CN105659864B - Multistage output BD2/GPS/Galileo navigation signal simulator - Google Patents

Abstract

The invention provides a multi-stage output BD2/GPS/Galileo navigation signal simulator. The simulator is composed of host computer subsystem, intermediate frequency modulation subsystem, and radio frequency subsystem; the host computer subsystem simulates and calculates various signal state parameters and navigation messages according to the set satellite constellation, carrier motion state, propagation error and environmental interference, and generates Baseband level data output; IF modulation subsystem completes signal spread spectrum and carrier modulation, realizes precise control of Doppler, code phase, carrier phase and relative level, completes modulation and control of interference signals, and combines to generate analog IF level Signal output; the radio frequency subsystem up-converts the signal and interference to a specified frequency point, performs power control, and outputs it through the coaxial cable or antenna after being combined by the radio frequency switch matrix. The simulator provided by the invention can be compatible with multiple frequency points of BD2/GPS/Galileo, multiple signal forms, has multi-channel multi-level output test capability and multiple high dynamic and interference signal representation capabilities. <pb pnum="1"/>

Description

Multistage output BD2/GPS/Galileo navigation signal simulator

Technical field

The present invention relates to field of satellite navigation, relate in particular to a kind of multistage output BD2/GPS/Galileo satellite and leadBoat signal simulator.

Background technology

Satellite navigation signal simulator is used for simulation and produces under various actual environments received by receiverThe satellite navigation signals that BD2/GPS/Galileo satellite navigation system is broadcast is satellite navigation system signals systemThe critical equipment of demonstration, system integration project test, various receiving equipment research and development test, be subject to always military andThe concern of industrial department. The external GPS/Galileo satellite navigation radio-frequency signal of having developed Multiple Type is simulatedDevice, but mostly function fix, expensive, the system that can simulate, frequency, signal structure, carrier are dynamicState, interference type very critical.

Satellite navigation signal simulator have an advantage utilizing real satellite signal testing incomparable--a kind of can reproduce, flexible controlled test environment is provided. Along with the modern times of GPS and GLONASSChange and the construction of Galileo and China's new generation satellite navigation system, can compatibility many in the urgent need to oneSystem multi-carrier frequency multi signal system, possess multichannel and multistage and export power of test and multiple height dynamically and interferenceSignal represents the satellite navigation signal simulator of ability.

The development that meets the simulator of above-mentioned requirements relates to series of key techniques, comprises multistage output simulatorThe design of complete machine structure, the conclusion of multi-signal version, different system satellite ephemeris is calculated and navigation electricityThe generation of literary composition information, the emulation meter of the various delay time errors on signal power, Doppler frequency shift, code and carrier waveCalculate emulation and the Track Pick-up of target dynamic characteristic, the DBMS emulation of base band measurement field and output format, suitableAnswer that multifrequency point, multi-band are wide, analog intermediate frequency level and the radio-frequency stage signal hardware production method of Multiple modulation mode, heightThe control method of dynamic high precision sophisticated signal waveform, the synthetic and radio-frequency modulations scheme of multi channel signals, noGeneration and the state modulator of interfering signal of the same type, etc. From mathematics model analysis, software programming to radio frequencyThe design of circuit, has a lot of technological difficulties.

At present international and domestic also do not meet above-mentioned requirements navigation signal simulator.

Summary of the invention

The object of the embodiment of the present invention is to provide a kind of compatible BD2/GPS/Galileo many frequencies, multi-signalVersion, possess multichannel and multistage export power of test and multiple height dynamically and interfering signal represent abilityNavigation signal simulator, thus filled up the international and domestic blank that also there is no corresponding product.

The object of the invention is to be achieved through the following technical solutions:

A kind of multistage output BD2/GPS/Galileo satellite navigation signal simulator, is characterized in that: adopt softThe wireless design philosophy of part is carried out framework based on " host computer+PCI-E (PeripheralComponentInterconnectExpress, peripheral hardware is interconnected fast) interface+DSP (DigitalSignalProcessor,Digital signal processor)+FPGA (FieldProgrammableGateArray, field-programmable gate arrayRow)+DAC (DigitaltoAnalogConverter, digital to analog converter)+quadrature up-conversion passage+RF switch matrix " architecture, to B1I, B1Q, B2I, B2Q, B3I, B3Q of BD2 systemThe signal of signal and GPSL1C/A coded signal and GalileoE1B many kinds of systems carries out analog simulation, bagDraw together mathematical simulation and physical simulation, and new signal system can be adapted to.

