A solar radio aiming and calibration method and system

Abstract

The present invention proposes a solar radio targeting calibration method and system. Based on GPS positioning, the solar azimuth and pointing direction are calculated. Then, according to the antenna pointing accuracy measurement scanning method, the antenna angle is adjusted to rotate the antenna azimuth and elevation respectively, obtaining power output curves at different pointing angles. The antenna elevation angle and azimuth are then calculated and corrected. The present invention proposes a solar radio targeting calibration system, comprising an information receiving module, an information processing module, a power analysis module, a curve fitting module, a coordinate conversion module, and a correction module. The collected power curve is curve-fitted to a standard solar radiation model. The solar coordinate position is read at the peak of the fitted curve and converted to the azimuth and elevation angle of the system's location, completing the pointing and positioning. Because the present invention uses solar radio signals for orientation, it is not affected by interference from the outdoor environment while ensuring accuracy and speed.

Description

Technical Field

[0001] The present invention relates to the technical field of astronomical aiming and orientation, and in particular to a solar radio aiming and calibration method and system. Background Art

[0002] With the deepening of new military reforms and technological developments, field mobile equipment requires real-time, accurate self-orientation to rapidly respond to unassisted launches, large-area transport, and long-term deployments. Currently, traditional orientation methods include geometric orientation, astronomical (observational) orientation, and gyrotheodolite orientation, each relying on fixed testing sites or inertial navigation. These methods have limited coverage, low efficiency, and large cumulative errors, making them unsuitable for field operations. Therefore, a field-appropriate aiming and orientation method with improved accuracy and speed is urgently needed. Summary of the Invention

[0003] In view of this, the present invention provides a solar radio aiming and calibration method and system, which are suitable for field environments and improve orientation accuracy and speed.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0005] A solar radio aiming and calibration method, comprising the following steps:

[0006] According to GPS positioning, the direction and orientation of the sun are obtained.

[0007] Adjust the antenna's elevation angle and turn it toward the sun to collect solar radio signals: According to the antenna pointing accuracy measurement scanning method, rotate the antenna counterclockwise, deviating from the center by -θ, to receive solar radio signals; adjust the antenna's azimuth direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals; rotate the antenna counterclockwise to change the elevation angle and deviate from the center by -θ to receive solar radio signals; adjust the antenna's elevation direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals.

[0008] Perform power spectrum analysis on solar radio signals to obtain power output curves at different antenna pointing angles; based on the power output curves, obtain the antenna azimuth and elevation angles.

[0009] According to the environmental parameters, the antenna azimuth and elevation angle are corrected for atmospheric errors.

[0010] Furthermore, the specific method for correcting the antenna azimuth and elevation angle is as follows:

[0011] AZ'=2Arcsin[sin(AZ / 2)cos(EL)]

[0012] EL′=2Arccos[sin(AZ) / sin(AZ / 2)]

[0013] Where EL is the uncorrected elevation angle; EL′ is the corrected elevation angle; AZ′ is the corrected azimuth angle; and AZ is the uncorrected azimuth angle.

[0014] Furthermore, the antenna adopts a Cassegrain parabolic antenna with an aperture of no more than 30 cm, a receiving frequency of 92.5 GHz ± 50 MHz, and a gain of no less than 46 dB.

[0015] A solar radio aiming and calibration system is characterized by comprising an antenna module, an information receiving module, an information processing module, a power analysis module, a curve fitting module, a coordinate conversion module and a correction module.

[0016] The antenna module rotates the antenna azimuth counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates it clockwise to a pointing angle of +θ, to receive solar radio signals, rotates the antenna pitch direction counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates the antenna pitch direction clockwise to a pointing angle of +θ, to receive solar radio signals.

[0017] The information receiving module amplifies, frequency-converts, and performs multiple filtering processes on the solar radio signals received by the antenna module to obtain the solar radio signals and transmit them to the information processing module.

[0018] The information processing module digitally collects solar radio signals and obtains their power output curve.

[0019] The curve fitting module performs curve fitting on the power output curve and the solar standard radiation model to obtain the radio signal fitting curve.

