JPH0514965U - Doppler frequency measuring device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] From the combination of two Doppler frequencies with the target ambiguity obtained using two types of PRFs, even if one of them is shifted by one frequency bin, Make sure that the true Doppler frequency is required. [Structure] Several types of PRF for transmitting waves in a specific direction space
Then, the reflected wave radiated from the phased array antenna 1 and reflected from the target is received by the receiver 5 and converted into a digital video reception signal. Next, frequency analysis by the FFT calculator 6, amplitude detection by the amplitude detector 7, and target detection by the target detector 8 are performed, and the Doppler frequency with ambiguity of the target is measured. Next, using the Doppler detection table 10, the true Doppler frequency is measured by the Doppler frequency measuring device 11. The Doppler detection table data calculator 9 changes the contents of the Doppler detection table according to the change of the radar parameter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to, for example, a target Doppler frequency measuring device in a radar using the PRF technique in medium PRF (Pulse Repetition Frequency).

[0002]

[Prior Art]

 FIG. 3 shows a Doppler frequency measuring device using a conventional multi-PRF technique. In FIG. 3, reference numeral 1 denotes a phased array antenna that radiates a transmitted wave in a space of a specific direction by several kinds of PRFs and receives a reflected wave. 2 denotes a phase control of the array antenna module to control the beam direction of the phased array antenna. Beam controller 3 is an exciter that generates a transmitted wave, 4 is a circulator that supplies a signal from the transmitter to the phased array antenna, and a received signal to a receiving detector, and 5 is a digital video signal of the received signal. A receiver for converting into a reception signal, 6 is an FFT (Fast Fourier Transform) operation for performing frequency analysis by weighting the digital video reception signal output from the above-mentioned receiver to suppress side lobes. And 7 is an amplitude for amplitude detection from the data output from the FFT calculator. A transmitter, 8 detects a target from the data output from the amplitude detector, and a target detector for measuring the Doppler frequency with ambiguity of the target, 10 is mapped as shown in FIG. The Doppler detection table in which the frequency is written, 11 is the combination of the two Doppler frequency data with the ambiguity of the target measured by the two types of PRF output from the above target detector. A Doppler frequency measuring device that measures the true Doppler frequency only when it exists, and a display device 12 that displays the Doppler frequency output from the Doppler frequency measuring device as the target speed.

The conventional Doppler frequency measuring device using the multi-PRF technique is configured as described above, and the transmission generated by the exciter 3 and passing through the circulator 4 is performed in a space in a specific direction designated by the beam controller 2. Waves are radiated from the phased array antenna 1 by several types of PRF, the reflected wave from the target is received by the phased array antenna 1, the received signal is passed through the circulator 4 and converted into a digital video reception signal by the receiver 5, and the FFT is performed. The arithmetic unit 6 performs weighting and frequency analysis for sidelobe suppression on the video reception signal, the amplitude detector 7 detects the amplitude from the video reception signal, and the target detector 8 detects the target. Measure the Doppler frequency with ambiguity of the target and From the two Doppler frequency data with target ambiguity measured by the two types of PRF output from the Doppler detector, only when the combination exists in the Doppler detection table 10 in which the Doppler frequency is written. The true Doppler frequency can be measured by the Doppler frequency measuring unit 11 using the Doppler detection table 10, and the true Doppler frequency on the display unit 12 can be displayed as the target speed.

[0004]

[Problems to be solved by the device]

 The Doppler frequency measuring device using the conventional multi-PRF technique as described above has the following problems. That is, in the conventional Doppler frequency measurement device, if one of the Doppler frequency bins is shifted by one bin due to the spread of the frequency due to weighting for suppressing side lobes or the fluctuation of the target Doppler frequency, Doppler frequency measurement was impossible because no data was written to the detection table. When radar parameters such as the Doppler frequency measurement range are changed, the contents of the Doppler detection table must be changed and ROM (Road Only Memory) must be replaced. The present invention was made to solve such a problem, and even if one of the Doppler frequency bins is shifted by one bin compared to the conventional one, it becomes possible to measure the Doppler frequency, and the Doppler detection table is also available. By providing a data calculator, it is an object to obtain a Doppler frequency measuring device that can easily change the contents of the Doppler detection table even during operation of the device.

