Abstract: In a method of temperature stabilization of a reference voltage, in a first prespecified time interval, a current having a first constant amperage and, in a second prespecified time interval, a current having a second constant amperage and alternately applied to a pn junction. During the first and second time intervals, voltages at the pn junction are supplied to an input of an analysis circuit. The analysis circuit forms the difference between the two voltages and adds the difference in a weighted manner to a voltage obtained from one of the first and second amperages. The weighted result is applied to an output of the analysis circuit. The first constant amperage is applied to the pn junction during both the first and second prespecified time intervals and the second constant amperage is applied to the pn junction during the second prespecified time interval.

Abstract: The invention provides a process and apparatus for the detection of obstacles by means of ultrasound waves having an enhanced ability to distinguish between echoes caused by obstacles and those caused by interference signals. Ultrasound pulses are emitted by an ultrasound transmitter unit, and are received by an associated ultrasound receiver unit. (A plurality of such transmitters and receives may also be used.) Ultrasound echoes detected by the receiver units are used to form echograms in which detected echoes are projected. The echogram thus measured is used to generate an analysis echogram, based on information contained in the measured echograms. In particular, the most recent analysis echogram is modified depending on the size and location of echoes contained in the measured echogram. Signals contained in the analysis echogram are then compared with predetermined threshold values to distinguish between echoes reflected from obstacles and echoes due to interference.

Abstract: An unmanned movable and steerable vehicle has a device for locating obstacles in relation to a coordinate system which moves along with the vehicle. Ultrasonic waves transmitted by transmitters on the vehicle in the driving direction thereof and ultrasonic waves reflected back to the vehicle by obstacles and received by receivers on the vehicle produce information whereby vehicle steering and/or braking signals function to prevent a collision. For the purpose of an interference-free, accurate location determination of an obstacle in relation to the coordinate system moved along with an unmanned movable and steerable vehicle, a single pulse is transmitted by two adjacent ultrasonic waves and also received again at the transmission sources. In a progression by one another sound source, after the first sound source has been switched off, the same procedure of transmitting a single pulse and, in the presence of an obstacle, the reception of a reflected ultrasonic echo is possible.