JPH0538584U - Radar equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a radar device in which the processing load of the tracking beam former and the clutter eliminator is reduced. [Structure] A search beam former 5 extracts a search beam component from a received signal that has passed through an antenna 1, a transmission / reception switch 2, a receiver 3 and an A / D converter 4. The tracking beam former 8 extracts a tracking beam component from the search beam that has passed through the clutter remover 6. The display 10 displays the result of the search signal processor 7 recognizing and identifying the target from the search beam and the tracking error information calculated from the tracking beam by the tracking signal processor 9. [Effect] By extracting the tracking beam component from the search beam after removing the clutter, the clutter removing device connected to the subsequent stage of the tracking beam forming device becomes unnecessary, and the processing load of the tracking beam forming device is eliminated. Can be reduced by the amount of clutter removed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a multi-beam radar device that performs search and tracking simultaneously.

[0002]

[Prior Art]

 FIG. 2 is a block diagram showing a conventional radar device. In the figure, 1 is an antenna for both transmission and reception, 2 is a transmission / reception switch that switches between transmission and reception of antenna 1, 3 is a receiver that amplifies and detects the signal received by antenna 1, and 4 is a digital signal that is amplified and detected. A / D converter for converting to data, 5 a search beam former for extracting a search beam component from digital data, 12 a tracking beam former for extracting a tracking beam component from digital data, 6 a search beam and a tracking beam The clutter remover that removes clutter from among the above, 7 is a search signal processor that recognizes and identifies the target from the search beam after clutter removal, and 9 is the tracking signal that calculates the tracking error of the target from the tracking beam after clutter removal. The processor 10 is a display for displaying the processing results of the search signal processor and the tracking signal processor, and 11 is a transmitter for supplying a transmission signal to the antenna 1.

When the duplexer 2 is in a transmitting state, the transmitter 11 supplies a transmission signal to the antenna 1. The N antennas 1 (N is an integer, FIG. 2 shows the case where N = 4) radiates the transmitted wave toward the free space. Next, when the transmission / reception switch 2 is in the receiving state, the N antennas 1 receive the reflected wave from the target. The receiver 3 amplifies and detects the received signal from the antenna 1. The A / D converter 4 converts the amplified and detected reception signal into digital data. The search beam former 5 performs N point FFT (Fast Fourier Transform) arithmetic processing on the N pieces of digital data received at the same time to extract N search beam components having different pointing angles. The clutter remover 6 removes clutter components from the time series digital data. The search signal processor 7 compares the digital data after clutter removal between N beams having different directional angles to recognize and identify a search target. On the other hand, the tracking beam former 12 subjects the N pieces of digital data received at the same time to N-point DFT (Discrete Fourier Transform) arithmetic processing to obtain a tracking beam component of the directivity angle instructed by the tracking signal processor 9. To extract. The clutter remover 6 removes clutter components from the time series digital data. The tracking signal processor 9 compares the digital data after clutter removal between M (M is an integer, FIG. 2 shows the case of M = 2) tracking beams to calculate a tracking error. The display 10 displays the information for the target calculated by the search signal processor 7 and the tracking signal processor 9.

[0004]

[Problems to be solved by the device]

 In the above radar device, since the tracking beam component is directly extracted from the digital data output from the A / D converter, the number of tracking beams can be increased without changing the calculation of the tracking beam former and the clutter remover. There is a problem that it leads to an increase in processing load.

The present invention has been made to solve such a problem, and an object thereof is to reduce the calculation processing load of the tracking beam generator and the clutter eliminator.

[0006]

[Means for Solving the Problems]

 The radar device according to the present invention has a function of extracting a tracking beam component from the search beam after removing the clutter.

[0007]

[Action]

 By extracting the tracking beam component from the search beam after removing the clutter, the clutter eliminator connected to the latter stage of the tracking beam former becomes unnecessary, and the processing load of the tracking beam former is increased. It can be reduced by the amount of clutter removed.

