CN117007870B - High-frequency broadband solar radio signal observation device - Google Patents

Abstract

The invention relates to the technical field of radio astronomical observation and communication, and discloses a high-frequency broadband solar radio signal observation device, wherein a receiving antenna is used for receiving a solar radio signal and outputting the solar radio signal to a noise source correction unit; the noise source correction unit is used for calibrating the solar radio signal according to the cold temperature data and the hot temperature data of the noise source and outputting a circularly polarized signal to the analog front-end system; the analog front-end system is used for processing the circularly polarized signals and outputting two paths of channel signals; the digital receiver is used for collecting the two paths of channel signals, carrying out frequency mixing processing on one path of channel signals, carrying out frequency conversion processing on the other path of channel signals, and then transmitting the signals to the display storage system; the display storage system comprises an upper computer and a data storage system, wherein the data storage system is used for displaying and storing signals transmitted by the digital receiver, and the upper computer is used for controlling the receiving antenna, the noise source correction unit, the analog front-end system and the digital receiver.

Description

A high-frequency and wide-band solar radio signal observation device

Technical field

The invention relates to the technical fields of radio astronomical observation and communication, and in particular to a high-frequency and wide-band solar radio signal observation device.

Background technique

High-frequency radio astronomy observation receiver systems currently generally use methods to expand the bandwidth of the acquisition system, but there are certain problems. Receiving system methods include analog superheterodyne down-conversion combined with low-IF sampling digital receivers, channelized acquisition digital receivers, compressed sampling acquisition digital receivers, single-bit sampling digital receivers and alternating sampling digital receivers. Among them, analog superheterodyne down-conversion combined with low-IF sampling digital receiver performs analog-to-digital and digital-to-analog conversion in the intermediate frequency band, which can reduce the digital signal processing capability and speed requirements of the A/D back-end digital signal processing part, but The requirements for the complexity of the RF front-end part are extremely high, resulting in high volume and cost of the airborne system. In addition, the superheterodyne architecture of the receiver causes the functional waveform software to be tightly coupled with the front-end circuit, making it difficult to expand new functions. The filtering and frequency conversion of digital receiver channels collected in a channelized manner make the system large and complex, with large in-band fluctuations and serious signal distortion. Compressed sampling mode acquisition digital receiver requires the signal to have corresponding sparsity. Single-bit sampling digital receivers have losses in amplitude and phase and the two-tone dynamics of the system are low. Digital receivers that utilize multiple ADCs for parallel time-alternating sampling significantly increase the sampling rate. However, the analog bandwidth of the ADC device becomes its limiting factor. Due to the differences in responses between parallel channels and the differences in sampling clocks between channels, parallelism occurs. Non-uniform errors in sampling are inevitable.

High-frequency radio astronomical observations have requirements for receiver system sampling and large bandwidth, and current receivers have problems such as large and complex systems, limited signal requirements, and serious signal distortion. Solar radio bursts in the centimeter-wave band can be divided into rising and falling bursts, pulse bursts and microwave bursts based on the characteristics of radiation intensity changing with time. According to the cyclotron radiation theory, the relationship between magnetic field and particle acceleration can be inferred based on the peak frequency and high-frequency end spectrum index. The low-frequency cutoff is related to various absorption mechanisms, and the relevant parameters and related properties of the emission region can also be inferred. At present, some high-resolution radio telescopes are used to study burst phenomena in the centimeter band. However, current solar radio telescopes in the centimeter band generally have low time and frequency resolution, which is not conducive to studying bursts in the centimeter band.

Contents of the invention

Existing centimeter-band solar radio telescopes have problems such as extremely high complexity requirements for the RF front-end part, making it difficult to expand new functions, or the filtering and frequency conversion make the system large and complex, causing large fluctuations in the band, and serious signal distortion, resulting in centimeter-band collected data. Solar radio telescopes have low time and frequency resolutions. In response to these problems, the present invention provides a high-frequency and wide-band solar radio signal observation device, which meets the requirements of a high-frequency radio telescope for continuous observation of 2-10 GHz radio signals, and can realize the spectrum and part of the solar radio signal in the 2-10 GHz frequency band. Traffic is monitored in real time, with a wide observation frequency band, good real-time performance, and a calibration function. It has high time resolution and frequency resolution, with the time resolution up to 2.4ms and the frequency resolution up to 0.15MHz, realizing high-frequency and broadband signal data acquisition and processing of astronomical radio signals.

