CN115567133B - Doppler frequency parameter calibration method and system for space-based measurement and control communication system - Google Patents
Doppler frequency parameter calibration method and system for space-based measurement and control communication system Download PDFInfo
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Abstract
Aiming at the USB link signals of the space-based measurement and control communication system, the invention provides a method for calibrating the Doppler frequency parameters of the USB space-based measurement and control communication system, researches the Doppler frequency and Doppler frequency change rate on-line calibration technology and provides technical support for the stable operation of the space-based measurement and control communication system. The invention realizes the calibration of Doppler frequency and Doppler frequency change rate of the DSSS/BPSK modulation signal of the USB link. The hardware device for realizing the Doppler frequency parameter calibration method of the satellite measurement and control communication system consists of a signal analysis module, a high-speed data acquisition unit and an embedded controller.
Description
Technical Field
The invention belongs to the technical field of satellite measurement and control communication measurement, and particularly relates to a Doppler frequency parameter calibration method for a USB space-based measurement and control communication system.
Background
In the field of aerospace measurement and control, along with development of aerospace technology, a situation that a plurality of aerospace measurement and control networks coexist for a long time is formed at present, for example, a main military aerospace measurement and control network in the United states comprises: an air force satellite measurement and control network, a tracking and data relay satellite space-based network, a naval satellite control network, a army satellite control network, a plurality of military satellite special control networks and the like. In order to fully exert the co-existence and complementary advantages of various aerospace measurement and control networks, two or more aerospace measurement and control network service supports are generally used in the same task. At present, a measurement and control network which is built and is in use in China is a unified carrier system (USB), and the telemetry and remote control information adopts a DSSS/BPSK modulation system.
At present, no formal regulations are issued in China for the calibration of a satellite simulator measurement and control communication system, and the calibration of the satellite simulator measurement and control communication system is generally off-site static calibration. However, as the USB link calibration technology is studied intensively, the conventional calibration method is not preferable.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a Doppler frequency parameter calibration method of a space-based measurement and control communication system based on spectrum analysis, so as to calibrate Doppler frequency and Doppler frequency change rate of a DSSS/BPSK modulation signal of a USB link. The hardware device for realizing the Doppler frequency parameter calibration method of the satellite measurement and control communication system consists of a signal analysis module, a high-speed data acquisition unit and an embedded controller.
The technical scheme adopted by the invention is as follows:
the invention provides a Doppler frequency parameter calibration method of a USB space-based measurement and control communication system, which comprises a Doppler frequency calibration method and a Doppler frequency change rate calibration method.
Further, the Doppler frequency calibration method comprises the following steps:
step 11, the doppler frequency when the satellite simulator simulates a uniform motion target is a fixed frequency, namely the satellite simulator realizes the simulation of the uniform motion target by adding a doppler frequency offset on the carrier frequency, and at the moment, the signal output by the satellite simulator is a frequency modulation signal with the fixed frequency offset:
the output signals when the satellite simulator simulates a uniform motion target are as follows:
wherein f d Namely the Doppler frequency to be calibrated, f is extracted from the signal shown in the formula (2) during calibration d ；C(t)D c (t) is a baseband signal, C (t) D c (t)＝±1；
Step 12, square operation is performed on the formula (2), because of C (t) D c (t) = ±1, obtainable:
as can be seen from equation (3), the squared signal contains 2 (f) c +f d ) The frequency component is subjected to FFT to obtain 2 (f) c +f d ) Values.
