The present invention relates to a computer system for measuring real time position of a plurality of animals, which system receives input from a plurality of sensors, communicating with at least tags carried by the animals, which system based of measurement of delay in radio communication calculates the actual position of the animals. It is the first object of the invention to achieve real time position of animals in a limited area. A further object is based of the real time position to analyse the behaviour of each of the animals. The sensors further performs communication with a plurality of reference tags, and performs a calibration of the real time position measured by the system, which system comprises a CPU with at least two cores, which system divides the data processing in a first real time position processing in the first core of the processor, and into a second processing of the activity of the animals performed in the second core of the processor. By using fixed reference tags together with tags, it the computer system performs an automatic calibration of all received signals from animals.
