Abstract: A plurality of positional sensing devices are situated at regular intervals within an environment and collect data for tracking objects moving within the environment. Phase shift of modulated Doppler pulses reflected from the sensing devices to objects are measured and converted into positional data indicating positions of detected objects within the environment. Associated timestamp data is also collected by the positional sensing devices. The positional data and associated timestamp data is aggregated from the plurality of positional sensors, and the aggregated positional data and is clustered to determine point clouds which are associated with the detected objects. The clusters are tracked by tracklets that track the position of each cluster over time. Trajectories for each detected object are determined by connecting tracklets together that are associated with the same detected object.

Abstract: This invention relates to a proximity alarm system for a worker operating in the vicinity of a moving machine and a method of operating such a system. The proximity alarm system comprises a machine unit for mounting on the moving machine and a worker unit configured to be carried about the person of the worker. The machine unit comprises a boundary field generator for generating an electric field that extends outwardly from the machine. The worker unit comprises an electric field pick-up sensor for detection of the electric field and a worker alarm unit comprising, for example, an audible alarm. The worker alarm unit is actuated in response to the electric field pick-up sensor detecting the electric field, thereby alerting the worker to the proximity of the moving machine.