Front-end radio frequency signal processing system based on airship meteorological detection platform

Abstract

The utility model provides a front-end radio-frequency signal processing system based on an airship meteorological detection platform, and the system comprises an antenna unit which comprises a positioning antenna, a sea reflex antenna, and an occultation antenna; the front radio frequency preprocessing unit comprises a Galileo radio frequency channel corresponding to the positioning antenna, a BDS radio frequency channel corresponding to the sea reflex antenna and a GPS radio frequency channel corresponding to the occultation antenna, and the radio frequency channels are used for conducting state gating, filtering and amplification processing on radio frequency signals input by the channels; the processed radio frequency signals are sent to a main load and a backup load after being subjected to signal branching; and the feed unit is connected with the front radio frequency preprocessing unit and is used for providing power supply for the front radio frequency preprocessing unit. The processing system provided by the utility model can meet the actual demand of obscuration detection load stand-alone cold backup, greatly improves the reliability of detection load, and optimizes a load stand-alone radio frequency signal processing scheme; the method has high commercial application value.

Description

Technical Field

[0001] The utility model belongs to the technical field of airship-borne detection, and in particular relates to a front-end radio frequency signal processing system based on an airship weather detection platform. Background Art

[0002] Occultation detection technology is an effective detection technology that uses the Global Navigation Satellite System (GNSS) to detect atmospheric and ionospheric environmental parameters. With the rapid development of commercial aerospace in recent years, this detection technology has been continuously improved, and the detection accuracy and speed have been greatly improved.

[0003] As an advanced payload-carrying technology in recent years, airborne exploration airships, with their ability to maintain stable, long-term flight at high altitudes, offer a unique and effective means of exploration for various scientific research and applications. For high reliability, current airborne occultation detection payloads require a single unit with cold backup, meaning the payload must be designed and assembled with both a primary and backup unit. During normal operation, the payload only requires the primary unit to operate. In the event of an anomaly, the backup unit remains operational, ensuring normal operation without affecting the payload's detection.

[0004] However, this results in a more complex amplifier processing module in the occultation RF front end, and due to the dual-master design, the overall structure of the single-machine payload is too large and too heavy, which increases the overall design, experiment and launch costs of the detection payload, which is not in line with the current development trend of miniaturization and low cost of satellite payloads. Utility Model Content

[0005] In view of this, the present invention aims to provide a front-end radio frequency signal processing system based on an airship weather detection platform to solve at least one of the above problems.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0007] The utility model provides a front-end radio frequency signal processing system based on an airship weather detection platform, comprising:

[0008] Antenna unit, comprising a positioning antenna, a sea reflection antenna, and an occultation antenna;

[0009] A front-end RF pre-processing unit, comprising a Galileo RF path corresponding to the positioning antenna, a BDS RF path corresponding to the sea-reflection antenna, and a GPS RF path corresponding to the occultation antenna. Each RF path is configured to perform state gating, filtering, and amplification on the RF signals inputted by each path, and then send the processed RF signals to the primary and backup payloads after signal branching.

[0010] A feeding unit is connected to the front RF preprocessing unit and is used to provide power supply for the front RF preprocessing unit.

[0011] Furthermore, the radio frequency path includes a microwave switch, a bandpass filter, a power amplifier, a low-pass filter, a high-pass filter and a splitter connected in sequence;

[0012] The microwave switch is further connected to a radio frequency matching resistor, and the splitter is a one-to-two splitter.

[0013] Furthermore, the microwave switch includes a switch chip;

[0014] The first pin of the switch chip is connected to the RF matching resistor via a first capacitor, the third pin of the switch chip is connected to a π-type attenuator via a second capacitor, the π-type attenuator is connected to a first connector, and the first connector is used to receive RF signals;

[0015] The fourth pin of the switch chip is grounded via a first resistor and a third capacitor connected in sequence, a second resistor is further connected to the line between the first resistor and the third capacitor, and the other end of the second resistor is grounded;

[0016] The fifth pin of the switch chip is connected to the band-pass filter via a fourth capacitor;

[0017] The sixth pin of the switch chip is grounded through a third resistor and a fifth capacitor connected in sequence. A fourth resistor is also connected to the line between the third resistor and the fifth capacitor. The fourth resistor is connected to the power supply terminal of the power amplifier.

[0018] Furthermore, the impedance value of the radio frequency matching resistor is 50Ω.

[0019] Furthermore, the switch chip is a HMC545AE model chip.

