CN114844557B - data receiving system - Google Patents
data receiving system Download PDFInfo
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- CN114844557B CN114844557B CN202210477861.3A CN202210477861A CN114844557B CN 114844557 B CN114844557 B CN 114844557B CN 202210477861 A CN202210477861 A CN 202210477861A CN 114844557 B CN114844557 B CN 114844557B
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- 230000003321 amplification Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18517—Transmission equipment in earth stations
Abstract
The present disclosure provides a data receiving system, comprising: an attenuator, which is arranged at the front end of the ka-band low-noise amplifier and is used for attenuating the ka-band satellite signal input into the ka-band low-noise amplifier so as to reduce the output level of the ka-band low-noise amplifier; the attenuator adopts a resistive attenuation network formed by combining a directional coupler with switch control, and the attenuation amount of the attenuator is adjustable. The data receiving system improves the dynamic range of the link without changing the complex design of the rear end of the link, and has no influence on the data receiving of the existing satellite and the receiving expansion capacity of different Ka satellites.
Description
Technical Field
The disclosure relates to the technical field of dynamic range design of ground data receiving systems, and in particular relates to a data receiving system.
Background
Along with the increase of satellite-ground link transmission rate, data transmission by using the Ka frequency band is a main working mode adopted by future remote sensing satellites. At present, in order to reduce cost and improve technical support capability, a remote sensing ground station adopts a data receiving system compatible with a plurality of frequency bands of a remote sensing satellite in a set of antenna: an S/X/Ka three-frequency antenna receiving system, wherein an X frequency band and a Ka frequency band multiplex part receive links.
The remote sensing satellite ground receiving station tracking and receiving system comprises a satellite servo feed subsystem, a channel subsystem and the like. The main task of the tracking channel is to extract an angle error signal, drive the antenna to capture a tracking satellite, and the main task of the data channel is to complete demodulation of S/X/Ka frequency band data.
However, due to the large difference of the Ka satellite orbit height and the transmitting power, when the same receiving link receives different satellite signals, the input and output levels of the devices are large in difference. For Ka satellites with higher effective omni-directional radiation power (EIRP) and lower orbit, when the satellite is over-top, the low-noise amplifier can be saturated or even has the risk of burning if the current system is not modified.
Disclosure of Invention
In view of this, the present disclosure provides a data receiving system, including: an attenuator, which is arranged at the front end of the ka-band low-noise amplifier and is used for attenuating the ka-band satellite signal input into the ka-band low-noise amplifier so as to reduce the output level of the ka-band low-noise amplifier; the attenuator adopts a resistive attenuation network formed by combining a directional coupler with switch control, and the attenuation amount of the attenuator is adjustable.
According to an embodiment of the present disclosure, the resistive damping network includes: the directional coupler comprises a first input end, a first output end and a second output end, wherein the first input end is used for inputting the ka-band satellite signals, the first output end is used for outputting the non-attenuated ka-band satellite signals, and the second output end is used for outputting the first attenuated ka-band satellite signals; the first switch comprises a second input end, a third output end and a fourth output end, wherein the second input end is connected to the second output end and is used for outputting the input satellite signal with the ka frequency band subjected to the first attenuation to the third output end or the fourth output end; the attenuation network comprises a third input end and a fifth output end, wherein the third input end is connected to the third output end and is used for carrying out second attenuation on the ka-band satellite signals subjected to first attenuation; the second switch comprises a fourth input end, a fifth input end and a sixth output end, wherein the fourth input end is connected to the third output end, the fifth input end is connected to the fifth output end, and the sixth output end is used for outputting the ka-band satellite signal which is input by the fourth input end and subjected to first attenuation or outputting the ka-band satellite signal which is input by the fifth input end and subjected to second attenuation; the third switch comprises a sixth input end, a seventh input end and a seventh output end, wherein the sixth input end is connected to the first output end, the seventh input end is connected to the sixth output end, the seventh output end is connected to the ka band low-noise amplifier, and the seventh output end is used for outputting the non-attenuated ka band satellite signals input by the sixth input end or outputting the first attenuated or second attenuated ka band satellite signals input by the seventh input end.
According to the embodiment of the disclosure, the attenuation amount of the attenuator is determined according to the antenna noise temperature, the field noise temperature, the system noise temperature, the environment temperature of the antenna and the quality factor of the data receiving system corresponding to the satellite.
