A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network

Area of Science:

• Robotics
• Wireless Sensor Networks
• Indoor Positioning Systems

Background:

• Accurate indoor positioning is crucial for applications like robotics and navigation.
• Existing systems often face challenges with accuracy and robustness in complex indoor environments.
• Wireless Sensor Networks (WSN) offer a flexible platform for developing such systems.

Purpose of the Study:

• To develop and implement a robust, high-accuracy ultrasonic indoor positioning system (UIPS).
• To enhance time-of-flight (TOF) estimation for improved distance measurement.
• To validate the system's performance in real-world positioning experiments.

Main Methods:

• Utilized a network of wireless ultrasonic beacons with known coordinates.
• Employed WiFi for data transmission and radio frequency (RF) for precise time synchronization (1 μs accuracy).
• Developed a new time-domain envelope detection method based on the least squares method (LSM) for TOF estimation.

Main Results:

• The novel TOF estimation method demonstrated effective envelope detection and filtering.
• Achieved high precision and low variance in pseudo-range measurements (0.61 mm and 0.23 mm, respectively).
• A maximum location error of 10.2 mm was recorded for a moving robot under line-of-sight conditions.

Conclusions:

• The developed UIPS provides a robust and accurate solution for indoor positioning.
• The proposed LSM-based TOF estimation significantly improves measurement accuracy.
• The system shows promise for applications requiring precise real-time localization.