The technical solution adopted by the present invention is: a high-frequency wide-band solar radio signal observation device, including a receiving antenna, a noise source correction unit, an analog front-end system, a digital receiver and a display storage system;

The receiving antenna is used to receive solar radio signals and output them to the noise source correction unit;

The noise source correction unit is used to calibrate the solar radio signal according to the cold temperature data and hot temperature data of the noise source, and output the circular polarization signal to the analog front-end system;

The analog front-end system is used to process the circularly polarized signal and output two channel signals;

The digital receiver is used to collect the two channel signals, perform mixing processing on one of the channel signals, perform frequency conversion processing on the other channel signal, and then transmit it to the display storage system;

The display storage system includes a host computer and a data storage system. The data storage system is used to display and store the signals transmitted by the digital receiver. The host computer is used to control the receiving antenna, noise source correction unit, analog front-end system and digital receiver.

Preferably, the noise source correction unit includes a microwave switch, which is controlled by the digital receiver to perform gating for alternately outputting solar radio signals into left and right circularly polarized signals.

Preferably, the noise source correction unit further includes a noise source and a mechanical switch;

When the device is in the calibration state, the host computer controls the mechanical switch to switch to the noise source output cold temperature data and hot temperature data mode, which is used to calibrate the solar radio signal;

When the device is in working condition, the host computer controls the mechanical switch to switch to the output circular polarization signal mode.

Preferably, the receiving antenna further includes a turntable control system for controlling the rotation direction of the receiving antenna, and the turntable control system is connected to the host computer.

Preferably, the analog front-end system is used to amplify and filter the circularly polarized signal, and perform mixing processing on the specified frequency band signal.

Preferably, the designated frequency band signals include signals of 2-2.7GHz, 3.8-4GHz, 5.1-5.3GHz, 6.4-6.6GHz and 7.7-7.9GHz.

Preferably, the two channel signals include a first channel signal and a second channel signal;

The digital receiver uses multiple filters to mix the first signal and the 9.3GHz LO local oscillator signal. The mixed signals correspond to 6.6-7.3GHz, 5.3-5.5GHz, 4-4.2GHz, 2.7-2.9GHz and 1.4-1.6GHz frequency bands,

The digital receiver uses a band-pass filter to amplify and filter the second signal, and perform down-conversion processing on the frequency band of 9-10 GHz. The gated frequency band of the band-pass filter includes 2.7-3.8 GHZ, 4-5.1GHz, 5.3-6.4GHz, 6.6-7.7GHz, 7.9-9GHz and 9-10GHz frequency bands.

Preferably, the digital receiver outputs a TTL level to control channel switching of the analog front-end system. When the digital receiver completes the acquisition of a channel signal, the TTL control level is changed so that the analog front-end The system outputs another channel signal.

Preferably, the digital receiver includes a high-speed ADC and a high-performance FPGA, wherein the high-speed ADC is used to collect the intermediate frequency signal and convert it into a digital signal, and then transmit the digital signal to the high-performance FPGA;

High-performance FPGA is used to digitize the digital signal, including data windowing, FFT operation, and data accumulation processing.

Preferably, the calibration of the radio signal is based on the following calibration formula:

;

Among them, R _sun is the display value of the host computer for observing the sun, R _sky is the display value of the host computer when the sky is clear, T _sun is the brightness temperature value of the sun, T _sky is the brightness temperature value of the sky, R _n is the heat temperature output of the noise source. The display value of the computer, R _l is the display value of the host computer when the cold temperature of the noise source is output, T _n is the hot temperature value of the noise source, and T _l is the cold temperature value of the noise source.

Beneficial effects of the above technical solution:

Compared with the existing technology, the high-frequency wide-band solar radio signal observation device provided by the present invention meets the requirements of high-frequency radio telescopes for continuous observation of 2-10 GHz radio signals, and can realize the spectrum and analysis of solar radio signals in the 2-10 GHz frequency band. Part of the traffic is monitored in real time, with a wide observation frequency band, good real-time performance, and a calibration function. It has high time resolution and frequency resolution, with the time resolution up to 2.4ms and the frequency resolution up to 0.15MHz, realizing high-frequency and broadband signal data acquisition and processing of astronomical radio signals.

Description of the drawings

Figure 1 is a schematic diagram of a high-frequency wide-band solar radio signal observation device provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of signal channel division of an analog front-end system provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of an analog channel switching method provided by an embodiment of the present invention;

Figure 4 is a schematic diagram of a software processing flow provided by an embodiment of the present invention.