According to an embodiment of the present disclosure, the attenuation amount, the antenna noise temperature, the field emission noise temperature, the system noise temperature, the ambient temperature, and the quality factor satisfy the following conditions:
wherein T is a For the antenna noise temperature, T LNA For the field to release noise temperature, T sys For the system noise temperature, T 0 Δgt is the degree of deterioration of the figure of merit, which is the ambient temperature.
According to an embodiment of the disclosure, the cavity of the attenuator is a waveguide structure.
According to an embodiment of the disclosure, the first switch and the second switch are switching diodes and the third switch is a waveguide switch.
According to an embodiment of the present disclosure, the first attenuation is 20dB in attenuation and the second attenuation is 10dB in attenuation.
According to an embodiment of the present disclosure, the main transmission line of the data receiving system is filled with air.
According to the embodiment of the disclosure, the working frequency of the attenuator is in the 25-27.5 GHz frequency band.
Drawings
The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments thereof with reference to the accompanying drawings in which:
fig. 1 schematically shows a block diagram of a data receiving system according to an embodiment of the present disclosure.
Fig. 2 schematically illustrates a block diagram of a resistive damping network configured to couple a switch control to a coupler in accordance with an embodiment of the present disclosure.
Detailed Description
For the purposes of promoting an understanding of the principles and advantages of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the embodiments in this disclosure, all other embodiments that a person of ordinary skill in the art would obtain without making any inventive effort are within the scope of protection of this disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
In the present disclosure, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may communicate with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art as the case may be.
In the description of the present disclosure, it should be understood that the terms "longitudinal," "length," "circumferential," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," and the like indicate an orientation or a positional relationship based on that shown in the drawings, merely to facilitate description of the present disclosure and to simplify the description, and do not indicate or imply that the subsystem or element being referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the present disclosure.
Like elements are denoted by like or similar reference numerals throughout the drawings. Conventional structures or constructions will be omitted when they may obscure the understanding of this disclosure. And the shape, size and position relation of each component in the figure do not reflect the actual size, proportion and actual position relation. In addition, in the present disclosure, any reference signs placed between parentheses shall not be construed as limiting the disclosure.
Similarly, in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. The description of the reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless explicitly specified otherwise.
In order to overcome the defects of the prior art, the embodiment of the disclosure provides a data receiving system with adjustable front-end attenuation, when receiving Ka satellite signals, attenuation is added at the front end of a field amplifier so that the output level of the field amplifier is smaller than the 1db compression point of low-noise amplifier output, the safety level of each device at the rear end of a link is met, the system is ensured to be in a linear state, and smooth receiving of satellite signals is ensured. The following is a detailed description.
Fig. 1 schematically shows a block diagram of a data receiving system according to an embodiment of the present disclosure.
As shown in fig. 1, the data system is an S/X/Ka three-frequency antenna receiving system, and the X-band and Ka-band multiplexing parts receive links.
Specifically, the data system comprises an attenuator which is arranged at the front end of the Ka-band low-noise amplifier, namely the attenuator is arranged between the Ka-band feed source and the Ka-low-noise amplifier, the input end of the attenuator is connected with the Ka-band feed source, and the output end of the attenuator is connected with the Ka-low-noise amplifier. The attenuator adopts a resistive attenuation network formed by combining a directional coupler with switch control, and the attenuation amount of the attenuator can be adjusted, so that the attenuation of the ka-band satellite signal input into the ka-band low-noise amplifier is carried out to different degrees, and the output level of the ka-band low-noise amplifier is reduced.
The Ka band of the data receiving system has the main technical indexes that: the working frequency band is f=25-27.5 GHz, the antenna noise temperature is Ta less than or equal to 180K, and the antenna axial ratio is less than or equal to 0.8dB.
In an embodiment of the present disclosure, the main transmission line of the data receiving system is filled with air, so that long-term operation stability of the data receiving system in a continuous wave environment can be ensured.
In an embodiment of the present disclosure, the cavity of the attenuator may be a waveguide structure, and the attenuator uses a waveguide as the cavity design, so that the loss of the signal may be reduced.
In an embodiment of the present disclosure, the technical indexes of the attenuator may be, for example:
the working frequency is in the frequency band of 25-27.5 GHz;
damping adjustment gear: 0dB, 20dB, 30dB;
adjusting precision: less than or equal to 2dB;
insertion loss at 0 dB: less than or equal to 0.5dB;
full band frequency response: less than or equal to 1.0dB (per gear);
standing waves of input and output: less than or equal to 1.35;
an input interface: WR34 flat flange
Output interface: WR34 sealing flange.
Fig. 2 schematically illustrates a block diagram of a resistive damping network configured to couple a switch control to a coupler in accordance with an embodiment of the present disclosure.