[0005]

[Means for Solving the Problems]

 The Doppler frequency measuring device according to the present invention writes the data when writing data to the Doppler detection table even if one of the Doppler frequency bins has one bin. Doppler detection table data calculator that enables measurement and changes the contents of the Doppler detection table according to changes in radar parameters. Doppler frequency measurement device that can change the contents of the Doppler detection table without the need for ROM conversion. Is proposed.

[0006]

[Action]

 In the present invention, when writing data to the Doppler detection table, the data is written even if one of the Doppler frequency bins is 1 bin, and if the data overlap, the data with the higher threat level of the target is written. By writing, it is possible to measure the Doppler frequency even when one of the Doppler frequency bins has one bin. Also, by equipping the Doppler detection table data calculator, the operation of the device according to the change of the radar parameter can be performed. It is possible to change the contents of the Doppler detection table even during the period.

[0007]

【Example】

 FIG. 1 is a diagram showing an embodiment of this invention. 1 to 8, 11 and 12 are exactly the same as the above conventional device. 9 is a Doppler detection table data calculator that calculates Doppler detection table data according to changes in radar parameters such as the Doppler frequency measurement range, and changes the contents of the Doppler detection table, and 10 is mapped as shown in FIG. It is a Doppler detection table in which the Doppler frequency is written in the shaded area. Even if either of the Doppler frequency bins is shifted by one bin, the target measured by the two types of PRF output from the target detector 8 will be described. The true Doppler frequency of the target can be obtained by the Doppler frequency measuring device 11 using the Doppler detection table 10 from the two Doppler frequency data having the ambiguity.

[0008]

[Effect of the device]

 As described above, this device cannot be measured by writing data to the data of the Doppler detection table in Doppler frequency measurement even if one of the Doppler frequency bins is shifted by one bin. In this case, the Doppler frequency can be measured.

Further, since the Doppler detection table data calculator is provided, the contents of the Doppler detection table can be changed according to the change of the radar parameter, and it is not necessary to replace the ROM as compared with the conventional method, and the operation of the apparatus can be performed. This has the effect that the contents of the Doppler detection table can be changed.

[Brief description of drawings]

FIG. 1 is a diagram showing a Doppler frequency measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a method of writing data of a Doppler detection table according to the present invention.

FIG. 3 is a diagram showing a conventional Doppler frequency measuring device.

FIG. 4 is a diagram showing a method of writing data in a conventional Doppler detection table.

[Explanation of symbols]

1 Phased Array Antenna 2 Beam Controller 3 Exciter 4 Circulator 5 Receiver 6 FFT (Fast Fourier Transf)
orm) calculator 7 amplitude detector 8 target detector 9 Doppler detection table data calculator 10 Doppler detection table 11 Doppler frequency measuring instrument 12 display

Claims (2)

[Scope of utility model registration request] 1. A phased array antenna for radiating a transmitted wave and receiving a reflected wave in a space of a specific direction by several kinds of PRFs, and a beam for controlling a beam direction of the phased array antenna by phase control of an array antenna module. A controller, an exciter that generates a transmission wave, a circulator that supplies a signal from the transmission section to the phased array antenna, and a reception signal to a reception detection section, and a reception that converts the reception signal into a digital video reception signal. A vessel,
The digital video received signal output from the receiver is subjected to weighting to suppress side lobes, and frequency analysis is performed on the FFT (Fast Fourier).
er Transform) calculator, an amplitude detector that detects amplitude from the data output from the FFT calculator, and a target from the data output from the amplitude detector to detect a target, and a Doppler frequency with ambiguity of the target From the target detector that measures the, and the two Doppler frequency data with the target ambiguity measured by the two types of PRFs output from the target detector, even if one of the frequency bins is shifted by one Doppler detection table written Doppler frequency so that the true Doppler frequency is obtained, the Doppler frequency measuring instrument that measures the true Doppler frequency using the Doppler detection table, and the Doppler frequency output from the Doppler frequency measuring instrument. Table showing as target speed A Doppler frequency measuring device in a radar, comprising: an indicator. 2. The Doppler frequency measurement according to claim 1, further comprising a Doppler detection table data calculator capable of calculating Doppler detection table data according to a change in radar parameter and changing the contents of the Doppler detection table. apparatus.