JPS60166879A - Receiving sensitivity adjusting system - Google Patents

Abstract

PURPOSE:To obtain a proper video receiving and display state over a total periphery, in a radar apparatus, by setting individual receiving sensitivity to a receiving sensitivity adjustment (STC) generator at every plural azimuth directions. CONSTITUTION:A min. sensitivity adjuster 15 and a slope adjuster 16 are set to a region 1, while a setting switch 17 is pressed, so as to obtain a video display state easiest to view. A corresponding adjustment amount is inputted to a sensitivity setting device 18 and the position of an antenna is inputted through an angle/digital converter. Each adjustment amount and the azimuth of the antenna at said time are collectively recorded to a memory part 22. Similar operation is also performed to regions 2, 3, 4. Operation is performed in interpolation calculation parts 23, 24, and a min. sensitivity adjusting amount and a slope adjusting amount are outputted to an STC generation part. An STC signal is outputted to an intermediate frequency amplification part 9 from an STC generator 14 and a proper amplification degree is imparted to each region.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to reception sensitivity adjustment (hereinafter referred to as rs'rOI) in the amplification of received radio waves in radar equipment.
(Also called meOonstant 0ontrol))
This paper relates to the improvement of the method.

The conventional methods of this type are shown in Figures 1, 2, and 3 below.
This will be explained using figures.

Figure 1 shows the configuration of a typical pulse radar device.
) is a transmitter that receives the synchronization pulse (a) and outputs a microwave pulse in synchronization with it; (3) is a transmitter/receiver switcher that switches between transmitting radio waves to the antenna and receiving radio waves from the antenna; (4) is a radio wave (5) is an antenna drive unit that rotates the antenna in a horizontal plane;
6) is an angle detector that detects the angular position of the antenna and converts it into a signal. Next, (7) is a local oscillator for superheterodyne detection.

(8) is a mixer that mixes the output from the local oscillator (7) and the radio waves received by the antenna and converts it into an intermediate frequency signal.

(9) is an intermediate frequency amplifier that amplifies the intermediate frequency signal, and (9) is a detector that converts the intermediate frequency signal into a video signal.

(Ill is a video amplifier that amplifies the video signal, α2 is a cathode ray tube that receives the video signal and displays PPI, (I3
Q4 is a deflection circuit that receives the angle signal and deflects the electron beam modulated by the video signal to a predetermined position on the cathode ray tube A3, and Q4 generates a signal synchronized with the synchronization signal that controls the gain of the intermediate frequency amplifier (9). 8TO generator, α
9 is a minimum sensitivity adjuster that controls the minimum sensitivity amount for the 8TO generator α, (lS is the same (slope adjuster that adjusts the slope for the 8TO generator I). Further, FIG. 3 is a diagram showing the relationship between the synchronization signal (a), the 8TO signal [with]), and the detected video signals (c) and (d).

Next, the operation of the conventional system will be explained using these.

A synchronization signal generator (1) generates a synchronization pulse (a) that determines the period of radio wave emission of the radar. This pulse is sent to the transmitter (
2) A microwave with K plus a certain pulse width is output, supplied to the antenna (4) via the transmitter/receiver switch (3), and emitted into the air. Further, this radio wave is reflected by various reflecting objects and received again by the antenna (4).

The radio wave received by the antenna (4) passes through the transmitter/receiver switcher (3) and enters the mixer (8), where it is superheterodyned and received by the output from the local oscillator (7) to become an intermediate frequency signal. This signal is the signal Φ from the 8TO generator I)
After being amplified by an intermediate frequency amplifier (9) whose gain is controlled by a detector α, it becomes a video signal after being detected.
will be displayed. At this time, the video signal modulates the brightness of the electron beam scanning on the side of the cathode ray tube α, but for the 9 display positions, the angular position of the antenna (4) at that point is determined by the angle detector (6) and the deflection circuit ( 11 receives and deflects the brightness-modulated electron beam toward an antenna (4).Furthermore, the antenna (4) is rotated by an antenna driver (5).

Since the PPI changes from moment to moment and is repeated over the entire circumference, a PPI display as shown in FIG. 2 is obtained as an example on the cathode ray tube aa.

