CN101505184A - Concealed satellite communication terminal - Google Patents

Concealed satellite communication terminal Download PDF

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Publication number
CN101505184A
CN101505184A CNA2009100738397A CN200910073839A CN101505184A CN 101505184 A CN101505184 A CN 101505184A CN A2009100738397 A CNA2009100738397 A CN A2009100738397A CN 200910073839 A CN200910073839 A CN 200910073839A CN 101505184 A CN101505184 A CN 101505184A
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signal
unit
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CN101505184B (en
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肖娜
王艳君
潘申富
王赛宇
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CETC 54 Research Institute
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CETC 54 Research Institute
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Abstract

The invention discloses a covert satellite communication terminal, which relates to covert communication terminal equipment in the field of satellite communication. The terminal consists of components such as a voice unit, a RS232 interface unit, a service selection unit, a baseband processing unit, an intermediate frequency unit, an interference canceling unit, a monitoring unit and the like. The terminal changes working parameters of a terminal through the control of the monitoring unit, thereby ensuring that a multi-user spread-spectrum signal for bearing low-speed information and certain broadband signal on a satellite transponder are transmitted in the same frequency band, and realizing the aim of covert satellite communication when the normal work of the broadband signal is not affected. The terminal also adopts an interference cancellation function, has the advantages of good communication form covertness, large system capacity, good anti-interference and anti-interception performances, high integration degree, steady and reliable performance, light weight, low power consumption, simple structure and the like, and is particularly suitable to be used as communication terminal equipment in a covert satellite communication system.

Description

Concealed satellite communication terminal
Technical field
The present invention relates to a kind of concealed satellite communication terminal in the satellite communication field, be specially adapted to as in the satellite communication system based on the communication terminal of covert communications application mode.
Background technology
Satellite communication is undertaken by external space satellite repeater, space resources places one's entire reliance upon, and the satellite repeater that is exposed to the space is subjected to enemy's soft destruction easily and kills and wounds firmly, the satellite communication signal is is also intercepted and captured easily, this is the weakness of satellite communication in application, is worth so the stupid sustainability that adopts the concealed satellite communication technology to strengthen our signal of communication has important use.
Summary of the invention
The objective of the invention is to avoid the weak point in the above-mentioned background technology and provide a kind of multiple user signals to be hidden under the broadband signal our station, when not influencing the broadband signal normal transmission, realize the concealed satellite communication terminal of covert communications, the present invention also have integrated degree height, stable and reliable for performance, in light weight, low in energy consumption, make and debugging is simple, can be than harsh environmental conditions (10 ℃～55 ℃) characteristics such as operate as normal down.
The object of the present invention is achieved like this: it comprises VU voice unit 1, RS232 interface unit 2, service selection unit 3, baseband processing unit 4, intermediate frequency unit 5, Interference Cancellation unit 6, monitoring unit 7, described intermediate frequency unit 5 is gone into end 3 pin and is connected with outside L frequency range intermediate frequency input port B, intermediate frequency unit 5 goes out end 4 pin and is connected with L frequency range medium frequency output end mouth A, intermediate frequency unit 5 is gone into end 2 pin and is gone out to hold 4 pin to be connected with baseband processing unit 4, intermediate frequency unit 5 is gone into end 5 pin and is gone out to hold 4 pin to be connected by data/address bus and monitoring unit 7, intermediate frequency unit 5 is under the frequency control signal control of monitoring unit 7 inputs, analog baseband signal from baseband processing unit 4 inputs is modulated into L frequency range intermediate-freuqncy signal, by the intermediate-freuqncy signal after the intermediate frequency outbound port A output modulation of output 4 pin connection; Intermediate frequency unit 5 goes out end 1 pin and goes into to hold 2 pin to be connected with Interference Cancellation unit 6, and the output complex baseband signal was to Interference Cancellation unit 6 after 5 pairs of L frequency range intermediate-freuqncy signals from outside L frequency range intermediate frequency input port B input of intermediate frequency unit were carried out quadrature demodulation; Interference Cancellation unit 6 is gone into end 3 pin and is gone out to hold 3 pin to be connected with monitoring unit 7, Interference Cancellation unit 6 goes out end 1 pin and goes into end 3 pin with baseband processing unit 4 and is connected, and the complex baseband signal of Interference Cancellation unit 6 after making intermediate frequency unit 5 demodulation under the Interference Cancellation parameter control that monitoring unit 7 is imported exported remaining spread-spectrum signal to baseband processing unit 4 after finishing the Interference Cancellation of input signal; Baseband processing unit 4 is gone into end 1 pin and is gone out to hold 5 pin to be connected with service selection unit 3, the discrepancy of baseband processing unit 4 holds 5 pin to hold 2 pin to be connected by the data/address bus and the discrepancy of monitoring unit 7, baseband processing unit 4 goes out end 2 pin and goes into to hold 6 pin to be connected with service selection unit 3, baseband processing unit 4 is under the control of the spreading code address parameter of monitoring unit 7 inputs, the original data bits that recovers after the spread-spectrum signal behind the Interference Cancellation carries out despread-and-demodulation and channel decoding of coming 6 inputs of self-interference cancellation unit is flowed, to carrying out band spectrum modulation from the business datum of service selection unit 3 inputs, export analog baseband signal behind base band shaping and the D/A switch, baseband processing unit 4 is sent to monitoring unit 7 with the internal work status signal, and monitoring unit 7 will show from the internal work status signal of baseband processing unit 4 inputs; Service selection unit 3 is gone into end 1 pin and is gone out to hold 2 pin to be connected with VU voice unit 1, service selection unit 3 is gone into end 3 pin and is gone out to hold 2 pin to be connected with RS232 interface unit 2, service selection unit 3 is gone into end 7 pin and is gone out to hold 1 pin to be connected with monitoring unit 7, service selection unit 3 is under the control of the service selection signal of monitoring unit 7 inputs, the original data bits stream input VU voice unit 1 or the RS232 interface unit 2 that recover after the decoding from baseband processing unit 4 inputs, service selection unit 3 is under the control of the service selection signal of monitoring unit 7 inputs, from going into end 1 pin from the voice data of VU voice unit 1 input with from selecting one tunnel business datum to output to baseband processing unit 4 asynchronous data of RS232 interface unit 2 inputs; Service selection unit 3 goes out end 2 pin and goes into to hold 3 pin to be connected with VU voice unit 1, the discrepancy of VU voice unit 1 holds 1 pin to be connected with outside phone interface C, the original data bits of recovering after 1 pair of decoding from 3 inputs of service selection unit of VU voice unit is exported analogue voice signal after flowing to line data tap, tone decoding, PCM decoding and 4/2 conversion, and 1 pair of analogue voice signal from outside phone interface C input of VU voice unit carries out exporting digital bit stream data behind 2/4 conversion, pcm encoder, speech coding and the data multiplexing; Service selection unit 3 goes out end 4 pin and goes into to hold 3 pin to be connected with RS232 interface unit 2, the discrepancy of RS232 interface unit 2 holds 1 pin to be connected with computer RS232 asynchronous data interface D, the original data bits stream that recovers after 2 pairs of decodings from 3 inputs of service selection unit of RS232 interface unit carries out together/asynchronous data conversion back output asynchronous data, and 2 pairs of asynchronous datas from computer RS232 asynchronous data interface D input of RS232 interface unit are carried out different/synchrodata and changed back output synchrodata.
