TWI727694B - Radar echo feature extraction system and method - Google Patents

Abstract

A radar echo feature extraction system, comprising: a starting unit, a rotating unit, a transmitting unit, a signal generating unit, a receiving unit, a signal processing unit, and an arithmetic processing unit. The signal generating unit generates electromagnetic signals and radiates to the transmitting unit. The rotating unit controls the different polarization directions of the transmitting unit and the receiving unit. When the electromagnetic signal is radiated to the rotating unit, an electromagnetic echo signal is generated. The receiving unit receives the electromagnetic echo signal, and processes the electromagnetic echo signal through the signal processing unit, and the signal The processing unit processes the electromagnetic echo signal to generate complex instantaneous spectrum information, and transmits the complex instantaneous spectrum information to the arithmetic processing unit, and the arithmetic processing unit processes the complex instantaneous spectrum information according to a plurality of calculation modes, and analyzes a plurality of target characteristic data.

Description

Radar echo feature extraction system and method

The present invention relates to a feature extraction system and method, in particular to a radar echo feature extraction system and method.

As an important feature of radar targets with micro-motion, micro-spectrum characteristics have been widely used in the field of radar target recognition in recent years, but the previous technology mainly focused on the main polarization measurement system, and most of them were performed in an ideal environment (microwave anechoic chamber) For related experiments, if there is an actual test in the field, the typical radar test target with micro-motion is a helicopter. The flight test cost is high, and it is not easy to quantitatively analyze its recognition accuracy.

In the prior art, the radar echo signal analyzed is generally the main polarization signal, and its signal strength is generally strong, and its Signal-to-Noise Ratio (Signal-to-Noise Ratio) is higher, so a higher recognition success rate can be obtained. However, the radar targets that actually require target recognition may have relatively small radar echoes. If there is no robust (adaptable to low signal-to-clutter ratio) micro-Doppler (or micro-spectrum) feature extraction algorithm, it is extremely It may cause the target recognition to fail.

In most previous studies, the experimental environment is in a microwave anechoic chamber. Since the absorbing material of the microwave anechoic chamber can absorb electromagnetic waves, it is not easily affected by the surrounding environmental clutter in measurement, so the obtained radar echo signal is relatively simple and easy to handle. However, this is very different from the actual radar application scenario in the field, and the successful target recognition in the microwave anechoic chamber is not equivalent to the success in the actual test under the general environment; even in the actual test in the field, it is very difficult to obtain The micro-Doppler characteristics of military targets with micro-movement characteristics such as helicopters are also quite difficult.

In view of the shortcomings of the above-mentioned conventional technology, the radar echo is too small and the algorithm robustness is insufficient, which leads to the failure of target recognition. Therefore, the present invention proposes the use of a radar echo feature extraction system and method to solve the above-mentioned shortcomings.

In order to achieve the above objective, a radar echo feature extraction system according to the present invention includes: an activation unit electrically connected to a rotating unit, the activation unit being used to set an activation information, the rotation The unit operates according to the activation information; a transmitting unit, the transmitting unit is electrically connected to a signal generating unit, the signal generating unit generates an electromagnetic signal, and the electromagnetic signal is radiated to the rotating unit through the transmitting unit; a receiving unit, The receiving unit is electrically connected to a signal processing unit, wherein the different polarization directions of the transmitting unit and the receiving unit can be controlled. When the electromagnetic signal is radiated to the rotating unit, a signal-level controllable electromagnetic echo signal is generated , The receiving unit receives the signal-level controllable electromagnetic echo signal, and uses the signal processing unit to process the signal-level controllable electromagnetic echo signal; and an arithmetic processing unit that is electrically connected to the signal processing unit Sexual connection, where the signal processing unit can control the size of the signal and the electromagnetic echo signal The processing is performed to generate complex instantaneous frequency spectrum information, and transfer the complex instantaneous frequency spectrum information to the arithmetic processing unit, and the arithmetic processing unit processes the complex instantaneous spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data.

In the radar echo feature extraction system of the present invention, the complex instantaneous frequency spectrum information includes: the number of output data, the number of output data obtained in one second, the bandwidth of the signal generator, and the micro-Doppler (micro-spectrum) ) Information echo signal and instrument parameters.