Generally, in a pulse radar, the power of the reflected wave received by the radar is expressed by the following equation.

−4・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・（11Pr=K・几, Pr is the received power, K is the transmitted power,
R is a proportionality constant determined by the antenna gain transmission wavelength and the radar effective reflection area of the reflecting object, and is the distance to the reflecting object. It is clear from the above formula that the received power is equal to 4 of the distance.
The reflected wave from a short distance is strong and the reflected wave from a long distance is weak. Therefore, if the amplification degree is adjusted at a long distance, it becomes an intermediate frequency amplifier (9) at a short distance.
However, it becomes saturated and it becomes impossible to compare the strength of the received radio waves. In order to prevent this, the aforementioned 8TO generator Q4 is set so that the gain of the intermediate frequency amplifier (9) is lowered for radio waves received from a short distance, and the gain is maximized for radio waves received from a long distance. The 8TO signal synchronized with a) is applied to the intermediate frequency amplifier (9) as a gain control signal. FIG. 3 is an example showing this relationship.

8TO which controls the gain of the intermediate frequency amplifier (9) in synchronization with the synchronization pulse (a) from the synchronization signal generator (11) and the synchronization pulse (a) from the synchronization signal generator (11)
Also, the video signal <c> after detection when not subjected to gain control and the video signal (d) when subjected to gain control are shown. Also, person and B in the figure are each 8T.
It shows the minimum sensitivity adjustment part and the slope adjustment part in the O signal.

According to such a conventional method, the minimum sensitivity adjuster 119
．． If the slope adjuster αe is set to a predetermined level, the STO signal will be the same in all areas regardless of the direction, so adjusting it in one direction will cause problems such as insufficient gain in the other direction and excessive gain in the other direction. However, in order to avoid this, the operator must manually adjust the required direction for each scan, which is cumbersome.

In order to improve the drawbacks of the conventional method described above, the present invention allows the minimum sensitivity adjustment and slope adjustment of the 8TO signal to be set for any plurality of directions.

Furthermore, a method is provided in which an appropriate minimum sensitivity adjustment amount and slope adjustment amount can be set by interpolation between the direction in which the setting is made and a direction in which another setting is made.

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. FIG. 4 is a block diagram of a pulse radar device using the sensitivity setting device shown in FIG. 5. In the figure (11
,121,+31. -, (141 is the same as shown in Fig. 1. Note that a!9 and ao are also the minimum sensitivity adjuster and slope adjuster, respectively, as in Fig. 1, but for the sake of explanation below. 8TO on 4 areas
It is assumed that four of each are provided so that the signal can be adjusted. Also [1? ) is a setting switch that registers the completion of each of these four pairs of adjustments, and 1 second is a sensitivity setting device that sets each adjustment amount of the 8TO signal. Figure 5 is a diagram explaining the sensitivity setting device, and in Figure 2 (19, (11,
+1? ) is the same as shown in Figure 4, and (19
is a buffer circuit for each signal.

■ is an analog-to-digital converter that converts the signal from the minimum sensitivity adjuster a and slope adjuster (11) into a digital amount, and ofJ is an angle-to-digital converter that converts the angle signal from the angle detector (6) into a digital amount. converter,(
2) is a part of the memory that records each digital amount mentioned above, ■
and (goods) is the minimum sensitivity adjuster a! 9 and slope adjuster aS for each k (Q adjustment amount (vAl, VA2.VA5° VA4 and v81 e v82 e vf35- v
f3A ) is set at the angle (θ1.θ2.θ3.θ4
) is an interpolation calculation unit that interpolates the minimum sensitivity adjustment amount (VA) and slope adjustment amount (Vs) for the azimuth ( ).

This is what performs the calculation.

Here, i=1.2.5.4 and θ5=01゜vA
5=■A1. ■55-vs1. Also, (c) is (1
9. This is a control circuit that controls data exchange between JQυ, (2), (c), and (goods).

The operation of FIG. 4 will be explained below using these.

