CN107786321A - A kind of carrier synchronization system suitable for unmanned plane trunking traffic platform - Google Patents
A kind of carrier synchronization system suitable for unmanned plane trunking traffic platform Download PDFInfo
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- CN107786321A CN107786321A CN201610738484.9A CN201610738484A CN107786321A CN 107786321 A CN107786321 A CN 107786321A CN 201610738484 A CN201610738484 A CN 201610738484A CN 107786321 A CN107786321 A CN 107786321A
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- frequency
- loop
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
- H04L7/027—Speed or phase control by the received code signals, the signals containing no special synchronisation information extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit
- H04L7/0274—Speed or phase control by the received code signals, the signals containing no special synchronisation information extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit with Costas loop
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
- H04L7/033—Speed or phase control by the received code signals, the signals containing no special synchronisation information using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
-
- 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
- H04B7/18502—Airborne stations
- H04B7/18504—Aircraft used as relay or high altitude atmospheric platform
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Radio Relay Systems (AREA)
Abstract
The present invention discloses a kind of carrier synchronization system suitable for unmanned plane trunking traffic platform, including：The input signal progress down coversion that frequency converter is used to receive is then output to multiplier；Digital controlled oscillator is used to produce carrier wave and export to multiplier；Multiplier is used to the signal received is mixed to obtain mixed frequency signal and exported；First Frequency-locked-loop and the second Frequency-locked-loop are used to carry out the frequency of mixed frequency signal frequency discrimination output frequency discrimination signal；Phase-locked loop is used to carry out the phase of mixed frequency signal phase demodulation output phase discrimination signal；Track loop is used for the phase discrimination signal for adjudicating the frequency discrimination signal of the first Frequency-locked-loop and the output of the second Frequency-locked-loop according to default threshold voltage and phase-locked loop exports, above three loop and the annexation of itself are switched according to court verdict, and control carrier frequency of the output to digital controlled oscillator.System provided by the invention can realize a wide range of and high-precision carrier synchronization.
Description
Technical field
The present invention relates to communication technical field, more particularly to a kind of carrier synchronization suitable for unmanned plane trunking traffic platform
System.
Background technology
Information transmission has become the essential part of today's social life.But work as and war or natural calamity occur
When evil, because the infringement of communication equipment can cause the appearance of information island.Radio communication forwarding platform based on unmanned plane
It is widely used because it has the advantages such as flexible, cost is low.But because UAS is a dynamic system, connect
Due to there is larger Doppler frequency shift in receipts machine, in this case, it is desirable to which carrier synchronization system must have larger capture model
Enclose.Wireless communication system requirement simultaneously has preferable communication quality, requires there is preferable carrier synchronization precision again.And individually reflect
Frequently, phase demodulation system or traditional phase demodulation frequency discrimination combined system can not meet this requirement well.
In the prior art, the requirement for existing carrier synchronization system has multiple solutions, e.g., 1, utilize second order
Costas loop phaselocked loop；2nd, second-order PLL and FLL handoff links are utilized；3rd, second order cross product discriminator ring auxiliary is utilized
Third order pll system；4th, the carrier track algorithm based on experience look-up table, filtered using the output of frequency-locked loop come feedback control loop
The bandwidth of ripple device.
But in existing solution, although the lock phase Costas loop precision of second order is high, capture range ratio
It is smaller, it is difficult to tackle UAV Communication system large-scale frequency deviation under the adverse circumstances that happen suddenly；Second order cross product FLL and three ranks
Phaselocked loop combination structural system is simple, precision is big, but because capture frequency scope is smaller, it is difficult to tackle high-speed flight or
It is the Doppler shift introduced under the extreme cases such as high wind；Can be with using the characteristic of experience look-up table Feedback adjusting loop wave filter
Adaptively changing bandwidth, precise synchronization at any time, but his Carrier Synchronization Algorithm that proposes is based on unmanned plane and satellite leads to
Letter, relative velocity between the two is larger, and the system is relative complex for Doppler effect.
The content of the invention
The invention aims to overcome the deficiencies in the prior art, there is provided one kind is applied to unmanned plane relay forwarding and communicated
The carrier synchronization system of terminal.
