JPH0213876A - Monopulse radar apparatus - Google Patents

Abstract

PURPOSE:To automatically prepare a reference table within a short time by receiving the operation order command inputted by a command input means to execute the initial calibration of the azimuth direction of the reference table according to a scheduled program. CONSTITUTION:An operation order command for performing the initial setting of the azimuth direction of a reference table is inputted by the switch operation of a command input means 17. A control means [containing a CPU 9 and a ROM (for control) 10] receives the operation order command inputted by the command input means 17 to execute the initial calibration of the azimuth direction of the reference table according to a predetermined program. As a result, only by inputting the operation order command by merely performing switch operation, the initial calibration of the reference table is automatically performed and the initial calibration of an azimuth direction can be automatically processed within a short time by simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a monopulse radar device that detects, for example, the position and altitude of an aircraft target.

(Prior art) In recent years, in target detection using 5SR (Secondary Surveillance Radar), an angle measurement method using monopulse has been used as a method for detecting the target direction due to its high accuracy, high detection rate, and low repetition frequency. However, it is beginning to be adopted due to its advantages such as being able to detect the target direction.

Regarding target detection using this monopulse angle measurement method, see "About Long Range P, P, 5B-58r S S R, 1985 Electronic Navigation Research Institute Research Presentation, Lecture Summary (May 1988)" Since the details have already been described, a brief explanation will be given here.

In general, a monopulse radar device is composed of an SSR antenna 2, a transceiver 3, and a target detector 4, as shown in FIG. transponder (
(not shown). Then, from the response signal, a response code signal shown in FIG. 3 and a monopulse signal synchronized with this response code signal are demodulated,
An azimuth reference pulse generated in accordance with the rotation of the SSR (one pulse generated when the antenna beam center passes through the magnetic north, hereinafter referred to as A RP [AziIIuthRef'eren
ce Pulse] signal) and an azimuth change pulse (pulses generated at a fixed number per antenna rotation, hereinafter referred to as
1sel signal) is input to the target detector 4.

In the target detector 4, the target orientation θT at the time when the antenna beam captures the target is determined by the on-bore sight angle θON
s off boresight angle is θopp, θT−θON+
It is determined by θopp. Here, on-bore sight angle θON
As shown in Fig. 4, is the direction of the antenna beam center from the magnetic north, and is the off-boresight angle θ. ,.

As shown in the figure, is the deviation angle of the target direction from the antenna beam center direction (here, a clockwise deviation from the beam center is defined as positive (+), and a counterclockwise deviation is defined as negative (-)). It is.

The on-bore sight angle θON can usually be determined by counting the ACP signals after the antenna beam center passes the magnetic north, that is, after the ARP signal is generated and until the target is detected. Also, the off-bore sight angle θ. 2
．． is the reference value in Fig. 6 obtained from the figure-8 curve characteristic shown in Fig. 5 (indicates the relationship between the off-boresight angle θ.2 and the monopulse value, which is mainly determined by the characteristics of the antenna and receiver). A table (generally a lookup table (
The monopulse value of the monopulse signal obtained from the response signal is given as an address to a reference table.

By the way, in a conventional monopulse radar device, when an antenna or a receiver is newly installed or replaced, an initial calibration in the azimuth direction is performed. This initial calibration of the azimuth direction creates a reference table unique to the radar using monopulse signals from a fixed target whose exact azimuth is known in advance, and plays a very important role in performing the monopulse n'' angle. Responsible for (
For monopulse/IP1 angle, the azimuth accuracy is already in practical use with a quantization unit of about 0.022"(3[i0°/2")). The above initial calibration will be explained below.

(1) First, a transponder (calibration target) whose exact direction is known (such as one measured by optical means) is installed. The direction data is input into the target detector 4 in advance.

(2) Rotate the antenna several dozen times and repeat the question several times to actually collect the response code signal (for identifying that it is a calibration transponder) and monopulse signal from the transponder.

