Angle of Arrival Estimation Using Reference Signal Correlation
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Solution Overview
Problem
Current satellite positioning systems, such as GPS, face challenges in accurately determining the angle of arrival (AoA) of signals in indoor environments due to limitations in legacy Bluetooth protocols like version 4.2, which affects navigation services and raises security concerns, especially in band-limited systems like Bluetooth.
Innovation Solution
A method involving a receiving device with multiple antennas that processes a packet signal from a transmitter to estimate the AoA by generating a reference signal based on received wireless signals, using techniques like Gaussian frequency shift modulation and beam-forming to correlate signal components and determine phase differences across multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy Bluetooth protocols (version 4.2) are used for signal transmission, then device compatibility is maintained, but angle of arrival estimation accuracy deteriorates due to band-limited constraints and lack of tone signal support
Solution Approach 1:
The patent creates a reference signal that copies the essential characteristics of the transmitted packet signal (frequency, modulation type, packet structure) without requiring the actual tone signal. This reference signal is then used for correlation-based AoA estimation, enabling accurate measurements with legacy Bluetooth protocols that lack dedicated tone signal transmission capability
Solution Approach 2:
The patent transforms the approach by changing from tone signal-based AoA estimation to packet signal-based estimation. It extracts relevant parameters from the packet signal (frequency, modulation characteristics, timing) and uses these to create a reference signal that enables accurate AoA measurement without requiring protocol changes
2Measurement precision
If tone signals are used for AoA estimation, then measurement accuracy is improved, but adaptability to legacy Bluetooth protocols deteriorates since they do not support dedicated tone signal transmission
Solution Approach 1:
The patent makes the AoA estimation method universal by enabling it to work with both modern protocols that support tone signals and legacy Bluetooth 4.2 protocols that use packet signals. The reference signal generation approach adapts to the available transmitted signal type, making the system compatible across different protocol versions while maintaining measurement capability
Solution Approach 2:
The reference signal acts as an intermediary between the transmitted packet signal and the AoA estimation process. Instead of directly using the packet signal or requiring a tone signal, the reference signal mediates the correlation process, enabling accurate AoA estimation while working with legacy Bluetooth protocol constraints
3Measurement precision
If multiple antennas are used for signal reception, then AoA estimation capability is enabled, but device complexity increases
Solution Approach 1:
The patent divides the signal reception function across multiple antennas, with each antenna independently receiving and processing the signal. The processed signals from multiple antennas are then correlated with the reference signal to determine phase differences, enabling AoA estimation while maintaining modular, manageable system architecture
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 enables accurate AoA estimation even with non-tone packet signals, improving indoor navigation and security by overcoming limitations in legacy Bluetooth protocols, enhancing the reliability of location-based services.
Implementation Method 1
obtaining a reference signal emulating one or more aspects of the first packet signal as transmitted by the transmitter based, at least in part, on a received wireless signal transmitted from the transmitter; and estimating an angle of arrival of the first packet signal based, at least in part, on the processed packet signal and the reference signal
Data Source
AI summary
Disclosed are systems, devices and methods for determining an angle of arrival (AoA) of a signal transmitted between devices. Particular implementations enable obtaining measurements of AoA from signals that are not pure tone signals. In one aspect, a reference signal may emulate one or more aspects of a packet signal as transmitted by a transmitter. An AoA of the packet signal may be determined based, at least in part, on the packet signal and the reference signal.