[0020] Furthermore, the feeding unit includes a second connector and a third connector integrated on the PCB board;

[0021] The second connector is used to supply power to the microwave switch and the power amplifier;

[0022] One end of the third connector is connected to the external debugging device, and the other end is connected to the second connector via a sixth capacitor. An end of the sixth capacitor away from the third connector is further connected to an inductor, and the other end of the inductor is grounded via a seventh capacitor and an eighth capacitor connected in parallel.

[0023] The inductor is also connected to a 5V power supply.

[0024] Furthermore, the second connector and the third connector are both SMA-KFD128 connectors.

[0025] Furthermore, screw positioning holes are provided at the four corners of the PCB board for installing and fixing it.

[0026] Compared with the prior art, the front-end radio frequency signal processing system based on the airship weather detection platform described in the present invention has the following beneficial effects:

[0027] The utility model describes a front-end radio frequency signal processing system based on an airship meteorological detection platform. The system uses a floating detection airship as a detection payload carrier, designs a preamplifier module for occultation detection signals, plans signal transmission paths for different navigation stars (BDS, GPS, Galileo), implements filtering, amplification, secondary filtering and branching processing of the occultation detection signals, and finally sends the radio frequency signal after the above preprocessing into the payload unit for in-depth processing. The application adopts a separate front-end radio frequency preprocessing unit to meet the actual needs of cold backup of the occultation detection payload unit, greatly improves the reliability of the detection payload, and optimizes the radio frequency signal processing scheme of the payload unit; and has high commercial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of a front-end radio frequency signal processing system based on an airship weather detection platform according to an embodiment of the present utility model;

[0030] Figure 2 This is a schematic diagram of the microwave switch circuit connection according to an embodiment of the present utility model;

[0031] Figure 3 This is a schematic diagram of the connection of the feed unit according to an embodiment of the present utility model;

[0032] Figure 4 This is a schematic diagram of the PCB layout of the feed unit according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0034] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0035] See also Figure 1 andFigure 3 As shown, this embodiment provides a front-end radio frequency signal processing system based on an airship weather detection platform, including:

[0036] Antenna unit, the antenna unit includes positioning antenna, sea reflection antenna, and occultation antenna;

[0037] The front-end RF pre-processing unit includes a Galileo RF path corresponding to the positioning antenna, a BDS RF path corresponding to the sea-reflection antenna, and a GPS RF path corresponding to the occultation antenna. Each RF path is used to perform state gating, filtering, and amplification on the RF signals input by each path, and then sends the processed RF signals to the primary and backup payloads after signal splitting.

[0038] The feeding unit is connected to the front RF pre-processing unit and is used to provide power supply for the front RF pre-processing unit.

[0039] Specifically, in this embodiment, Figure 1 As shown, the outermost part of the system is the GNSS navigation signal data receiving antenna. The receiving antennas are divided into three types, which are used to receive navigation information at different frequencies, namely the positioning antenna, the forward antenna (including the forward occultation antenna and the forward sea reflection antenna) and the rear antenna (including the rear occultation antenna and the rear sea reflection antenna). Among them, the forward antenna needs to be placed in front of the airship's flight direction, the rear antenna needs to be placed behind the airship's flight direction, and the positioning antenna is located on the top of the airship to receive positioning signals.

[0040] In response to different navigation system signals, this application designs the front-end RF path into a separate cavity; in order to receive navigation signals from the GPS, BDS, and Galileo systems respectively, the preamplifier system is divided into three independent cavities. A PCB board is placed in each cavity for electrical performance processing of the received navigation RF signal. The independent cavity design also ensures that the three RF processing paths do not interfere with each other, maximizing the isolation of the paths and the reliability of RF signal processing.

[0041] Since the initial detection information collected by the antenna contains interference signals of various frequencies and the initial detection signal power is very weak, the navigation signal captured by the antenna needs to be preprocessed. The preprocessing mainly includes state selection, filtering, frequency selection and amplification of the detection signal. After filtering out the detection signal from the interference signal, it is amplified until the signal power strength meets the requirements that can be recognized by the internal data processing unit of the back-end payload.

[0042] The system described in this embodiment uses a floating detection airship as a detection payload carrier. By designing a preamplifier module for the occultation detection signal and planning the signal transmission paths of different navigation stars (BDS, GPS, Galileo), the occultation detection signal is filtered, amplified, secondary filtered and branched. Finally, the radio frequency signal after the above preprocessing is sent to the payload unit for in-depth processing. The present invention uses a separate pre-RF preprocessing unit to meet the actual needs of the occultation detection payload unit cold backup, greatly improves the reliability of the detection payload, and optimizes the payload unit radio frequency signal processing solution; it has high commercial application value.

