Vehicle-Side Target Location Using Unwrapped Differential RF Phase
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Solution Overview
Problem
The challenge of accurately locating a target, such as a rider or delivery, in urban areas using GPS signals is exacerbated by signal blocking from skyscrapers, crowded environments, bad weather, and night conditions, leading to wasted time, increased CO2 emissions, and a poor user experience.
Innovation Solution
A vehicle-based Wi-Fi system using multiple antennae and a data-driven model, like LSTM, processes CSI data to determine the side of the target by analyzing amplitude and phase differences, without requiring rider photos or heavy computation, achieving high accuracy in both line of sight and non-line of sight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signals are used for target location, then location information can be obtained, but signal blocking by buildings and attenuation in crowded environments causes location failure
Solution Approach 1:
The patent introduces RF signals as an intermediary mechanism to indirectly determine target location. Instead of directly using GPS signals that are blocked by buildings, the system uses RF packets transmitted between vehicle and target to extract CSI data, which serves as a mediator to infer spatial relationship and target side without requiring direct line-of-sight GPS signals.
Solution Approach 2:
The patent replaces the GPS-based mechanical positioning system with an RF signal-based electromagnetic field sensing system. By substituting the reliance on satellite signals with local RF packet exchange and CSI analysis, the system achieves location determination in environments where GPS is blocked, effectively replacing one physical mechanism with another that is less susceptible to the identified harmful factors.
2Measurement precision
If multiple antennae and data-driven models are used to determine target side, then localization accuracy improves to 95.44%, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential features from the RF packets needed for side determination - specifically the CSI data containing amplitude and phase information. By taking out and focusing only on these critical parameters rather than processing entire packets or using heavy computational models, the system achieves high accuracy while maintaining computational efficiency suitable for real-time vehicle systems.
Solution Approach 2:
The patent transforms the raw RF signal data into meaningful parameters by analyzing amplitude differences and phase differences across multiple antennae. By changing the representation from raw packets to extracted CSI parameters, and further to computed phase/amplitude differences, the system converts complex signal processing into simpler comparative measurements that achieve high precision without requiring excessive computational resources.
3Measurement precision
If the vehicle waits for GPS signal availability, then location accuracy may be maintained, but time is wasted and CO2 emissions increase
Solution Approach 1:
The patent performs preliminary localization using RF packets as soon as the vehicle approaches the target area, rather than waiting for GPS signals to become available. By taking preliminary action with the alternative RF-based method, the system determines target side information immediately, allowing the vehicle to proceed without idle waiting time and reducing both time loss and associated CO2 emissions from prolonged engine idling.
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 system achieves 95.44% accuracy in determining the target's side, reducing user frustration and CO2 emissions by providing real-time, privacy-respecting localization in challenging environments.
Implementation Method 1
receive RF packets, via a second wireless connection, from a target at the location
Implementation Method 2
determine a phase difference of subcarriers of the received signals between each of the multiple antennae
Data Source
AI summary
A vehicle side target location method includes receiving a request, via a first wireless connection, for the vehicle to travel to a location, in response to the vehicle being less than a predetermined distance from the location, receiving RF packets, via a second wireless connection having a multiple antenna radio frequency (RF) transceiver having an identification (ID), from a target at the location, identifying packets based on the ID of the RF transceiver, extracting channel state information (CSI) from received signals associated with the identified packets, determining a phase difference of subcarrier phase data of the received signals between each of the multiple antennae, filtering noise of the phase difference of subcarriers based on subcarrier selection to obtain multiple robust phase difference signals, and feeding the multiple robust phase difference signals to a classifier to obtain a side of the vehicle associated with the location of the target.