Described navigation signal simulator at least comprises host computer subsystem, IF Modulation subsystem and radio frequencySystem three parts. Wherein host computer subsystem is used for the man-machine interaction graphical interfaces that provides good, and according toSignal structure, constellation orbital, carrier movement state, propagated error and environmental disturbances that user arranges, calculateVarious satellite navigation signals state parameters, navigation message, multipath signal state parameter that intended receivers receivesWith interference signal status parameter, produce base band level measurement field data and export; Real time conrtol hardware signal is sent out simultaneouslyRaw device produces corresponding intermediate frequency/radiofrequency signal and exports; IF Modulation subsystem is for adding up according to host computer subsystemThe telegraph text data and the signal condition parameter stream that calculate complete band spectrum modulation, sub-carrier modulation and the carrier wave of each passageModulation, realizes the accurate control of Doppler, code phase, carrier phase and the relative level of different channel signals;Complete modulation and the control of various multipaths and interfering signal; And close road, Digital Up Convert, digital-to-analogue through numeral and turnChange, amplify and filtering generates the analog intermediate frequency level signal of specifying and exports; Radio Frequency Subsystem, for receivingAnalog intermediate frequency/Low Medium Frequency/baseband signal and interference upconvert to the frequency of specifying, carry out Hierarchical clustering, and warpThe radiofrequency signal of multiple carrier frequency and signal structure and interfering signal are closed road and are exported by RF switch matrix.

Wherein, mark between described navigation signal simulator host computer subsystem and IF Modulation subsystem, is adoptedAccurate PCI-E EBI is realized high speed data transfer; Time base circuit by IF Modulation subsystem passes throughPCI-E interface produces interrupt to upper loom system, and host computer subsystem responses interrupts, by the signal calculatingState parameter, text bit stream and control command data communication message frame format is according to the rules connect by PCI-EOral instructions are passed to IF Modulation subsystem, and receive the status information that IF Modulation subsystem returns.

Orthogonal I, Q is adopted between described navigation signal simulator IF Modulation subsystem and Radio Frequency SubsystemAnalog if signal connection is also connected by I2C interface simultaneously, with control radio frequency output signal frequency andPower; There is provided special multi output clock driver circuit that can external frequency marking in addition for each IF Modulation boardUse with the RF up-converter circuit of each frequency, to ensure the clock homology of all intermediate frequencies and radio circuit.