Purpose of the present invention can also reach by following measure:
Baseband processing unit 4 of the present invention comprises encoder 8, spread spectrum modulator 9, spectrum-spreading code generator 10,19, forming filter 11, D/A converter 12, low pass filter 13, A/D converter 14, digital down converter 15, sign indicating number capture circuit 16, digital correlator 17, code tracking circuit 18, carrier recovery circuit 20, signal-to-noise ratio (SNR) estimation circuit 21, channel decoder 22, the business datum signal that 8 pairs of service selection unit of described encoder 3 go out the need modulation of end 5 pin input carries out chnnel coding and differential coding, data behind coding input spread spectrum modulator 9 is gone into end 1 pin, spectrum-spreading code generator 10 goes out at monitoring unit 7 under the control of spreading code address parameter of end 2 pin input to generate local spreading code, and spreading code is imported spread spectrum modulator 9 go into end 3 pin, spread spectrum modulator 9 the coding of encoder 8 input after the spreading code XOR formation modulated spread spectrum signal mutually of data and spectrum-spreading code generator 10 outputs, modulated spread spectrum signal input forming filter 11 is gone into end 1 pin, forming filter 11 carries out the baseband frequency spectrum shaping with the modulated spread spectrum signal of input, the signal input D/A converter 12 of base band shaping is gone into end 1 pin, D/A converter 12 carries out steering D/A conversion with the input signal of base band shaping, data behind the steering D/A conversion are inputed to low pass filter 13 go into end 1 pin, low pass filter 13 carries out analogue low pass filtering with the input signal behind the steering D/A conversion, the signal after the low-pass filtering is inputed to intermediate frequency unit 5 go into end 2 pin; The complex baseband signal behind Interference Cancellation that 14 pairs of Interference Cancellation unit of A/D converter 6 go out the input of end 1 pin carries out mould/transformation of variables, data input digit low-converter after mould/transformation of variables 15 is gone into end 1 pin, digital down converter 15 produces the local digital carrier wave according to the carrier frequency control word that carrier recovery circuit 20 goes out the input of end 2 pin, the signal that goes out the input of end 2 pin with A/D converter 14 carries out complex multiplication operation, carries out Digital Down Convert; Digital down converter 15 goes out to hold 3 pin respectively the Digital Down Convert signal to be inputed to yard capture circuit 16 and goes into end 1 pin, digital correlator 17 is gone into end 1 pin, sign indicating number capture circuit 16 goes out to hold the local spreading code of 1 pin input to make related operation the Digital Down Convert signal and the spectrum-spreading code generator 19 of input, the correlation and the predefined thresholding of computing are compared, the sign indicating number synchronizing signal that thresholding is relatively drawn exports code tracking circuit 18 to and goes into end 1 pin, the correlation value signal that code tracking circuit 18 goes out to hold 3 pin to import to digital correlator 17 under the sign indicating number synchronizing signal control of sign indicating number capture circuit 16 inputs is carried out data processing and the phase difference value of transmitting-receiving pseudo-code is estimated, according to estimated value the phase place of local spreading code is adjusted, it is synchronously accurate that the transmitting-receiving pseudo-code is obtained, and exports adjusted receipts pseudo-code clock to spectrum-spreading code generator 19 and go into end 2 pin; Monitoring unit 7 goes out to hold 2 pin that the spreading code address parameter is outputed to spectrum-spreading code generator 19 and goes into end 3 pin, spectrum-spreading code generator 19 is under the driving of the adjusted receipts pseudo-code clock signal of code tracking circuit 18 inputs, spreading code address parameter according to monitoring unit 7 inputs generates local spreading code, export the local spreading code that generates to yard capture circuit 16 respectively and go into end 2 pin, digital correlator 17 is gone into end 2 pin, digital correlator 17 goes out to hold the local spreading code of 1 pin input to carry out related operation digital signal and the spectrum-spreading code generator 19 that digital down converter 15 goes out the input of end 3 pin, the related operation value is sent into code tracking circuit 18 respectively go into end 3 pin, carrier recovery circuit 20 is gone into end 1 pin, signal-to-noise ratio (SNR) estimation circuit 21 is gone into end 1 pin, channel decoder 22 is gone into end 1 pin; The related operation value of 20 pairs of digital correlators of carrier recovery circuit, 17 inputs carries out after the data processing transmitting-receiving carrier beat being estimated, constantly local carrier frequency is adjusted according to the carrier beat estimated value, export adjusted carrier frequency control word to digital down converter 15 and go into end 2 pin, the related operation value of 21 pairs of digital correlators of signal-to-noise ratio (SNR) estimation circuit, 17 inputs is carried out the estimation of signal power and noise power, obtain the estimated value of input signal signal to noise ratio, go into end 2 pin with what the estimated value of signal to noise ratio exported monitoring unit 7 to, channel decoder 22 carries out the error-correcting decoding of input signal, exports the original data bits stream after the decoding to service selection unit 3 and goes into end 6 pin.
Interference Cancellation of the present invention unit 6 comprises A/D converter 23, digital down converter 24, matched filter 25, carrier recovery circuit 26, timing estimation circuit 27, delay memory 28, Canceller 29, decoding and re-encoder 30, power adjusting circuit 31, D/A converter 32, the complex baseband signal behind intermediate frequency demodulation that 23 pairs of intermediate frequency units of described A/D converter 5 go out the input of end 1 pin carries out mould/transformation of variables, data input digit low-converter after mould/transformation of variables 24 is gone into end 1 pin, digital down converter 24 produces the local digital carrier wave according to the carrier frequency control word that carrier recovery circuit 26 goes out the input of end 2 pin, the digital signal that goes out the input of end 2 pin with A/D converter 23 is carried out complex multiplication operation, carries out Digital Down Convert; Digital down converter 24 goes out end 3 pin and exports the signal of Digital Down Convert to matched filter 25 and go into end 1 pin, matched filter 25 carries out Waveform Matching with the Digital Down Convert signal of input, signal after the Waveform Matching is inputed to timing estimation circuit 27 respectively go into end 1 pin, delay memory 28 is gone into end 1 pin, signal after the Waveform Matching of 27 pairs of inputs of timing estimation circuit carries out data processing and extracts signal of timing error, carry out the timing adjustment of loop according to signal of timing error, the optimum sampling point of restoring signal, timing estimation circuit 27 goes out to hold 2 pin to export the adjusted data of timing to carrier recovery circuit 26 respectively and goes into end 1 pin, decoding and re-encoder 30 are gone into end 1 pin, the adjusted signal of timing of 26 pairs of inputs of carrier recovery circuit carries out after the data processing transmitting-receiving carrier beat being estimated, constantly the frequency of local carrier is adjusted according to estimated value, exported adjusted carrier frequency control word to digital down converter 24 and go into end 2 pin; The adjusted signal of timing of decoding and 27 inputs of 30 pairs of timing estimation circuit of re-encoder carries out channel decoding earlier, initial data after the channel decoding is carried out secondary coding, go out to hold 2 pin to export Canceller 29 to by decoding and re-encoder 30 signal behind the secondary coding and go into end 2 pin, delay memory 28 is gone into the signal that end 1 pin goes out matched filter 25 after the Waveform Matching of end 2 pin input and is stored, export the signal after the storage to Canceller 29 and go into end 1 pin, monitoring unit 7 goes out to hold 3 pin that the Interference Cancellation parameter is exported to Canceller 29 and goes into end 4 pin, Canceller 29 goes out delay memory 28 wideband interferer signal that obtains through coding again that the mixed signal of delayed storage of end 2 pin input and decoding and re-encoder 30 go out the input of end 2 pin and carries out the counteracting of wideband interferer signal, export the spread-spectrum signal that obtains after offsetting to power adjusting circuit 31 and go into end 1 pin, power adjusting circuit 31 will be offset the automatic adjusting range of the remaining spread-spectrum signal in back, export the adjusted spread-spectrum signal of amplitude to D/A converter 32 and go into end 1 pin, 32 pairs of inputs of D/A converter carry out steering D/A conversion through the adjusted signal of power, export the data behind the steering D/A conversion to baseband processing unit 4 and go into end 3 pin.
The present invention compares with background technology has following advantage:
1. the present invention adopts the method for noninductive lift-launch, with the spread-spectrum signal of carrying low speed information and a certain band signal frequency band transmission altogether of having a lot of social connections on the satellite repeater, because the spread-spectrum signal bandwidth is less than the broadband signal bandwidth, spread-spectrum signal power is much smaller than broadband signal power, after so broadband signal is transmitted through satellite repeater, on frequency spectrum, there is not tangible envelope to rise and fall, make human observer, user or scouter not observe the existence of spread-spectrum signal, but therefore system's long period safety, work reliably, to realize concealed satellite communication.
2. the present invention has adopted baseband processing unit 4, Interference Cancellation unit 6 circuit, because the power of broadband signal is much larger than the power of spread-spectrum signal, therefore when the basic modulation parameter of broadband signal is known, can adopt effective interference cancellation techniques to balance out broadband signal is all or part of, to reduce the interference of broadband signal to spread-spectrum signal, further improve the signal to noise ratio of spread-spectrum signal, strengthen communication stability and disguise, guarantee that also directly-enlarging system has big as far as possible capacity simultaneously.
3. the present invention can be under the situation that does not influence the broadband signal operate as normal, and with a certain band signal frequency band altogether of having a lot of social connections on the satellite repeater, so it can be used to not have band resource, perhaps band resource is subjected to carrying out emergency communication under the serious situation about disturbing.
4. the integrated degree height of the present invention is low in energy consumption, stable and reliable for performance, can be under than rugged environment (10 ℃～55 ℃) condition operate as normal.
5. the present invention adopts the standard profile structure, and is simple in structure, and inner compact, cost is low, has application value.