[0008]

【Example】

 Example 1. FIG. 1 is a block diagram showing an embodiment of the present invention, showing a case where the number N of search beams and the number M of tracking beams (N and M are integers) are N = 4 and M = 2, respectively. ing. In the figure, 1 to 7, 10 and 11 are exactly the same as the above conventional device. Reference numeral 8 is a tracking beam former for extracting a tracking beam component from the search beam after removing the clutter, and 9 is a tracking signal processor for calculating a target tracking error from the tracking beam.

When the duplexer 2 is in the transmitting state, the transmitter 11 supplies a transmission signal to the antenna 1. The N antennas 1 radiate the transmitted wave toward the free space. Next, when the duplexer 2 is in the receiving state, the N antennas 1 receive the reflected wave from the target. The receiver 3 amplifies and detects the received signal from the antenna 1. The A / D converter 4 converts the amplified and detected reception signal into digital data. The search beam former 5 performs N point FFT arithmetic processing on the N pieces of digital data received at the same time to extract N search beam components having different directivity angles.

In order to simplify the explanation of the operation, it is assumed that the N antennas 1 have the same directional characteristics and are arranged in a straight line at the element spacing d. When the transmission wavelength is λ and the directional characteristic of the antenna 1 is x (θ) (θ is the angle from the front of the antenna), the k-th search beam shape y obtained as a result of the N-point FFT calculation by the search beam generator 5 (K, θ) and the beam directivity angle θ (k) are given by “Equation 1” and “Equation 2”, respectively.

[0011]

[Equation 1]

[0012]

[Equation 2]

However, θ and k are

[0014]

[Equation 3]

[0015]

[Equation 4]

[0016]

Next, the clutter remover 6 removes the clutter component from the time series digital data. The search signal processor 7 compares the digital data after clutter removal between the N beams represented by "Equation 1" to recognize and identify the search target. On the other hand, the tracking beam former 8 performs digital arithmetic processing on the digital data after clutter removal to extract the tracking beam component of the directivity angle designated by the tracking signal processor 9.

Here, it will be described that the tracking beam can be formed from the search beam. Letting f (t) be the relative received power at the beam directivity angle sin ⁻¹ t instructed by the tracking signal processor 9 to the tracking beam former 8, f (t) is the Nth order in the range of “Equation 5”. When it does not have the above harmonic components, f (t) can be Fourier series expanded as shown in "Equation 6".

[0019]

[Equation 5]

[0020]

[Equation 6]

However, T is

[0022]

[Equation 7]

It is At this time, F (n) is obtained as follows.

[0024]

[Equation 8]

[0025]

[Equation 9]

The following holds. Further, by substituting the obtained F (n) into “Equation 6”, the relative received power f (t) at the beam directivity angle sin ⁻¹ t is

[0027]

[Equation 10]

Is represented as Of these, f (kT / N) is equal to the relative received power in the search beam with a directivity angle of θ (k), so a tracking beam with an arbitrary directivity angle is a digital beam obtained from N search beams. It can be seen that the data can be equivalently calculated by substituting the data into "Equation 10".

The tracking signal processor 9 calculates a target tracking error from M tracking beams. The display device 10 displays information on the target calculated by the search signal processor 7 and the tracking signal processor 9.

[0030]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

By extracting the tracking beam component from the search beam, the processing load on the tracking beam former can be reduced.

Further, since the tracking beam former uses the digital data after the clutter is removed, the clutter remover after the tracking beam is not needed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional radar device.

[Explanation of symbols]

 1 antenna 2 transmission / reception switch 3 receiver 4 A / D converter 5 search beam former 6 clutter remover 7 search signal processor 8 tracking beam former 9 tracking signal processor 10 indicator 11 transmitter

Claims (1)

[Scope of utility model registration request] 1. An antenna, a duplexer, a receiver and A
Search beamformer for forming a plurality of search beams by digitally processing a plurality of received signals passing through a D / D converter, a clutter remover for removing clutter from the search beam, and a plurality of clutter-removed beams Search signal processor that detects a target from the search beam, a tracking beam former that forms a tracking beam by digitally processing a plurality of search beams from which clutter has been removed, and a tracking that tracks a target from a plurality of tracking beams. A radar device comprising a signal processor, a display for displaying outputs of a search signal processor and a tracking signal processor, and a transmitter for supplying a transmission signal to an antenna via a duplexer.