[0043] At the same time, a feeding unit and a microwave switch are also designed. The feeding unit can facilitate independent power supply debugging of the preamplifier, simplifying the debugging process; the microwave switch can realize the selection of the input status of the front-end RF signal.

[0044] In some embodiments, the radio frequency path includes a microwave switch, a bandpass filter, a power amplifier, a low-pass filter, a high-pass filter, and a splitter connected in sequence;

[0045] The microwave switch is also connected to a radio frequency matching resistor, and the splitter is a one-to-two splitter.

[0046] Specifically, in this embodiment, each RF path is designed independently, and the RF detection signal captured by the detection antenna is preprocessed within each path. A one-to-two splitter is used at the back end for signal branching design, and the processed detection signal is sent to the primary stand-alone machine and the backup stand-alone machine respectively, meeting the actual needs of cold backup of the detection payload stand-alone machine and achieving high reliability.

[0047] In addition, the present application adds a separate temperature detection chip in each independent RF path cavity inside the front RF preprocessing unit. The chip is placed near the LNA (Low Noise Amplifier) ​​to monitor the working status of the LNA in real time.

[0048] In some embodiments, the microwave switch includes a switch chip U80;

[0049] The first pin RF2 of the switch chip U80 is connected to the RF matching resistor R128 (in this embodiment, the impedance value of the RF matching resistor is 50Ω) through the first capacitor C379. The third pin RF1 of the switch chip U80 is connected to the π-type attenuator (in this embodiment, the π-type attenuator is composed of resistors R1, C7, and C9) through the second capacitor C382. The π-type attenuator is connected to the first connector J7, which is used to receive RF signals.

[0050] The fourth pin B of the switch chip U80 is grounded via a first resistor R131 and a third capacitor C383 connected in sequence. A second resistor R8 is further connected to the line between the first resistor R131 and the third capacitor C383, and the other end of the second resistor R8 is grounded.

[0051] The fifth pin RFC of the switch chip U80 is connected to the bandpass filter through the fourth capacitor C380;

[0052] The sixth pin A of the switch chip U80 is grounded through the third resistor R127 and the fifth capacitor C378 connected in sequence. The line between the third resistor R127 and the fifth capacitor C378 is also connected to the fourth resistor R7, and the fourth resistor R7 is connected to the power supply end of the power amplifier.

[0053] In this application, when the receiving antenna collects the detection signal, it will first amplify the initial signal to a certain extent, and then send it to its respective RF processing channels. After entering, it will first pass through the internal microwave switch. The function of the microwave switch is to select the input state of the front-end signal.

[0054] Specifically, the microwave switch is in the on-state by default upon power-up, and the impedance of the microwave switch and the RF path are matched, with an impedance value of 50Ω. This prevents signal power attenuation due to impedance mismatch. When the microwave switch is closed, the detection signal passes smoothly for further filtering and amplification. When the microwave switch is open, the detection signal cannot pass, and the back-end path and RF matching resistor are connected. At this time, the back-end payload collects noise power, which is a key parameter for back-end occultation data analysis.

[0055] J7 is the RF signal entry, model SMA-KFD128. The front end is connected to the antenna via an RF coaxial cable. After entering, the RF signal first passes through the π-type attenuator composed of R1, C7, and C9. During actual testing, a 0-ohm resistor was soldered to the R1 position, and no components were placed at C7 and C9, short-circuiting the RF signal with the back end. Based on the actual debugging results, the attenuation of the RF signal can be controlled and adjusted by modifying the resistance and capacitance values ​​at the three positions of the π-type attenuator to meet the RF input signal amplitude requirements of the back-end RF processing unit.

[0056] U80 is a microwave switch chip, model HMC545AE, which has very low insertion loss and small package advantages, insertion loss < 0.27dB, package type SOT26, suitable for application in the field of RF signal gating, the pass-through gating function of the chip is realized through Boolean logic, that is, when the control chip control pins A and B are respectively at 1 and 0, RF1 on, RF2 OFF, the antenna RF pass-through is turned on, that is, the RF signal can pass through, when the control A pin and the B pin are respectively at 0 and 1, RF1 OFF, RF2 ON, the antenna RF pass-through is turned off, the RF signal cannot pass through, RF2 is turned on, that is, connected to the matching resistance end, the resistance value of the matching resistance is 50 ohms; The initial working state, the on-off of the chip is set to A pin high level and B pin low level through hardware circuit, that is, the RF signal is connected.

[0057] It should be noted that if subsequent state switching is required, the control signals CTRL_A1 and CTRL_B1 will be introduced to the back-end baseband processing unit on the hardware link, which can be controlled by the baseband.