Detailed ways

The embodiments of the present application will be described in further detail below. Obviously, the described embodiments are only some of the embodiments of the present application and are not exhaustive of all embodiments. It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other.

The terms "first", "second", etc. (if present) in the description and claims are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, such as processes, methods, systems, products or devices that include a series of steps or units, and are not necessarily limited to those explicitly listed may include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

It should be understood that the term "and/or" used in this article is only an association relationship describing related objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A alone exists, and A and A exist simultaneously. B, there are three situations of B alone. In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

Example

Figure 1 is a schematic diagram of a high-frequency wide-band solar radio signal observation device provided by an embodiment of the present invention, including a receiving antenna, a noise source correction unit, an analog front-end system, a digital receiver and a display storage system; the receiving antenna is used to receive solar radio The signal is output to the noise source correction unit; the noise source correction unit outputs the cold temperature data and hot temperature data of the noise source for solar radio signal calibration, or outputs a circular polarization signal to the analog front-end system; the analog front-end system The digital receiver is used to process the circularly polarized signal and output two channel signals; the digital receiver is used to collect the two channel signals, perform mixing processing on one channel signal, and perform mixing processing on the other channel signal. Frequency conversion processing, and then transmitted to the display storage system; the display storage system includes a host computer and a data storage system, the data storage system is used to display and store the signals transmitted by the digital receiver, and the host computer is used to control the reception Antennas, noise source correction units, analog front-end systems and digital receivers. Preferably, the high-frequency wide-band solar radio signal observation device includes a five-meter diameter parabolic receiving antenna, a set of noise source correction units, an analog front-end system, a digital receiver and a display storage system. Also included is a workstation and data processing software. It can realize real-time monitoring of the spectrum and partial flow of solar radio signals in the 2-10GHz frequency band. It has a wide observation frequency band, good real-time performance, and has a calibration function. It has high time resolution and frequency resolution, with the time resolution up to 2.4ms and the frequency resolution up to 0.15MHz.

The receiving antenna is preferably a large-diameter five-meter parabolic antenna. The antenna feed is left and right circular polarization and outputs left and right circular polarization signals. Five-meter antenna system used to support radio observations of the sun and moon. It can use the sun's trajectory to realize program tracking, and has working modes such as designated, standby, manual, and collection. The tracking mode that can be set by the antenna control computer is program control or manual control, ensuring that the pointing accuracy of the receiving antenna is better than 1/10 of the beam width, and the follow-up tracking accuracy is better than 1/10 of the beam width. Preferably, the program control specifically means that the receiving antenna includes a turntable control system for controlling the rotation direction of the receiving antenna, and the turntable control system is connected to the host computer.

The servo control and antenna control computers have communication functions with other computers and have local control and remote control functions. The control software can display time, antenna position, motion status, longitude, latitude, altitude and other information, and can also be run directly on the workstation to remotely control the antenna and servo system.

Noise source correction unit, including noise source, microwave switch and mechanical switch. The microwave switch is controlled by the digital receiver to perform gating, and is used to alternately output the solar radio signal into left and right circularly polarized signals. Noise source and mechanical switch. When the device is in the calibration state, the host computer controls the mechanical switch to switch to the noise source output cold temperature data and hot temperature data mode, which is used to calibrate the solar radio signal; when the device is in the working state, The host computer controls the mechanical switch to switch to output circular polarization signal mode. Preferably, the input end of the microwave switch is connected to the receiving antenna, the output end of the microwave switch outputs left- and right-hand circularly polarized signals cyclically and alternately, the output ends of the microwave switch and the noise source are respectively connected to the input end of the mechanical switch, and the mechanical switch is moved from the upper position Machine control, you can choose to output the antenna signal or the noise source signal. When the noise source correction unit is working, the host computer controls the mechanical switch so that the system receives the cold temperature signal of the noise source and the hot temperature data of the noise source. The collected radio signals can be calibrated according to the following formula.

Calibration of radio signals is based on the following calibration formula:

;

Among them, R _sun is the display value of the host computer for observing the sun, R _sky is the display value of the host computer when the sky is clear, T _sun is the brightness temperature value of the sun, T _sky is the brightness temperature value of the sky, R _n is the heat temperature output of the noise source. The display value of the computer, R _l is the display value of the host computer when the cold temperature of the noise source is output, T _n is the hot temperature value of the noise source, and T _l is the cold temperature value of the noise source.

The analog front-end system uses a combination of direct acquisition and frequency conversion, which can amplify and filter the frequency band of 2-10GHz, and perform mixing processing on some frequency bands. Figure 2 is a schematic diagram of the signal channel division of the analog front-end system provided by an embodiment of the present invention. The signal channel division scheme includes: after the first signal is mixed with the LO local oscillator signal of 9.3GHz, the signal is moved as a whole, and the original 2-2.7GHz , 3.8-4GHz, 5.1-5.3GHz, 6.4-6.6GHz and 7.7-7.9GHz signals were moved to new frequency bands, corresponding to 6.6-7.3GHz, 5.3-5.5GHz, 4-4.2GHz and 2.7-2.9GHz respectively. and 1.4-1.6GHz frequency band, using multiple filters with operating frequency bands of 6.6-7.3GHz, 5.3-5.5GHz, 4-4.2GHz, 2.7-2.9GHz and 1.4-1.6GHz respectively to filter the signal. Preferably, The suppression capability of the filter at 1GHz outside the sideband reaches more than 70dB, which can meet the requirements of 70dB out-of-band suppression and 70dB image suppression for the analog front-end system.

The second signal is amplified and filtered by a gated bandpass filter and output, and one of the signals is down-converted in the 9-10GHz frequency band. The operating frequency bands of the filters used when channelizing the second signal should be 2.7-3.8GHZ, 4-5.1GHz, 5.3-6.4GHz, 6.6-7.7GHz, 7.9-9GHz and 9-10GHz. Preferably, the filter's suppression capability at 1 GHz outside the sideband band reaches more than 70 dB.

The digital receiver uses a dual-channel 2.6Gsps acquisition board to collect two signals. The collected and processed signals are transmitted to the display storage system through optical fiber for display and storage. The digital receiver is mainly composed of high-speed ADC and high-performance FPGA. When the digital receiver is working, the high-speed ADC first collects the intermediate frequency signal processed by the analog front-end unit, converts the analog signal into a digital signal, and turns it into a digital quantity, and then transmits the data to the FPGA through the JESD204B high-speed interface for digital processing. , the processing content includes data windowing, FFT operation, data accumulation processing, etc. The processed data can be transmitted to the host computer through optical fiber or PCIe interface to perform display and storage functions.

Figure 3 is a schematic diagram of an analog channel switching method provided by an embodiment of the present invention. The channel switching of the analog front-end system is controlled by the TTL level output by the digital receiver. When the digital receiver completes the acquisition of the analog signal of one channel, the digital receiver Change the TTL control level to allow the analog front-end system to output the analog signal of the next channel. In this way, the acquisition of the channel signal used is completed and the operation is continuously cycled.

Figure 4 is a schematic diagram of the software processing flow provided by one embodiment of the present invention, which includes continuous data collection, real-time display of images and continuous storage of files. It mainly includes three parts: the main program, which completes software initialization, parameter configuration, image display and response to user input instructions. Related content; data collection thread, completes the work of data collection, caching and dumping; data storage thread, completes the data storage work.

The main functions of the system include continuous data collection, real-time display of images and continuous storage of files. Therefore, the design of the interface display software is shown in Figure 4, which mainly includes three parts:

(1) Main program, completes software initialization, parameter configuration, image display and response to user input instructions;

(2) Data collection thread, completes the work of data collection, caching and dumping;

(3) Data storage thread to complete the data storage work.

When the host computer is running, the data acquisition function of the system is first started, and then the digital receiver outputs the original data to the host computer. After the host computer obtains the data, it starts the storage function, starts to store the data and performs drawing display based on the real-time acquired data, and draws the full-band spectrum curve and spectrum image for display. At the same time, the host computer sets the power display function of the corresponding frequency point to draw and display a certain frequency point separately. After completing the above functions, users can decide when to stop collection and storage.

In summary, the present invention provides a high-frequency wide-band solar radio signal observation device, which meets the requirements of a high-frequency radio telescope for continuous observation of 2-10 GHz radio signals, and can realize the spectrum and analysis of solar radio signals in the 2-10 GHz frequency band. Part of the traffic is monitored in real time, with a wide observation frequency band, good real-time performance, and a calibration function. It has high time resolution and frequency resolution, with the time resolution up to 2.4ms and the frequency resolution up to 0.15MHz, realizing high-frequency and broadband signal data collection and processing of astronomical radio signals. The high-frequency wide-band solar radio signal observation device of the present invention can solve the problems existing in the existing technology in a targeted manner. It adopts direct radio frequency acquisition, avoids frequency mixing, simplifies the system structure, has large bandwidth, high collection accuracy, flexible use, and can obtain richer information. Astronomical radio data. The acquisition frequency band is wide and has high time resolution and frequency resolution.