In the radar echo feature extraction system of the present invention, when a center frequency of the signal generating unit becomes larger and a bandwidth remains unchanged, the micro-Doppler spread bandwidth of the signal-level controllable electromagnetic echo signal will be greater than The inherent bandwidth of the signal generating unit, or when the center frequency of the signal generating unit becomes smaller and the bandwidth remains unchanged, the micro-Doppler spread bandwidth of the signal-level controllable electromagnetic echo signal will be smaller than the The inherent bandwidth of the signal generating unit.

In the radar echo feature extraction system of the present invention, the plurality of calculation modes include: a first calculation mode and a second calculation mode.

In the radar echo feature extraction system of the present invention, the arithmetic processing unit adds the complex instantaneous spectrum information to each group of instantaneous spectrum information signal amplitudes through the first calculation mode to obtain the target feature data.

In the radar echo feature extraction system of the present invention, the arithmetic processing unit uses the second calculation mode to convert the complex instantaneous frequency spectrum information to a The first instantaneous spectrum information is used as the first reference spectrum information, and the first reference spectrum information is subtracted from the subsequent complex instantaneous spectrum information to obtain the target characteristic data.

In the radar echo feature extraction system of the present invention, the transmitting unit and the receiving unit are an antenna unit, and the polarization direction of the antenna unit can be selected as the main polarization direction, the cross polarization direction or other polarization directions.

In another preferred embodiment of the present invention, a radar echo feature extraction method includes: using the activation unit to set the activation information, and activate the rotation unit through the activation information, and the rotation unit is based on the activation The information rotates; the signal generating unit generates the electromagnetic signal and radiates to the rotating unit through the transmitting unit; wherein the different polarization directions of the transmitting unit and the receiving unit can be controlled, when the electromagnetic signal is radiated to the rotating unit , Will generate the signal size controllable electromagnetic co-wave signal, the receiving unit receives the signal size controllable electromagnetic echo signal, and uses the signal processing unit to process the signal size controllable electromagnetic echo signal; and the signal processing The unit processes the electromagnetic echo signal with controllable signal size to generate complex instantaneous spectrum information, and transmits the complex instantaneous spectrum information to the arithmetic processing unit, and the arithmetic processing unit processes the complex instantaneous spectrum according to a plurality of calculation modes Information, and then analyze multiple target characteristic data.

In the radar echo feature extraction method of the present invention, the arithmetic processing unit adds the complex instantaneous spectrum information to the amplitude of each group of instantaneous spectrum information signals through a first calculation mode of the plurality of calculation modes, and then Obtain the target characteristic data.

According to the radar echo feature extraction method of the present invention, the arithmetic processing unit first uses a first instantaneous spectrum information as the first reference spectrum information for the complex instantaneous frequency spectrum information through the second calculation mode, and then uses the first instantaneous frequency spectrum information as the first reference spectrum information. The other complex instantaneous frequency spectrum information is subtracted from the first reference frequency spectrum information, and then the target characteristic data is obtained after calculation through the first calculation mode.

The above summary and the following detailed description and drawings are all for the purpose of further explaining the methods, means and effects adopted by this creation to achieve the intended purpose. The other purposes and advantages of this creation will be explained in the subsequent description and diagrams.

1: Start the unit

2: Rotating unit

3: launch unit

4: signal generating unit

5: Receiving unit

6: Signal processing unit

7: Operation processing unit

The first figure is a schematic diagram of the radar echo feature extraction system of the present invention; the second figure is a time-frequency diagram of echoes with a larger micro-doppler (micro-spectrum) spreading bandwidth of the present invention; the third figure is this Invented the micro-doppler (micro-spectrum) echo time-frequency diagram with a smaller spreading bandwidth; the fourth diagram is a schematic diagram of the micro-doppler (micro-spectrum) information of the main polarization measurement of the present invention; the fifth diagram is The schematic diagram of the simulated value of the radar cross-sectional area of the present invention; the sixth diagram is a schematic diagram of the metal blade scene; the seventh diagram is a schematic diagram of the main polarization measurement of the present invention; the eighth diagram is the cross-polarization measurement of the present invention Schematic.

The following is a specific example to illustrate the implementation of this creation. Those who are familiar with this technique can easily understand the advantages and effects of this creation from the content disclosed in this manual.