Described host computer subsystem at least comprises man-machine interaction graphical interfaces module, the conversion of time coordinate systemModule, carrier movement trajectory computation module, satellite position calculation and visible satellite timetable generation module, leadAvionics literary composition configuration and generation module, error and signal condition computing module, interference simulation module, data binding and layoutWith modulation card communication module, base band data generation module, measurement result record and analysis module ten software mouldsPiece. Wherein man-machine interaction graphical interfaces module is for receiving user's configuration and data input, with data and figureThe result of shape mode display translation daemon software module, and the communication control providing with hardware signal generatorFunction processed; The operation of time coordinate system modular converter for carrying out between civil time, changing between coordinate system,Conversion between when arriving UTC when comprising each navigation system, turning between geodetic coordinates and ECEF coordinate systemChange, assist between conversion between the earth's core body-fixed coordinate system and Horizon/geographic coordinate system, WGS84 and CGS2000The conversion of view coordinate system, the conversion of agreement coordinate system between Beijing 54 and CGS2000, wherein said navigation isDuring system, comprise: during BD2 system, during gps system, during Galileo system; Carrier movement trajectory computation moduleBe used for according to typical carrier movement model generation carrier movement track, and allow user to configure carrier fortune voluntarilyDynamic track; Satellite position calculation and visible satellite timetable generation module are used for according to normal in defined constellationThe aeronautical satellite situation of work is selected the satellite that will simulate, by ephemeris/almanac file (track being set by the userParameter or the ephemeris/almanac source file providing are derived, and are obtained the emulation valid data of epoch by interpolation or extrapolation)Or up injection information source files is calculated the satellite position in emulation moment; Choose the elevation angle according to carrier positions to be greater thanThe satellite of minimum shield angle, generates visible satellite timetable; The time of carrier movement data is corresponded in this tableTurnover rate (being also the traffic rate with hardware modulation card), provide each emulation receive moment epoch eachNo. PRN of visible satellite, and the position of the each visible star antenna phase center of corresponding x time; Navigation electricityLiterary composition configuration and generation module are for the space segment according to selected navigation system/user interface control documents and useFamily configuration information again to navigation message frame structure on graphical interfaces generates each visible satellite in institute's emulation periodNavigation message bit stream; This module is supported the simulation that user is switched the control of satellite data and almanac data,Allow user to revise the information in particular data territory, and complete the automatic Verification of text; Wherein satellite orbit ginsengThe amendment of number, ephemeris error, ionospheric correction parameters can be mapped with the calculating of satellite-signal state;Error and signal condition computing module are used for according to the customer location in each emulation moment epoch and comprise ephemeris mistakePropagation delay in poor satellite position calculation vacuum, simulation calculation comprises the star clock mistake of relativistic effect errorDifference and earth rotation error, in simulation calculation spatial, signal amplitude declines and comprises ionosphere delay, rightThe delay error of tropospheric delay, multipath error, and then the signal condition that obtains corresponding signal x time,Comprise signal power, pseudo-code phase, bit rate, carrier phase, carrier Doppler frequency and rate of change thereof;Interference simulation module, for according to interference type and the parameter of user's option and installment on interface, is calculated to generate and is doneDisturb signal condition controling parameters; Data binding and layout and modulation card communication module will for communication protocol according to the rulesThe navigation message, signal condition parameter and the various controling parameters packing framing that calculate, pass through PCI-E interfaceSend to modulation card, and receive the status information that modulation card returns; Base band data generation module will be for navigatingThe signal that the navigation message that text configuration and generation module produce and error and signal condition computing module produceState parameter, form writing in files according to the rules, forms base band data file; Measurement result record with pointAnalyse the data that module produces for recording upper computer software emulation, comprise the carrier movement under certain renewal rateState, satellite motion state, satellite-signal state, each simulation model training verification data, these data supplyThe reproduction completely of test environment is supported in analyzing and processing and playback afterwards simultaneously; Receive tested receiver feedbackData, compare analysis with the corresponding data of record, thus provide commenting whole closed-loop measuring effectValency.

Described IF Modulation subsystem adopts the form of three (easily extensible) PCI-E boards, three boards26S Proteasome Structure and Function is identical, and every board at least can produce I, Q orthogonal simulation intermediate-freuqncy signal of two frequency bins, orI, Q orthogonal simulation intermediate-freuqncy signal of at least one frequency adds I, Q orthogonal simulation intermediate-freuqncy signal of a road interference,Circuit on every board comprises a PCI-E bridging chip, a DSP, a FPGA, a SRAM,A FLASH, two-digit upconverter DUV, two digital to analog converter DAC, two signal condition mouldsPiece, a PRM module; Described PCI-E board is by its work schedule of state machine control in FPGA; MakeThe bridge joint of PCI-E bus and local bus is realized with PCI-E bridging chip; The data that host computer subsystem sendsControl command, text and signal condition parameter are read and resolved to storage in sram, by DSP, calculates letterNumber mode control word storage are in sram; FPGA reads controling parameters and completes spread spectrum and adjusts from SRAMSub-carrier modulation, quadrature carrier modulation, the multi-channel digital of making, be applicable to GalileoE1B signal close road,Wherein the P code of the each frequency Q of BD2 branch road is produced by the special PRM module of correspondence; Digital up converter complete fromLow Medium Frequency is to the Digital Up Convert of intermediate frequency, and digital to analog converter completes digital-to-analogue conversion, and Signal-regulated kinase is by low passWave filter, amplifier and power splitter composition, complete the conditioning that exports analog if signal.

Described navigation signal simulator at least has three grades of live signal output interfaces, comprises radio-frequency stage signalOutput, the output of analog intermediate frequency level signal, base band level observed quantity and telegraph text data export. Wherein radio-frequency stage signalExport the multisystem multichannel satellite-signal that arrives receiver antenna for emulation, by the N-type of Radio Frequency SubsystemInterface and SMA interface export simultaneously; Wherein, N-type interface connects antenna, and SMA interface connects coaxial cable; MouldIntend intermediater-frequency stage signal and export the analog if signal for the each signal of the each system of emulation, as corresponding receiver mouldIntend emulation, the test and validation signal of IF input terminal, the SMA interface by IF Modulation subsystem exports;Base band level observed quantity and telegraph text data export for the text parameter of emulation input receiver information process unit andOriginal observed quantity, is exported with document form data by host computer subsystem; Described text parameter comprises:Satellite ephemeris, star clock, Ionospheric Parameters, almanac and difference and integrity information in text; DescribedOriginal observed quantity comprise: pseudorange, carrier doppler, carrier phase, Δ pseudorange.

