Asea Aktiebolag

Asea Ab

Sven-Erik Soderstrom

Folke Lofgren

Anders Persson

Bernt Ling

In a cloud height measuring device, the attenuation caused by deposits on the output and/or receiver windows of the device (e.g. by rain and/or dirt) are compensated for by measuring the degree of reflection of light from the window(s) when illuminated by light pulses. By means of a special measuring sequence in a processor unit included in the cloud height measuring device, light pulses separate from those used for the cloud height measurement itself, can be employed to assess the extent of the fouling. The measurement energy can then be controlled during the cloud height measurement proper, so that the total attenuation, caused by rain and dirt on the windows, is properly compensated for.

Cloud height measuring device with compensation for window fouling

The invention relates to a fiber optic temperature-measuring apparatus, based on the photo-luminescence of a solid material which is subjected to the temperature to be measured. The apparatus is characterized in that several sensors made of such a temperature-sensitive luminescent material are located in various places, each one being connected to a light-emitting diode via at least one optical fiber. Luminescent light emitted from each sensor is arranged to be supplied, via at least one separate optical fiber, possibly partially via the above-mentioned fiber and a fiber branch, to a receiver unit, common to all the sensors, the excitation light signal from each light-emitting diode being time-division multiplexed.

Fiber optic temperature-measuring apparatus

In visibility measuring apparatus, a transmitter including at least one transmitter optic for emitting light signals and at least one receiver including at least one receiver optic for receiving the emitted light signals are positioned in a measuring base defined by the distance between the at least one transmitter optic and the at least one receiver optic. A central unit controls the light emitting signals and processes the light signals received from the at least one receiver optic. Signal light conductors interconnect at least some of the transmitter and transmitter optics, the central unit and the transmitter and the receiver optics and the central unit. In a modified embodiment each measuring base may include a separate transmitter optic and a separate receiver optic. Additionally, calibration signals may be transmitted from the central unit to each receiver optic by additional light conductors with separate light conductors for returning a reference signal from each receiver optic to the central unit. Temperature induced variations in the transmission capacity of the signal light conductors can be compensated by using a coil of light conductors in parallel therewith.

Visibility measuring apparatus using light conductors

A visibility measuring system which comprises a radiation emitter which is capable of emitting radiation such as laser pulses in the medium in which the visibility range is to be measured, the radiation emitter being rotatable to emit the pulses in varying directions, a number of reflectors which are spaced at differing predetermined distances from the radiation emitter and laterally with respect to one another, and a radiation receiver for receiving and detecting radiation pulses reflected from each reflector; the measuring system including a device responsive to the amplitude of reflected pulses to control the direction of pulse emission from the radiation emitter to reflect from the not more than two reflectors needed to identify the current visibility range.

Automatic visibility measuring system

A cloud altitude measuring means for detecting the existence of and the distance to a cloud comprising a light emitting means, a light receiving means, a plurality of integrators activated at separate time intervals to receive the output signal from the light receiving means, a signal summation device to receive and determine the difference between the signals in the said integrators, and a signal processing circuit to receive the output signal from the signal summation device, which circuit comprises a memory circuit to store a first series of measurement value pulses from said summation device and a comparison device for comparing the first series of measurement value pulses stored in the memory with a second time delayed series of measurement value pulses to detect a cloud echo when the comparative difference between the measurement value pulses exceeds a specified value.

Cloud altitude measuring apparatus

The existence of an object within a predetermined range interval is detected by emitting a series of signal pulses for each range interval and detecting the echo signal pulses. First and second integrators that are respectively responsive to echo signal pulses and to noise pulses integrate the detected signals during different time intervals. The integrated signal and noise components are compared to determine their difference and an indicating pulse is generated by a level detector whenever the compared signals are greater than a predetermined value. First and second delay circuits are provided for controlling the interconnection of the integrators to the respective detectors. Third and fourth time delays respectively control the zeroizing of the integrators and the connection of the level detector to the comprising means.

Cloud altitude measuring means

In cloud measuring apparatus a transmitter emits light pulses towards the cloud in a receiver located adjacent the transmitter and detects light reflected from the cloud, the receiver having a sensitivity that with increasing distance from the receiver first decreases to a certain distance and at greater distances from the certain distance the sensitivity increases.

Growing community of inventors

Vesteras, Sweden

Sven-Erik Soderstrom