A kind of carrier synchronization system suitable for unmanned plane relay forwarding communications platform of offer of the embodiment of the present invention, including the
One Frequency-locked-loop, the second Frequency-locked-loop, phase-locked loop, track loop, digital controlled oscillator, multiplier and frequency converter；
The input signal progress down coversion that the frequency converter is used to receive is then output to the multiplier；
The digital controlled oscillator is used to produce carrier wave and export to the multiplier；
The multiplier is used to the signal received is mixed to obtain mixed frequency signal and exported；
First Frequency-locked-loop and the second Frequency-locked-loop are used to carry out the frequency of the mixed frequency signal in frequency discrimination output mirror
Frequency signal；
The phase-locked loop is used to carry out the phase of the mixed frequency signal phase demodulation output phase discrimination signal；
The track loop is used to adjudicate first Frequency-locked-loop and second frequency locking according to default threshold voltage
The frequency discrimination signal of loop output and the phase discrimination signal of phase-locked loop output, switch first frequency locking according to court verdict and return
Road, the second frequency locking circuit and the phase-locked loop and the annexation of itself, and output is controlled to the digital controlled oscillator
Carrier frequency.
Wherein, first Frequency-locked-loop includes four phase frequency discriminators and the first loop filter, and the four phases frequency discriminator is used
In the Doppler frequency that capture is drawn by its nonlinear characteristic, first loop filter is used for according to the first preparatory condition
The signal of four phases frequency discriminator output is filtered.
Wherein, second Frequency-locked-loop includes symbol cross product discriminator device and the second loop filter, the symbol cross product
Frequency discriminator is used to reduce frequency difference；Second loop filter is used for according to the second preparatory condition to the symbol cross product discriminator device
The signal of output is filtered.
Wherein, the track loop is additionally operable to the output signal by detecting second Frequency-locked-loop, is looked into by numerical value
Table is looked for linearly to change the bandwidth of second loop filter.
Wherein, the phase-locked loop includes section's Stas phase discriminator and Three links theory wave filter, section's Stas phase demodulation
Device is used for the control for realizing precise phase；The Three links theory wave filter is used for according to the 3rd preparatory condition to section's Stas
The signal of phase discriminator output is filtered.
The present invention compared with prior art, has advantages below：
The system uses two Frequency-locked-loops and a phase-locked loop, and three kinds of situations are divided into according to frequency difference and difference：(1)
Frequency difference is larger；(2) frequency difference is smaller and difference is larger；(3) frequency difference is smaller and difference is smaller.Track loop is to three loops (two locks
Frequency loop and a phase-locked loop) switch over and avoid phase-locked loop from being directly switch to the first poor frequency locking of frequency locking precision returning
Road, and the second moderate Frequency-locked-loop of net synchronization capability is to switch to, avoid synchronization accuracy from having larger fluctuation, improve loop
Capture range, avoid the phenomenon for occurring losing lock in extreme circumstances.
Brief description of the drawings
Fig. 1 is a kind of carrier synchronization system suitable for unmanned plane relay forwarding communication terminal that the embodiment of the present invention one provides
The block diagram of system.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, the every other implementation that those skilled in the art are obtained under the premise of creative work is not made
Example, belongs to the scope of protection of the invention.
Embodiment one
The embodiment of the present invention one provides a kind of carrier synchronization system suitable for unmanned plane relay forwarding communication terminal, such as schemes
Shown in 1, including：Two Frequency-locked-loops (being referred to as the first Frequency-locked-loop and the second Frequency-locked-loop), phase-locked loop, tracking ring
Road, digital controlled oscillator, multiplier and frequency converter.
The input signal progress down coversion that frequency converter is used to receive is then output to multiplier；
Digital controlled oscillator is used to produce carrier wave and export to multiplier；
Multiplier is used to the signal received is mixed to obtain mixed frequency signal and exported；
First Frequency-locked-loop and the second Frequency-locked-loop are used to carry out the frequency of mixed frequency signal frequency discrimination output frequency discrimination signal；
Specifically, in the present embodiment, as shown in figure 1, the first Frequency-locked-loop includes four phase frequency discriminators and the first loop is filtered
Ripple device, four phase frequency discriminators are used for the Doppler frequency by the traction capture of its nonlinear characteristic, can be quickly by frequency difference from 500Hz
Enter the range of linearity of cross product discriminator device with quick traction to 10Hz or so, the first loop filter is used for according to the first default bar
The signal that part exports to four phase frequency discriminators filters；
Second Frequency-locked-loop includes symbol cross product discriminator device and the second loop filter, and symbol cross product discriminator device is used to reduce
Frequency difference；The signal that second loop filter is used to export symbol cross product discriminator device according to the second preparatory condition filters；
In the present embodiment, frequency discrimination refers to differentiate frequency whether within normal deviation range with gate circuit, if
It is abnormal to be output to corresponding control terminal error signal so that frequency is normal；
Phase-locked loop is used to carry out the phase of mixed frequency signal phase demodulation output phase discrimination signal；
Specifically, in the present embodiment, as shown in figure 1, phase-locked loop includes section's Stas phase discriminator and Three links theory is filtered
Ripple device, section's Stas phase discriminator are used for the control for realizing precise phase；Three links theory wave filter is used for according to the 3rd preparatory condition
The signal of section's Stas phase discriminator output is filtered；
In the present embodiment, phase demodulation refers to whether adjust the phase of the signal of output with gate circuit (typically with phaselocked loop)
Correctly, if incorrect can export corresponding adjustment signal；
Track loop is used to adjudicate the mirror that the first Frequency-locked-loop and the second Frequency-locked-loop export according to default threshold voltage
Frequency signal and the phase discrimination signal of phase-locked loop output, then according to court verdict two Frequency-locked-loops of switching and phase-locked loop and certainly
The annexation of body, and control carrier frequency of the output to digital controlled oscillator；It is additionally operable to by detecting the defeated of the second Frequency-locked-loop
Go out signal, linearly change the bandwidth of the second loop filter by numerical value look-up table.
