JPH063444A - Angle measuring radar device - Google Patents

Abstract

(57) [Abstract] [Purpose] In the angle-measuring radar using a phased array antenna, the sum and difference of signals received by the reception beams in four directions are not obtained at the stage of analog signals, Amplify the reception data of the reception beam in the direction. [Structure] The radar control unit 5 receives the tracking beam information from the data processing unit 4 to specify a transmission beam direction, and offsets the transmission beam direction to the left and right in the azimuth direction and up and down in the elevation direction by a predetermined angle. The received beam direction is set and the received beam direction is designated one by one for each cycle of the transmission pulse. In response to this, the beam control unit 7 controls the transmitted and received beam directions of the phased array antenna, The reception data received by the reception beam passes through the reception unit 2 and the signal processing unit 3, and the reception data for four directions corresponding to four transmissions is stored in the input buffer 8 and is measured based on the reception data in these four directions. The angle calculation processing unit 9 calculates the angle measurement and sends the target data with the angle information to the data processing unit 4. The data processing unit performs tracking processing and target acquisition, and then sends tracking beam information to the radar control unit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a transmission beam a plurality of times and receives it by changing the angle of the reception beam for each transmission. The present invention relates to a radar device that measures an angle and that uses a phased array antenna.

[0002]

2. Description of the Related Art In a conventional radar device using a phased array antenna, the angle measuring process is performed by an amplitude monopulse system and has a structure as shown in FIG. In FIG. 6, 1 is a phased array antenna, 21 is a receiving unit, 3
1 is a signal processing unit, 41 is a data processing unit, 51 is a radar control unit, 6 is a transmission unit, and 7 is a beam control unit.

The phased array antenna 1 scans the beam in accordance with the beam data transferred from the beam controller 7 and irradiates the beam with a transmission signal input from the transmitter 6. The received signal has a sum component Σ of two beam patterns that are overlapped in the azimuth (AZ: azimuth) direction and an elevation (EL: height) direction and a difference component Δ that is obtained by inverting the phases of the two beams. can get.

The receiving unit 21 obtains accurate angles in the azimuth (AZ: azimuth) direction and the elevation (EL: height) direction from the received signals (Σ, Δ) received from the phased array antenna 1. The signal processing unit 31 A / D-converts the received signal and detects only the target signal by digital signal processing. The data processing unit 41 calculates transmission beam information and transfers it to the radar control unit 51. The radar controller 51 transfers the transmission timing signal to the transmitter 6 and the beam information to the beam controller 7.

[0005]

However, in the amplitude monopulse system as in the above-mentioned prior art, since the sum component and the difference components in the azimuth direction and the elevation direction are taken from the received data by one transmission pulse, the steps of the analog signal are taken. Therefore, the sum component generation circuit and the two difference component generation circuits are required, and as shown in the reception unit 21, the reception unit 2 of the sum component system
1a, the receiving unit 21b of the azimuth (AZ) direction difference component system, and the receiving unit 21c of the high and low (EL) direction difference component system require three receiving units, and the phase difference and phase between the receiving units are Fluctuations, amplitude differences, and amplitude fluctuations must be suppressed as much as possible, and even in an AGC circuit that uses signals of the sum component system, the operation of the azimuth difference system and the operation of the height difference system must be kept balanced. In addition, the distribution of the local oscillator output to each receiving mixer must be kept balanced,
There is a problem that much consideration is required at the designing and manufacturing stage, which is difficult and troublesome, and further, special attention and labor are required for maintenance and adjustment in order to maintain the balance even at the operation stage of the device.

In view of the above-mentioned problems of the prior art, an object of the present invention is to set one receiving system and to set receiving beams in two directions in the azimuth direction and two directions in the elevation direction, that is, one transmission cycle. The reception beam is set in one direction per time, the reception data is sequentially obtained in a time-divisional manner, these are stored, and then the sum component, the azimuth direction difference component, and the elevation direction difference component are obtained. An object of the present invention is to provide an angle-measuring radar device that solves the problem caused by the existence of three systems.