Described navigation signal simulator can arrange different system and signal form on host computer graphical interfaces,The various errors that are superimposed upon on signal are set, carrier dynamic parameter and movement locus are set, each satellite is setThe power output of signal, arranges the frame structure of BD2D1 code and D2 code text; Output signal type is set; AndAccording to above-mentioned setting, output signal is accurately controlled.

Described IF Modulation subsystem adopts DDS technology to carry out digital wave compose; Employing Low Medium Frequency numeralQuadrature carrier modulation system is to ensure that unification realizes each letter under limited DDS clock rate and many bandwidth requirementsNumber form and avoid spectral aliasing is avoided larger spurious components simultaneously; With I, Q two-way analog if signalOutput to Radio Frequency Subsystem and carry out the generation that quadrature up-conversion can suppress image component, reduce radio frequency filteringThe requirement of device.

Described Radio Frequency Subsystem adopts orthogonal modulation mode that analog if signal is upconverted to appointment frequency;Each up-conversion passage is communicated with host computer by main control singlechip, obtains user configuration information, to controlOutput signal frequency processed and power; RF switch matrix is adopted to realize for simulatedB1/B2/B3/L1/E1 radiofrequency signal and the interfering signal of simulating or external interfering signal are combinedHe He road exports; Signal after closing road is divided into two-way by power splitter again, a road directly output to N-type interface byThe antenna transmission of corresponding band exports, and another road outputs to SMA interface and exports for coaxial cable after amplifier,So that being provided, wired and wireless two kinds of RF test signal export.

As seen from the above technical solution provided by the invention, with domestic and international existing navigation signal simulatorCompare, the navigation signal simulator that the embodiment of the present invention provides has following technological merit:

(1) can realize to BD2B1I, B1Q, B2I, B2Q, B3I, B3Q, GPSL1/A,The analog simulation of GalileoE1B many kinds of system navigation signals, comprises mathematical simulation and physical simulation; Support is manyThe test of constellation combination airmanship;

(2) possess base band data, analog if signal, the multistage loop design checking of radiofrequency signal and surveyExamination evaluation capacity;

(3) various interfering signals can be produced, as mono-tone interference, Sweeping nonlinearity, broadband interference, manyFootpath interference and Deceiving interference, also can merge external source of radio-frequency interference;

(4) good hardware reusability, software Reconfigurability and system expandability is there is: energyEnough realize that multisystem, multiband, multi-band are wide, the flexible combination of multichannel, multiple reference points;

(5) support Navigation Signal System, the research of navigation message format design and verify;

(6) generation of various exemplary dynamic and User Defined high dynamic signal is supported.

(7) good controllability and observability is there is, abundant intermediate object program fan-out capability. Not onlyCan be used for debugging and the test of receiver and critical component thereof, system integration project test can also be used for.

Accompanying drawing explanation

The multistage output BD2/GPS/Galileo satellite navigation signal simulator that Fig. 1 provides for the embodiment of the present inventionGeneral structure schematic diagram;

Fig. 2 is the structural representation of a kind of host computer subsystem that the embodiment of the present invention provides;

The main interface of a kind of host computer man-machine interaction schematic diagram that Fig. 3 provides for the embodiment of the present invention;

A kind of host computer subsystem master-plan flow chart that Fig. 4 provides for the embodiment of the present invention;

A kind of upper computer software that Fig. 5 provides for the embodiment of the present invention divides the monitoring of thread navigation message and time ginsengThe flow chart that number upgrades;

Fig. 6 is the structural representation of a kind of IF Modulation subsystem that the embodiment of the present invention provides;

Fig. 7 is the functional block diagram of a kind of IF Modulation card that the embodiment of the present invention provides;

A kind of IF Modulation card DSP program flow diagram that Fig. 8 provides for the embodiment of the present invention;

Each satellite-signal passage in a kind of IF Modulation card FPGA program that Fig. 9 provides for the embodiment of the present inventionOne of the structural representation of tributary signal passage;

Figure 10 is the structural representation of a kind of Radio Frequency Subsystem that the embodiment of the present invention provides.