(3) Accurate azimuth θa of the calibration target during data collection and antenna beam center azimuth (on-bore sight angle θos
) is known, so from the relationship θ0FF-θT-θON, the off-boresight angle θ for the monopulse value is determined as shown in FIG. 1. Pro-soto sequentially. For example, if the antenna beam and target are
When the orientation relationship is as shown in c), in Fig. 7, A,
It will be plotted at positions B and C.

(4) In the plot of Fig. 7, in the collected data, for a certain monopulse value, there is not necessarily one off-boresight angle θopp, but there may be two or more, or there may be no total heat, so the off-boresight angle Data interpolation (for a certain monopulse value, the corresponding off-boresight angle θo
pp) or averaging (if there are two or more corresponding off-boresight angles θopp for a certain monopulse). Furthermore, if the figure-8 curve obtained by plotting is distorted due to measurement variations,
Correct the figure 8 curve as appropriate.

(5) If the data variation is large, (2) ~
The operation (4) is performed again, and the finally obtained reference table is stored in the nonvolatile memory so that it can be used in actual operation.

In order to perform the above initial calibration, the conventional target detector 4 is constructed as shown in FIG.

In FIG. 9, a response code signal, a monopulse signal, an ARP signal, and an ACP signal output from the transceiver 3 are input to the target detector 4. The response code signal is used to detect the code of the calibration target in the initial calibration, and is input to the radar interface 7. The monopulse signal is converted into a digital signal by an A/D (analog/digital) converter 5 and input to a radar interface 7.

The ARP signal and ACP signal are input to the antenna direction detector 6. This antenna azimuth detector 6 calculates azimuth data θON of the center of the antenna beam by counting the ACP signal using the ARP signal as a clear signal.
This antenna orientation data θ. N is input to the radar interface 7.

The calibration target azimuth input switch 23 uses optical means or the like to accurately determine the azimuth J? The calibration target azimuth data θT that has been determined is manually inputted, and this calibration target azimuth data θT is input to the radar interface 7.

On the other hand, the arithmetic processing unit (CPU) 9 connects the radar interface 7 and the data RAM via the system bus 8 according to the control program stored in the control ROM 10.
Non-volatile memory 12 for storing IL reference table, TTY
Interface 13, serial interface 15
TTY (non-procedural data/command input/output device) connected to the TTY interface 13.
When an initial calibration execution command is input by the operator 24 through 14, a response code signal is input, a calibration target code is detected from the response code signal, and the initial calibration mode is entered and the following processing is performed.

First, the monopulse value, antenna beam center azimuth data θON, and calibration target azimuth data θT output from the radar interface 7 are stored in the data RAM II via the system bus 8, respectively. Here, TTY14
The operator 24 issues operation commands such as start data collection, end data collection, continue data collection, output collected data, output reference table data, output processing parameters, correct collected processing data, update reference table data, and update processing parameters. When received, the collected data and reference table stored in the data RAMLI and the non-volatile memory 12 are sequentially output and displayed on a printer or the like (not shown) in accordance with each operation command, and the operator 24 performs data plot processing and monitors. After undergoing correction processing and reference table creation processing, the finally obtained reference table is stored in the nonvolatile memory 12.

Note that the serial interface 15 is used for outputting target data during actual operation modes other than initial calibration.

However, in the conventional initial calibration control as described above,
Since the operator creates the reference table based on his/her judgment, the process is not only complicated and takes a long time, but also
``Due to individual differences among operators, there were times when it was not possible to obtain an appropriate reference table. Furthermore, an input/output device such as a TTY for inputting operation commands and outputting data is required only for initial calibration, resulting in a complicated configuration and increased cost.