The transmission and reception of microwaves, the amplification and detection of received radio waves, and the display on a cathode ray tube (Iz) are the same as in the conventional system, so here we will explain the operations related to reception sensitivity control, focusing on the sensitivity setting equipment. , 8TO for explanation
The four areas where signals can be set individually are area 1. Area 2.
Area 3. and region 4. First, while pressing the setting switch αη for area 1, set the minimum sensitivity adjuster α and the slope adjuster H so that the video display condition is most easily viewed. For the sensitivity setter value, the corresponding minimum sensitivity adjustment (c) and adjustment amount from the slope adjuster Qe are converted to analog signals through buffer circuit 0.
The signal is input to the digital converter (2), and the position of the antenna (4) at that time is input through the angle-to-digital converter t2a. At this time, when the control circuit (c) receives a signal indicating the pressed state from the setting switch
) and the antenna direction (θ1) at that time are stored in a part of the memory (
2) are recorded all at once.

Similarly, area 2. Area 3. Each adjuster is set so that the display condition is easy to see even if there is one in area 4, and each adjustment amount and antenna direction are also recorded in a part of the memory.

At the same time, the interpolation calculation unit (To) and (Incorporated) perform calculations based on equations (2) and (3) based on the above input data, and calculate the 8TO for the antenna direction at that time.
The minimum sensitivity adjustment amount (VA) and slope adjustment amount (v
8) is output to the 8TO generating section a4.

The 8TO generator U outputs an STO signal based on these control amounts to the intermediate frequency amplification section (9).

Appropriate amplification is given to each region, and cathode ray tube az
Moreover, it is possible to obtain stable images for all areas, and it is also possible to avoid the operator's troublesome operations for each area.

Further, in the above-described embodiment, two types of adjustment amounts, the minimum sensitivity adjustment and the slope adjustment, are used for the 8TO signal, but in principle, there is no restriction on the type as long as the reception sensitivity is controlled. Also, regarding the control amount regulator, if the difference in the setting direction is determined by the control circuit (c), etc.
It is not necessary to provide a plurality of regulators, and it is possible to use only one pair of regulators.

As described above, in the present invention, the receiving sensitivity control amount is set regarding amplification of received radio waves from any direction.

By interpolating the required reception sensitivity control amount between the set direction and the direction in which another reception sensitivity control amount was set, appropriate reception can be achieved for each area. Set the sensitivity.

There is an advantage that a uniform video display state can be achieved over the entire circumference.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional pulse radar device. FIG. 2 is a diagram showing an example of video display on a cathode ray tube. Fig. 3 is a diagram showing the relationship between a synchronization signal, an 8TO signal, and a detected video signal, Fig. 4 is a block diagram of a pulse radar device according to the present invention, and Fig. 5 is a sensitivity setting according to the present invention. In Figure 9, (1) is a synchronizing signal generator, (2) is a transmitter, (3) is a transmitter/receiver switch, (
4) is an antenna, and (5) is an antenna drive unit. (6) is an angle detector, (7) is a local oscillator, and (8) is a mixer. (9) is an intermediate frequency amplifier, CI (I is a detector, (1
11 is a video amplifier, a2 is a cathode ray tube, (11 is a deflection circuit, Q41 is an 8TO generator, a!9 is a minimum sensitivity adjuster, aS is a slope adjuster, aη is a setting switch,
(I is a sensitivity setting device, (19 is a buffer circuit, (A)
is an analog-to-digital converter. Qa is an angle-to-digital converter, ■ is a part of memory. (To), (Good) is an interpolation calculation section, and (C) is a control circuit. In the drawings, the same or corresponding parts are designated by the same reference numerals. @ 1 Figure 2 Figure 2 0 degree Figure 3

Claims (1)

[Scope of Claims] In a radar device used for monitoring the ground surface or near the sea surface, an intermediate frequency amplifier that amplifies received radio waves converted to an intermediate frequency signal, and an 8TO generator that generates a signal to control the gain of the amplifier. and an adjuster that sets the reception sensitivity control amount for multiple azimuth directions, records the control amount of the adjuster, and performs interpolation calculations between the two successive directions to determine the required reception sensitivity control amount. By providing a sensitivity setting device that calculates the sensitivity of the 8TO generator and sets the sensitivity for the 8TO generator, individual reception sensitivity settings can be made for each specific azimuth direction. Proper video reception and display conditions all around KL5
A reception sensitivity adjustment method characterized by: