A satellite navigation sounding signal receiving and processing system

Abstract

This invention provides a satellite navigation radiosonde signal receiving and processing system, belonging to the field of satellite navigation radiosonde signal receiving and processing technology. The technical problem to be solved is: to provide an improvement in the hardware structure of a satellite navigation radiosonde signal receiving and processing system. The technical solution adopted to solve this problem is: the receiver internally includes an RF front-end preprocessing module, a power divider module, a single-channel receiving module, and a control processing module; the RF front-end preprocessing module internally includes a front bandpass filter, a low-noise amplifier, and a rear bandpass filter. The signal input terminal of the front bandpass filter is connected to the receiving antenna, and the signal output terminal of the front bandpass filter is connected to the signal input terminal of the rear bandpass filter through the low-noise amplifier; the signal output terminal of the rear bandpass filter is connected to the first input terminal of the power divider module. This invention is applied to the receiving and processing of satellite navigation radiosonde signals.

Description

Technical Field

[0001] This invention provides a satellite navigation radiosonde signal receiving and processing system, belonging to the field of satellite navigation radiosonde signal receiving and processing technology. Background Technology

[0002] Currently, satellites transmit radio signals for positioning and navigation, providing all-weather, high-precision, fast, and real-time three-dimensional navigation and positioning capabilities. This technology is widely used in fields such as navigation guidance, engineering surveying, geodynamics, meteorology, and atmospheric physics. Meteorological sounding using satellite navigation and positioning systems is a new type of meteorological detection method that can replace traditional radio theodolites or radar equipment for positioning. It is used to acquire data such as wind speed and direction within the meteorological area to be measured, effectively improving the efficiency of meteorological sounding data collection.

[0003] However, currently available satellite navigation-based signal receiving instruments are limited by their hardware structure and performance, and cannot simultaneously receive signals from multiple radiosondes. Furthermore, when the instruments are powered on, they are easily affected by environmental factors. During the reception and processing of radiosonde signals, their sensitivity and anti-interference performance are poor, and they cannot meet the requirements for radiosonde signal processing. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to solve the following technical problem: to provide an improvement in the hardware structure of a satellite navigation sounding signal receiving and processing system.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a satellite navigation sounding signal receiving and processing system, including a receiver, wherein the receiver is internally provided with a radio frequency front-end preprocessing module, a power divider module, a single-channel receiving module, and a control processing module;

[0006] The radio frequency front-end preprocessing module is internally equipped with a front bandpass filter, a low-noise amplifier, and a rear bandpass filter. The signal input terminal of the front bandpass filter is connected to the receiving antenna, and the signal output terminal of the front bandpass filter is connected to the signal input terminal of the rear bandpass filter through the low-noise amplifier.

[0007] The signal output terminal of the post-bandpass filter is connected to the first input terminal of the power divider module.

[0008] The single-channel receiving module is internally equipped with a matching unit, a first amplifier, a crystal filter, a discriminator, an RF synthesizer, a second amplifier, and a low-pass filter. The input of the matching unit is connected to the output of the power divider module. The output of the matching unit is connected to the input of the discriminator through the first amplifier and the crystal filter. The output of the discriminator is connected to the control processing module.

[0009] The output of the control processing module is connected to the input of the radio frequency synthesizer, and the output of the radio frequency synthesizer is connected to the second input of the power divider module after passing through a second amplifier and a low-pass filter.

[0010] The control processing module also includes a controller, a coupler, a splitter, a frequency sweep module, and a multi-channel demodulation module. The input of the coupler is connected to the radio frequency synthesizer, and the output of the coupler is connected to the splitter and the frequency sweep module respectively. The splitter is connected to the input of the multi-channel demodulation module, and the control terminals of the frequency sweep module and the multi-channel demodulation module are both connected to the controller.

[0011] The power input terminal of the control processing module is connected to the power module.

