阅读说明：本技术 一种太阳射电辐射计及频谱观测系统与控制方法 (Solar radio radiometer and spectrum observation system and control method ) 是由 严发宝 尚自乾 张园园 张磊 陈耀 武昭 苏艳蕊 路光 王冰 刘洋 徐珂 刘乾 于 2020-05-18 设计创作，主要内容包括：本发明公开了一种太阳射电辐射计及频谱观测系统与控制方法,其技术方案为：包括依次连接的切换开关、放大器I、滤波器I、混频器、放大器II、滤波器II、模拟数字转换器、FPGA信号处理模块和上位机；其中,所述切换开关接入两个不同的参考负载以提供亮温标定,且切换开关连接天线,并根据平衡判断调整天线与参考源的输出频率或占空比。本发明针对射电天文中太阳射电辐射计观测系统结构增益引起灵敏度降低及积分引起时间分辨率降低的情况,提出改善型的零平衡迪克型观测结构,既可以作为频谱观测设备也可以做辐射计观测,并给出了定标原理跟过程,可以灵活调整积分带宽,同时采用滑动积分的形式保证频谱、辐射计原始数据的时间分辨率。(The invention discloses a solar radio radiometer and a spectrum observation system and a control method, and the technical scheme is as follows: the device comprises a change-over switch, an amplifier I, a filter I, a mixer, an amplifier II, a filter II, an analog-digital converter, an FPGA signal processing module and an upper computer which are connected in sequence; the switch is connected with the antenna and adjusts the output frequency or the duty ratio of the antenna and the reference source according to balance judgment. Aiming at the conditions that the sensitivity is reduced due to the structural gain of a solar radiometer observation system in radio astronomy and the time resolution is reduced due to integration, the invention provides an improved zero-balance Dick type observation structure which can be used as a spectrum observation device and can be used for radiometer observation, provides a calibration principle and a calibration process, can flexibly adjust the integration bandwidth, and simultaneously adopts a sliding integration mode to ensure the time resolution of the spectrum and the radiometer original data.)

1. A solar radio radiometer and spectrum observation system is characterized by comprising a change-over switch, an amplifier I, a filter I, a mixer, an amplifier II, a filter II, an analog-digital converter, an FPGA signal processing module and an upper computer which are connected in sequence; the switch is connected with the antenna and adjusts the output frequency or the duty ratio of the antenna and the reference source according to balance judgment.

2. The solar radioradiometer and spectrum observation system of claim 1, wherein the FPGA signal processing module comprises a square wave generator and a synchronization module, and the square wave generator and the synchronization module synchronously mark whether the output is an antenna or a reference source.

3. The solar radioradiometer and spectroscopy system of claim 1, wherein the FPGA signal processing module is connected to a switch by a switch drive.

4. A solar radioradiometer and spectrum observation control method, wherein the solar radioradiometer and spectrum observation system according to any one of claims 1 to 3 is used, and the method comprises:

the upper computer sends an instruction to the square wave generator and the synchronization module, and the square wave generator and the synchronization module calculate integrals under different connection states and carry out balance judgment;

the square wave generator and the synchronization module separate out frequency spectrum data and perform pre-integration in the FPGA signal processing module; and then, performing sliding integration on the upper computer to obtain a stable frequency spectrum graph.

5. The solar radioradiometer and the frequency spectrum observation control method according to claim 4, wherein the square wave generator and the synchronization module adjust the pulse duty ratio according to the total integration time requirement of the system by finally balancing the judgment output value, thereby adjusting the ratio time of the antenna to the reference input.

6. The solar radioradiometer and the spectrum observation control method according to claim 4, wherein the zero balance of the system is realized by judging and adjusting the on-time duty ratio of the antenna and the reference load.

7. The solar radioradiometer and the spectrum observation control method according to claim 4, wherein the spectrum observation integration time τ is₁+τ₂τ 1 is pre-integration time performed in the FPGA signal processing module, and τ 2 is integration time performed by the upper computer; the internal pre-integration time of the FPGA and the integration time of the upper computer need to be reasonably distributed when the frequency spectrum is observed.

8. The solar radioradiometer and the spectrum observation control method according to claim 7, wherein the upper computer keeps performing sliding accumulation on data within a set time τ 2 and recalculates an integral value; the spectrum observation time resolution is determined by recording the slip time again each time, and the sensitivity of spectrum observation is determined for data within a fixed time τ 2.

9. The solar radioradiometer and frequency spectrum observation control method according to claim 4, wherein for the radiation flux observation process, the size of the integral bandwidth B is adjusted for the data uploaded by the FPGA signal processing module through the upper computer, and the integral time τ is controlled at the same time, so that the system sensitivity is improved.

10. The solar radioradiometer and the spectrum observation control method according to claim 9, wherein the data is kept sliding accumulated for a certain time τ, and the integral value is recalculated, and the time resolution of the raw data of the radioradiometric intensity is determined by each sliding time.

Technical Field

The invention relates to the field of solar radio radiometers, in particular to a solar radio radiometer, a frequency spectrum observation system and a control method.

Background

Any object emits electromagnetic waves to the outside under certain conditions, and a radiometer, as a high-sensitivity electromagnetic wave detection device, is widely applied in the fields of space weather, remote sensing to the ground, target detection and identification, security inspection and the like, and the two most common and applied radiometers have the following structures: full power radiometers, Dicke-type radiometers, and other types of radiometers, wherein the Dicke-type radiometers are classified into balanced and unbalanced types.

The full-power radiometer is simple in structure, directly utilizes the square law detector to convert power signals into voltage, and utilizes the ADC to conduct quantitative collection and uploading after passing through the low-pass filter (pre-integrator). The Dicke-type radiometer can reduce the effect of system gain stability on system sensitivity. The balanced (zero balance) dick radiometer has the following implementation method: an antenna channel noise injection method, an impulse noise injection method, a gain modulation method, and the like. Taking the impulse noise injection method as an example,the zero-balance radiometer adjusts the noise injected by the diode noise source by controlling the diode switch, so that T is measured_a"is equal to T_refThe influence caused by the gain in the unbalanced type is eliminated, so that the influence of the gain is reduced.

Although the structure of the existing radiometer has the characteristics of convenience, low cost and convenience for realization in various fields, the inventor finds that the existing radiometer has the following problems:

(1) when the solar radio radiation flow in the radio astronomy is observed, the solar spectrum and the radio radiation flow are generally observed at the same time, and only the radiation flow can be observed by the two structures (namely, a radiometer);

(2) in the calibration process, a standard source still needs to be provided externally for calibration, and the synchronization time sequence is more and the control requirement is higher; the calibration process usually needs a cold and heat source, and the brightness temperature (T) of the cold and heat calibration source_c，T_h) Closer to the light temperature (T) of the input signal_a) The more accurate the value, but the more difficult and expensive the cold source tends to be made;

(3) the integral bandwidth in the sensitivity calculation formula is determined by a filter in front of a detector, and digital control cannot be performed according to the sensitivity requirement;

(4) due to the fact that the square law detector and the ADC are adopted, certain nonlinear errors can be caused by the square law detector and the ADC, and the errors are increased easily due to the fact that two nonlinear devices are used.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a solar radiometer and a spectrum observation system and a control method, and provides an improved observation structure aiming at the conditions that the sensitivity is reduced due to the gain of a solar radiometer observation system structure in radio astronomy and the time resolution is reduced due to integration, so that the improved observation structure can be used as spectrum observation equipment and radiometer observation, the integration bandwidth can be flexibly adjusted, and the time resolution of the spectrum and radiometer original data is ensured by adopting a sliding integration mode.

In order to achieve the purpose, the invention is realized by the following technical scheme:

in a first aspect, an embodiment of the present invention provides a solar radioradiometer and a spectrum observation system, including a switch, an amplifier I, a filter I, a mixer, an amplifier II, a filter II, an analog-to-digital converter, an FPGA signal processing module, and an upper computer, which are connected in sequence; the switch is connected with the antenna and adjusts the output frequency or the duty ratio of the antenna and the reference source according to balance judgment.

