Vehicle Wireless Ranging Using Polarized Antennas and Phase Selection
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Solution Overview
Problem
Existing distance measurement systems using Bluetooth communication struggle with accurate distance estimation due to varying phase differences and signal strength fluctuations, particularly when radio waves are blocked by human bodies, and using multiple antennas increases cost and power consumption.
Innovation Solution
A wireless system utilizing two antennas on the vehicle and one on the mobile terminal, with different polarization directions and wavelengths, to measure distance based on received signal strength indications and phase differences, reducing the need for additional antennas and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If four antennas are used for distance measurement, then measurement accuracy is improved, but cost increases
Solution Approach 1:
The patent changes the parameter of antenna polarization direction by using two antennas with orthogonal polarizations (first antenna with first polarization direction, second antenna with second polarization direction different from the first). This parameter change allows the system to overcome signal blockage issues and maintain measurement accuracy without increasing the number of antennas to four, thereby resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If four antennas are used for distance measurement, then measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent uses two antennas with different polarization directions instead of four antennas, which reduces the power consumption associated with antenna switching while maintaining measurement accuracy. The orthogonal polarization configuration allows the system to capture sufficient signal information with fewer antennas, directly addressing the power consumption issue.
3Device complexity
If RSSI is used for distance estimation in high-frequency Bluetooth communication, then communication is simplified, but measurement accuracy deteriorates due to phase difference variation
Solution Approach 1:
The patent changes the approach from using only RSSI to using phase difference information between multiple channels in combination with RSSI from two antennas with different polarizations. This parameter change in the measurement method allows the system to maintain simplicity while significantly improving distance estimation accuracy by compensating for phase difference variations.
Solution Approach 2:
The patent combines multiple measurement parameters (RSSI from first antenna, RSSI from second antenna, phase difference between channels) to create a composite measurement approach. This composite method leverages the strengths of each parameter while mitigating their individual weaknesses, achieving both simplicity and accuracy.
4Device complexity
If one antenna is used for communication, then device complexity is reduced, but measurement accuracy deteriorates when radio waves are blocked
Solution Approach 1:
The patent changes the parameter of antenna polarization direction to create two antennas with orthogonal polarizations. This parameter change enables the system to maintain communication and measurement capabilities even when radio waves are blocked, as the orthogonal polarization provides alternative signal paths, resolving the contradiction between device complexity and measurement precision under blockage conditions.
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
Accurately measures distance between the vehicle and mobile terminal with high precision while maintaining cost-effectiveness by using fewer antennas, ensuring consistent measurement accuracy regardless of the mobile terminal's position.
Implementation Method 1
a phase difference between a plurality of channels is proposed
Implementation Method 2
a first polarization direction of the first antenna is different from a second polarization direction of the second antenna
Implementation Method 3
propagation characteristics of Bluetooth radio waves
Data Source
AI summary
A wireless system capable of accurately and inexpensively measuring a distance between a vehicle and a mobile terminal is provided. When a first sum of a first received signal strength indication and a second received signal strength indication is larger than a second sum of a third received signal strength indication and a fourth received signal strength indication, a distance between the vehicle and the mobile terminal is obtained from a phase difference between a first radio wave and a second radio wave. When the first sum of the first received signal strength indication and the second received signal strength indication is smaller than the second sum of the third received signal strength indication and the fourth received signal strength indication, the distance between the vehicle and the mobile terminal is obtained from a phase difference between a third radio wave and a fourth radio wave.