DE1176217B - Arrangement for displaying direction and distance for pulse radar devices with rotating antenna - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: H 04 ρ

Number: File number: Registration date: Display day:

German class: 21 a4 - 48/63

D 23151 IXd / 21 a4
June 15, 1956
20th August 1964

The invention relates to radar assemblies of the type in which echo signals on a with certain Pulse repetition rate described track are recorded. The echoes can be in Be mapped in the form of a deflection from the track, e.g. B. for devices with A shield, or as a brightness modulation of a track, such as B. in a representation of an all-round search device in which a radial time axis is rotated in synchronism with an antenna so that the targets are spaced from the center of rotation of the track and in angular positions around the same corresponding to the actual ones Distances and directions are shown on the screen.

The object of the present invention relates to an arrangement in such radar devices, in which the display of all fixed targets in a radar image deleted or significantly in their strength is weakened.

The invention is accordingly based on a known arrangement for indicating direction and Distance for impulse radars with rotating antennas, at which signals transmitted during a Around the antenna to suppress echoes from fixed targets with corresponding received signals of the previous antenna circuit delayed by a storage tube can be combined in opposite directions.

A pulse radar device with a panorama screen and fixed target masking by counter-circuit is known the received impulses of the respective antenna circuit and the through a storage tube correspondingly delayed reception pulses from a previous antenna revolution. With this well-known The device only stores the signals every second antenna cycle. Should from everyone Incoming radar messages are used, it is necessary to have two separate ones Use storage tubes. A switching system is required because the reading and Otherwise the writing rays would interfere with each other.

In contrast, the arrangement according to the invention for indicating direction and distance for pulse radar devices with a rotating antenna is designed in such a way that the reading beam of the storage tube scans simultaneously with the incoming radar message a particularly small fraction of a period of the antenna revolution is delayed and that on the memory arrangement for indicating direction
and distance for pulse radars with
rotating antenna

Applicant:

Decca Limited, London

Representative:

Dipl.-Ing. Dr. M. Herzfeld, patent attorney,

Düsseldorf, Kreuzstr. 32

Named as inventor:
Robert Matthews, London

tube radar message to be written with which the write beam is modulated for the same delay time is delayed.

The most important advantage of the inventive design of such an arrangement over the Known apparatus discussed above is that, although only one storage tube is used, all of them incoming radar messages can be made usable.

In the case of a radar system, which is a brightness-modulated track on the screen of a cathode ray tube has, the display arrangement can be designed such that it generates signals that with the video signals fed to the grid circuit of the cathode ray tube will. These additional signals must be opposite to the radar image signals Own polarity.

In the case of a radar system with a deflection modulated track on a cathode ray tube the signals of the corresponding deflection device emanating from the aforementioned display arrangement are fed.

The present invention is primarily intended to suppress large area signals from solid Aim, e.g. B. from sprawling buildings or hills. In such cases it generally is insignificant if the opposing signals do not match the corresponding radar image signals extinguish exactly, especially when it comes to image displays with light-modulated traces, because in this case the small amplitude or the thin edge of the remaining echo is added serves to indicate the unwanted signal weakly,

409 657/316

deleted or weakened in their amplitude. In the drawing is a schematic of an impulse radar system illustrated with a pulse generator 10, the pulse frequency of which by an exciter-5 pulse generator 11 is controlled. The power of the transmitter is transmitted through a scanning antenna 12; and the echoes picked up by the targets are sent to a receiver by this scanning antenna 13 supplied, which outputs a video signal.

The scanning antenna 12 is mechanically coupled to a resolution device 14, which is one of a low frequency oscillator 15 coming low frequency alternating voltage in sine and Resolves cosine components, which the angular

while at the same time the recognizability of the image is retained. When the radar reception and imaging system is not saturated, the arrangement allows targets that are not included in the representation are e.g. B. to make moving targets visible in the areas that would otherwise be caused by the unevenness of the Are clouded at the bottom.