[0007]

The present invention has the following means for achieving the above object. That is, the angle-measuring radar device of the present invention performs phase control of the phased array antenna so that the transmission / reception beam direction of the phased array antenna is directed to the specified angle based on the beam angle information specifying the beam direction. A beam control unit, which receives the tracking beam information for determining the transmission beam direction, specifies the transmission beam direction, and
There is also a reception beam direction of one direction for each cycle of the transmission pulse in four directions offset by a predetermined angle to the left and right of the azimuth (AZ) direction and the top and bottom of the elevation (EL) direction around the transmission beam direction. A radar control unit for transmitting designated beam angle information to a beam control unit; a buffer memory for storing reception data of four cycles sequentially received by the four reception beams; and reception data of four reception beams from the buffer memory. An angle measurement calculation processing unit that receives and calculates the target angle and outputs the target data to which the angle data is added; Upon receiving the target data with angle data from the angle measurement calculation processing unit,
A data processing unit for transmitting tracking beam information to the radar control unit after performing target acquisition and tracking processing, and an angle-measuring radar device.

[0008]

The operation of the angle-measuring radar device of the present invention having the above-mentioned construction will be described below. In the device of the present invention, the radar control unit designates the transmission beam direction based on the tracking beam information from the data processing unit, and the azimuth (AZ) direction and the high and low (E) directions are centered on the transmission beam direction.
The directions of the reception beams in a total of 4 directions of 2 directions of L) are set by calculation or a table, and for each transmission cycle,
The beam angle information designating the reception beam in each one of the four directions is sent to the beam control unit, and the reception data in the four directions is obtained as time-divisional data for four cycles, so that the reception unit has one system. The received data can be digitized and then stored in a memory capable of storing data for four cycles, and the post-sum component and difference component can be easily obtained.

Therefore, a circuit for generating a sum component and a difference component at the stage of an analog signal of the received signal becomes unnecessary, and the number of the receiving system which has been conventionally used for three systems is improved to one system. , The difference component can be obtained by the memory and the digital circuit of the operation, and it is difficult to maintain the sameness of various characteristics between the receivers of the conventional three systems and the trouble of obtaining the sum or difference at the analog signal stage. Problem will be solved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In FIG. 1, 1 is a phased array antenna,
2 is a receiving unit, 3 is a signal processing unit, 4 is a data processing unit, 5 is a radar control unit, 6 is a transmission unit, 7 is a beam control unit, 8 is an input buffer, 9 is an angle measurement calculation processing unit, and 10 is an offset. It is a beam table.

The signal received from the phased array antenna 1 is amplified and frequency-converted by the receiver 2, and A / D converted by the signal processor 3 to be digital signal processed.
The signal-processed digital data is input to the input buffer 8
To temporarily store. When the reception data for four reception beams is stored in this buffer, the accurate angle of the target detected by the angle measurement calculation processing unit 9 is received and the angle information is added to the data processing unit 4. Transfer the target data. The data processing unit 4 transfers the tracking beam information to the radar control unit 5 after performing target acquisition and tracking processing.

In the radar control section 5, the reception beam obtained by offsetting the azimuth (AZ) and elevation (EL) directions by a certain angle from the center of the beam to be transmitted from the tracking beam information as shown in FIG. Four
The offset data is calculated or read from the offset beam table 10 and transferred to the beam control unit 7. Also, the transmission timing is transmitted to the transmission unit 6. Then, for one transmission, the reception beam is received in one of the four directions, and thereafter the direction of the reception beam is changed for each transmission.

Therefore, by performing the transmission four times, the received data from the four receive beams are aligned. The angle measurement calculation processing unit 9 performs angle measurement calculation based on the amplitude (level) of the received signal obtained from the four received beams.
The calculation principle itself is the same as the conventional amplitude monopulse angle measuring method. For simplicity of explanation, only two beams in the azimuth direction or the elevation direction will be extracted and described.

Now, assuming that the two receiving beams are beam 1 and beam 2, respectively, as shown in FIG. 3, the two beams are partially overlapped and the angle between the beams at that time is set to be the receiving beam width θBW. To be done. At this time, if the reception levels from the target detected by the respective reception beams are V1 and V2, the ratio (sum-difference ratio) Rv of the difference level to the sum level of the amplitudes is expressed by the formula 1.

[0015]

## EQU1 ## Rv = (V2-V1) / (V2 + V1)

On the other hand, the relationship between the sum-difference ratio Rv and the displacement angle θ from the target transmission beam center direction can be obtained in advance by calculation and experiment once the shape of the reception beam pattern is determined. .