(Problems to be Solved by the Invention) As described above, in the conventional monopulse radar device, when creating a reference table in the initial calibration of the azimuth direction, the operator directly operates the reference table to create the reference table, which requires complicated processing. Not only does this take a long time, but it is also affected by individual differences among operators, and it may not even be possible to obtain an appropriate reference table. In addition, input/output devices such as TTY are required only for calibration to input operation commands and output data, resulting in a complicated configuration and increased cost.

This invention has been made to solve the above-mentioned problems, and provides a monopulse radar device that has a simple configuration and can automatically create a reference table in the initial calibration of the azimuth direction in a short time. The purpose is to

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above object, the monopulse radar device according to the present invention has an off-boresight angle and a monopulse value indicating the azimuth deviation between the target and the center of the antenna beam. , and detects the direction of the target by detecting a monopulse value from a received wave and determining an off-boresight angle corresponding to the monopulse value from the reference table; a command input means for inputting an operation instruction command by switch operation for initial calibration of the azimuth direction of the reference table; and an initial calibration of the azimuth direction of the reference table in response to the operation instruction command inputted by the command input means. and a control means for executing the program according to a predetermined program.

(Function) In the monopulse radar device with the above configuration, the initial calibration of the reference table is automatically performed by simply inputting an operation command by operating a switch, eliminating the need for the operator to create a reference table, and eliminating the need for the operator to create a reference table. An appropriate reference table is obtained without any influence of differences, and a data input/output device is not required, and the initial calibration of the azimuth direction can be automatically and quickly processed with a simple configuration.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG.

Fig. m1 shows the configuration when the present invention is applied to the target detector of the monopulse radar device shown in Figs. 2 and 9. In FIG. 1, the same parts as in FIG. 9 are designated by the same reference numerals, and different parts will be described here.

The target detector shown in FIG. 1 includes an initial processing on/off switch 16, an initial processing command setting switch 17, and a collected data correction switch 18 for initial calibration.
, a processing parameter setting switch 19, an input command switch 20, and a reference table creation processing switch 21 are provided, and these are connected to the system bus via a parallel interface 22, and setting commands are sent to the CPU 9 in response to switch operations. It looks like this. Reference numeral 25 denotes a printer for outputting and displaying stored data as appropriate. Note that the TTY 14 and TTY interface 13 shown in FIG. 9 are not used here.

In the target detector configured as described above, command input operations that were conventionally performed using an input device such as a TTY can be performed using dedicated switches 16 to 21 provided for initial calibration, and the creation of a reference table for collected data is performed using software. This will be executed automatically. That is, when the CPU 9 inputs the ON instruction command from the initial processing on/off switch 16, the CPU 9 enters the initial calibration mode and proceeds with processing according to the operation instruction commands for the switches 17 to 21 input via the parallel interface 22. Then, the data collected for each monopulse value is temporarily stored in the RAM 11, and depending on the data collection condition, the above-mentioned interpolation, averaging, etc.
After correcting the figure 8 curve, etc., it is finally stored in the nonvolatile memory 12 as a reference table.

The above initial calibration process is executed in the following steps.

(1) First, initial processing on/off switch I
Turn on B to set the initial calibration mode. in this case,
The target detector 4 collects only calibration target data without performing normal target detection.

(2) Select the command to be operated from now using the initial processing command setting switch 17. The commands include "Start data collection", "End data collection", "
"Continue data collection", "Output collected data", "Output reference table data", "Output processing parameters", "Correct collected processing data", "Update reference table data", "Update processing parameters", etc. It may be selected as appropriate depending on the collection situation.

(3) The selected command is output to the CPU 9 each time the input command switch 20 is pressed down, and the CPU 9 performs an operation according to the command.

(4) Collect data by rotating the antenna several thousand times and plot the data as shown in FIG. Once the necessary data has been obtained, data collection is terminated using the data collection end command.

(5) The collected data is temporarily stored in RAM II.

If you want to refer to the contents, you can have the printer 25 output them using a collected data output command, a processing parameter output command, etc. as necessary.