The operation principle of the present embodiment system is specially：Frequency conversion is first passed through when the present embodiment system receives input signal
Device carries out down coversion, the signal of signal after frequency conversion and digital controlled oscillator output by multiplier obtain mixed frequency signal and export to
Horizontal lock is entered in two Frequency-locked-loops and phase-locked loop, specifically, being carried out in three steps lock phase：(1) under original state, if now four phase
The voltage of frequency discriminator output signal is more than upper voltage limit U1, first switches to the first Frequency-locked-loop, using four phase frequency discriminators by frequency difference
It is pulled to the range of linearity of cross product discriminator device；(2) when the voltage of four phase frequency discriminator output signals is less than upper voltage limit U1, cross product discriminator
The voltage of device output signal is more than lower voltage limit U2, is then switched to the second Frequency-locked-loop, is reduced using symbol cross product discriminator device
Frequency difference；(3) when the voltage of cross product discriminator device output signal is less than lower voltage limit U2, phase-locked loop, locking phase are then switched to；
The voltage of signal returns to (1) (2) state according to threshold voltage (U1, U2), repeated (1) departing from (3) state when being such as interfered
(2) process.
The system is applied on the relay forwarding communication terminal of unmanned plane, and unmanned plane during flying is about highly 3km, using 160
The airborne antenna of beam angle is spent, area of effective coverage is more than 1000km.The business transfer process of the carrier synchronization system is as follows,
Input signal after frequency converter by with digital controlled oscillator caused by original carrier be multiplied by multiplier；Believe caused by being multiplied
Number it is respectively fed to four phase frequency discriminators, symbol cross product discriminator device and Costas loop phase discriminator and carries out frequency discrimination and phase demodulation.Symbol cross product
The loop exponent number of frequency discriminator and Costas loop phase discriminator very little, is not suitable for the demodulation of demodulation high dynamic signal.Reflected using four phases
Frequency device can utilize its nonlinear characteristic traction capture Doppler frequency, can quickly by frequency difference from 500Hz with quick traction
To the range of linearity of 10Hz or so entrance cross product discriminator device.This process can solve cross product discriminator device reference frequency output and compare
The characteristics of narrow, can be to realize the accurate tracking of carrier frequency after frequency difference is dropped in a certain particular range.Finally utilize Coase
This ring phase discriminator of tower realizes precise phase control.Output and default two threshold voltage of the track loop based on three wave filters
(i.e. upper voltage limit U1With lower voltage limit U2), when the four filtered output voltages of phase frequency discriminator are more than U1Shi Ze switches to the first lock
Frequency loop, when the output of four phase frequency discriminators is less than U2And the output of symbol cross product discriminator device is more than U2The second Frequency-locked-loop is switched to, works as fork
Product frequency discriminator output is less than U2When, switch to phase-locked loop.U1And U2Value when being respectively that symbol cross product discriminator device enters linear zone
The output voltage of symbol cross product discriminator device when the output voltage and Costas loop of four phase frequency discriminators enter dynamic range.Track ring
The carrier frequency that the signal of road output is used for adjusting digital controlled oscillator makes input signal and the signal of digital controlled oscillator output gradual
Diminish, so as to realize the synchronization of frequency and phase.Track loop passes through numerical value by the output signal of the second Frequency-locked-loop of detection
Look-up table linearly changes the bandwidth of the second loop filter, causes introducing additionally to be made an uproar because the second loop filter bandwidth crosses conference
Sound, the second loop filter bandwidth is too small and can influence synchronization accuracy.By the method for an experience look-up table come feedback regulation
Second loop filter, make the second loop filter adaptively changing bandwidth, solve bit synchronization and carrier wave under dynamic environment
The problem of synchronous, precise synchronization is realized at any time.
