S-band navigation radar detection system compatible with wave measurement function

Abstract

The invention belongs to the technical field of radar overall technology and marine survey, and discloses an S-band navigation radar system compatible with a wave measurement function, which comprises a radar hardware system and a radar software system, and is characterized in that the hardware part comprises an antenna, a turntable and a display control terminal; the software part inverts sea wave field parameters based on radar images, and the sea state information of sea wave direction spectrum, dominant wave period, dominant wave direction, wave height and the like is obtained by inversing the collected radar images. According to the invention, high-time-distance-resolution, all-weather, large-range and long-term ocean wave flow information monitoring can be effectively realized.

Description

Technical Field

[0001] The invention belongs to the fields of radar overall technology and ocean measurement technology. Background Art

[0002] China is a large maritime country, and marine environmental monitoring is particularly important. For marine environmental monitoring and marine development and utilization, existing technologies are divided into two types: field measurement and marine remote sensing measurement, which rely on basic data of ocean waves, characteristics of ocean waves changing over time, and other information. Traditional field measurement methods can accurately measure the characteristics of ocean waves changing over time at the test point through field measurement methods such as wave buoys, ocean survey ships, and acoustic Doppler current meters. However, field measurement methods have some defects: (1) They can only collect data at a specific time on a local point line, and cannot comprehensively measure ocean wave data over a large range. (2) Field test operations are easily affected by ocean conditions and meteorological environment. (3) It is difficult to obtain real-time and continuous ocean wave data from test data. Traditional field measurement methods cannot meet the environmental monitoring requirements of all-weather and large-scale continuous measurement. In recent years, ocean remote sensing measurement methods obtain ocean wave information through optical imaging or electromagnetic waves, and are divided into satellite aerial remote sensing technology, high-frequency ground wave radar technology, and microwave radar technology. Among them, satellite aerial remote sensing technology has a long sampling time, low resolution, and consumes a lot of manpower and material resources, and cannot achieve all-weather and long-term observation. High-frequency ground wave radar has the advantages of long detection distance, large coverage, and all-weather operation, but its resolution is at the kilometer level and the area it occupies is hundreds to tens of thousands of square meters. Microwave radar has the advantages of less external interference and high time-distance resolution, but its effective detection distance is only a few kilometers.

[0003] Therefore, in the field of existing ocean measurement technology, it is urgent to develop technologies for high time-distance resolution and all-weather, large-scale, long-term ocean wave and current information monitoring. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes an S-band navigation radar detection system compatible with wave measurement function, which can not only effectively realize all-weather large-scale long-term monitoring of ocean wave and current conditions, but also solve the problem of high time-distance resolution.

[0005] The present invention proposes an S-band navigation radar detection system compatible with wave measurement function, which is realized by the following technical solutions:

[0006] The system includes a radar hardware system and a radar software system; wherein the radar hardware system includes an antenna unit, a turntable unit, a display and control terminal unit, and a connecting cable; wherein the antenna unit includes a crack waveguide antenna and a PM antenna, the turntable unit includes a servo module, a feeder module, a transmitting module, a receiving module, a signal processing module, an interface module, and a PM module, and the display and control terminal unit includes a display and control platform body, a control unit, and an integrated information processing unit; the antenna unit and the turntable unit are installed outside the cabin, and the display and control terminal is installed inside the cabin, the connecting cable of the crack waveguide antenna is connected to the feeder module of the turntable unit, and the turntable unit and the display and control terminal unit are connected together through a connecting cable; the radar software system includes display and control software, signal processing software, detection and tracking software, and wave current measurement software.

[0007] Furthermore, the servo module in the radar hardware system includes a servo control board, a brushless DC motor, a motor driver, and a safety switch; the feeder module includes a rotary joint, a three-terminal circulator, and a waveguide coaxial converter; the transmitting module includes a modulation board, a pulse transformer, and a magnetron; the receiving module includes a limiter, a low-noise amplifier, and an intermediate frequency amplifier; the control unit includes a switch power supply, an EBL knob, and a VRM knob.

[0008] Furthermore, the display and control software in the radar software system includes visual computing, electronic nautical charts, communication management, and status monitoring; the signal processing software includes interference suppression, cloud and rain suppression, video accumulation, and STC processing; the wave current measurement software monitors the sea state information, including: collecting radar echo images, taking the time and space distribution of the radar echo image for Fourier transform to obtain a three-dimensional image spectrum, filtering the three-dimensional image spectrum according to the wave dispersion relationship to obtain a two-dimensional and one-dimensional image spectrum, converting the image spectrum into a wave spectrum, and obtaining sea state information according to the wave spectrum.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] (1) Based on the existing navigation radar system, the sea surface radar echo intensity information is used to invert the wave parameters, and a wave current parameter inversion model is established between the radar echo intensity and the wave height, thereby realizing all-time and all-weather real-time monitoring of the sea state information in a large area of ​​sea.

[0011] (2) Conventional sea state monitoring will cause radar beam pointing deviation, position change of the measurement area relative to the radar and additional Doppler frequency shift due to changes in the ship's motion posture and displacement, which will affect the measurement accuracy of waves and currents. The motion compensation processing of the software in this radar system will eliminate the negative impact of changes in the ship's motion posture on wave and current measurement, thereby improving the accuracy of sea state detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a flow chart of the present invention; DETAILED DESCRIPTION

[0013] The present invention proposes an S-band navigation radar detection system compatible with wave measurement function, which has the advantages of all-day, all-weather, high temporal and spatial resolution, and real-time observation compared with traditional ocean measurement and detection means.