[0012] The radio frequency synthesizer is internally equipped with a frequency and phase detector, a loop filter, and a first oscillator. The output of the frequency and phase detector is connected to the input of the first oscillator through the loop filter, and the output of the first oscillator is connected to a second amplifier.

[0013] The single-channel receiving module is also equipped with a second oscillator, the output of which is connected to the discriminator, the control processing module, and the frequency and phase detector.

[0014] The radio frequency synthesizer is model PLL:LMX2571.

[0015] The controller is equipped with an STM32F103C8T6 chip.

[0016] The beneficial effects of this invention compared to the prior art are as follows: The radiosonde signal receiving and processing system provided by this invention, by setting an RF front-end preprocessing module at the signal receiving end, can achieve a high degree of suppression of out-of-band interference signals. At the same time, by setting a 1:2 power divider module at the single-channel receiving module, it can realize real-time channel reception and frequency sweep data processing. In addition, the high-speed analog-to-digital converter (ADC) used in this invention can directly perform undersampling processing on the second intermediate frequency signal, and then transmit the sampled digital signal to the baseband DSP digital signal processing for GSFK signal demodulation, which can effectively improve the sensitivity of signal acquisition and improve the efficiency and accuracy of signal reception. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings:

[0018] Figure 1 This is a schematic diagram of the circuit structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the circuit structure of the control processing module of the present invention;

[0020] In the diagram: 1 is the power divider module, 2 is the control processing module, 3 is the power supply module, and 4 is the second oscillator;

[0021] 10 is the receiving antenna, 11 is the front bandpass filter, 12 is the low-noise amplifier, and 13 is the rear bandpass filter;

[0022] 21 is a matching circuit, 22 is a first amplifier, 23 is a crystal filter, 24 is a discriminator, 25 is an RF synthesizer, 26 is a second amplifier, and 27 is a low-pass filter;

[0023] 31 is the controller, 32 is the coupler, 33 is the splitter, 34 is the frequency sweep module, 35 is the multi-channel demodulation module, 251 is the frequency and phase detector, 252 is the loop filter, and 253 is the first oscillator. Detailed Implementation

[0024] like Figure 1 and Figure 2 As shown, the satellite navigation sounding signal receiving and processing system provided by the present invention includes a receiver, wherein the receiver is internally provided with a radio frequency front-end preprocessing module, a power divider module 1, a single-channel receiving module, and a control processing module 2;

[0025] The radio frequency front-end preprocessing module is internally equipped with a front bandpass filter 11, a low noise amplifier 12, and a rear bandpass filter 13. The signal input terminal of the front bandpass filter 11 is connected to the receiving antenna 10, and the signal output terminal of the front bandpass filter 11 is connected to the signal input terminal of the rear bandpass filter 13 through the low noise amplifier 12.

[0026] The signal output terminal of the rear bandpass filter 13 is connected to the first input terminal of the power divider module 1.

[0027] The single-channel receiving module is internally equipped with a matching unit 21, a first amplifier 22, a crystal filter 23, a discriminator 24, an RF synthesizer 25, a second amplifier 26, and a low-pass filter 27. The input terminal of the matching unit 21 is connected to the output terminal of the power divider module 1. The output terminal of the matching unit 21 is connected to the input terminal of the discriminator 24 through the first amplifier 22 and the crystal filter 23. The output terminal of the discriminator 24 is connected to the control processing module 2.

[0028] The output of the control processing module 2 is connected to the input of the radio frequency synthesizer 25, and the output of the radio frequency synthesizer 25 is connected to the second input of the power divider module 1 through the second amplifier 26 and the low-pass filter 27.

[0029] The control processing module 2 is further provided with a controller 31, a coupler 32, a splitter 33, a frequency sweep module 34, and a multi-channel demodulation module 35. The input terminal of the coupler 32 is connected to the radio frequency synthesizer 25, and the output terminal of the coupler 32 is connected to the splitter 33 and the frequency sweep module 34 respectively. The splitter 33 is connected to the input terminal of the multi-channel demodulation module 35. The control terminals of the frequency sweep module 34 and the multi-channel demodulation module 35 are both connected to the controller 31.