As a further limitation, the FPGA signal processing module includes a square wave generator and a synchronization module, and the output is synchronously marked as an antenna or a reference source through the square wave generator and the synchronization module.

As a further limitation, the FPGA signal processing module is connected to the switch through a switch drive.

In a second aspect, an embodiment of the present invention further provides a solar radioradiometer and a spectrum observation control method, where the solar radioradiometer and the spectrum observation system are adopted and include:

the upper computer sends an instruction to the square wave generator and the synchronization module, and the square wave generator and the synchronization module calculate integrals under different connection states and carry out balance judgment;

the square wave generator and the synchronization module separate out frequency spectrum data and perform pre-integration in the FPGA signal processing module; and then, performing sliding integration on the upper computer to obtain a stable frequency spectrum graph.

As a further limitation, the square wave generator and the synchronization module finally balance and judge the output value to adjust the pulse duty ratio according to the total integration time requirement of the system, so that the occupation time of the antenna and the reference input is adjusted.

As a further limitation, the zero balance of the system is realized by judging and adjusting the on-time duty ratio of the antenna and the reference load.

As a further limitation, the spectrum observation integration time τ is τ₁+τ₂τ 1 is pre-integration time performed in the FPGA signal processing module, and τ 2 is integration time performed by the upper computer; reasonably distributing FPGA internal pre-integration time and in the process of observing frequency spectrumAnd (5) integrating time by the upper computer.

As a further limitation, the upper computer keeps performing sliding accumulation on the data within the set time τ 2, and recalculates the integral value; the spectrum observation time resolution is determined by recording the slip time again each time, and the sensitivity of spectrum observation is determined for data within a fixed time τ 2.

As a further limitation, for the radiation flow observation process, the upper computer adjusts the size of the integral bandwidth B for the data uploaded by the FPGA signal processing module, and meanwhile, the integral time tau is controlled, so that the system sensitivity is improved.

As a further limitation, the data is kept sliding accumulated for a certain time τ, and the integral value is recalculated, the time resolution of the raw data of the intensity of the radio-radiation being determined by each repetition of the sliding time.

The beneficial effects of the above-mentioned embodiment of the present invention are as follows:

(1) one or more embodiments of the invention enable spectrum observation while completing solar radiometer observation;

(2) the calibration process of one or more embodiments of the invention can calibrate not only the low brightness temperature of the low input antenna but also the high brightness temperature of the input antenna, and simultaneously does not need an external calibration source, the time sequence synchronization control is simple, and the calibration process is easier to obtain and implement and has low cost compared with the traditional cold and heat source mode;

(3) according to one or more embodiments of the invention, a square law detector is not adopted, so that the nonlinearity of the system is reduced, the problem that the sensitivity bandwidth is determined by a front-end filter of the square law detector is solved, and the direct acquisition structure of the ADC is utilized to realize the arbitrary digital control change of the integral bandwidth and the integral time in the FPGA;

(4) one or more embodiments of the invention can flexibly adjust the integral bandwidth of solar radio radiation intensity observation so as to improve the sensitivity, and simultaneously, a sliding integral mode is adopted to ensure the time resolution of spectrum observation and solar radio radiometer observation raw data under a certain integral time tau.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a schematic diagram of a prior art full power radiometer configuration;

fig. 2 is a schematic view of a conventional dick-type radiometer;

FIG. 3 is a schematic diagram of a conventional balanced Dike radiometer;

FIG. 4 is a schematic block diagram of the present invention in accordance with one or more embodiments;

FIG. 5 is a schematic diagram illustrating an integration process of data by an upper computer during spectrum observation according to one or more embodiments of the present invention;

FIG. 6 is a schematic diagram illustrating an integration process of data by an upper computer during a radiation flux observation according to one or more embodiments of the present disclosure;

FIG. 7 is a schematic diagram of the integration process of a conventional radiometer configuration;

FIG. 8 is a system workflow diagram of the present invention in accordance with one or more embodiments.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.