[0020] The coordinate conversion module reads the time point at the peak of the radio signal fitting curve; reads the solar longitude and latitude coordinates at that time point, and converts the solar coordinate system into the hour angle coordinate system of the system location based on the system longitude and latitude coordinates; in the hour angle coordinate system, the longitude and latitude coordinates of the antenna are converted into the azimuth and elevation angle of the antenna.

[0021] The correction module performs atmospheric error correction on the azimuth and pitch angles according to the pitch angles and environmental parameters, and outputs the corrected azimuth and pitch angles of the antenna.

[0022] Furthermore, the information receiving module includes a first frequency conversion unit, a second frequency conversion unit, an acquisition card and a filter.

[0023] The filter performs a first filtering on the solar radio signal and transmits it to the first frequency conversion unit.

[0024] The first frequency conversion unit amplifies and frequency-converts the solar radio signal after the first filtering, and transmits it to the second frequency conversion unit after the second filtering.

[0025] The second frequency conversion unit amplifies and frequency-converts the solar radio signal after the second filtering for the second time. After the third filtering, the solar radio signal is obtained and transmitted to the acquisition card.

[0026] The acquisition card transmits the solar radio signal to the information processing module.

[0027] Furthermore, the curve fitting module adopts Gaussian fitting method.

[0028] Furthermore, the frequency of the solar radio signal is 92.5GHz±50MHz.

[0029] Beneficial effects:

[0030] 1. The present invention proposes a solar radio aiming calibration method. Before calibration, the azimuth relationship between the antenna null point and the north reference is established. According to GPS positioning, the solar azimuth and direction are calculated. Then, according to the antenna pointing accuracy measurement scanning method, the antenna angle is adjusted and the azimuth and pitch of the antenna are rotated respectively to obtain the power output curves at different pointing angles. The antenna pitch angle and azimuth are calculated and corrected.

[0031] 2. The present invention adopts Gaussian fitting method for curve fitting, and the orientation accuracy is high.

[0032] 3. The present invention proposes a solar radio targeting and calibration system, comprising an antenna module, an information receiving module, an information processing module, a power analysis module, a curve fitting module, a coordinate conversion module, and a correction module. The collected power curve is fitted to the solar standard radiation model. The solar coordinate position is read at the peak of the fitted curve and converted into the antenna's azimuth and elevation angles to complete pointing and positioning. Because the present invention uses solar radio signals for orientation, it is not affected by interference from the field environment while ensuring accuracy and speed.

[0033] 4. The antenna and two-dimensional turntable used in the system of the present invention are Cassegrain parabolic antennas with an aperture of 0.3m, a frequency of 92.5GHz±50MHz, and a gain of ≥46.0dB. They can generate directional high-gain, low-sidelobe antenna beams to improve reception accuracy.

[0034] 5. This invention selects solar radio signals with a frequency of 92.5 GHz ± 50 MHz. This is because bursts are rare at this frequency, and their intensity is not significantly increased compared to the quiet background. In this frequency band, the sun primarily emits blackbody radiation, which is weakly absorbed by the Earth's atmosphere. Furthermore, due to the high frequency, the signal energy is high, resulting in a strong signal transmission capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the system of the present invention.

[0036] Figure 2 This is a flow chart of the system of the present invention.

[0037] Figure 3 It is a composition diagram of the device of the present invention.

[0038] Figure 4 This is the signal atmospheric attenuation curve. DETAILED DESCRIPTION

[0039] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0040] The present invention proposes a solar radio sighting calibration method. Before calibration, the antenna null pointing is established with an azimuth relationship with the north reference. The specific process of the method is as follows:

[0041] Calculate the direction and orientation of the sun based on the current GPS position;

[0042] Adjust the antenna's elevation angle and turn it toward the sun to collect solar radio signals: Based on the antenna pointing accuracy measurement scanning method, rotate the antenna counterclockwise, deviating from the center by -θ, to receive solar radio signals; adjust the antenna's azimuth direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals; rotate the antenna counterclockwise to change the elevation angle and deviate from the center by -θ to receive solar radio signals; adjust the antenna's elevation direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals;

[0043] Perform power spectrum analysis on solar radio signals to obtain power output curves at different antenna pointing angles; obtain antenna azimuth and elevation angles based on the power output curves;

[0044] Based on environmental parameters, the antenna azimuth and elevation angles are corrected for atmospheric deviation. The antenna's pointing direction deviates from the sun's true position, so correction is required. The specific methods for correcting azimuth and elevation angles are:

[0045] AZ'=2Arcsin[sin(AZ / 2)cos(EL)]

[0046] EL′=2Arccos[sin(AZ) / sin(AZ / 2)]

[0047] Where EL is the uncorrected elevation angle; EL′ is the corrected elevation angle; AZ′ is the corrected azimuth angle; and AZ is the uncorrected azimuth angle.

[0048] The antenna used in this method is Figure 3This embodiment also includes a two-dimensional turntable that carries the antenna and rotates it up and down, left and right, changing the antenna's pitch angle and azimuth.

[0049] The antenna mainly consists of four parts: reflector antenna (main reflector, sub-reflector), feed source and polarizer.

[0050] Antenna: The antenna is a Cassegrain parabolic antenna with an aperture no larger than 30 cm. The receiving frequency is within the 92.5 GHz ± 50 MHz band and the gain is no less than 46 dB. The primary reflector is a parabola with an aperture of 300 mm, and the secondary reflector is a hyperbolic surface. The antenna produces a directional, high-gain, low-sidelobe antenna beam.

[0051] Feed source: A variable-angle conical horn antenna is used, and the horn mouth is loaded with longitudinal slots to achieve equalization of the radiation pattern and improve radiation efficiency.

[0052] Polarizer: A rectangular waveguide polarizer is used to achieve linear polarization radiation characteristics.

[0053] According to the aperture antenna theory, the theoretical gain of the antenna is estimated under a 300mm aperture reflective surface. According to the surface antenna theory, the antenna gain is the product of its maximum theoretical gain and the total radiation efficiency. The specific calculation formula is:

[0054]

[0055] Where S is the area of ​​the primary reflector; D is the diameter of the primary reflector; and η is the total radiation efficiency of the antenna. λ is the wavelength, and η is the antenna efficiency. According to the antenna design standards, the received η is calculated as 50% (calculated according to the standards, add the efficiency calculation table). For a 300mm diameter antenna, the gain at 92.5GHz is 46.3dB.

[0056] The design indicators of the antenna are as follows:

[0057] Diameter: 0.3m;

[0058] Frequency: 92.5GHz±0.1GHz;

[0059] Gain: ≥46.0dB;

[0060] Polarization: linear polarization;

[0061] Sidelobe: ≤-12dB.

[0062] Based on the research and analysis of the physical mechanism and changing laws of solar radio signals, the frequency of the solar radio signal selected by the present invention is 92.5GHz±50MHz. In this frequency band, the sun mainly radiates as a black body, and the earth's atmosphere absorbs it weakly. Moreover, due to the high frequency and high signal energy, the signal transmission capability is strong, and the directional error is small. The radio signal from the sun is a dynamic weak signal. It is necessary to fully understand the physical mechanism and changing laws of the radio signal in order to receive and accurately calibrate it and eliminate the instrument effect during the observation process. Figure 4 As shown in the figure, the influence of rainfall attenuation, atmospheric absorption, cloud attenuation and the combination of main attenuation factors on solar radio signals are analyzed.

[0063] like Figure 1 and Figure 2 As shown, the present invention proposes a solar radio aiming and calibration system, comprising:

[0064] The antenna module rotates the antenna azimuth counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates it clockwise to a pointing angle of +θ, to receive solar radio signals, rotates the antenna pitch direction counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates the antenna pitch direction clockwise to a pointing angle of +θ, to receive solar radio signals.

[0065] The information receiving module amplifies, frequency-converts, and performs multiple filtering processes on the solar radio signals received by the antenna module to obtain the solar radio signals and transmit them to the information processing module.