FIG. 4 shows an example of the sum-difference ratio-displacement angle characteristic in the measurable range. Such characteristic data is previously stored in the angle measurement calculation processing unit, and the reception level V
By inputting 1 and V2, the target displacement angle θ can be known from the above characteristic by performing the calculation of Expression 1.

Similarly, in the case of four receiving beams, as shown in FIG.
And the reception levels thereof are A, B, C, and D, respectively, the sum S of these is expressed by Equation 2,

[0019]

[Equation 2] S = A + B + C + D

Since the amplitude difference dAZ in the azimuth (AZ) direction and the amplitude difference dEL in the elevation (EL) direction are expressed by Equations 3 and 4, respectively,

[0021]

## EQU3 ## dAZ = (C + D)-(A + B)

[0022]

## EQU00004 ## dEL = (A + C)-(B + D)

The sum-difference ratio R _{AZ in the} azimuth direction and the sum-difference ratio R _{EL in the} elevation direction are given by equations 5 and 6, respectively.

[0024]

[Equation 5] R _AZ = (dAZ) / S

[0025]

[Equation 6] R _EL = (dEL) / S

Therefore, the angle measurement calculation processing unit 9 is made to have the sum-difference ratio-displacement angle characteristic data in the azimuth direction and the sum-difference ratio-displacement angle characteristic data in the elevation direction, and the input buffer 8
By giving the input data A, B, C, and D from Eqs. 2 to 6 the arithmetic functions of Eqs. 2 to 6, the displacement angles in the azimuth direction and the elevation direction from the target transmission beam center direction are known. It will be possible.

[0027]

As described above, the angle-measuring radar device of the present invention sets four receiving beam directions offset by a predetermined angle in the azimuth direction and the elevation direction with the transmitting beam direction as the center, Since the reception beam directions of one direction are sequentially received for each transmission, the reception data received by the reception beams of the four reception directions are stored in the buffer memory, and the sum / difference signal ratio is calculated from that. , Unlike the conventional amplitude monopulse angle measuring radar device, a circuit for obtaining a sum signal or a difference signal at the stage of a received analog signal becomes unnecessary, and the sum signal system, the azimuth direction difference signal system, and the high / low direction difference signal system are called. Since three receiving systems are not required and only one receiving system is required, it is troublesome and difficult to adjust the analog signal circuit, and it is necessary to adjust the characteristics of the three receiving systems. There is an advantage that but is removed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a beam arrangement diagram for four reception beam angle measurement.

FIG. 3 is a principle diagram of 2-beam angle measurement calculation.

FIG. 4 is a diagram showing an example of a sum / difference ratio vs. displacement angle characteristic.

FIG. 5 is a principle diagram of 4-beam angle measurement calculation.

FIG. 6 is a block diagram showing a configuration of a conventional amplitude monopulse angle measuring radar device.

[Explanation of symbols]

 1 Phased Array Antenna 2 Receiver 3 Signal Processor 4 Data Processor 5 Radar Controller 6 Transmitter 7 Beam Controller 8 Input Buffer 9 Angle Measurement Calculation Processor 21 Receiver 31 Signal Processor 41 Data Processor 51 Radar Controller

Claims (1)

[Claims] 1. A phased array antenna; a beam controller for controlling the phase of the phased array antenna so that the transmitting / receiving beam direction of the phased array antenna is directed to a specified angle based on beam angle information specifying the beam direction; Receiving the tracking beam information for determining the beam direction, the transmission beam direction is designated, and the beam is offset by a predetermined angle to the left and right in the azimuth (AZ) direction and up and down in the elevation (EL) direction about the transmission beam direction.
A radar control unit that sends beam angle information to the beam control unit that sequentially specifies the reception beam direction for each direction of the transmission pulse in one direction; and for four periods that are sequentially received by the four reception beams. A buffer memory for storing the reception data of the signal; and an angle measurement calculation processing unit for receiving the reception data of four reception beams from the buffer memory, calculating the target angle, and outputting the target data to which the angle data is added; Angle measurement radar device, comprising: a data processing unit that receives target data with angle data from the target, performs target acquisition and tracking processing, and then sends tracking beam information to the radar control unit. .