As shown in fig. 2, the resistive damping network may include, for example:
the directional coupler comprises a first input end, a first output end and a second output end. The first input end is used for inputting the ka-band satellite signals, the first output end is used for outputting the non-attenuated ka-band satellite signals, and the second output end is used for outputting the first attenuated ka-band satellite signals.
The first switch comprises a second input end, a third output end and a fourth output end. The second input end is connected to the second output end and is used for outputting the input satellite signal with the ka band after the first attenuation to the third output end or the fourth output end.
An attenuation network includes a third input and a fifth output. The third input end is connected to the third output end and is used for carrying out second attenuation on the ka-band satellite signals subjected to first attenuation.
The second switch comprises a fourth input end, a fifth input end and a sixth output end. The fourth input end is connected to the third output end, the fifth input end is connected to the fifth output end, and the sixth output end is used for outputting the ka-band satellite signals which are input by the fourth input end and pass through the first attenuation or outputting the ka-band satellite signals which are input by the fifth input end and pass through the second attenuation.
The third switch comprises a sixth input end, a seventh input end and a seventh output end, wherein the sixth input end is connected to the first output end, the seventh input end is connected to the sixth output end, the seventh output end is connected to the ka band low noise amplifier, and the seventh output end is used for outputting the non-attenuated ka band satellite signals input by the sixth input end or outputting the ka band satellite signals input by the seventh input end and subjected to first attenuation or second attenuation.
In an embodiment of the disclosure, the first switch and the second switch are switching diodes and the third switch is a waveguide switch. The attenuation of different gears of the attenuator can be realized through the first switch, the second switch and the third switch. For example, the attenuation amount of the first attenuation is 20dB, the attenuation amount of the second attenuation is 10dB, that is, the attenuation amount of the second attenuation is 10dB according to the transmission principle in combination with the application environment, in consideration of the production cost, the first stage adopts a 20dB directional coupler as a 20dB attenuator, and then 2 branches are controlled through a switch to select whether 10dB attenuation is superimposed or not. If the first switch is not used, the 20dB and 30dB are divided into two paths by other devices, so that the signal strength is influenced, and the first switch is divided into two paths, so that the influence on an output signal is small. If the second switch is not used, both 20dB and 30dB need to be connected to the third switch, at which time the third switch needs 3 input inlets, but the current waveguide switch is basically a 2-to-1 switch, i.e. two input interfaces and one output interface.
In implementing the data receiving system provided by the embodiments of the present disclosure, the inventors also found that: the same attenuation at different locations in the channel link, different attenuations at the same location, all affect the system quality factor (GT) value for strong signal satellites. In order to realize the low noise amplifier unsaturation when the Ka is in high elevation angle, the attenuation is needed to be increased before the station amplification, but the attenuation is too much, so that the GT value of a receiving system is reduced, the signal to noise ratio of the received satellite signal is lower, the error rate is larger, even the normal locking demodulation is not possible, and the attenuation needed for different satellites is different. Therefore, an accounting design and the use of adjustable attenuation are needed to satisfy the data reception of different satellites.
In an embodiment of the disclosure, the attenuation amount of the attenuator may be determined according to the antenna noise temperature, the field noise temperature, the system noise temperature, the environment temperature where the antenna is located, and the quality factor of the data receiving system corresponding to the satellite.
Specifically, the GT value of the data receiving system is calculated as follows:
G/T＝G-10log 10 (T sys )
if the attenuation L is increased before the field is placed, the antenna noise temperature worsens by DeltaT:
the data receiving system GT value deteriorates:
wherein T is a For the noise temperature of the antenna, T LNA To make a noise at field temperature, T sys To make system noise temperature, T 0 For the ambient temperature to which the antenna is exposed, 293K is typically taken, ΔGT is the degree of deterioration of the quality factor. Based on this condition, different attenuation ranges can be rationally designed for different satellites.
Table 1 shows the satellite signal to noise ratio (Eb/N0) margin calculations.
TABLE 1
As can be seen from the data in Table 1, the design of different attenuation ranges is adopted for different satellites in combination with the existing system composition and technical parameters of the ground, so that satellite signals can be safely received when the satellite signals are over-top, eb/N0 can be reduced to the minimum, and the signal quality is ensured. For example, for a low-orbit Ka satellite, attenuation needs to be increased before being placed, and not more than 22db is needed to satisfy normal reception demodulation of satellite signals. The three gears of 0dB, 20dB and 30dB of the attenuator meet the use requirement of a data receiving system.
