Application of Low-cost Tracking Systems in Educational Training Applications

The paper presents problems related to measurement accuracy of tracking systems, which are widely used in immersive simulations based on Virtual Reality technology. Possibility of tracking movements of the user makes the simulation in virtual environment more realistic. This is very important in case of training simulations of situations, where mistake of an operator would threaten the life and health of himself or other people or could lead to substantial material losses. The authors’ many years of experience in creating interactive Virtual Reality applications allows them to conclude, that possibility of use of professional tracking systems is often not possible for educational facilities like schools or universities due to budget reasons. Professional tracking systems are usually more accurate and have more programming support of their use in Virtual Reality applications than the low-cost solutions. However, low-cost devices are often tens of times cheaper than the professional systems. The research presented in the paper is an attempt of answering the question – how the immersion level related to accuracy of position and orientation representation of real object in a virtual environment influences the evaluation of usefulness of a given tracking system for training applications. A particular attention was paid to tracking of user's movement, which allows him to naturally interact with the computer generated environment. Displaying a simulation reacting properly and smoothly to real movements performed by the user will allow him to develop the most necessary reflexes, which would not be possible using only non-natural interaction devices, such as mouse or keyboard. On the other hand, development of improper reflexes related to user's position being wrongly read can bring more harm than benefit to the training process. The paper presents results of study of accuracy of one of the tracking systems available on the market – the PST 55 system. This device uses retro-active markers, which are widely used also in measurement systems not dedicated to use in the VR system. The real position of tracked objects was verified using an industrial photogrammetric measurement system TRITOP from GOM company. The results of the comparative study allowed to determine how accurate is the studied tracking system and how the accuracy affects the feeling of immersion.