Further, the Doppler frequency change rate calibration method comprises the following steps:
when the satellite simulator simulates an acceleration moving target, the Doppler frequency of the target simulation signal linearly changes along with time, namely, the signal form output by the satellite simulator is a linear frequency modulation signal, the Doppler frequency change rate corresponds to the slope of the linear frequency modulation, the signal is required to be de-modulated during calibration, and the Doppler frequency change rate is calculated from the demodulation signal; the output signal model when the satellite simulator simulates an acceleration moving object is as follows:
the frequency of the visible signal in the formula (4) is required to linearly change along with time, the changing slope a is the Doppler frequency change rate to be calibrated, the signal is firstly subjected to line demodulation processing during calibration to obtain the change relation between the instantaneous frequency and the time, and then the Doppler frequency change rate a is calculated by the frequency change range deltaf and the corresponding change time t, wherein the calculation formula is as follows:
the invention also provides a satellite simulator Doppler frequency calibration system, which comprises a signal analysis module, an oscilloscope data acquisition module and an embedded controller;
the 1PPS signal of the calibrated satellite simulator is input to a trigger channel of the oscilloscope data acquisition module to be used as trigger synchronization, and the calibrated satellite simulator, the signal analysis module and the oscilloscope data acquisition module are set to be crystal oscillator synchronization;
when in calibration, the output signal of the satellite simulator to be calibrated is down-converted to intermediate frequency by the signal analysis module, the intermediate frequency signal is subjected to A/D conversion by the oscilloscope data acquisition module, and then the digital intermediate frequency signal is processed by using calibration software in the embedded controller to obtain Doppler frequency measurement value.
The invention also provides a system for calibrating the Doppler frequency change rate of the satellite simulator, which comprises a signal analysis module and an embedded controller, wherein a calibrated signal is input to the signal analysis module during the Doppler frequency change rate calibration, digital IQ data is obtained by utilizing the DDC function of the signal analysis module, the digital IQ data is input to the embedded controller through a PXIe bus, and the signal processing and the extraction and the calibration of Doppler frequency change rate parameters are realized by using calibration software in the embedded controller.
Compared with the prior art, the method has the beneficial effects that the Doppler frequency and Doppler frequency change rate on-line calibration technology is researched aiming at the USB link signal of the space-based measurement and control communication system, and technical support is provided for the stable operation of the space-based measurement and control communication system.
Drawings
FIG. 1 is a graph of a DSSS/BPSK modulated signal according to the invention;
figure 2 is a schematic diagram of a doppler frequency calibration system of the present invention;
FIG. 3 is a block diagram of a satellite simulator Doppler frequency calibration system according to the present invention;
fig. 4 is a time domain waveform diagram of LFM signal and LFM-BPSK complex modulated signal according to the present invention;
FIG. 5 is a graph of the BPSK/LFM complex modulated signal according to the invention;
FIG. 6 is a diagram showing the demodulation result of the BPSK/LFM modulation signal according to the invention;
FIG. 7 is a graph of the square of the BPSK/LFM signal according to the invention;
FIG. 8 is a graph showing the result of the demodulation of the square of the BPSK/LFM modulated signal according to the invention;
figure 9 is a block diagram of a satellite simulator doppler frequency rate of change calibration system according to the present invention.
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the accompanying drawings. It is noted that the drawings are in a very simplified form and utilize non-precise ratios, and are intended to facilitate a convenient, clear, description of the embodiments of the invention.
The signal power spectrum obtained by simulating the DSSS/BPSK modulated signal is shown in figure 1.
(1) The satellite simulator Doppler frequency calibration principle analysis.
The Doppler frequency when the satellite simulator simulates a uniform motion target is a fixed frequency, namely the satellite simulator realizes the simulation of the uniform motion target by adding a Doppler frequency offset on the carrier frequency, and at the moment, the signal output by the satellite simulator is a frequency modulation signal with the fixed frequency offset.
C (t) is a common ranging code, A c Representing the amplitude of the in-phase branch signal, D c (t) represents a C code navigation message, f c Representing the carrier frequency of the carrier wave,
represents an initial phase, t represents time, S I And (t) is a simulator signal model of the navigation satellite.
The output signals when the satellite simulator simulates a uniform motion target are as follows:
wherein f d Namely the Doppler frequency to be calibrated, f is extracted from the signal shown in the formula (2) during calibration d . The signal shown in (2) is DSSS/BPSK modulated signal, which is spread spectrum signal C (t) D by pseudo code c (t) BPSK-modulating the carrier wave as a baseband signal, due to the baseband signal C (t) D c The pattern of (t) being bipolar, i.e. C (t) D c (t) = ±1, and the probability of taking the value 1 and-1 is equal, when the baseband signal C (t) D c (t) no dc component, resulting in no carrier frequency component in the spectrum of the BPSK modulated signal. FIG. 1 shows a DSSS/BPSK modulated signal spectrum, which is seen to contain no carrier frequency component, so that Doppler frequency f cannot be obtained by direct measurement of signal carrier frequency d Is a measurement of (a).