Please refer to the first figure, the schematic diagram of the radar echo feature extraction system of the present invention, wherein the radar echo feature extraction system includes an activation unit 1, a rotating unit 2, a transmitting unit 3, a signal generating unit 4, a receiving unit 5, The signal processing unit 6 and the arithmetic processing unit 7 are composed. The starting unit 1 is electrically connected to the rotating unit 2, and the starting unit 1 is used to set starting information, and the rotating unit 2 operates according to the starting information, wherein the starting information is used to set the speed of the rotating unit 2 , The angle of rotation, and the speed and angle of rotation of the aforementioned activation information should not be limited by this embodiment.

Then, the transmitting unit 3 is electrically connected to the signal generating unit 4, the signal generating unit 4 generates an electromagnetic signal, and the electromagnetic signal is radiated to the rotating unit 2 through the transmitting unit 3, wherein the transmitting unit 3 is an antenna unit, and The choice of the polarization direction of the antenna unit is due to the fact that electromagnetic waves have electric and magnetic fields during the propagation process. The vibration direction of the electric field is called the polarization direction. Generally speaking, when the electromagnetic wave radiates to an object, the polarization of the electromagnetic field is The direction will be changed. If the polarization direction of the emitted electromagnetic wave is the same as the polarization direction of the received electromagnetic wave (the electromagnetic wave received at this time is the scattered wave of the electromagnetic wave scattered by the object after the emitted electromagnetic wave is radiated to the object), which is called the main polarization. If the polarization direction of the emitted electromagnetic wave is the same as that of the received electromagnetic wave (the electromagnetic wave received at this time is the emitted electromagnetic wave). After the wave radiates to the object, the polarization direction of the scattered wave scattered by the object to the electromagnetic wave is perpendicular to each other, which is called cross polarization, and because the scattered wave of general objects has much larger main polarization component than the cross polarization component, it is also called The main polarization echo is a strong signal, and the cross polarization echo is a weak signal. The polarization direction of the antenna unit in this case can be selected as the main polarization direction, cross polarization direction or other polarization directions, so the size of the echo signal The strength is controllable.

Then, the receiving unit 5 is electrically connected to the signal processing unit 6, wherein when an electromagnetic signal is generated through the signal generating unit 4, the electromagnetic signal is radiated to the rotating unit 2 through the transmitting unit 3, and an electromagnetic echo signal is generated The receiving unit 5 is used to receive the electromagnetic echo signal, and is used to process the electromagnetic echo signal through the signal processing unit 6. In addition, the receiving unit 5 is an antenna unit, and the polarization direction of the antenna unit can be selected Main polarization direction, cross polarization direction or other polarization direction, so the echo signal strength can be controlled.

In yet another preferred embodiment, the transmitting unit 3 is electrically connected to the signal generating unit 4, wherein the polarization direction of the transmitting unit 3 and the receiving unit 5 can be controlled. When the electromagnetic signal is radiated to the rotating unit 2, The receiving unit 5 receives an electromagnetic echo signal (which can be a weak electromagnetic echo signal with a controllable signal size), and the polarization direction of the transmitting unit 3 and the receiving unit 5 is controlled by controlling the transmitting unit 3 and The receiving unit 5 has different polarization directions to obtain different electromagnetic echo signals (which can be a weak electromagnetic echo signal with a controllable signal size). For example, when the transmitting unit 3 is in the horizontal direction and the receiving unit 5 Is the horizontal direction, the transmitting unit 3 is the vertical direction and the receiving unit 5 is the horizontal direction, the transmitting unit 3 is the horizontal direction and the receiving unit 5 is the vertical direction, or the transmitting unit 3 is the vertical direction and the receiving unit 5 is vertical In the direction, different electromagnetic echo signals (which can be a weak electromagnetic echo signal with controllable signal size) can be obtained by controlling the different polarization directions of the transmitting unit 3 and the receiving unit 5, which can be used as a robustness verification of the calculation mode This can be used for long-range detection radars, and the aforementioned control of the different polarization directions of the transmitting unit 3 and the receiving unit 5 should not be limited by this embodiment.

