GPS and Inertial Measurement Unit (IMU) as a Navigation System for the Visually Impaired

Abstract

The current GPS (Sirf 3) devices do not give the right heading when their speed is less than 10 km/h. This heading is also less reliable when the GPS is used in the big cities where it is surrounded by buildings. Another important problem is that the change of orientation of the visually impaired needs a long delay to be detected by the GPS due to the fact that the GPS must reach certain speed for obtaining the new heading. It can take from 2 seconds to 15 seconds depending on the GPS signal conditions. In order to avoid these problems, we have proposed the use of one GPS coupled to the IMU (inertial measurement unit). This IMU has one 3 axis compass, a one axis gyroscope and one 3 axis accelerometer. With this system, we can update the heading information every second. The user Interface is developed in the Smart Phone which gives the information of heading and distance to the destination. In this paper, we are also going to describe the advantages of using the heading and distance to the final destination, updated every second, to navigate in cities.