Because the baseband code pattern of the DSSS/BPSK signal is bipolar, under the condition of equal probability value, the baseband signal does not contain direct current component, so that the spectrum of the signal after BPSK modulation does not have carrier frequency component, but the DSSS/BPSK signal is subjected to square transformation, the spectrum of the signal has twice carrier frequency component, and the characteristics can be used for obtaining the DSSSCarrier frequency of S/BPSK signal. Square operation is performed on equation (2), due to D c (t) C (t) = ±1, obtainable:
from the above equation, the squared signal contains 2 (f c +f d ) The frequency component is subjected to FFT to obtain 2 (f) c +f d ) Value of f is known to be c Frequency value, calculating the obtainable Doppler frequency f d Values.
(2) Satellite simulator Doppler frequency calibration is achieved.
The invention adopts a digital intermediate frequency receiver structure to build a hardware part of a calibration system, realizes the function of a radio frequency front end, realizes square conversion, FFT conversion and Doppler frequency calculation of a digital intermediate frequency signal by using LabView software, thereby realizing calibration, and a Doppler frequency calibration realization schematic diagram is shown in the following figure.
As shown in fig. 2, the analog rf front-end of the calibration system has the functions of down-converting an input rf signal to an intermediate frequency, performing intermediate frequency amplification, filtering, and a/D conversion to obtain a digital intermediate frequency signal, and the digital signal processing part implements square conversion, FFT conversion, and doppler frequency extraction of the digital intermediate frequency signal. The invention uses a signal analysis module and an oscilloscope data acquisition module as a Doppler frequency calibration system hardware device to realize the function of an analog radio frequency front end, and uses LabView software to realize the function of digital signal processing. The Doppler frequency calibration system hardware composition is shown in the following figure.
As shown in fig. 3, the 1PPS signal of the satellite simulator to be calibrated is input to the trigger channel of the oscilloscope data acquisition module as trigger synchronization, and the satellite simulator to be calibrated, the signal analysis module and the oscilloscope data acquisition module are set as crystal oscillator synchronization. When in calibration, the output signal of the satellite simulator to be calibrated is down-converted to intermediate frequency by the signal analysis module, the intermediate frequency signal is subjected to A/D conversion by the oscilloscope data acquisition module, and then the digital intermediate frequency signal is processed by using calibration software in the embedded system controller to obtain Doppler frequency measurement value.
(3) Satellite simulator Doppler frequency rate of change calibration.
When the satellite simulator simulates an acceleration moving target, the Doppler frequency of the target simulation signal linearly changes along with time, namely, the signal output by the satellite simulator is in a form of a linear frequency modulation signal, the Doppler frequency change rate corresponds to the slope of the linear frequency modulation, the signal is required to be de-modulated during calibration, and the Doppler frequency change rate is calculated from the demodulation signal. The output signal model when the satellite simulator simulates an acceleration moving object is as follows:
the frequency of the visible signal is required to linearly change along with time, the changing slope a is the Doppler frequency change rate to be calibrated, the signal is firstly subjected to line demodulation processing during calibration to obtain the change relation between the instantaneous frequency and the time, and then the Doppler frequency change rate a is calculated by the frequency change range deltaf and the corresponding change time t, wherein the calculation formula is as follows:
where Δf is the frequency variation and t is the time required for the frequency variation Δf, as can be seen from equation (4), the signal being calibrated is not a simple chirped (LFM) signal, but is a pseudo code spread spectrum signal D at the same time as the chirping c (t) C (t) BPSK-modulates the carrier, and the signal is a BPSK/LFM complex modulated signal. Fig. 4 is a simulation diagram of a time domain representation of LFM signals and BPSK/LFM complex modulated signals.
As shown in fig. 4, since the instantaneous frequency is no longer linearly changed due to the abrupt change of carrier frequency phase caused by BPSK modulation, the doppler frequency rate value cannot be extracted by means of direct line demodulation. Fig. 5 shows the frequency spectrum of the BPSK/LFM complex modulated signal and the instantaneous frequency versus time obtained by demodulating the same.