Description of drawings
Fig. 1 is the electric functional-block diagram of the embodiment of the invention.
Fig. 2 is the electrical schematic diagram of baseband processing unit 4 embodiment of the present invention.
Fig. 3 is the electrical schematic diagram of Interference Cancellation of the present invention unit 6 embodiment.
Embodiment
Referring to figs. 1 through Fig. 3, the present invention includes VU voice unit 1, RS232 interface unit 2, service selection unit 3, baseband processing unit 4, intermediate frequency unit 5, Interference Cancellation unit 6, monitoring unit 7, Fig. 1 is the electric functional-block diagram of the embodiment of the invention, and embodiment presses Fig. 1 connection line.Wherein VU voice unit 1 is made of two wires interface circuit, PCM coding-decoding circuit, encoding and decoding speech circuit etc., and its effect is to finish low speed speech data behind 2/4 line conversion, PCM encoding and decoding, encoding and decoding speech, dislodging machine input and the compressed encoding of simulated voice and multiple/minute connection function of dislodging machine signal.By the setting of monitoring unit 7, can make terminal works in FXS or FXO mode, can connect analog station or stored-program control exchange by outside phone interface C.Two wires interface circuit in the embodiment VU voice unit 1 adopts MY2199 type application-specific integrated circuit (ASIC) to make, and the encoding and decoding speech circuit adopts commercially available AMBE-2000 type application-specific integrated circuit (ASIC) to make, and the PCM coding-decoding circuit adopts commercially available TP3057N type application-specific integrated circuit (ASIC) to make.RS232 interface unit 2 its effects of the present invention are to carry out together/the asynchronous data conversion, and to realize the asynchronous data communication between terminal and the computer, embodiment RS232 interface unit 2 adopts the special-purpose 232 interface circuits making of MAX3232EEAE types.3 its effects of service selection of the present invention unit are under the control of monitoring unit 7, select one tunnel business datum to insert satellite communication system from one road simulated voice of input and one tunnel asynchronous serial data, embodiment service selection unit 3 adopts EP2C70F672I8 type FBGA chip manufacturings.Monitoring unit 7 of the present invention is made of liquid crystal display, button, indicator light, monitoring microprocessor and peripheral chip etc., it mainly acts on and comprises terminal is carried out parameter setting and status poll, man-machine interface is provided, receives extraneous control etc., and embodiment monitoring unit 7 adopts homemade monitoring unit circuit production.
Intermediate frequency unit 5 of the present invention is gone into end 2 pin and is gone out to hold 4 pin to be connected with baseband processing unit 4, its effect is that the baseband signal of baseband processing unit output is carried out intermediate frequency Modulation, intermediate frequency unit 5 goes out end 4 pin and is connected with L frequency range medium frequency output end mouth A, and its effect is that the intermediate-freuqncy signal after the intermediate frequency Modulation is exported.Intermediate frequency unit 5 is gone into end 3 pin and is connected with outside L frequency range intermediate frequency input port B, and its effect is the intermediate-freuqncy signal that receives outside input, and the intermediate-freuqncy signal of input is carried out quadrature demodulation.Intermediate frequency unit 5 goes out end 1 pin and goes into to hold 2 pin to be connected with Interference Cancellation unit 6, and its effect is to send Interference Cancellation unit 6 to carry out the counteracting of interference signal the complex baseband signal behind intermediate frequency demodulation.Intermediate frequency unit 5 its effects are exactly that the baseband signal of baseband processing unit 4 outputs is carried out intermediate frequency Modulation, and the output of the intermediate-freuqncy signal after the modulation, intermediate frequency unit 5 also receives the intermediate-freuqncy signal of outside input simultaneously, and to the input intermediate-freuqncy signal carry out quadrature demodulation, send Interference Cancellation unit 6 to carry out the interference signal counteracting complex baseband signal behind intermediate frequency demodulation then, send the signal behind the Interference Cancellation baseband processing unit 4 to carry out despread-and-demodulation again.Embodiment intermediate frequency unit 5 adopts active modulation chip of AD8345 type and the active demodulation chip of AD8348 type to make.
The main effect of baseband processing unit 4 of the present invention comprises to be carried out exporting analog baseband signal after band spectrum modulation and the spectrum shaping to the business datum of input, and remaining complex baseband signal behind the Interference Cancellation carried out despread-and-demodulation and channel decoding, finally recover original data bit flow.It comprises encoder 8, spread spectrum modulator 9, spectrum-spreading code generator 10,19, forming filter 11, D/A converter 12, low pass filter 13, A/D converter 14, digital down converter 15, sign indicating number capture circuit 16, digital correlator 17, code tracking circuit 18, carrier recovery circuit 20, signal-to-noise ratio (SNR) estimation circuit 21, channel decoder 22, Fig. 2 is the electrical schematic diagram of baseband processing unit 4 embodiment of the present invention, and embodiment presses Fig. 2 connection line.Wherein encoder 8 its effects are differential coding and convolutional encodings of finishing the input data.Spread spectrum modulator 9 its effects are band spectrum modulation of finishing signal.Spectrum-spreading code generator 10,19 its effects are to generate local spreading code.Forming filter 11 its effects are that the baseband frequency spectrum of finishing coding back data is shaped.12 its effects of D/A converter are that the signal after being shaped is carried out the D/A conversion, are analog signal with digital signal transition.Low pass filter 13 is used for the harmonic component of the signal spectrum that filtering digital processing process produces.14 its effects of A/D converter are to carry out the A/D conversion to received signal, are digital signal with analog-signal transitions.Digital down converter 15 its effects are to carry out the orthogonal digital down-conversion to received signal.16 its effects of sign indicating number capture circuit are to finish catching of local spreading code, obtain the synchronously thick of transmitting-receiving pseudo-code.Digital correlator 17 its effects are relevant despreadings of finishing spread-spectrum signal.18 its effects of code tracking circuit are the adjustment by the code tracking loop, and it is more accurate synchronously to obtain to receive and dispatch pseudo-code.Carrier recovery circuit 20 its effects are by special algorithm the transmitting-receiving carrier beat to be estimated, and constantly adjust the frequency of local carrier according to estimated result, make the deviation of transmitting-receiving carrier frequency reduce as much as possible, thereby make system obtain maximum processing gain.21 its effects of signal-to-noise ratio (SNR) estimation circuit are signal-to-noise ratio (SNR) estimation of finishing input signal.Channel decoder 22 its effects are the data of baseband demodulation output to be carried out error-correcting decoding handle.Embodiment D/A converter 12 adopts the commercially available special-purpose D/A chip manufacturing of AD9709 type, and A/D converter 14 adopts commercially available special-purpose A/D chip AD9288 to make, and low pass filter 13 adopts the LC filter to make.Embodiment encoder 8 of the present invention, spread spectrum modulator 9, spectrum-spreading code generator 10,19, forming filter 11, digital down converter 15, sign indicating number capture circuit 16, digital correlator 17, code tracking circuit 18, carrier recovery circuit 20, signal-to-noise ratio (SNR) estimation circuit 21 and channel decoder 22 each functional modules adopt a slice EP2C70F672I8 type FBGA chip manufacturing.
The main effect of Interference Cancellation of the present invention unit 6 is that the wideband interferer signal in the complex baseband signal behind intermediate frequency demodulation is balanced out.It comprises A/D converter 23, digital down converter 24, matched filter 25, carrier recovery circuit 26, timing estimation circuit 27, delay memory 28, Canceller 29, decoding and re-encoder 30, power adjusting circuit 31, D/A converter 32, Fig. 3 is the electrical schematic diagram of Interference Cancellation of the present invention unit 6 embodiment, and embodiment presses Fig. 3 connection line.Wherein 23 its effects of A/D converter are to carry out the A/D conversion to the received signal, are digital signal with analog-signal transitions.Digital down converter 24 its effects are that input signal is carried out the orthogonal digital down-conversion.Matched filter 25 its effects are Waveform Matching of finishing received signal, with the restricting signal bandwidth with reduce intersymbol interference.Carrier recovery circuit 26 its effects are by special algorithm the transmitting-receiving carrier beat to be estimated, and constantly adjust the frequency of local carrier according to estimated result, make the deviation of transmitting-receiving carrier frequency reduce as much as possible, thereby make system obtain maximum processing gain.27 its effects of timing estimation circuit are the adjustment by the bit timing track loop, obtain the optimum sampling point of signal at receiving terminal.Delay memory 28 its effects are the data after the stored waveform coupling, and give Canceller 29 data of storage.Canceller 29 its effects are counteractings of finishing interference signal.Decoding and re-encoder 30 its effects are that the signal after regularly recovering is carried out channel decoding earlier, and the initial data after will deciphering is again carried out secondary coding, to obtain the symbol of interference signal.Power adjusting circuit 31 its effects are to adjust to certain amplitude automatically with offsetting the remaining spread-spectrum signal in back, to satisfy the interface requirement of back level Despread and demodulator.32 its effects of D/A converter are to carrying out the D/A conversion through the adjusted signal of overpower, digital signal being converted to analog signal.Embodiment A/D converter 23 adopts two AD9432BST-80 type A/D chip manufacturings, and D/A converter 32 adopts two AD9762ARU type D/A chip manufacturings.Embodiment digital down converter 24 of the present invention, matched filter 25, carrier recovery circuit 26, timing estimation circuit 27, delay memory 28, Canceller 29, decoding and re-encoder 30, power adjusting circuit 31 each functional modules adopt a slice EP2C35F484I8 type FBGA chip manufacturing.
Each circuit block among Fig. 1 of the present invention, Fig. 2, Fig. 3 all adopts the external direct current power supply power supply, so does not mark the power supply unit label among the figure.
The concise and to the point operation principle of the present invention is as follows: concealed satellite communication terminal can be under the situation that communication satellite lost efficacy or former transponder is disturbed, with multi-user's spread-spectrum signal of carrying low speed information and a certain band signal frequency band transmission altogether of having a lot of social connections on other satellite repeater.Because the spread-spectrum signal bandwidth is less than the broadband signal bandwidth, spread-spectrum signal power is much smaller than broadband signal power, therefore spread-spectrum signal is difficult for being found, but system's long period safety, work reliably, to realize emergency communication or covert communications, the design of the present invention simultaneously has the interference offset device interface, receiving terminal can seal in interference offset device before carrying out Base-Band Processing, the broadband signal that will receive on star is partly or entirely offset, further improve the signal to noise ratio of spread-spectrum signal, strengthen communication stability and disguise.Its inside mainly is made up of VU voice unit 1, RS232 interface unit 2, service selection unit 3, baseband processing unit 4, intermediate frequency unit 5, Interference Cancellation unit 6 and monitoring unit 7.Each several part has all adopted modularity design technology, constitutes to have the corresponding units of standalone feature.