Detailed description of the invention

The present invention is described in detail, the knot of navigation signal simulator described in the embodiment of the present invention below in conjunction with accompanying drawingStructure schematic diagram as shown in Figure 1, mainly comprises following three subsystems: host computer subsystem, IF Modulation subsystemSystem, Radio Frequency Subsystem.

1, host computer subsystem, for good man-machine interaction graphical interfaces is provided, and arrange according to userSignal structure, constellation orbital, carrier movement state, propagated error and environmental disturbances, calculate intended receiversThe various satellite navigation signals state parameters, navigation message, multipath signal state parameter and the interfering signal that receiveState parameter, produces base band level measurement field data and exports; Real time conrtol hardware signal generator produces phase simultaneouslyIntermediate frequency/the radiofrequency signal of answering exports.

The structure of a kind of host computer subsystem that the embodiment of the present invention provides as shown in Figure 2, comprises man-machine interaction figureShape interface module, time coordinate system modular converter, carrier movement trajectory computation module, satellite position calculationCalculate with visible satellite timetable generation module, navigation message configuration and generation module, error and signal conditionModule, interference simulation module, data binding and layout and modulation card communication module, base band data generation module, measurementOutcome record and analysis module ten software modules. Software support user is to mode of operation and each functional module phaseSetting and the replacement of related parameter, support the reproduction/playback completely of test environment.

Configuration and the data input of man-machine interaction graphical interfaces module receives user, aobvious with data and graphics modeShow the result that exports daemon software module, and communication control function is provided. For BD2 system, supportText configurable functionality. Current Set up-conservancy is text by user's wearable, so as when to need from fileIn directly obtain corresponding configuration as input. As shown in Figure 3, main interface supports that user simulates navigation signalThe basic setup of device mode of operation and user's initial position and dynamically arrange, navigation signal simulator is in operationVisible star signal condition parameter real time rendering can be provided under duty, various geometric dilution of precision numerical value is real-timeDemonstration, carrier movement status data real time rendering, carrier movement Track View, starry sky view, substar railMark figure.

Host computer subsystem master-plan flow process, as shown in Figure 4, in each emulation moment epoch, needs to generateThe navigation message corresponding with this moment, calculates a series of corresponding satellite-signal state parameters, supports and intermediate frequencyMod subsystem real-time data communication, generates base band data file, preserves various functional realiey with textIntermediate object program, and support user interface display translation.

Before starting emulation, by human-computer interaction interface, user selects navigation system and the frequency of required emulation,Emulation initial time and simulation time length are set, set ephemeris source file (optional), set satellite shieldingThe dynamic scenario of angle and receiver, and whether introduce the various error terms of conversion for range error.

Satellite-signal state parameter computational process is as follows. First user's (receiver) in current emulation moment is calculatedPosition, speed and acceleration, and utilize from ephemeris source file or for extracting the constellation orbital that defines or pushing awayThe ephemeris parameter calculating calculates position and the speed of satellite; Judge that each satellite is for user's current location thusWhether visible, for visible star, then calculate its spatial error and (comprise ionospheric transmission delay, convection currentLayer transmission delay, earth rotation error, relativistic effect error, multipath error), star clock error and ephemerisError; And then obtain the signal x time of this satellite, and calculate pseudorange, carrier phase and Duo PuStrangle the signal condition parameters such as frequency.

Be provided with 2 threads in software altogether, main thread has been used for navigation message generation, satellite-signal state ginsengThe data communication of the functions such as number calculating and host computer and IF Modulation card; Thread is divided to deposit navigation for monitoringThe data structure of text bit (corresponding every satellite stores a superframe) and update time parameter. Main threadBe system default, a point thread need to create in main thread.

For a point thread, if the operation pattern that user selects is to send data in real time to IF Modulation cardOr generate base band data file, then need the text bit of getting visible star to PCI-E interface or base band data literary compositionPart, the text bit of visible star will be fallen by " consumption ", in order to ensure the reality of visible star text bit transferTime property and correctness will be monitored the data structure of depositing navigation message bit in case " getting sky " in point thread,In addition the time parameter (Z counting) that needs to upgrade in time in text, ensures that telegraph text data is corresponding with the emulation momentThe correctness of relation. Divide the flow process that the monitoring of thread navigation message and time parameter upgrade, as shown in Figure 5.