As can be seen from FIG. 6, the frequency spectrum of the BPSK/LFM modulated signal is different from that of the chirp signal, and the instantaneous frequency obtained after the demodulation existsThe mutation no longer changes linearly with time. Therefore, to extract the doppler frequency change rate, the influence of the phase mutation introduced by BPSK modulation should be removed first. From the above analysis, it can be seen that twice the carrier frequency can be obtained by squaring the DSSS/BPSK signal, and the LFM modulated signal can be obtained by squaring the BPSK/LFM modulated signal without the influence of phase mutation introduced by BPSK modulation. The phase jump introduced by BPSK modulation is due to the pseudo-code spread spectrum signal D c (t) C (t) due to code phase inversion of the baseband signal C (t) D c The pattern of (t) being bipolar, i.e. C (t) D c (t) = ±1, and the probability of taking the value 1 and-1 is equal, and the signal is squared with (C (t) D c (t)) 2 =1, and the effect of phase mutation after code phase inversion and BPSK modulation is removed. Fig. 7 shows the square spectrum of the BPSK/LFM signal and the squared demodulation result.
As shown in fig. 8, the spectrum obtained by squaring the BPSK/LFM signal, i.e., the LFM signal spectrum, changes linearly in the instantaneous frequency seen after demodulation. Therefore, the signal can be square transformed and then demodulated to obtain the transformation relation delta f=f between the instantaneous frequency and time during calibration c +at, and according to d (f c The Doppler frequency rate of change parameter is calculated by +at)/dt differential calculation. The invention uses PXIe-5663E signal analysis module as Doppler frequency change rate calibration system hardware device, uses LabView software to extract and calibrate Doppler frequency change rate parameters, and the calibration system is shown in figure 9.
The calibrated signal is input to the signal analysis module during calibration, digital IQ data is obtained by using the DDC function of the signal analysis module, the digital IQ data is input to the embedded controller through the PXIe bus, and the signal processing and the extraction and calibration of Doppler frequency change rate parameters are realized by using calibration software in the controller.
It should be noted that the foregoing is merely illustrative and explanatory of the invention, and that any modifications and substitutions of the invention will be apparent to those skilled in the art, and are intended to be within the scope of the invention.
Claims (3)
1. The Doppler frequency parameter calibration method for the space-based measurement and control communication system is characterized by comprising a Doppler frequency calibration method and a Doppler frequency change rate calibration method;
the Doppler frequency calibration method comprises the following steps:
step 11, the doppler frequency when the satellite simulator simulates a uniform motion target is a fixed frequency, namely the satellite simulator realizes the simulation of the uniform motion target by adding a doppler frequency offset on the carrier frequency, and at the moment, the signal output by the satellite simulator is a frequency modulation signal with the fixed frequency offset:
the output signals when the satellite simulator simulates a uniform motion target are as follows:
wherein S is I (t) is a simulator signal model of the navigation satellite, C (t) is a common ranging code, ac represents the in-phase branch signal amplitude, dc (t) represents a C code navigation message, fc represents a carrier frequency,
represents an initial phase, t represents time, f d Namely the Doppler frequency to be calibrated, f is extracted from the signal shown in the formula (2) during calibration d ；C(t)D c (t) is a baseband signal, C (t) D c (t)＝±1；
Step 12, square operation is performed on the formula (2), because of C (t) D c (t) = ±1, obtainable:
as can be seen from equation (3), the squared signal contains 2 (f) c +f d ) The frequency component is subjected to FFT to obtain 2 (f) c +f d ) The value is calculated to obtain Doppler frequency f d A value;
the Doppler frequency change rate calibration method comprises the following steps:
when the satellite simulator simulates an acceleration moving target, the Doppler frequency of the target simulation signal linearly changes along with time, namely, the signal form output by the satellite simulator is a linear frequency modulation signal, the Doppler frequency change rate corresponds to the slope of the linear frequency modulation, the signal is required to be de-modulated during calibration, and the Doppler frequency change rate is calculated from the demodulation signal; the output signal model when the satellite simulator simulates an acceleration moving object is as follows:
wherein S is I (t) is a simulator signal model of the navigation satellite, C (t) is a common ranging code, ac represents the in-phase branch signal amplitude, dc (t) represents a C code navigation message, fc represents a carrier frequency,
representing an initial phase, t representing time, a being the slope of the change;
the frequency of the visible signal in the formula (4) is required to linearly change along with time, the changing slope a is the change rate of the Doppler frequency to be calibrated, the signal is firstly subjected to frequency demodulation processing during calibration to obtain the change relation between the instantaneous frequency and the time, and then the Doppler frequency change rate a is calculated by the frequency change range deltaf and the corresponding change time t, wherein the calculation formula is as follows:
2. a satellite simulator Doppler frequency calibration system adopting the method for calibrating Doppler frequency parameters of a space-based measurement and control communication system as claimed in claim 1, which is characterized by comprising a signal analysis module, an oscilloscope data acquisition module and an embedded controller;
the method comprises the steps that a 1PPS signal of a satellite simulator is input into a trigger channel of an oscilloscope data acquisition module to serve as trigger synchronization, and the satellite simulator, a signal analysis module and the oscilloscope data acquisition module are set to be crystal oscillator synchronization;
during calibration, the output signal of the satellite simulator is down-converted to intermediate frequency by the signal analysis module, the intermediate frequency signal is A/D converted by the oscilloscope data acquisition module, and then the digital intermediate frequency signal is processed by using the calibration software in the embedded controller to obtain Doppler frequency f d Values.
3. The Doppler frequency change rate calibration system of the satellite simulator adopts the Doppler frequency parameter calibration method of the space-based measurement and control communication system as claimed in claim 1, and is characterized by comprising a signal analysis module and an embedded controller, wherein a calibrated signal is input into the signal analysis module during Doppler frequency change rate calibration, digital IQ data is obtained by utilizing the DDC function of the signal analysis module, the digital IQ data is input into the embedded controller through a PXIe bus, and signal processing and extraction and calibration of Doppler frequency change rate parameters are realized by using calibration software in the embedded controller.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106338744A (en) * | 2015-12-25 | 2017-01-18 | 深圳艾科创新微电子有限公司 | Beidou signal simulation device, testing device for simulating Beidou signal, and debugging system |
| CN113328765A (en) * | 2021-04-25 | 2021-08-31 | 北京航空航天大学 | Method for realizing universal receiver of multiple spread spectrum systems under high dynamic condition |
| CN113824662A (en) * | 2021-11-22 | 2021-12-21 | 北京航天驭星科技有限公司 | Carrier synchronization method and device, electronic equipment and computer readable medium |
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| CN101132191B (en) * | 2007-10-15 | 2010-06-02 | 北京航空航天大学 | Baseband signal processing method for GNSS receiver |
| CN102508268B (en) * | 2011-11-10 | 2014-10-08 | 航天恒星科技有限公司 | Foundation navigation signal observation data generation method |
| CN105717521A (en) * | 2014-12-04 | 2016-06-29 | 上海精密计量测试研究所 | Fast acquisition method of high dynamic pseudo satellite signal |
| CN105738876A (en) * | 2014-12-10 | 2016-07-06 | 上海精密计量测试研究所 | Device for calibrating instantaneous Doppler frequency offset of PD radar seeker echo simulator |
| CN107864107B (en) * | 2017-12-27 | 2020-07-28 | 北京理工大学 | Frequency offset estimation method for terahertz communication |
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| CN106338744A (en) * | 2015-12-25 | 2017-01-18 | 深圳艾科创新微电子有限公司 | Beidou signal simulation device, testing device for simulating Beidou signal, and debugging system |
| CN113328765A (en) * | 2021-04-25 | 2021-08-31 | 北京航空航天大学 | Method for realizing universal receiver of multiple spread spectrum systems under high dynamic condition |
| CN113824662A (en) * | 2021-11-22 | 2021-12-21 | 北京航天驭星科技有限公司 | Carrier synchronization method and device, electronic equipment and computer readable medium |
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