[0066] The information receiving module includes a first frequency conversion unit, a second frequency conversion unit, an acquisition card and a filter;

[0067] The filter performs a first filtering on the solar radio signal and transmits it to the first frequency conversion unit;

[0068] The first frequency conversion unit amplifies and frequency-converts the solar radio signal after the first filtering, and transmits it to the second frequency conversion unit after the second filtering;

[0069] The second frequency conversion unit amplifies and frequency-converts the solar radio signal after the second filtering for the second time, obtains the solar radio signal after the third filtering, and transmits it to the acquisition card;

[0070] The acquisition card transmits the solar radio signal to the information processing module.

[0071] The information processing module digitally collects solar radio signals, performs power spectrum analysis, and obtains their power curves. After down-conversion, the solar radio signals enter the digital A / D system for digital acquisition. Signals with a 100MHz bandwidth are collected and recorded and stored; the power value recording resolution is less than 0.1 seconds.

[0072] The curve fitting module fits the power curve to the standard solar radiation model to obtain the radio signal fitting curve. Because the calibration error of the Gaussian fitting value is less than the calibration error of the average value, less than the calibration error of the maximum probability value, and less than the calibration error of the root mean square value, the fitting method of the present invention uses the Gaussian function to fit the power peak, providing the precise time point corresponding to the time point with a time accuracy of less than 0.1 second.

[0073] The coordinate conversion module reads the time point at the peak of the radio signal fitting curve; reads the solar longitude and latitude coordinates at that time point, and based on the antenna's longitude and latitude coordinates, converts the solar coordinate system to the antenna's location's hour-angle coordinate system. In the hour-angle coordinate system, the antenna's longitude and latitude coordinates are converted to the antenna's location's azimuth and elevation angle. In the solar coordinate system, the J2000 epoch (right ascension and declination coordinates) is used to convert the coordinates to the antenna's location's hour-angle coordinate system. Given the calculated J2000 coordinates (east longitude, north latitude) of the antenna's location, these coordinates can be converted to the antenna's location's azimuth and elevation angle. Azimuth is defined as 0 degrees due north and 90 degrees due east, with an azimuth range of 0 to 360 degrees. The elevation angle is 0 degrees horizontally and 90 degrees zenithally.

[0074] The correction module corrects the azimuth and elevation angles for atmospheric errors based on the elevation angles and environmental parameters, and outputs the corrected azimuth and elevation angles of the antenna location.

[0075] The design indicators of the first frequency conversion unit are as follows:

[0076] Input frequency: 92.5GHz±0.1MHz;

[0077] Input power: -40dBm, max: -15dBm;

[0078] Local oscillator Lo frequency: 10.7GHz~13.3GHz, local oscillator frequency multiplication: ×8;

[0079] Local oscillator power: 0~5dBm;

[0080] IF output: 2.5~8.5GHz;

[0081] Gain: 23dB;

[0082] Noise figure: ≤4dB;

[0083] Power supply: +5V, current 300mA.

[0084] The design indicators of the second frequency conversion unit are as follows:

[0085] Input frequency: 3.4GHz

[0086] Output intermediate frequency: 190MHz;

[0087] Gain: ≥45dB;

[0088] Noise figure: ≥3dB;

[0089] Local oscillator LO output: frequency: 11.075GHz, power: 0~3dBm;

[0090] Power output: +5V;

[0091] Power input: +5V;

[0092] Clock output: 10MHz; power: 4±2dBm.

[0093] The design indicators of the filter are as follows:

[0094] Center frequency: 92.5GHz;

[0095] Bandpass frequency: 90~95GHz;

[0096] Insertion loss: ≤-1dB;

[0097] Out-of-band suppression: <-40dB@77~88.5GHz, <-40dB@98.5~110GHz;

[0098] Return loss in passband: <-15dB.

[0099] The acquisition card is designed as follows: CH0 converts analog signals into digital signals using a 12-bit ADC. This digital signal is then sent via a high-speed bus to the FPGA controller for temporary storage in onboard memory. Due to the large amount of data, the acquisition card requires the FPGA controller to transfer the onboard memory data to the control computer's high-capacity hard drive via the PCIe 2.0 x8 bus. The acquisition card's clock signal, CLK_IN, is provided by the CLK_OUT port of the second frequency conversion unit. The control computer powers and communicates with the acquisition card via the PCIe bus on the motherboard. The control computer's power supply provides +5V power to the second frequency conversion unit.