Then, the arithmetic processing unit 7 is electrically connected to the signal processing unit 6, wherein the signal processing unit 6 processes the electromagnetic echo signal to generate complex instantaneous spectrum information, and transmits the complex instantaneous spectrum information to the arithmetic processing Unit 7, and the arithmetic processing unit 7 processes the complex instantaneous spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data, where the complex instantaneous spectrum information includes: the number of output data, the number of data obtained in one second The pen output data, the bandwidth of the signal generator, the echo signal with micro-Doppler (micro-spectrum) information, and the instrument parameters should not be limited by this embodiment.

In yet another preferred embodiment, the radar echo feature extraction method of the present invention firstly uses the activation unit 1 to set the activation information, and activates the rotation unit 2 through the activation information, and the rotation unit 2 is based on the activation information. Start the information to rotate; then, the signal generating unit 4 generates the electromagnetic signal, and radiates to the rotating unit 2 through the transmitting unit 3; and then, it can be controlled The polarization direction of the transmitting unit 3 and the receiving unit 5, after the electromagnetic signal is scattered by the rotating unit 2, an electromagnetic echo signal with micro-Doppler (micro-spectrum) information (can be a signal size can be Controlled weak electromagnetic echo signal), the receiving unit 5 is used to receive the electromagnetic echo signal with micro-Doppler (micro-frequency spectrum) information (it can be a weak electromagnetic echo signal with a controllable signal size), and pass The signal processing unit 6 is used to process electromagnetic echo signals with micro-Doppler (micro-spectrum) information (it can be a weak electromagnetic echo signal with a controllable signal size); then, the signal processing unit 6 will have The electromagnetic echo signal (which can be a weak electromagnetic echo signal with a controllable signal size) of micro-duppler (micro-spectrum) information is processed to generate complex instantaneous spectrum information, and the complex instantaneous spectrum information is passed to the arithmetic processing Unit 7, and the arithmetic processing unit 7 processes the complex instantaneous frequency spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data.

Please refer to the second and third diagrams, and the second and third diagrams are based on the first diagram for the schematic diagram of the radar echo feature extraction system and further illustrate the micro-doppler (micro-spectrum) spread spectrum of the present invention The echo time-frequency diagram with a larger width and the echo time-frequency diagram with a smaller micro-doppler (micro-spectrum) spreading bandwidth of the present invention; first, when the radar echo feature extraction system is the main polarization measurement system, As shown in Figure 2, when the center frequency of the signal generating unit 4 becomes larger and the bandwidth remains unchanged, the electromagnetic echo signal with micro-Doppler (micro-spectrum) information will have a micro-Doppler spreading bandwidth greater than this The inherent transmitting signal bandwidth of the signal generating unit 4, and after being received by the receiving unit 5, it can be seen that in addition to the inherent transmitting signal bandwidth of the signal generating unit 4, there is a faintly periodic spread spectrum signal at other frequencies, forming a black and white Alternate This stripe pattern with periodic spread spectrum signal is the electromagnetic echo signal with micro-Doppler (micro-spectrum) information contributed by the rotating unit 2.

In another preferred embodiment, as shown in FIG. 3, when the center frequency of the signal generating unit 4 becomes smaller and the bandwidth remains unchanged, the electromagnetic echo signal with micro-Doppler (micro-spectrum) information is received by the receiving unit 5 After receiving, the signal processing unit 6 processes the electromagnetic echo signal with micro-Doppler (micro-spectrum) information to generate complex instantaneous spectrum information, which can be seen with micro-Doppler (micro-spectrum) The micro-doppler spreading bandwidth of the electromagnetic echo signal of the information is smaller than the inherent transmission signal bandwidth of the signal generating unit 4, so there is no spreading signal that appears in a vague period at other frequencies, and the complex instantaneous spectrum information is passed to the calculation The processing unit 7, and the arithmetic processing unit 7 processes the complex instantaneous frequency spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data, wherein the plurality of calculation modes include the first calculation mode and the second calculation mode. The multiple target characteristic data are shown in Figure 4. It can be seen that although the electromagnetic echo signal bandwidth with micro-Doppler (micro-spectrum) information is smaller than the inherent transmission signal bandwidth of the signal generating unit 4, the second calculation mode is still The target feature can be extracted.

