PressureRef4PIL – Position reference with direction estimator for Indoor location systems


Indoor navigation is an important enabling technology for applications such as navigation aid, location-based information and advertisement, as well to provide enhanced emergency response.

Several approaches have been proposed in recent years but none of them was able to achieve meter-level accuracy. More recently, a new approach has emerged as a solution for the accuracy issue. This approach relies on inertial sensors to track a user by continuously estimating displacement from a known position. Most recent smartphones are equipped with several sensors (e.g.: accelerometer, gyroscope, magnetometer) that provide the necessary hardware for this indoor navigation systems based on inertial sensors.

As previously stated, these indoor navigation systems, based on inertial sensor, define the actual position estimating displacement from a previously known position. On the other hand, these systems rely on low-cost sensors that introduce position errors due noise itself but also drift (from gyroscope) and magnetic interference (from magnetometer). Eventually, these cumulative errors will lead to an erroneous estimation current position.

This project proposed the development of pressure surface with communication capabilities to work as position references for an accurate indoor tracking system.

The main idea was to study and develop a pressure surface with an array of piezoelectric sensors that detect persons walking direction and send this information to the smartphone either using low energy Bluetooth or an ultra-low frequency antenna. The later can interact with compass enabled phones in order to give those accurate references (less than 1 meter precision) and user orientation and direction.


Author: João Barbosa

Type: MSc thesis

Partner: Faculdade de Engenharia da Universidade do Porto

Year: 2015



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