[0100] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solar radio sighting calibration method, characterized in that: The specific steps include: According to GPS positioning, obtain the direction and orientation of the sun; Adjust the antenna's elevation angle and turn it toward the sun to collect solar radio signals: Based on the antenna pointing accuracy measurement scanning method, rotate the antenna counterclockwise, deviating from the center by -θ, to receive solar radio signals; adjust the antenna's azimuth direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals; rotate the antenna counterclockwise to change the elevation angle and deviate from the center by -θ to receive solar radio signals; adjust the antenna's elevation direction and rotate it clockwise to the pointing angle +θ to receive solar radio signals; Perform power spectrum analysis on solar radio signals to obtain power output curves at different antenna pointing angles; obtain antenna azimuth and elevation angles based on the power output curves; According to environmental parameters, the antenna azimuth and elevation angle are corrected for atmospheric errors; The specific method for correcting the antenna azimuth and elevation angle is: AZ'=2Arcsin[sin(AZ / 2)cos(EL)] EL′=2Arccos[sin(AZ) / sin(AZ / 2)] Where EL is the uncorrected elevation angle; EL′ is the corrected elevation angle; AZ′ is the corrected azimuth angle; and AZ is the uncorrected azimuth angle.

2. The method according to claim 1, wherein The antenna adopts a Cassegrain parabolic antenna with a diameter not greater than 30 cm, a receiving frequency of 92.5 GHz ± 50 MHz, and a gain not less than 46 dB.

3. A solar radio sighting and calibration system, using the solar radio sighting and calibration method according to claim 1 or 2, characterized in that: It includes antenna module, information receiving module, information processing module, power analysis module, curve fitting module, coordinate conversion module and correction module; The antenna module rotates the antenna azimuth counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates it clockwise to a pointing angle of +θ, to receive solar radio signals, rotates the antenna pitch direction counterclockwise, deviating from the center -θ, to receive solar radio signals, rotates the antenna pitch direction clockwise to a pointing angle of +θ, to receive solar radio signals; The information receiving module amplifies, converts the frequency and performs multiple filtering processes on the solar radio signals received by the antenna module to obtain the solar radio signals and transmit them to the information processing module; The information processing module digitally collects solar radio signals and obtains their power output curves; The curve fitting module is used to fit the power output curve to the solar standard radiation model to obtain the radio signal fitting curve; Coordinate conversion module, reads the time point of the peak of the radio signal fitting curve; Read the solar longitude and latitude coordinates at that time point, and convert the solar coordinate system into the hour angle coordinate system of the system location based on the system longitude and latitude coordinates. In the hour angle coordinate system, the longitude and latitude coordinates of the antenna are converted into the azimuth and elevation angle of the antenna. The correction module performs atmospheric error correction on the azimuth and pitch angles according to the pitch angles and environmental parameters, and outputs the corrected azimuth and pitch angles of the antenna.

4. The solar radio targeting and calibration system according to claim 3, wherein: The information receiving module includes a first frequency conversion unit, a second frequency conversion unit, an acquisition card and a filter; The filter performs a first filtering on the solar radio signal and transmits it to the first frequency conversion unit; The first frequency conversion unit amplifies and frequency-converts the solar radio signal after the first filtering, and transmits it to the second frequency conversion unit after the second filtering; The second frequency conversion unit amplifies and frequency-converts the solar radio signal after the second filtering for the second time, obtains the solar radio signal after the third filtering, and transmits it to the acquisition card; The acquisition card transmits the solar radio signal to the information processing module.

5. The solar radio targeting and calibration system according to claim 3, wherein: The curve fitting module adopts Gaussian fitting method.

6. The solar radio aiming and calibration system according to claim 3 or 4, characterized in that: The frequency of the solar radio signal is 92.5 GHz ± 50 MHz.

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