In the case of a brightness-modulated radar device, the above-mentioned representation is on the storage tube preferably held in a form similar to the radar image. For example, if the radar image should be the image of an all-round search device, the memory display should preferably be off a similar picture showing the goals at intervals

from a center of rotation and at angular intervals of 15 position of the antenna. The two of the same corresponding to the respective distances, output signals of the dissolving device 14 are and location shows. It should be noted, however, that there are two demodulators 16, 17 supplied which which generate direct voltages derived from such a storage tube, which correspond to the sine and Co signals proportional to both a B-screen and a sine of the angular position of the antenna Image of an all-round search device are supplied 20 are. These two DC voltages are respectively can. used to measure the amplitude of two sawing

The write beam of the storage tube is deflected in such a way that the sawtooth generators 18 and 19 generated that he can steer himself constantly flocking at a short distance. Each of the relaxation generators 18, located behind the reading beam, while the closure 19 also includes an amplifier with phase reading beam synchronous with the scanning of the radar inverter, so that two sawtooth output image scans. Thus, the reading beam is created signals of opposite polarity almost exactly one image period (i.e. in the case of a will. The two output signals of the Kippgene image In the case of an all-round detector, an antenna 18 has a pair of deflection coils period) behind the writing beam. Through this attachment 20, 21 of a cathode ray tube 22 and the two Order is the cancellation or attenuation of 30 output signals of the ripple generator 19 one at a time Signals from the first image, which are fed to the previous second pair of deflection coils 23, 24. By going track appear, so that now this arrangement is - in a known manner - a only moving targets are shown radial scan on the screen of the cathode ends. Such an arrangement enables the radiation tube to be achieved, this scanning being synchronous using a typical radar device, the display 35 is rotated with the rotation of the scanning antenna, of targets moving at a very low speed If the video signal of the receiver 13 is now uneven, z. B. up to about half a mile per indirect tube 22 would be fed to the Hour, move on. To modulate the delay of the write beam of the same, one would do so The beam is preferably just sufficient to collapse an image of a locator on the screen Influencing the reading and writing 40 hold.

To prevent beam. The extent of the delay The ripple generators 18, 19 are by means of a

is not critical, however, provided that it is sufficient from a gate pulse generator 50, about the mutual influence of the two, which controls the moment of the beginning and the To prevent rays. The required delay duration of the sawtooth pulse shapes is determined. This tion of the write beam can be generated by feeding the 45 gate pulse generator, which is generated by gate pulses Signals through an electrical delay current - the received radar transmission pulses by means of a circle can be achieved. The trigger pulse for the threshold circuit 51 are synchronized, which At the beginning of the track for the write beam, the video signal is supplied from the receiver 13 moderately from the trigger pulse for the radar image, the threshold value circuit in such a way Using the same delay current 50 directs it to the large amplitudes of the transmit circuit derived to ensure that the impulses separates from the other video signals, The demodulators 16, 17 also control four

exact positions appear on the screen, with further ripple generators 52, 53, 54 and 55. The the actual extent of the deceleration used, the two tilt generators 52, 53 feed the four disruptions is irrelevant. Assuming that 55 steering coils 56, 57. 58, 59, which the reading beam the delay is small, can control the position of a storage cathode ray tube 60. the Trace of the write beam on the screen of the storage flip-flop generators 52, 53 are made by the Torimpulscherröhre (For example, in the case of the image of an all-round search generator 50 controlled, but the tilting device the angular position and the center of rotation) rators 54, 55 a short time after the other four controlled by the same control signals that triggered 60 ripple generators, this delay the position of the read beam trace and the trace of the by a delay electrical circuit 65 Determine the radar image. If desired, it can be effected which of the video output signals Differential amplifiers in the video circuits for which are supplied by the receiver 13. The video radar image and the storage tube are used. signals will be after they have the delay current below An embodiment of the invention will have passed through an amplifier 66 finding described with reference to the at- and fed to a threshold value circuit 67, lying drawing, which is a block drawing of a showing the large amplitude of the transmission pulse from the Radar imager, in which fixed targets separate from other video signals. The transmission pulses