其中縱軸是時間，當訊號處理單元6以一秒鐘可獲取10組瞬時頻譜資訊(也就是說，若只有記錄一秒的時間，t₁到t_N的N即為10)，而每組瞬時頻譜資訊其時間間隔為0.1秒，且每組瞬時頻譜資訊其紀錄的頻寬為200Hz(-100~100Hz)，其中負頻率是以原發射電磁波的載波頻率做為0Hz，故負頻率是對應到該旋轉單元2遠離該接收單元5時產生的負都普勒頻偏。 Then, the signal processing unit 6 processes the electromagnetic echo signal with micro-doppler (micro-spectrum) information to generate complex instantaneous spectrum information, and the complex instantaneous spectrum information is passed to the arithmetic processing unit 7, and the arithmetic The processing unit 7 processes the complex instantaneous frequency spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data. The plurality of calculation modes include the first calculation mode and the second calculation mode. If the calculation processing unit 7 selects the second calculation mode In an arithmetic mode, first, the processing is performed based on the obtained complex instantaneous spectrum information, and the complex instantaneous spectrum information is shown in the following table:

The vertical axis is time. When the signal processing unit 6 can obtain 10 sets of instantaneous spectrum information in one second (that is, if there is only one second of recording time, _{N from t 1} to t N is 10), and each group The instantaneous spectrum information has a time interval of 0.1 second, and each set of instantaneous spectrum information has a recorded bandwidth of 200Hz (-100~100Hz), where the negative frequency is the carrier frequency of the original emitted electromagnetic wave as 0Hz, so the negative frequency corresponds to When the rotating unit 2 is far away from the receiving unit 5, the negative Doppler frequency offset is generated.

Then, add the signal amplitudes of each instantaneous spectrum information, for example, put A(t1,f1), A(t1,f2),...,A(t1,f _M ) on the frequency axis (horizontal axis) Sequentially add, the total value is (A(t1,f1)+A(t1,f2)+…+A(t1,f _M )), and so on, each instantaneous spectrum information is summed, A set of time series will be obtained. There will be N elements (t ₁ ~t _N ) in this time series. Finally, after Fourier transform of this time series, the corresponding peak frequency (period) of the spectrum will be the rotation The actual rotation frequency (period) of the unit 2 is twice (half), so far, the rotation speed of the rotation unit 2 is extracted, that is, a plurality of target characteristic data.

In yet another preferred embodiment, if the arithmetic processing unit 7 selects the second arithmetic mode, the same vertical axis is time, and the signal processing unit 6 can obtain 10 sets of instantaneous spectrum information in one second (that is, if Only one second is recorded, _{N from t 1} to t N is 10), and the time interval of each set of instantaneous spectrum information is 0.1 second, and the recording bandwidth of each set of instantaneous spectrum information is 200Hz (-100~100Hz) ), where the negative frequency is because the carrier frequency of the originally emitted electromagnetic wave is taken as 0 Hz, so the negative frequency corresponds to the negative Doppler frequency offset generated when the rotating unit 2 is far away from the receiving unit 5.

Then, first use the first measured instantaneous spectrum information A(t1,f1)~A(t1,f _M ) as a reference spectrum, and then subtract this reference spectrum from each subsequent measured spectrum, such as A(t2,f1)-A(t1,f1), A(t2,f2)-A(t1,f2),..., A(t2,f _M )-A(t1,f _M ) to get a new set of The instantaneous spectrum of A(t3,f1)-A(t1,f1), A(t3,f2)-A(t1,f2),...,A(t3,f _M )-A(t1,f _M ) Get a new set of instantaneous spectra, and then N-1 sets of new instantaneous spectra will be obtained in sequence. The last set of new instantaneous spectra is A(t _N ,f1)-A(t1,f1), A(t _N ,f2)-A(t1,f2),...,A(t _N ,f _M )-A(t1,f _M ), finally, pass the N-1 sets of new instantaneous spectrum information through the steps of the first calculation mode After obtaining a set of time series and performing fast Fourier transformation, the extracted blade speed frequency (period) can be obtained. At this point, the speed of the rotating unit 2 is extracted, that is, multiple target feature data.

