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The purpose of this paper is to design and test effective indoor navigation solutions for visually impaired people in situations where GPS, bluetooth or Wi-Fi signals are unavailable. The authors use the inertial measurement units (IMU), the compass and the barometer of a smart phone.

The authors have used commercial Android smart phones with IMU, compass and barometer to record a path and to give navigation instructions in an adapted way using a mobility-specific vocabulary. The method proposed is to save paths taking into account different indoor waypoints such as the stairs (change from one floor to another) and the change of direction of the trajectory of the path (e.g. one-fourth turn right or left), recording data from the IMU sensor’s, compass and barometer of the smart phone. Having this information and the characteristics of the each segment (distance, azimuth to the north and pressure) of the path, it is possible to provide functional navigation guidance to the visually impaired subject. Three different visually impaired people (one partially sighted and two fully blind) and three sighted people have tested the paths. The efficiency of the navigation is analyzed in terms of distance and time using the comparison between blind and sighted people.

The main finding is that it is possible to guide visually impaired people some hundreds of meters just using the sensors of a smart phone under certain conditions: the visually impaired person has to understand the guidance instructions and respect some strategies (e.g. not to walk diagonally across vast spaces). Additionally it is observed that the visually impaired participants walked distances, which are not much different to the optimal values. On the other hand; because of their hesitations using their white cane to find free paths, they take in some cases 50 percent more time to arrive (for a few minutes path, this time is not critical and even more efficient than looking for a guide). One thing to highlight is that even with this hesitation, the subjects arrived to the final destination.

This paper demonstrates how an IMU coupled to a compass and a barometer from a Smart Phone employing a spoken mobility language (e.g. next corridor to the left; at the end of the stairs turn right, turn left, etc.) can guide visually impaired people inside buildings.

The aim of this work is to improve navigation solutions for the visually impaired, specifically problems with the heading given by the current GPS antennas. This heading is not reliable when the speed of the pedestrian or of the car is less than 10 km/h. The solution proposed is the use of one inertial measurement unit (IMU) coupled to a GPS, giving the navigation information in the way of heading and distance to the final destination.

The authors have developed their system using their IMU (compass, gyroscope and accelerometer) developed in the laboratory. They have also developed the user interface in one Smart Phone in the Android operating system coupled to the IMU using the Bluetooth transmission. Furthermore, the authors have tested their system in bad GPS reception conditions in Paris. They also used two other GPS systems (Navigon and Ariadne GPS) for testing the best way of giving the information: either “car navigation information: turn left or right at 100 meters … ” or “heading and distance to the final destination: destination at 2 o'clock, 150 meters”.

The main finding is that we can have a better way of navigation (for the visually impaired in pedestrian navigation) using one IMU, coupled to a compass and a GPS antenna in cities even in the case of hesitation of the user, using the information of “heading and distance to the final destination”.

This paper demonstrates how GPS coupled to an IMU can give a better way of navigating for the visually impaired; in especial using the information about heading and distance to the final destination.