The system uses two Frequency-locked-loops and a phase-locked loop, and three kinds of situations are divided into according to frequency difference and difference：(1)
Frequency difference is larger；(2) frequency difference is smaller and difference is larger；(3) frequency difference is smaller and difference is smaller.Track loop is to three loops (two locks
Frequency loop and a phase-locked loop) switch over and avoid phase-locked loop from being directly switch to the first poor frequency locking of frequency locking precision returning
Road, and the second moderate Frequency-locked-loop of net synchronization capability is to switch to, avoid synchronization accuracy from having larger fluctuation, improve loop
Capture range, avoid the phenomenon for occurring losing lock in extreme circumstances.
The foregoing is only a preferred embodiment of the present invention, but protection scope of the present invention be not limited thereto,
Any one skilled in the art is in technical scope disclosed by the invention, the change or replacement that can readily occur in,
It should all be included within the scope of the present invention.Therefore, protection scope of the present invention should be with scope of the claims
It is defined.
Claims (5)
- A kind of 1. carrier synchronization system suitable for unmanned plane trunking traffic platform, it is characterised in that including：First frequency locking returns Road, the second Frequency-locked-loop, phase-locked loop, track loop, digital controlled oscillator, multiplier and frequency converter；The input signal progress down coversion that the frequency converter is used to receive is then output to the multiplier；The digital controlled oscillator is used to produce carrier wave and export to the multiplier；The multiplier is used to the signal received is mixed to obtain mixed frequency signal and exported；First Frequency-locked-loop and the second Frequency-locked-loop are used to carry out the frequency of the mixed frequency signal in frequency discrimination output frequency discrimination letter Number；The phase-locked loop is used to carry out the phase of the mixed frequency signal phase demodulation output phase discrimination signal；The track loop is used to adjudicate first Frequency-locked-loop and second Frequency-locked-loop according to default threshold voltage The frequency discrimination signal of output and the phase discrimination signal of phase-locked loop output, according to court verdict switch first Frequency-locked-loop, The second frequency locking circuit and the phase-locked loop and the annexation of itself, and control load of the output to the digital controlled oscillator Wave frequency rate.
- 2. the system as claimed in claim 1, it is characterised in that first Frequency-locked-loop includes four phase frequency discriminators and the first ring Path filter, the four phases frequency discriminator are used for the Doppler frequency by the traction capture of its nonlinear characteristic, first loop The signal that wave filter is used to export the four phases frequency discriminator according to the first preparatory condition filters.
- 3. the system as claimed in claim 1, it is characterised in that second Frequency-locked-loop includes symbol cross product discriminator device and the Second Ring Road wave filter, the symbol cross product discriminator device are used to reduce frequency difference；Second loop filter is used for pre- according to second If the signal that condition exports to the symbol cross product discriminator device filters.
- 4. system as claimed in claim 3, the track loop is additionally operable to the output by detecting second Frequency-locked-loop Signal, linearly change the bandwidth of second loop filter by numerical value look-up table.
- 5. the system as claimed in claim 1, it is characterised in that the phase-locked loop includes section's Stas phase discriminator and the 3rd ring Path filter, section's Stas phase discriminator are used for the control for realizing precise phase；The Three links theory wave filter is used for basis The signal that 3rd preparatory condition exports to section's Stas phase discriminator filters.
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| CN201610738484.9A CN107786321A (en) | 2016-08-29 | 2016-08-29 | A kind of carrier synchronization system suitable for unmanned plane trunking traffic platform |
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| CN201610738484.9A CN107786321A (en) | 2016-08-29 | 2016-08-29 | A kind of carrier synchronization system suitable for unmanned plane trunking traffic platform |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111435091A (en) * | 2019-01-14 | 2020-07-21 | 中国科学院微电子研究所 | Self-adaptive phase alignment module and method and vibration gyroscope measurement and control circuit |
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- 2016-08-29 CN CN201610738484.9A patent/CN107786321A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111435091A (en) * | 2019-01-14 | 2020-07-21 | 中国科学院微电子研究所 | Self-adaptive phase alignment module and method and vibration gyroscope measurement and control circuit |
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Application publication date: 20180309 |