability.
Solution Approach 2:
The flag state serves as preliminary information that pre-establishes the likely location status. When the flag indicates exterior presence, the system can confidently proceed with low-latency unlocking without interior search, as the preliminary flag data provides sufficient security assurance for that decision context.
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 approach reduces activation latency while maintaining high security levels, ensuring the fob is never passively locked inside the vehicle, providing low-latency passive unlocks, and ensuring user security during locking, with accurate inside/outside determination facilitating correct passive entry system operation.
Implementation Method 1
A series of one or more short range antennas may be provided inside and outside of the vehicle for use in determining fob locations. The antennas may be activated sequentially to transmit a series of encoded signals to any nearby fobs, which the fobs then respond to via an onboard transmitter to the controlling system located within the vehicle. The responses from the fobs carry signal level information that was acquired during the activation of the antennas.
Data Source
AI summary
A method and system is disclosed for determining presence of a portable transmitter relative to a boundary. The presence may be determined according to whether the portable transmitter is interior or exterior to the boundary. The boundary may be defined as a wireless boundary that corresponds with an intersection or overlapping portion set by multiple antenna fields.