2, intermediate-freuqncy signal mod subsystem, for the telegraph text data and the signal that calculate according to host computer subsystemState parameter stream completes band spectrum modulation, sub-carrier modulation and the carrier wave of the each visible satellite respective channel of each system and adjustsSystem, realizes the accurate control of Doppler, code phase, carrier phase and the relative level of different channel signals;Complete modulation and the control of various multipaths and interfering signal; And through numeral close road, Digital Up Convert, DAC,Amplification and filtering generate the analog intermediate frequency level signal of specifying and export.

The structure of a kind of intermediate-freuqncy signal mod subsystem that the embodiment of the present invention provides as shown in Figure 6, adopts three(easily extensible) PCI-E board synthesizes the signal of different frequent points respectively. Every board at least can produce twoI, Q orthogonal simulation intermediate-freuqncy signal of individual frequency, or the signal of a frequency adds a road interfering signal. Intermediate frequencyModulation card utilizes PCIE interface module to realize the needs that carry out real-time massive dataflow exchange with host computer; UtilizeHigh performance DSP, as central control unit, meets the demand of system high-speed computing and data transmission; ProfitComputational accuracy and the HDR of multi-channel digital Waveform composition in system is met with high-speed high capacity FPGARequirement. Other circuit on board comprises SRAM, FLASH, digital up converter, digital to analog converter,Signal conditioning circuit, PRM module, and power supply and reset circuit.

The exemplary functions block diagram of each piece IF Modulation card as shown in Figure 7. Whole by the state machine control in FPGAThe work schedule of individual IF Modulation board; Use PCI-E bridging chip is realized PCI-E bus and local busBridge joint; Control is read and resolved to the data storage that host computer subsystem sends in sram, by High Performance DSPOrder processed, text and signal condition parameter, calculate signal condition control word and store in sram; FPGAFrom SRAM, read controling parameters and be stored in inner mode control register the numeral of FPGA insideWaveform composition module is Loading Control word from status register again, complete each passage band spectrum modulation, be suitable forIn sub-carrier modulation, the quadrature carrier modulation of GalieoE1B signal, multi-channel digital closes road, produces numeralIntermediate-freuqncy signal; Digital up converter completes from Low Medium Frequency to the Digital Up Convert of higher intermediate frequency, digital to analog converterComplete digital-to-analogue conversion, then generate through signal conditioning circuit (comprising low pass filter, amplifier and power splitter)Orthogonal (I, Q) analog if signal of specifying exports. For the satellite-signal of different frequent points and branch road, itsGeneration channel design difference, and multipath signal generation passage is identical with corresponding satellite-signal generation channel design.

DSP on IF Modulation card is for calculating Waveform Control word and some systems of each signalling channelControl word, comprising: satellite ID control word; Carrier frequency control word; Code frequency control word; Navigation message controlWord processed; Carrier phase control word; Code phase control word; Amplitude control words. As shown in Figure 8, DSP is at PCI-EInterrupt from SRAM, reading in data when arriving, then by data type conversion and store in Another SRAM;When FPGA interrupts arriving, read the data in FIFO and be converted into corresponding control word, controlling FPGA'sWork. FPGA interrupts having high priority, and the mode of interrupt inquiry is adopted to the interruption of PCI-E. OutsideInterrupt producing once each second, the every 20 milliseconds of renewals of Satellite Observations are once, so DSP is in eachHave no progeny and calculate 50 sub-frame signals mode control words stored in SRAM.

In the FPGA of Fig. 7 one of each satellite-signal passage tributary signal passage structure as shown in Figure 9,Primarily of code NCO, PRN code generator, epoch counter, navigation message shift register, band spectrum modulationDevice, multiplier, carrier wave NCO, quadrature modulator and series of parameters register composition. Individual signals passageExport I, Q two-way digital medium-frequency signal. Low Medium Frequency digital quadrature carrier wave in digital wave compose process, is adopted to adjustSystem processed is to ensure that unification realizes each signal form and keeps away under limited DDS clock rate and many bandwidth requirementsExempt from spectral aliasing, it also avoid larger spurious components; Support with I, Q two-way analog if signal defeated simultaneouslyGo out, enable Radio Frequency Subsystem adopt quadrature up-conversion to suppress the generation of image component, if orthogonal signallingAmplitude and phase equalization meet the demands, radio-frequency filter then can be saved, simultaneously RF spot can be adapted toVariation.