[0030] The power input terminal of the control processing module 2 is connected to the power module 3.

[0031] The radio frequency synthesizer 25 is internally equipped with a frequency and phase detector 251, a loop filter 252, and a first oscillator 253. The output terminal of the frequency and phase detector 251 is connected to the input terminal of the first oscillator 253 through the loop filter 252, and the output terminal of the first oscillator 253 is connected to the second amplifier 26.

[0032] The single-channel receiving module is also equipped with a second oscillator 4, and the output of the second oscillator 4 is connected to the discriminator 24, the control processing module 2, and the frequency and phase discriminator 251, respectively.

[0033] The radio frequency synthesizer 25 is model PLL:LMX2571.

[0034] The chip model inside the controller 31 is STM32F103C8T6.

[0035] The satellite navigation radiosonde signal receiving and processing system provided by this invention has a multi-channel receiving function (2 / 4 / 8 channel receiving + 1 channel frequency sweeping), and is capable of simultaneously receiving signals transmitted by multiple radiosondes. The receiver is set to receive radiosonde and satellite positioning data sent back by the radiosondes through an antenna, including meteorological elements such as temperature, humidity, and air pressure, as well as positioning information, and sends the received data to the controller for further processing in real time through a serial port. The receiver adopts a microstrip antenna with a fixed omnidirectional antenna.

[0036] The satellite navigation radiosonde receiver provided by this invention supports multi-channel wireless reception and can receive data from multiple radiosondes at the same time. The receiver mainly consists of four parts: an RF front-end preprocessing module, a 1:2 power divider unit, a single-channel receiving module, and a control processing unit.

[0037] The RF front-end preprocessing module mainly consists of two-stage bandpass filters (BPF) and a low-noise amplifier (LNA). The third-order elliptic function bandpass filter, designed with high-Q inductors and high-frequency capacitors, has advantages such as low insertion loss, low ripple, and high rectangular coefficient. It has a high degree of suppression of out-of-band interference signals, ensuring a high rejection ratio for out-of-band interference signals while minimizing insertion loss for useful signals within the passband. The low-noise amplifier used in this invention is specifically a highly integrated dedicated MMIC chip SPF5043Z. This type of amplifier, when powered by 5V, has a high gain (18dB), excellent noise figure (0.8), and good input / output port VSWR (VSWR < 2) at 0.9GHz. The receiving frequency band used in the embodiment is 400-406MHz. Actual measurements show that the above three indicators are even better in this frequency band.

[0038] The aforementioned RF front-end link structure effectively improves the performance of the entire multi-channel data transmission and reception system. By setting two stages of highly selective, low-insertion-loss bandpass filters, the system's anti-interference capability is enhanced. The integrated low-noise amplifier not only provides high gain and low noise figure for the weak signal received by the antenna but also plays a crucial role in reducing the noise figure of the entire system's back-end link. According to the cascaded circuit noise figure calculation method, the total link noise figure N... F The calculation formula is:

[0039] ;

[0040] In the formula, N n G represents the noise figure of a certain stage of the amplifier circuit in the link. n This represents the gain of the amplifier stage, from which we can deduce that the overall noise figure of the link depends on: the insertion loss R of the passive circuit at the low-noise amplifier front end. L The noise figure N of the low-noise amplifier itself F The gain G of the low-noise amplifier; the above three points basically determine the overall noise figure level of the receiving system, and thus determine the lower limit of the static sensitivity that the system can achieve; among them, the first item is determined by the insertion loss of the bandpass filter at the front end of the link; the second and third items are completely determined by the low-noise amplifier. It can be seen that the RF front-end preprocessing module composed of these two main circuits has a significant impact on the overall system performance. Its performance largely determines the effectiveness (receiving sensitivity) and reliability (anti-interference performance) of the multi-channel data transmission receiving system.

