A cooperative radar system for collision avoidance and communications between vehicles

In order to improve reliability, security on roads or exploitation of automatic guided transports, many sensors are being developed to equip vehicles. Research has been carried out at INRETS and IEMN on low cost microwave collision avoidance sensors for metro guided transports and for road vehicles. For this goal, an original radar system has been designed in ours laboratories. It is based on cooperative collision avoidance radar which uses a transponder inside targets. The proposed system is made of a couple of microwave transmitting and receiving equipment fixed on each vehicle, one ahead and the other behind. In order to avoid interferences between the transmitted and the received signals, two duplex frequencies of 2.2 and 2.4 GHz are used respectively for downlink and for uplink. The system is based on pseudo-random sequences combined with a correlation receiver and has a broadband of about 50-100 MHz. This bandwidth has been exploited to establish a high data flow communication between sensors. The aim of this paper is to describe the mock-up realized and technical solutions developed using spreading spectrum techniques to allow multi-user access and to combine the two desired main functionalities, localization and communication, inside a unique cooperative radar system. The system performances have been evaluated in terms of BER using simulations and main results will be presented