are fed to a gate pulse generator 68 for generating gate or fade-out pulses that are used for this purpose serve, the beginning and the duration of the sawtooth waveforms emanating from the ripple generators 54, 55 to control. In addition, the output power of the amplifier 66 is used to generate the To modulate the write beam of the storage cathode ray tube 60. It can thus be seen that the time distractions for the writing beam in terms of the time deviations for the reading beam and for the Picture tube 22 are delayed by a short period of time and that the same delay also applies to the Image signals is applied which are used to modulate the write beam. The output power from the reading beam of the tube 60 becomes amplified by means of an amplifier 70 and fed to a combiner 71, where it is connected to the video output of the receiver 13 is mixed in such a way that the signals coming from the amplifier 70 can be deducted from the received signals. The output of the combiner 71 becomes the Grids fed to the tube 22 to modulate the brightness of the beam thereof.

The storage tube 60 is preferably of the type in which the reading beam is randomly stored Clears signals, although it is optionally possible to have its own clearing circuit to delete all stored signals, once per revolution of the antenna.

It can be seen that according to the arrangement illustrated in the drawing, the write beam the storage tube is deflected so that it always remains a short distance behind the reading beam, while the reading beam scans synchronously with the picture tube 22. The reading beam is thus located - provided that adjacent tracks do not overlap on the storage tube - on the Storage tube almost exactly one image period (i.e. one antenna revolution in the case of an all-round search image) behind the writing beam. This arrangement causes a decrease in amplitude or a cancellation at the input of the tube 22 for those signals shown on the previous screen appear. However, even if adjacent tracks on the storage tube overlap should and the delay of the write beam is such that the read beam is that immediately before reads the written track, the arrangement works in such a way that signals that are on the previous Track appear to be reduced in amplitude or deleted. In any case, the picture will Show moving targets, while fixed targets are reduced in amplitude or deleted will. It should be noted in particular that this arrangement requires only a short delay, the duration of which is not critical. This delay (which is around 10 to 30 microseconds, for example could be) can easily be generated by the electrical delay circuit 65 will. The video signals and the gate pulse for the write beam time deflections become exactly the same Time delayed since the gate pulse is obtained from the video signals; and it is still to be noted that the gate pulses for the ripple generators 18, 19, 52 and 53 of received signals in the same Way are derived like the gate pulses for the ripple generators 54, 55, thereby ensuring is that there is no difference in the timing of the Torimp'ulse, apart from the delay introduced by the delay circuit 65.

In the arrangement according to the drawing, the representation on the storage tube is similar to that required Image executed. This is not necessary, but beneficial because it is similar to use Allows deflection systems and thus facilitates the achievement of similar distractions. Further are all relaxation generators with respect to the amplitude of the sawtooth pulses by DC voltages controlled which of demodulated sine and cosine components obtained from a resolver will. This arrangement further contributes to a high degree of similarity between the to enable different scans to be achieved.

Claims (4)

Patent claims: 1. Arrangement for the display of direction and distance for pulse radars with rotating Antenna, in which signals that are received during an antenna revolution for the purpose of Suppression of echoes emanating from fixed targets with corresponding, through a Storage tube opposite to the delayed reception signals of the previous antenna revolution are combined directed, characterized in that the reading beam of the The storage tube scans at the same time as the incoming radar message, so that the write beam track, in order to avoid the reading beam from being disturbed by the writing beam in particular a small fraction of a period of the antenna revolution is delayed and that the radar message to be written on the storage tube with which the write beam is modulated is delayed by the same delay time. 2. Arrangement according to claim 1, which has an amplifier for amplifying the by the reading beam having read signals, characterized in that the amplifier is so in the Gain can be regulated so that the echoes emanating from fixed targets are suppressed will. 3. Arrangement according to claim 1 or 2, characterized in that the write beam is triggered by the immediately received transmission pulses after a corresponding delay. 4. Arrangement according to one of the preceding claims, characterized in that the Reading beam and the beam of the actual picture tube through the immediately received transmission pulses can be triggered without delay. Considered publications:
French Patent No. 930 240;
British Patent Nos. 604 672, 643 521,
256. 1 sheet of drawings 409 657/316 8.64 © Bundesdruckerei Berlin