[0041] This invention also provides a 1:2 power divider module. The signal receiving and processing system provided by this invention can realize the real-time reception function of six channels. The main feature is the addition of a 1:2 power divider module after the RF front-end module. This module can divide the signal after unified processing at the front end into two equal-amplitude signals, which are then fed one-to-one into the back-end receiving module to realize real-time channel reception and frequency sweep data processing. The power divider module provided by this invention adopts the classic Wilkinson power divider form. First, the output of a 1:2 power divider is fed into the real-time channel reception and frequency sweep modules respectively for processing, thereby realizing a 1:2 power divider.

[0042] The RF signal after passing through the power divider module is fed into a high-performance single-channel receiver module. This receiver module adopts a classic superheterodyne double-conversion architecture, with fixed intermediate frequency (IF) points for both stages. The first IF is 58.05MHz. The reason for using such a high IF frequency is that the RF front-end bandpass filter can provide good image rejection and local oscillator isolation in the operating frequency band. The second IF is 450kHz, and the lower frequency facilitates IF digitization. This invention uses a high-speed analog-to-digital converter (ADC) to directly undersample the second IF signal, and then transmits the sampled digital signal to the baseband DSP digital signal processing for GSFK signal demodulation.

[0043] This invention integrates up to four modules, each with independent demodulation capabilities. Since each channel operates independently in real time, the system requires an independent overall control and power supply unit to integrate the power supply of each module and control each module. The overall control and power supply module mainly supplies power to each module, controls the working status and operating parameters of each module in real time, receives the demodulated data from the modules, packages and processes it, and provides it to the backend for processing.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A satellite navigation sounding signal receiving and processing system, comprising a receiver, characterized in that: The receiver is internally equipped with an RF front-end preprocessing module, a power divider module, a single-channel receiving module, and a control processing module. The radio frequency front-end preprocessing module is internally equipped with a front bandpass filter, a low-noise amplifier, and a rear bandpass filter. The signal input terminal of the front bandpass filter is connected to the receiving antenna, and the signal output terminal of the front bandpass filter is connected to the signal input terminal of the rear bandpass filter through the low-noise amplifier. The signal output terminal of the post-bandpass filter is connected to the first input terminal of the power divider module. The single-channel receiving module is internally equipped with a matching unit, a first amplifier, a crystal filter, a discriminator, an RF synthesizer, a second amplifier, and a low-pass filter. The input of the matching unit is connected to the output of the power divider module. The output of the matching unit is connected to the input of the discriminator through the first amplifier and the crystal filter. The output of the discriminator is connected to the control processing module. The output of the control processing module is connected to the input of the radio frequency synthesizer, and the output of the radio frequency synthesizer is connected to the second input of the power divider module after passing through a second amplifier and a low-pass filter. The control processing module also includes a controller, a coupler, a splitter, a frequency sweep module, and a multi-channel demodulation module. The input of the coupler is connected to the radio frequency synthesizer, and the output of the coupler is connected to the splitter and the frequency sweep module respectively. The splitter is connected to the input of the multi-channel demodulation module, and the control terminals of the frequency sweep module and the multi-channel demodulation module are both connected to the controller. The power input terminal of the control processing module is connected to the power module.

2. The satellite navigation sounding signal receiving and processing system according to claim 1, characterized in that: The radio frequency synthesizer is internally equipped with a frequency and phase detector, a loop filter, and a first oscillator. The output of the frequency and phase detector is connected to the input of the first oscillator through the loop filter, and the output of the first oscillator is connected to a second amplifier.

3. The satellite navigation sounding signal receiving and processing system according to claim 2, characterized in that: The single-channel receiving module is also equipped with a second oscillator, the output of which is connected to the discriminator, the control processing module, and the frequency and phase detector.

4. The satellite navigation sounding signal receiving and processing system according to claim 3, characterized in that: The radio frequency synthesizer is model PLL:LMX2571.

5. The satellite navigation sounding signal receiving and processing system according to claim 4, characterized in that: The controller is equipped with an STM32F103C8T6 chip.

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