In yet another preferred embodiment, please refer to the fifth and sixth diagrams, and the fifth and sixth diagrams are based on the schematic diagram of the radar echo feature extraction system based on the first diagram and further illustrate the metal blade scene. The schematic diagram and the schematic diagram of the radar cross section simulation value; the rotating unit 2 of the present invention obtains the radar cross section (radar cross section, RCS) polarization response through the metal blade, and then according Different electromagnetic wave incident angles judge the radar cross-sectional area of the metal blade, where HH represents the horizontal main polarization, VV represents the vertical main polarization and the cross-polarization of the HV meter, and you can see that HH is within VV at most of the incident angle (Azimuth) Therefore, the horizontal main polarization is larger than the vertical main polarization on average; in addition, when the horizontal angle is 0 degrees (Azimuth=0 degrees, the leftmost side of the figure) and 180 degrees (Azimuth=180 degrees, the rightmost side of the figure), It can be seen that the RCS values corresponding to the vertical axis of HH are all far above 0dB, so it can be seen that the RCS is obviously greater than 0dB.

In yet another preferred embodiment, please refer to the seventh figure, and the seventh figure is the schematic diagram of the radar echo feature extraction system according to the first figure and the second figure is the micro-doppler (micro-spectrum) spread spectrum The wider echo time-frequency diagram further illustrates the schematic diagram of the main polarization measurement; first, when the radar echo feature extraction system is the main polarization measurement system, use the first calculation mode and the second calculation mode to calculate After the electromagnetic echo signal with micro-Doppler (micro-spectrum) information, the normalized spectrum is obtained (that is, the amplitude of the entire spectrum is divided by the maximum amplitude value in the spectrum, so that the maximum peak value of the spectrum is 1), you can see two The calculation mode has a maximum value at 2 times the actual rotation frequency of the rotating unit 2, that is, 2Hz. The global maximum value of the first calculation mode (Algo.1) appears at 0Hz. The reason is that the reflection of the surrounding environment is not deducted. The second calculation mode (Algo.2) effectively suppresses the echo component without Doppler frequency deviation, and then highlights the spread spectrum signal, so that the frequency spectrum obtained by the second calculation method is at 2 of the actual rotation frequency of the rotation unit 2. The multiplier is a global maximum.

In yet another preferred embodiment, please refer to the eighth figure, and the first Figure 8 is a schematic diagram of the cross-polarization measurement based on the schematic diagram of the radar echo feature extraction system based on the first figure; first, when the radar echo feature extraction system is a cross-polarization measurement system, the transmitting unit 3 When vertical polarization is selected, and the receiving unit 5 is horizontally polarized, and the blade speed is increased to 2 Hz, the first calculation mode and the second calculation mode are used to calculate information with micro-Doppler (micro-spectrum) It can be seen that the signal-to-noise ratio has dropped by 15-20dB (corresponding to the RCS difference between the main polarization and the cross polarization of the rotating unit 2 in the fifth figure), but the two algorithms can still be at 4Hz A maximum value is formed (the first calculation mode (Algo.1) is a local maximum, and the second calculation mode (Algo.2) is a global maximum), that is, twice the rotation frequency of the actual rotating unit 2 to obtain a good micro-duplex The success rate and accuracy of Le Domain target recognition, and because the signal-to-noise ratio is significantly reduced, the overall noise of the spectrum has been improved to a certain extent.

For those who need to be clarified, the above are only the preferred embodiments of this case, and are not intended to limit the creation. If changes are made based on the concept of this creation, it does not depart from the spirit of this creation, such as: configuration or layout The changes in the form, and the equivalent effects of various changes, modifications and applications, should be included in the scope of rights in this case, and shall be stated.

1: Start the unit

2: Rotating unit

3: launch unit

4: signal generating unit

5: Receiving unit

6: Signal processing unit

7: Operation processing unit

Claims (9)

