A device and its use for measuring the instantaneous
velocity vector of objects (1), (3) and (4) moving relative to each other are described, wherein the device is permanently installed on the object (1), referred to as the measuring platform, and, for example,
road traffic moves along with the flow of traffic. By means of the presented device several measuring barriers (7) send beams orthogonal to the movement of the measuring platform (1), each beam being designed as a sequence of temporally separated electromagnetic pulses. If the beams of the measuring barrier (7) are reflected by the stationary objects in the environment (29), the electromagnetic pulses propagated back are registered in the
detector part of the distance measuring sensors (6) of the device and the lateral distance (11) of the objects to the direction of movement x of the measuring platform (1) is calculated from the
transit time of the pulses. The lateral measuring range, defined by the measuring barriers (7), is divided into sensitive distance ranges A (8) and disjoint, non-sensitive distance ranges A (9) by the selection of the areas to be monitored. If an object (3) passes through the sensitive distance area A (8) and a sequence of valid distance measurements is taken in A (8), the computer evaluates the presence of an object in A (8) as, for example, a motor vehicle, and the time of the beginning and end of the passage through A (8) is determined using the current
system time of the computer. From the known distances {x i | i ∈ {1,n}} of the distance measuring sensors {S i | i={1,n}} (6) among themselves and parallel to the direction of movement of the measuring platform (1) and from the associated measuring times t j of passing and the associated distance y i (t j) the
relative velocity vector of the passing object (3), e.g. a motor vehicle, is calculated. The speed of the measuring platform (1) in the direction of movement x is calculated from the ongoing distance data to the lateral environment (29). The
absolute velocity of the object (3) in the x-direction is calculated as the sum of the speed of the measuring platform (1) itself and the x-component of the
relative velocity vector of the object (3) to the measuring platform (1). Continuously measured rotation rates and accelerations of the measuring platform (1) using an
inertial measurement unit enable support for the calculation and correction of the velocities as well as real-time
quality control of the measurement data.