According to the data receiving system provided by the embodiment of the disclosure, the attenuator is arranged at the front end of the Ka-band low-noise amplifier, so that the dynamic range of the link is improved without changing the complex design of the rear end of the link, the data receiving of the existing satellite is not affected, and the subsequent receiving expansion capacity of different Ka satellites is also provided. Further, the attenuation amount of the attenuator is determined according to the antenna noise temperature, the field noise temperature, the system noise temperature, the environment temperature of the antenna and the quality factor of the data receiving system corresponding to the satellite, so that reasonable design of different attenuation ranges of different satellites is realized, the satellite signal can be safely received when the satellite is overturned, the signal to noise ratio can be reduced at least, and the signal quality is ensured. The data receiving system fully considers the multi-satellite adaptability of the system, has the data receiving capability of multiple satellites, and can realize the satellite data receiving of multiple satellites, all-day time and all-weather.
Those skilled in the art will appreciate that the features recited in the various embodiments of the disclosure may be combined and/or combined in various combinations, even if such combinations or combinations are not explicitly recited in the disclosure. In particular, features described in various embodiments of the present disclosure may be combined and/or combined in various ways without departing from the spirit and teachings of the present disclosure. All such combinations and/or combinations fall within the scope of the present disclosure.
While the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be understood that the foregoing embodiments are merely illustrative of the invention and are not intended to limit the invention, and that any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the present disclosure are intended to be included within the scope of the present disclosure.
Claims (8)
1. A data receiving system, comprising:
an attenuator, which is arranged at the front end of the ka-band low-noise amplifier and is used for attenuating the ka-band satellite signal input into the ka-band low-noise amplifier so as to reduce the output level of the ka-band low-noise amplifier;
the attenuator adopts a resistive attenuation network formed by combining a directional coupler with switch control, and the attenuation amount of the attenuator is adjustable;
wherein the attenuator comprises:
the directional coupler comprises a first input end, a first output end and a second output end, wherein the first input end is used for inputting the ka-band satellite signals, the first output end is used for outputting the non-attenuated ka-band satellite signals, and the second output end is used for outputting the first attenuated ka-band satellite signals;
the first switch comprises a second input end, a third output end and a fourth output end, wherein the second input end is connected to the second output end and is used for outputting the input satellite signal with the ka frequency band subjected to the first attenuation to the third output end or the fourth output end;
the attenuation network comprises a third input end and a fifth output end, wherein the third input end is connected to the third output end and is used for carrying out second attenuation on the ka-band satellite signals subjected to first attenuation;
the second switch comprises a fourth input end, a fifth input end and a sixth output end, wherein the fourth input end is connected to the third output end, the fifth input end is connected to the fifth output end, and the sixth output end is used for outputting the ka-band satellite signal which is input by the fourth input end and subjected to first attenuation or outputting the ka-band satellite signal which is input by the fifth input end and subjected to second attenuation;
the third switch comprises a sixth input end, a seventh input end and a seventh output end, wherein the sixth input end is connected to the first output end, the seventh input end is connected to the sixth output end, the seventh output end is connected to the ka band low-noise amplifier, and the seventh output end is used for outputting the non-attenuated ka band satellite signals input by the sixth input end or outputting the first attenuated or second attenuated ka band satellite signals input by the seventh input end.
2. The data receiving system of claim 1, wherein the attenuation amount of the attenuator is determined according to an antenna noise temperature, a field noise temperature, a system noise temperature, an environment temperature where an antenna is located, and a quality factor of the data receiving system corresponding to a satellite.
3. The data receiving system of claim 2, wherein the attenuation, the antenna noise temperature, a field emission noise temperature, a system noise temperature, an ambient temperature, and the quality factor satisfy the following conditions:
wherein T is a For the antenna noise temperature, T LNA For the field to release noise temperature, T sys For the system noise temperature, T 0 Δgt is the degree of deterioration of the quality factor, which is the ambient temperature to which the antenna is exposed.
4. The data receiving system of claim 1, wherein the cavity of the attenuator is a waveguide structure.
5. The data receiving system of claim 1, wherein the first switch and the second switch are switching diodes and the third switch is a waveguide switch.
6. The data receiving system according to claim 1, wherein an attenuation amount of the first attenuation is 20dB, and an attenuation amount of the second attenuation is 10dB.
7. The data receiving system of claim 1, wherein a main transmission line of the data receiving system is filled with air.
8. The data receiving system of claim 1, wherein the attenuator operates at a frequency in the 25-27.5 GHz band.
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