A radar echo feature extraction system, including: an activation unit electrically connected to a rotating unit, the activation unit being used for setting activation information, and the rotating unit operates according to the activation information; and a transmitting unit , The transmitting unit is electrically connected with a signal generating unit, the signal generating unit generates an electromagnetic signal, the electromagnetic signal is radiated to the rotating unit through the transmitting unit; a receiving unit, the receiving unit is electrically connected with a signal processing unit , Wherein the different polarization directions of the transmitting unit and the receiving unit can be controlled. When the electromagnetic signal is radiated to the rotating unit, an electromagnetic echo signal with a controllable signal size is generated, and the receiving unit receives the signal with a controllable electromagnetic signal. The echo signal is used to process the electromagnetic echo signal with a controllable signal size through the signal processing unit. When a center frequency of the signal generating unit becomes larger and a bandwidth remains unchanged, the signal size is controllable electromagnetic echo The micro-Doppler spread bandwidth of the signal will be greater than the inherent bandwidth of the signal generating unit, or when the center frequency of the signal generating unit becomes smaller and the bandwidth remains the same, the signal size is controllable. Electromagnetic echo signal The micro-Doppler spread bandwidth of the signal generating unit is smaller than the inherent bandwidth of the signal generating unit; and an arithmetic processing unit which is electrically connected to the signal processing unit, wherein the signal processing unit can control the magnitude of the signal The electromagnetic echo signal is processed to generate complex instantaneous spectrum information, and the complex instantaneous The spectrum information is transmitted to the arithmetic processing unit, and the arithmetic processing unit processes the complex instantaneous spectrum information according to a plurality of calculation modes, and then analyzes a plurality of target characteristic data. For example, the first radar echo feature acquisition system in the scope of patent application, where the complex instantaneous spectrum information includes: the number of output data, how many output data can be obtained in one second, the bandwidth of the signal generator, and the micro-Doppler (Micro spectrum) Information echo signal and instrument parameters. For example, the first radar echo feature extraction system in the scope of the patent application, wherein the plurality of calculation modes include: a first calculation mode and a second calculation mode. For example, the third radar echo feature extraction system in the scope of patent application, wherein the arithmetic processing unit first adds the complex instantaneous spectrum information to the amplitude of each group of instantaneous spectrum information signals through the first calculation mode to obtain the target feature data. For example, the third radar echo feature extraction system in the scope of the patent application, wherein the arithmetic processing unit first uses a first instantaneous spectrum information as the first reference spectrum information through the second calculation mode. The first reference spectrum information is subtracted from the other subsequent complex instantaneous spectrum information, and then the target characteristic data is obtained after calculation through the first calculation mode. For example, the first radar echo feature extraction system in the scope of the patent application, in which the transmitting unit and the receiving unit are an antenna unit, and the polarization direction of the antenna unit can be selected as the main polarization direction, the cross polarization direction or other polarities. Orientation. A radar echo feature extraction method using the radar echo feature extraction system as described in claim 1, comprising: using the activation unit to set the activation information, and activate the rotation unit through the activation information, and The rotating unit rotates according to the activation information; the signal generating unit generates the electromagnetic signal and radiates to the rotating unit through the transmitting unit; wherein the different polarization directions of the transmitting unit and the receiving unit can be controlled, when the electromagnetic signal After radiating to the rotating unit, an electromagnetic echo signal with a controllable signal size will be generated, and the receiving unit receives the electromagnetic echo signal with a controllable signal size, and is used to process the electromagnetic echo with a controllable signal size through the signal processing unit Signal, wherein when the center frequency of the signal generating unit becomes larger and the bandwidth remains unchanged, the micro-Doppler spread bandwidth of the signal-level controllable electromagnetic echo signal will be greater than the inherent bandwidth of the signal generating unit, Or when the center frequency of the signal generating unit becomes smaller and the bandwidth remains unchanged, the micro-doppler spread bandwidth of the signal-level controllable electromagnetic echo signal will be smaller than the inherent bandwidth of the signal generating unit; and The signal processing unit processes the signal size controllable electromagnetic echo signal to generate complex instantaneous frequency spectrum information, and transmits the complex instantaneous frequency spectrum information to the arithmetic processing unit, and the arithmetic processing unit processes the signal according to a plurality of calculation modes Complex instantaneous spectrum information, and then analyze multiple target characteristic data. For example, the seventh radar echo feature extraction method in the scope of the patent application, wherein the arithmetic processing unit adds the complex instantaneous spectrum information to the amplitude of each group of instantaneous spectrum information signals through a first calculation mode of the plurality of calculation modes, Then obtain the target characteristic data. For example, the 7th radar echo feature extraction method in the scope of the patent application, wherein the arithmetic processing unit uses a second calculation mode of the plurality of calculation modes to first use a first instantaneous spectrum information as a first calculation mode for the complex instantaneous frequency spectrum information. The first reference spectrum information is subtracted from the subsequent complex instantaneous spectrum information and the first reference spectrum information is calculated through the first calculation mode to obtain the target characteristic data.

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