Obviously, the above-mentioned embodiments of the present invention are only examples to clearly illustrate the present invention, and are not intended to limit the implementation of the present invention. For those of ordinary skill in the art, based on the above description, they can also make There are other different forms of changes or modifications, and it is impossible to exhaustively enumerate all the embodiments here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims (8)

1. A high-frequency wide-band solar radio signal observation device, characterized by including a receiving antenna, a noise source correction unit, an analog front-end system, a digital receiver and a display storage system; The receiving antenna is used to receive solar radio signals and output them to the noise source correction unit; The noise source correction unit is used to calibrate the solar radio signal according to the cold temperature data and hot temperature data of the noise source, and output the circular polarization signal to the analog front-end system; The analog front-end system is used to process the circularly polarized signal and output two channel signals; The digital receiver is used to collect the two channel signals, perform mixing processing on one of the channel signals, perform frequency conversion processing on the other channel signal, and then transmit it to the display storage system; The display storage system includes a host computer and a data storage system. The data storage system is used to display and store the signals transmitted by the digital receiver. The host computer is used to control the receiving antenna, noise source correction unit, analog front-end system and digital receiver; The noise source correction unit includes a microwave switch, which is controlled by the digital receiver to perform gating, and is used to alternately output solar radio signals into left and right circularly polarized signals; The noise source correction unit also includes a noise source and a mechanical switch; When the device is in the calibration state, the host computer controls the mechanical switch to switch to the noise source output cold temperature data and hot temperature data mode, which is used to calibrate the solar radio signal; When the device is in working condition, the host computer controls the mechanical switch to switch to the output circular polarization signal mode. 2. The high-frequency wide-band solar radio signal observation device according to claim 1, wherein the receiving antenna further includes a turntable control system for controlling the rotation direction of the receiving antenna, and the turntable control system is connected to a host computer. 3. The high-frequency wide-band solar radio signal observation device according to claim 1, characterized in that the analog front-end system is used to amplify and filter the circularly polarized signal, and perform mixing processing on the designated frequency band signal. . 4. The high-frequency wide-band solar radio signal observation device according to claim 3, characterized in that the designated frequency band signals include 2-2.7GHz, 3.8-4GHz, 5.1-5.3GHz, 6.4-6.6GHz and 7.7-7.9GHz signal of. 5. The high-frequency wide-band solar radio signal observation device according to claim 1, characterized in that the two channel signals include a first signal and a second signal; The digital receiver uses multiple filters to mix the first signal and the 9.3GHz LO local oscillator signal. The mixed signals correspond to 6.6-7.3GHz, 5.3-5.5GHz, 4-4.2GHz, 2.7-2.9GHz and 1.4-1.6GHz frequency bands, The digital receiver uses a band-pass filter to amplify and filter the second signal, and perform down-conversion processing on the frequency band of 9-10 GHz. The gated frequency band of the band-pass filter includes 2.7-3.8 GHZ, 4-5.1GHz, 5.3-6.4GHz, 6.6-7.7GHz, 7.9-9GHz and 9-10GHz frequency bands. 6. The high-frequency wide-band solar radio signal observation device according to claim 1, characterized in that the digital receiver outputs a TTL level to control channel switching of the analog front-end system. When the digital receiver completes one channel When collecting signals, the TTL level is changed so that the analog front-end system outputs another channel signal. 7. The high-frequency wide-band solar radio signal observation device according to claim 1, characterized in that the digital receiver includes a high-speed ADC and a high-performance FPGA, wherein the high-speed ADC is used to collect intermediate frequency signals and convert them into digital signals, and then Transmit digital signals to high-performance FPGA; High-performance FPGA is used to digitize the digital signal, including data windowing, FFT operation, and data accumulation processing. 8. The high-frequency wide-band solar radio signal observation device according to claim 1, characterized in that the calibration of the solar radio signal is based on the following calibration formula: (R _sun -R _sky )/(T _sun -T _sky )=(R _n -R _l )/(T _n -T _l ); Among them, R _sun is the display value of the host computer for observing the sun, R _sky is the display value of the host computer when the sky is clear, T _sun is the brightness temperature value of the sun, T _sky is the brightness temperature value of the sky, and R _n is the heat temperature output of the noise source. The display value of the computer, R _l is the display value of the host computer when the cold temperature of the noise source is output, T _n is the hot temperature value of the noise source, and T _l is the cold temperature value of the noise source.