In the process of concealed satellite communication terminal work, from the analogue voice signal of outside phone with enter the VU voice unit 1 and the RS232 interface unit 2 of concealed satellite communication terminal respectively from the asynchronous data of outer computer, the analogue voice signal of 1 pair of input of VU voice unit carries out 2/4 line conversion, pcm encoder, speech coding and data multiplexing, and the data after the multiple connection are input to service selection unit 3, RS232 interface unit 2 is converted to synchrodata to the asynchronous data of input simultaneously, and synchrodata is input to service selection unit 3, service selection unit 3 is under the control of monitoring unit 7, from the simulated voice of input and asynchronous serial data, select one tunnel business datum to be linked in the baseband processing unit 4,4 pairs of input signals of baseband processing unit carry out chnnel coding, band spectrum modulation and base band shaping, and send intermediate frequency unit 5 to carry out intermediate frequency Modulation the data behind the base band shaping, the intermediate-freuqncy signal output after intermediate frequency Modulation unit 5 will be modulated.In addition, intermediate frequency unit 5 receives the intermediate-freuqncy signal of outside input, and to the input intermediate-freuqncy signal carry out quadrature demodulation, send Interference Cancellation unit 6 zero intermediate frequency signals after the demodulation then, the signal of the 6 pairs of inputs in Interference Cancellation unit carries out the counteracting of interference signal, and a remaining spread-spectrum signal in counteracting back send baseband processing unit 4, the complex baseband signal of 4 pairs of inputs of baseband processing unit carries out despread-and-demodulation and decoding, and the data after the decoding output to service selection unit 3, service selection unit 3 is sent into VU voice unit 1 or RS232 interface unit 2 to the demodulating data of input under the control of monitoring unit 7.If service selection unit 3 is sent into VU voice unit 1 to demodulating data, VU voice unit 1 is just carried out data tapping, tone decoding, PCM decoding and 4/2 line conversion to the digital signal of input, and the analogue voice signal that recovers after the 4/2 line conversion is exported to external phone; If service selection unit 3 is sent into RS232 interface unit 2 to demodulating data, RS232 interface unit 2 just carries out together/the asynchronous data conversion the demodulating data of input, and the asynchronous data after will changing is exported to outside computer.In the communication process, monitoring unit 7 finishes that the frequency of medium-frequency receiving and sending local vibration source is selected, the power level setting of intermediate frequency output signal, spreading code address choice, the setting of Interference Cancellation parameter, the functions such as detection of this machine work signal to noise ratio.
Mounting structure of the present invention is as follows: complete machine adopts standard 1U cabinet, and cabinet inside adopts modular construction, and each module all adopts independently circuit to realize; Machine shape is of a size of 482.6 millimeters * 44 millimeters * 420 millimeters, in the cabinet both sides rail plate can be installed, the cabinet front portion is equipped with LCD, keypad and indicator light, the cabinet rear portion is equipped with supply socket, intermediate frequency input port B socket, medium frequency output end mouth A socket, outside phone interface C socket and computer RS232 asynchronous data interface D socket, the assembly cost invention.

Claims (3)

1. concealed satellite communication terminal, it comprises VU voice unit (1), RS232 interface unit (2), service selection unit (3), intermediate frequency unit (5), monitoring unit (7), it is characterized in that: also comprise baseband processing unit (4), Interference Cancellation unit (6), described intermediate frequency unit (5) is gone into end 3 pin and is connected with outside L frequency range intermediate frequency input port B, intermediate frequency unit (5) goes out end 4 pin and is connected with L frequency range medium frequency output end mouth A, intermediate frequency unit (5) is gone into end 2 pin and is gone out to hold 4 pin to be connected with baseband processing unit (4), intermediate frequency unit (5) is gone into end 5 pin and is gone out to hold 4 pin to be connected by data/address bus and monitoring unit (7), intermediate frequency unit (5) is under the frequency control signal control of monitoring unit (7) input, analog baseband signal from baseband processing unit (4) input is modulated into L frequency range intermediate-freuqncy signal, by the intermediate-freuqncy signal after the intermediate frequency outbound port A output modulation of output 4 pin connection; Intermediate frequency unit (5) goes out end 1 pin and goes into to hold 2 pin to be connected with Interference Cancellation unit (6), and intermediate frequency unit (5) is exported complex baseband signal to Interference Cancellation unit (6) to carrying out from the L frequency range intermediate-freuqncy signal of outside L frequency range intermediate frequency input port B input after the quadrature demodulation; Interference Cancellation unit (6) is gone into end 3 pin and is gone out to hold 3 pin to be connected with monitoring unit (7), Interference Cancellation unit (6) goes out end 1 pin and goes into end 3 pin with baseband processing unit (4) and is connected, and Interference Cancellation unit (6) complex baseband signal after making intermediate frequency unit (5) demodulation under the Interference Cancellation parameter control that monitoring unit (7) is imported is exported remaining spread-spectrum signal to baseband processing unit (4) after finishing the Interference Cancellation of input signal; Baseband processing unit (4) is gone into end 1 pin and is gone out to hold 5 pin to be connected with service selection unit (3), the discrepancy of baseband processing unit (4) holds 5 pin to hold 2 pin to be connected by data/address bus with the discrepancy of monitoring unit (7), baseband processing unit (4) goes out end 2 pin and goes into to hold 6 pin to be connected with service selection unit (3), baseband processing unit (4) is under the control of the spreading code address parameter of monitoring unit (7) input, the original data bits that recovers after the spread-spectrum signal behind the Interference Cancellation carries out despread-and-demodulation and channel decoding of coming self-interference cancellation unit (6) input is flowed, to carrying out band spectrum modulation from the business datum of service selection unit (3) input, export analog baseband signal behind base band shaping and the D/A switch, baseband processing unit (4) is sent to monitoring unit (7) with the internal work status signal, and monitoring unit (7) will show from the internal work status signal of baseband processing unit (4) input; Service selection unit (3) is gone into end 1 pin and is gone out to hold 2 pin to be connected with VU voice unit (1), service selection unit (3) is gone into end 3 pin and is gone out to hold 2 pin to be connected with RS232 interface unit (2), service selection unit (3) is gone into end 7 pin and is gone out to hold 1 pin to be connected with monitoring unit (7), service selection unit (3) is under the control of the service selection signal of monitoring unit (7) input, the original data bits stream input VU voice unit (1) or the RS232 interface unit (2) that recover after the decoding from baseband processing unit (4) input, service selection unit (3) is under the control of the service selection signal of monitoring unit (7) input, from going into end 1 pin from the voice data of VU voice unit (1) input with from selecting one tunnel business datum to output to baseband processing unit (4) the asynchronous data of RS232 interface unit (2) input; Service selection unit (3) goes out end 2 pin and goes into to hold 3 pin to be connected with VU voice unit (1), the discrepancy of VU voice unit (1) holds 1 pin to be connected with outside phone interface C, VU voice unit (1) is exported analogue voice signal after flowing to line data tap, tone decoding, PCM decoding and 4/2 conversion from the original data bits recovered after the decoding of service selection unit (3) input, VU voice unit (1) carries out exporting digital bit stream data behind 2/4 conversion, pcm encoder, speech coding and the data multiplexing to the analogue voice signal from outside phone interface C input; Service selection unit (3) goes out end 4 pin and goes into to hold 3 pin to be connected with RS232 interface unit (2), the discrepancy of RS232 interface unit (2) holds 1 pin to be connected with computer RS232 asynchronous data interface D, RS232 interface unit (2) is to carrying out from the original data bits stream that recovers after the decoding of service selection unit (3) input with/asynchronous data conversion back output asynchronous data, and RS232 interface unit (2) is different to carrying out from the asynchronous data of computer RS232 asynchronous data interface D input/synchrodata conversion back output synchrodata.