[0058] In some embodiments, the feeding unit includes a second connector J1 and a third connector J2 integrated on the PCB board;

[0059] The second connector J1 is used to power the microwave switch and the power amplifier;

[0060] One end of the third connector J2 is connected with the external debugging device, and the other end is connected with the second connector J1 through the sixth capacitor C3. The end of the sixth capacitor C3 away from the third connector J2 is also connected with the inductor L1. The other end of the inductor L1 is connected with the ground through the seventh capacitor C1 and the eighth capacitor C2 in parallel connection;

[0061] The inductor is also connected with a 5V power supply.

[0062] Specifically, in the present embodiment, a separate feeding unit is designed for the power supply debugging of the preamplifier module, and the specific circuit diagram is as shown in Figure 3 The basic function of the feeding unit is to provide power supply for the preamplifier through the SMA connector. The connector model of the feeding unit is SMA-KFD128.

[0063] In actual use, J1 is connected with the pre-radiation preprocessing unit, and J2 is connected with the debugging device. The power supply is 5V. After the power supply enters, C1 and C2 are filter and voltage stabilizing capacitors, which ensure that the power supply entering the board is stable and reliable. Among them, L1 is a 1uH inductor. The function of the inductor is to isolate the alternating current RF signal. Through the 5V power supply, the RF signal leakage is prevented while ensuring the stability of the power supply. C3 is a 100pF capacitor on the RF pass-through. According to actual needs, it can be replaced with a terminating resistor.

[0064] The present application has strong practicality and reliability for the design of the feed unit, and can meet the debugging needs with a small number of components.

[0065] In some embodiments, screw positioning holes are provided at the four corners of the PCB board for mounting and fixing the PCB board.

[0066] Specifically, in this embodiment, Figure 4 This is a schematic diagram of the specific PCB layout of the feed unit. Four screw positioning holes are added at the four corners of the PCB for installation and fixation during actual testing. J1 and J2 are SMA connectors, and the 5V_VIN1 and GND through-holes are power supply welding points. Power supply can be achieved by welding power wires at these two points.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit 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 front-end radio frequency signal processing system based on an airship weather detection platform, characterized in that: include: Antenna unit, comprising a positioning antenna, a sea reflection antenna, and an occultation antenna; A front-end RF pre-processing unit, comprising a Galileo RF path corresponding to the positioning antenna, a BDS RF path corresponding to the sea-reflection antenna, and a GPS RF path corresponding to the occultation antenna. Each RF path is configured to perform state gating, filtering, and amplification on the RF signals inputted by each path, and then send the processed RF signals to the primary and backup payloads after signal branching. A feeding unit is connected to the front RF preprocessing unit and is used to provide power supply for the front RF preprocessing unit.

2. The system according to claim 1, wherein: The radio frequency path includes a microwave switch, a bandpass filter, a power amplifier, a low-pass filter, a high-pass filter and a splitter connected in sequence; The microwave switch is further connected to a radio frequency matching resistor, and the splitter is a one-to-two splitter.

3. The system according to claim 2, characterized in that: The microwave switch includes a switch chip; The first pin of the switch chip is connected to the RF matching resistor via a first capacitor, the third pin of the switch chip is connected to a π-type attenuator via a second capacitor, the π-type attenuator is connected to a first connector, and the first connector is used to receive RF signals; The fourth pin of the switch chip is grounded via a first resistor and a third capacitor connected in sequence, a second resistor is further connected to the line between the first resistor and the third capacitor, and the other end of the second resistor is grounded; The fifth pin of the switch chip is connected to the band-pass filter via a fourth capacitor; The sixth pin of the switch chip is grounded through a third resistor and a fifth capacitor connected in sequence. A fourth resistor is also connected to the line between the third resistor and the fifth capacitor. The fourth resistor is connected to the power supply terminal of the power amplifier.

4. The system according to claim 3, wherein: The impedance value of the RF matching resistor is 50Ω.

5. The system according to claim 3, wherein: The switch chip is a HMC545AE model chip.

6. The system according to claim 2, characterized in that: The feeding unit includes a second plug-in connector and a third plug-in connector integrated on the PCB board; The second connector is used to supply power to the microwave switch and the power amplifier; One end of the third connector is connected to the external debugging device, and the other end is connected to the second connector via a sixth capacitor. An end of the sixth capacitor away from the third connector is further connected to an inductor, and the other end of the inductor is grounded via a seventh capacitor and an eighth capacitor connected in parallel. The inductor is also connected to a 5V power supply.

7. The system according to claim 6, characterized in that: The second connector and the third connector are both SMA-KFD128 connectors.

8. The system according to claim 6, characterized in that: The four corners of the PCB are provided with screw positioning holes for installing and fixing the PCB.

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