(6) When manually correcting the data referred to in (5), input a collection processing data correction command using the collection data correction switch 18, and use the monopulse value (for example, 0 to 255 in the case of 8 bits) as an index to turn off the data. Correct boresight angle.

(7) When setting various parameters necessary for initial calibration, operate the processing parameter setting switch 19 to input a processing parameter update command, and then input the set parameter values through the switch 19. In addition, the parameters include an offset to correct the vertical deviation of the figure-8 curve, and a main beam parameter (designation of monopulse value upper limit and monopulse value lower limit) that specifies which part of the figure-8 curve is actually used. .

(8) After data collection is complete, turn on the reference table creation processing switch 21, apply interpolation, average, and figure-8 curve correction to the collected data, and store it in non-volatile memory 2 as the final reference table. do.

(9) After storing the reference table, turn off the initial processing on/off switch 16 to end the initial calibration processing.

According to the initial calibration process described above, each radar is The method most suitable for the device can be selected as appropriate.

Therefore, a monopulse radar system having a target detector with the above configuration uses software to automatically process the collected data interpolation, averaging, correction of figure-8 curve, etc. that were conventionally performed by an operator during initial calibration. Since the reference table is automatically created, the initial calibration process is dramatically shorter and easier, eliminating individual differences between operators.Furthermore, since no input/output device is required for initial calibration, it is simple and economical. It becomes something like that.

In the above embodiment, each switch has one function, but it goes without saying that software can perform a variety of processes, such as operating two functions with one switch.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a monopulse radar device that has a simple configuration and can automatically create a reference table in the initial calibration of the azimuth direction in a short time. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a monopulse radar device according to the present invention, FIG. 2 is a block diagram showing the configuration of a monopulse radar device to which this invention is applied, and FIG. 3 is a response of the monopulse radar device. FIG. 4 is a waveform diagram showing the relationship between the code signal and the monopulse signal, FIG. 4 is a characteristic diagram showing the relationship between the target azimuth of the monopulse radar device, the on-boresight angle, and the off-boresight angle, and FIG. 5 is the off-boresight angle. FIG. 6 is a diagram showing a reference table obtained from the characteristic diagram of FIG. 5,
FIG. 7 is an S-curve characteristic diagram based on data collected in the initial calibration in the target detector of the monopulse radar device, and FIG. 8 is a characteristic diagram showing the relationship between the antenna beam and the target with respect to the data collected in the initial calibration. FIG. 9 is a block diagram showing the configuration of a target detector in a conventional monopulse radar device. ■...Target, 2...SSR antenna, 3...Transmitter/receiver, 4...Target detector, 5...A/D converter, 6
...Antenna direction detector, 7...Radar interface, 8...System bus, 9...CPU, 10
...ROM. 13...TTY interface, 14...TTY
. 15... Serial interface, 1B... Initial processing on/off switch, 17... Initial processing command setting switch, 18... Collection data modification switch, 19... Processing parameter setting switch, 2
0...Manual command switch, 21...Reference table creation processing switch, 22...Parallel interface, 23...Target direction input switch for calibration, 24...
・Operator, 25...Printer. Applicant's representative Patent attorney Takehiko Suzue Page 2 Figure 4 t-shape 1 Lux value Figure 5 Figure 6 Figure 7 (a) (b) (c)

Claims (1)

[Claims] It is equipped with a reference table showing the relationship between the off boresight angle, which indicates the azimuth deviation between the target and the center of the antenna beam, and the monopulse value, and detects the monopulse value from the received wave and calculates the off boresight angle corresponding to the monopulse value. In a monopulse radar device that detects the azimuth of the target by determining it from the reference table, a command input means for inputting an operation command for initial calibration of the azimuth direction of the reference table by operating a switch; A monopulse radar apparatus comprising: a control means for receiving an operation command inputted by an input means and executing initial calibration of the azimuth direction of the reference table according to a predetermined program.