[0014] The embodiments provided by the present invention are as follows Figure 1 As shown. The antenna unit of the preferred radar hardware system realizes the sharing of transmission and reception through the circulator in the feeder unit. When the radar is working, the servo module controls the antenna to rotate clockwise at a specified speed through the servo control board. The encoder obtains the antenna angle in real time and feeds it back to the servo control board and sends it to the signal processing module. The signal processing module parses and obtains the antenna azimuth coding information in real time and feeds it back to the servo control module to realize the closed-loop control of the servo motor. The servo module has a safety switch that can directly switch the power supply to stop the antenna from rotating. The transmitting module receives the trigger signal sent by the signal processing module, generates a high-voltage pulse through the modulator and the pulse transformer, and excites the magnetron to transmit a microwave high-power pulse signal. After the transmission is completed, the signal processing module controls the radar to enter the receiving state.

[0015] During the receiving stage of the radar hardware system, the received pulse signal enters the limiter to limit the high-power signal and perform safety protection on the low-noise amplifier circuit. The low-noise amplifier circuit in the receiving module amplifies the power of the received echo pulse signal. The amplified RF signal passes through the STC circuit to complete time sensitivity control, and is mixed by the frequency source. The image frequency is suppressed by the filter, and the intermediate frequency signal is output. The intermediate frequency signal is coherently processed. After completing STC, co-channel interference suppression, cloud and rain suppression, accumulation, CFAR and other processing, the obtained video information is sent to the radar display and control terminal through the connecting cable.

[0016] The wave current measurement software in the radar software system optimizes the implementation steps of sea state information monitoring including:

[0017] Step (1): Perform FFT on the grayscale value of the collected radar image to obtain three-dimensional, two-dimensional, and one-dimensional image spectra. The radar imaging grayscale value (radar echo intensity) is linearly related to the actual energy of the waves. A modulation transfer function is multiplied on the basis of the image spectrum.

[0018] Step (2): The modulation transfer function (MTF) in step (1) is defined as M = F(k) / I(k), where I(k) is the one-dimensional image spectrum and F(k) is the one-dimensional wave number spectrum.

[0019] Step (3): Convert the two-dimensional image wave vector spectrum into a two-dimensional ocean wave wave vector spectrum:

[0020] Step (4): After inverting the two-dimensional wave vector spectrum in step (2) to obtain the two-dimensional wave spectrum, the two-dimensional frequency direction spectrum can be obtained: The one-dimensional spectrum is

[0021] Step (5): The directional propagation function describing the propagation direction of the wave field is in The average wave direction is In the formula

[0022] Step (6): Use step (5) to get the main wave period Main wave direction Where: f p is the frequency corresponding to the spectrum peak;

[0023] Step (7): Invert the formula obtained in step (3) to obtain the two-dimensional wave vector spectrum F (2) (k x ,k y )and Where N is the number of spectral coordinates in the dispersion relation, I (3) (k x ,k y ,w) is the three-dimensional image spectrum obtained after three-dimensional Fourier transform, N x ,N y ,N t is the coordinate number of the wave number and frequency component after Fourier transformation, I (2) (k x ,k y ) is the two-dimensional wave vector spectrum of the wave component that falls on the dispersion relation after filtering integration, and N is the number of spectral coordinates on the dispersion relation;

[0024] Step (8): Obtain the effective wave height from the formula obtained in step (7): Where A, B are constants to be determined, which depend on the radar system and the assembly properties of each experiment. They must be determined for each different assembly.

Claims

1. An S-band navigation radar detection system compatible with wave measurement function, characterized in that: The system includes a radar hardware system and a radar software system; wherein the radar hardware system includes an antenna unit, a turntable unit, a display and control terminal unit, and a connecting cable; wherein the antenna unit includes a crack waveguide antenna and a PM antenna, the turntable unit includes a servo module, a feeder module, a transmitting module, a receiving module, a signal processing module, an interface module, and a PM module, and the display and control terminal unit includes a display and control platform body, a control unit, and an integrated information processing unit; the antenna unit and the turntable unit are installed outside the cabin, and the display and control terminal is installed inside the cabin, the connecting cable of the crack waveguide antenna is connected to the feeder module of the turntable unit, and the turntable unit and the display and control terminal unit are connected together through a connecting cable; the radar software system includes display and control software, signal processing software, detection and tracking software, and wave current measurement software.

2. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The servo module comprises a servo control board, a brushless DC motor, a motor driver and a safety switch.

3. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The feeder module comprises a rotary joint, a three-terminal circulator and a waveguide coaxial converter.

4. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The transmitting module includes a modulation board, a pulse transformer and a magnetron.

5. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The receiving module includes a limiter, a low noise amplifier and an intermediate frequency amplifier.

6. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The control unit includes a power switch, an EBL knob, and a VRM knob.

7. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The display and control software includes visual computing, electronic nautical charts, communication management, and status monitoring.

8. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The signal processing software includes interference suppression, cloud and rain suppression, video accumulation, and STC processing.

9. The S-band navigation radar detection system compatible with the wave measurement function according to claim 1, characterized in that: The detection and tracking software includes point track aggregation, filter tracking, and track fusion.

10. An S-band navigation radar detection system compatible with wave measurement function according to any one of claims 1 to 9, characterized in that: The monitoring of sea state information by the wave current measurement software includes the following steps: collecting radar echo images, taking the time and space distribution of the radar echo images for Fourier transformation to obtain a three-dimensional image spectrum, filtering the three-dimensional image spectrum according to the wave dispersion relationship to obtain a two-dimensional and one-dimensional image spectrum, converting the image spectrum into a wave spectrum, and obtaining sea state information according to the wave spectrum.

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