SU125930A1 - Photoelectric device for determining the boundaries of clouds in flight - Google Patents

Description

Among the well-known cloud meters there is no instrument that allows determining the volume boundaries, the shape of the clouds and the height of its upper boundary without using an artificial light source.

The proposed ceilometer, containing a photographic lens with an angle of coverage of 50-70 °, in the focal plane of which a block of photocells is mounted, connected through an amplifier to an oscilloscopic indicator or radio receiver, has no marked drawbacks. The device is based on the use of a natural sharp difference between the coefficient of the brightness of clouds and the coefficient of brightness of the terrestrial aerolandscape. It does not need an artificial light source, which is used in all known cloud meters. The device uses a block of photocells and a switch, which improves the accuracy of determining the nature of clouds over the flight region. A switch designed to sequentially take electrical signals from photocells allows the switching frequency to vary depending on sensor parameters and flight mode, and the photo lens has a wrap angle of 50-70 ° to increase light cloud information. In addition, the device compensates for the inequality of sensitivity of the constituent elements of the photocell block by adjusting the scheme before each flight and reducing the distortions in the cloud information to completely insignificant quantities; it almost gives an electronic photograph of cloudiness over a very large area, and this area increases with increasing flight altitude. over the clouds, allows you to judge the limits of clouds by the time interval between similar marks on the indicator tape, and also has a constant Operational advantages in shape, size, weight, etc. compared with the known.

A schematic diagram of the device is shown in FIG. one.

If9 125930-2 -

The device consists of the following elements: a photographic lens /, a photocell 2 installed in the focal plane of the lens, amplifier 3, power source 4. The amplifier’s electrical signals can be fed to the oscilloscope 5 for direct recording or to a radio transmitter 6 for transmission to the ground.

In flight, the image of the terrain in the focal plane of the device

moves at a speed of -r-,

where: V с-speed of the aircraft;

f-lens focal length; H - flight altitude.

At each fixed point in time, a photocurrent flows in the photocell circuit, which is proportional to the integrated brightness of the terrain objects and clouds projected onto the photocell. During the flight, the photocurrent reproduces in time the actual brightness characteristic of the flying aerolandscape. The oscillogram of the photocurrent will look similar to that shown in FIG. 2

This type of oscillogram of the photocurrent is determined by the following factors: the luminance coefficient of the terrestrial aerolandscape is on average (for summer) 0.14 and only certain objects have a luminance factor higher than 0.2; the luminance factor for clouds varies between 0.6 and 0.9, i.e., significantly (4 or more times) exceeds the reflectivity of the terrestrial aerolandscape.

The fluctuations of the cloud brightness factor are determined by the state of cloudiness. For example, thunderstorm clouds have a brightness factor of about 0.5. Thus, it is enough to get into the field of the lens of a small cloud, as the photocurrent increases markedly. When flying over a solid cloud, the photocurrent amplitude is mainly determined by the cloud luminance factor, i.e. the state of cloudiness. Waveform analysis allows determining with sufficient accuracy the state of clouds on the flight route.

A variation of the circuit provided in FIG. 1 is a diagram depicted in FIG. 3. Here, in the focal plane of the lens 7, not one but several photocells 8 are located, located on a line perpendicular to the direction of flight of the aircraft.

The image of the terrain projected onto the focal plane of the lens is reproduced in the form of the photocurrents of many photocells, with each photocell probing a certain strip of terrain. In this case, the angle of view of each photocell is significantly narrowed, and the latter more accurately record the appearance of even small clouds.

- As can be seen from FIG. 3, in this version of the device, an additional switching element 9 (mechanical or electronic) is used, the purpose of which is to connect the photo cells in series to the amplifier 10, which is supplied from the current source 11 and sends signals to the oscilloscope 12 or to the radio transmitter 13.

The oscillogram here will look like the one shown in FIG. 4. Each photocell generates a photocurrent, the amplitude of which is proportional to the integrated luminance of terrain objects and clouds at the time of switching. The frequency of the switch is chosen from the condition of obtaining a full-fledged picture of the terrain. As can be seen from FIG. 4, with the increase in the number of photocells using the entire angle of view of the lens, the accuracy of measuring cloudiness is significantly improved.

The minimum dimensions of photocells (for the same lens) can be selected, based on the condition that the predetermined dimensions of the clouds are determined on the oscillogram. Strip width on

the flight path of the aircraft, viewed by photoelectric devices, is determined by the formula L N,

where: I - flight altitude;

a-side of the photocell, perpendicular

flight direction; n is the number of photocells.

Object invented shadows

A photoelectric device for determining the boundaries of clouds in flight, containing photocells, a lens, a switch, an amplifier, a radio transmitter and a radio receiver, characterized in that, in order to determine the volume boundaries of clouds without the use of artificial light sources, in it a block of photoelectric cells is placed perpendicular to the focal plane. in the direction of flight, and a photographic lens with a coverage angle of 50-70 ° is used to increase the light information about clouds.

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Fig z flight