We present the realization of a cooperative radar system for ranging applications with integrated data-transmission capability. The simultaneous transmission is performed by the radar-hardware without the necessity of additional components or an auxiliary data-link. Therefore, the data are directly embedded in the transmitted chirp of a frequency-modulated continuous-wave radar sensor. A second station, acting as receiver, uses an identical, but unmodulated chirp for down-conversion. The resulting signal then is processed by a non-coherent demodulator setup, extracting the communication data. Measurement results from transmission of messages with different bit-rates are shown. By utilizing existing radar-hardware a transmission rate of up to 256 kbps is possible, without the need of a dedicated transceiver. Additionally, a method to optimize the ranging results by variable distribution of the available signal power between distance-measurement and communication system is presented.

We present the implementation of a cooperative radar system on a gantry rail crane for distance measurements in an industrial environment. The measurement approach is based on the dual-ramp frequency-modulated continuous-wave principle, using identical sensor-nodes at the endpoints of the range of interest. Pseudo-range information is exchanged via a dedicated data-link between these stations. At the sensor-node a flexible high-performance signal processing and remote management engine is implemented. The system setup is controlled by a single host-PC, which is used as a man–machine interface for configuration of the remotely controlled measurement stations, system surveillance, and visualization of the measurement data. Indoor characterization of the developed hardware is sufficient for an efficient calibration of the system, minimizing distance offsets. On-site measurements at distances up to 1000 m with an accuracy better than 2 cm confirm the performance of the ranging system. Furthermore, the results are verified by simulation.

Mobile robot systems are being used more often in tasks that protect human operators from dangerous environments, but these benefits can be easily lost if the robots spend much of their time being repaired. This implies that any increment in their reliability will also improve their benefits. One way to achieve this is by adding redundant elements to the robot, but this adds complexity and cost to the design. On the other hand, cooperative mobile robots formed by members with the same basic structure provide a natural redundancy of elements, which may be used for reliability improvement. This work presents an architecture that takes advantage of the analytical and sensor redundancy present in groups of cooperative mobile robots in order to increase the reliability of the whole system. First, the design of the architecture is portrayed and the faults to be detected are described. The different layers of the system are then explained and analyzed using several simulations to test their capabilities and limitations. Finally, the experimental results on a group of small mobile robots are shown, validating the results delivered by simulations. These results show that the proposed architecture is able to detect and isolate correctly most of the faults tested.