2. concealed satellite communication terminal according to claim 1, it is characterized in that: baseband processing unit (4) comprises encoder (8), spread spectrum modulator (9), spectrum-spreading code generator (10,19), forming filter (11), D/A converter (12), low pass filter (13), A/D converter (14), digital down converter (15), sign indicating number capture circuit (16), digital correlator (17), code tracking circuit (18), carrier recovery circuit (20), signal-to-noise ratio (SNR) estimation circuit (21), channel decoder (22), described encoder (8) carries out chnnel coding and differential coding to the business datum signal that service selection unit (3) go out the need modulation of end 5 pin input, data behind coding input spread spectrum modulator (9) are gone into end 1 pin, spectrum-spreading code generator (10) goes out the control local spreading code of generation down of the spreading code address parameter of end 2 pin input at monitoring unit (7), and spreading code is imported spread spectrum modulator (9) go into end 3 pin, spread spectrum modulator (9) the coding of encoder (8) input after the spreading code XOR formation modulated spread spectrum signal mutually of data and spectrum-spreading code generator (10) output, modulated spread spectrum signal input forming filter (11) is gone into end 1 pin, forming filter (11) carries out the baseband frequency spectrum shaping with the modulated spread spectrum signal of input, the signal input D/A converter (12) of base band shaping is gone into end 1 pin, D/A converter (12) carries out steering D/A conversion with the input signal of base band shaping, data behind the steering D/A conversion are inputed to low pass filter (13) go into end 1 pin, low pass filter (13) carries out analogue low pass filtering with the input signal behind the steering D/A conversion, the signal after the low-pass filtering is inputed to intermediate frequency unit (5) go into end 2 pin; A/D converter (14) carries out mould/transformation of variables to the complex baseband signal behind Interference Cancellation that Interference Cancellation unit (6) go out the input of end 1 pin, data input digit low-converter (15) after mould/transformation of variables is gone into end 1 pin, digital down converter (15) produces the local digital carrier wave according to the carrier frequency control word that carrier recovery circuit (20) goes out the input of end 2 pin, the signal that goes out the input of end 2 pin with A/D converter (14) carries out complex multiplication operation, carries out Digital Down Convert; Digital down converter (15) goes out to hold 3 pin respectively the Digital Down Convert signal to be inputed to a yard capture circuit (16) and goes into end 1 pin, digital correlator (17) is gone into end 1 pin, sign indicating number capture circuit (16) goes out to hold the local spreading code of 1 pin input to make related operation the Digital Down Convert signal and the spectrum-spreading code generator (19) of input, the correlation and the predefined thresholding of computing are compared, the sign indicating number synchronizing signal that thresholding is relatively drawn exports code tracking circuit (18) to and goes into end 1 pin, the correlation value signal that code tracking circuit (18) goes out to hold 3 pin to import to digital correlator (17) under the sign indicating number synchronizing signal control of sign indicating number capture circuit (16) input is carried out data processing and the phase difference value of transmitting-receiving pseudo-code is estimated, according to estimated value the phase place of local spreading code is adjusted, it is synchronously accurate that the transmitting-receiving pseudo-code is obtained, and exports adjusted receipts pseudo-code clock to spectrum-spreading code generator (19) and go into end 2 pin; Monitoring unit (7) goes out to hold 2 pin that the spreading code address parameter is outputed to spectrum-spreading code generator (19) and goes into end 3 pin, spectrum-spreading code generator (19) is under the driving of the adjusted receipts pseudo-code clock signal of code tracking circuit (18) input, spreading code address parameter according to monitoring unit (7) input generates local spreading code, export the local spreading code that generates to a yard capture circuit (16) respectively and go into end 2 pin, digital correlator (17) is gone into end 2 pin, digital correlator (17) goes out to hold the local spreading code of 1 pin input to carry out related operation digital signal and the spectrum-spreading code generator (19) that digital down converter (15) goes out the input of end 3 pin, the related operation value is sent into code tracking circuit (18) respectively go into end 3 pin, carrier recovery circuit (20) is gone into end 1 pin, signal-to-noise ratio (SNR) estimation circuit (21) is gone into end 1 pin, channel decoder (22) is gone into end 1 pin; Carrier recovery circuit (20) carries out after the data processing transmitting-receiving carrier beat being estimated to the related operation value of digital correlator (17) input, constantly local carrier frequency is adjusted according to the carrier beat estimated value, export adjusted carrier frequency control word to digital down converter (15) and go into end 2 pin, signal-to-noise ratio (SNR) estimation circuit (21) carries out the estimation of signal power and noise power to the related operation value of digital correlator (17) input, obtain the estimated value of input signal signal to noise ratio, go into end 2 pin with what the estimated value of signal to noise ratio exported monitoring unit (7) to, channel decoder (22) carries out the error-correcting decoding of input signal, exports the original data bits stream after the decoding to service selection unit (3) and goes into end 6 pin.
3. concealed satellite communication terminal according to claim 1, it is characterized in that: Interference Cancellation unit (6) comprise A/D converter (23), digital down converter (24), matched filter (25), carrier recovery circuit (26), timing estimation circuit (27), delay memory (28), Canceller (29), decoding and re-encoder (30), power adjusting circuit (31), D/A converter (32), described A/D converter (23) carries out mould/transformation of variables to the complex baseband signal behind intermediate frequency demodulation that intermediate frequency unit (5) goes out the input of end 1 pin, data input digit low-converter (24) after mould/transformation of variables is gone into end 1 pin, digital down converter (24) produces the local digital carrier wave according to the carrier frequency control word that carrier recovery circuit (26) goes out the input of end 2 pin, the digital signal that goes out the input of end 2 pin with A/D converter (23) is carried out complex multiplication operation, carries out Digital Down Convert; Digital down converter (24) goes out end 3 pin and exports the signal of Digital Down Convert to matched filter (25) and go into end 1 pin, matched filter (25) carries out Waveform Matching with the Digital Down Convert signal of input, signal after the Waveform Matching is inputed to timing estimation circuit (27) respectively go into end 1 pin, delay memory (28) is gone into end 1 pin, the signal of timing estimation circuit (27) after to the Waveform Matching of input carries out data processing and extracts signal of timing error, carry out the timing adjustment of loop according to signal of timing error, the optimum sampling point of restoring signal, timing estimation circuit (27) goes out to hold 2 pin to export the adjusted data of timing to carrier recovery circuit (26) respectively and goes into end 1 pin, decoding and re-encoder (30) are gone into end 1 pin, carrier recovery circuit (26) carries out after the data processing transmitting-receiving carrier beat being estimated to the adjusted signal of timing of input, constantly the frequency of local carrier is adjusted according to estimated value, exported adjusted carrier frequency control word to digital down converter (24) and go into end 2 pin; Decoding and re-encoder (30) are carried out channel decoding earlier to the adjusted signal of timing of timing estimation circuit (27) input, initial data after the channel decoding is carried out secondary coding, go out to hold 2 pin to export Canceller (29) to by decoding and re-encoder (30) signal behind the secondary coding and go into end 2 pin, delay memory (28) is gone into the signal that end 1 pin goes out matched filter (25) after the Waveform Matching of end 2 pin input and is stored, export the signal after the storage to Canceller (29) and go into end 1 pin, monitoring unit (7) goes out to hold 3 pin that the Interference Cancellation parameter is exported to Canceller (29) and goes into end 4 pin, Canceller (29) goes out delay memory (28) wideband interferer signal that obtains through coding again that the mixed signal of delayed storage of end 2 pin input and decoding and re-encoder (30) go out the input of end 2 pin and carries out the counteracting of wideband interferer signal, export the spread-spectrum signal that obtains after offsetting to power adjusting circuit (31) and go into end 1 pin, power adjusting circuit (31) will be offset the automatic adjusting range of the remaining spread-spectrum signal in back, export the adjusted spread-spectrum signal of amplitude to D/A converter (32) and go into end 1 pin, D/A converter (32) carries out steering D/A conversion to input through the adjusted signal of power, exports the data behind the steering D/A conversion to baseband processing unit (4) and goes into end 3 pin.
CN2009100738397A 2009-02-27 2009-02-27 Concealed satellite communication terminal Withdrawn - After Issue CN101505184B (en)

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CN101764664B (en) * 2010-01-29 2013-01-16 哈尔滨工业大学 PCM signal monitoring device with error detection alarming function and error detection alarming method thereof
CN107087282A (en) * 2017-05-23 2017-08-22 广东欧珀移动通信有限公司 Interference elimination method, device, storage medium and terminal
CN107359901A (en) * 2017-08-03 2017-11-17 中国电子科技集团公司第五十四研究所 A kind of synchronization timing device and method for the incoherent band spectrum modulation of satellite channel
CN110995301A (en) * 2019-12-25 2020-04-10 南京天际易达通信技术有限公司 Parasitic communication method based on signal cancellation
CN113131967A (en) * 2021-06-17 2021-07-16 北京全路通信信号研究设计院集团有限公司 CDMA security coding and decoding method and system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101764664B (en) * 2010-01-29 2013-01-16 哈尔滨工业大学 PCM signal monitoring device with error detection alarming function and error detection alarming method thereof
CN107087282A (en) * 2017-05-23 2017-08-22 广东欧珀移动通信有限公司 Interference elimination method, device, storage medium and terminal
CN107087282B (en) * 2017-05-23 2019-09-24 Oppo广东移动通信有限公司 Interference elimination method, device, storage medium and terminal
CN107359901A (en) * 2017-08-03 2017-11-17 中国电子科技集团公司第五十四研究所 A kind of synchronization timing device and method for the incoherent band spectrum modulation of satellite channel
CN110995301A (en) * 2019-12-25 2020-04-10 南京天际易达通信技术有限公司 Parasitic communication method based on signal cancellation
CN113131967A (en) * 2021-06-17 2021-07-16 北京全路通信信号研究设计院集团有限公司 CDMA security coding and decoding method and system
CN113131967B (en) * 2021-06-17 2021-08-31 北京全路通信信号研究设计院集团有限公司 CDMA security coding and decoding method and system

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