For E1B-I branch road, passage forms with Fig. 9 similar, just has secondary carrying owing to also modulating in base bandRipple, need to add when band spectrum modulation subcarrier. The jump frequency of subcarrier S code is a times of PRN code, because ofThis can produce PRN code clock with S code NCO, when every two S code clocks can produce a PRN code simultaneouslyClock. The C code of GPSC/A code, BD2B1I/B2I/B3I is generated by linear shift register in addition, and BD2 frequentlyThe P code of point B1Q/B2Q/B3Q is produced by the special PRM module of correspondence, and the PRN code of E1-B is still at presentIn the situation of not announcing its generator polynomial, can according to the space segment of Galileo system/user segment ICD corresponding4092 chips of satellite store in FPGA, realize code generator with the forms of memory.

3, Radio Frequency Subsystem, for by the analog intermediate frequency/Low Medium Frequency/baseband signal receiving and interference up-conversionTo the frequency of specifying, carry out numerical control power attenuation, and through RF switch matrix by multiple carrier frequency and signal structureRadiofrequency signal and interfering signal close road export.

The structure of a kind of Radio Frequency Subsystem that the embodiment of the present invention provides as shown in Figure 10, this Radio Frequency Subsystem bagDraw together six up-conversions and Hierarchical clustering passage and a RF switch matrix. Five signal up-converter modules respectivelyBy the IQ analog intermediate frequency signal of the B1/B2/B3/L1/E1 frequency of about the 46MHz that IF Modulation subsystem exportsMode with orthogonal modulation upconverts to the radiofrequency signal of corresponding frequency separately, simultaneously accurate by attenuation networkControl its power output; Intermediate frequency interference upconverts to and specifies frequency and carry out jamming power control by another moduleSystem. Realized any combination of Zhe Wu road signal, a road interference and external interference source by RF switch matrix.After closing road, total antenna exports with cable and exports two kinds of way of outputs, and the power difference requiring separately, cable is defeatedGo out for-110dBm (20dB ~+40dB), antenna exports and requires effectively to receive in 10m.

The above, be only preferably detailed description of the invention of the present invention, but not office of protection scope of the present inventionBe limited to this, any be familiar with those skilled in the art the present invention disclose technical scope in, can be easilyVariation or the replacement expected, within all should being encompassed in protection scope of the present invention. Therefore, protection of the present inventionScope should be as the criterion with the protection domain of claim.

Claims (7)

1. A multistage output BD2/GPS/Galileo satellite navigation signal simulator is characterized in that, comprising: The upper computer subsystem is used to provide a good human-computer interaction graphical interface, and calculate various satellite navigation signal state parameters received by the target receiver according to the signal structure, constellation orbit, carrier motion state, propagation error and environmental interference set by the user, The navigation message, multipath signal state parameters and interference signal state parameters generate baseband-level measurement domain data output; at the same time, the hardware signal generator is controlled in real time to generate corresponding intermediate frequency/radio frequency signal output; The intermediate frequency modulation subsystem is used to complete the spread spectrum modulation, subcarrier modulation and carrier modulation of each channel according to the message data and signal state parameter stream calculated by the upper computer subsystem, and realize the Doppler, code phase and carrier phase of signals of different channels and relative level precise control; complete the modulation and control of various multipath and interference signals; and generate specified analog intermediate frequency level signal output through digital combination, digital up-conversion, digital-to-analog conversion, amplification and filtering; The radio frequency subsystem is used to up-convert the received analog intermediate frequency/low intermediate frequency/baseband signal and interference to a specified frequency point, perform power control, and convert various carrier frequency and signal structure RF signals and interference through the RF switch matrix Signal combination output; Wherein, a standard PCI-E bus interface is adopted between the host computer subsystem and the intermediate frequency modulation subsystem to realize high-speed data transmission; the time base circuit of the intermediate frequency modulation subsystem generates an interruption to the upper host computer subsystem through the PCI-E interface, and the upper host The machine subsystem responds to the interrupt, and transmits the calculated signal state parameters, message bit stream and control command data to the IF modulation subsystem through the PCI-E interface according to the specified communication message frame format, and receives the status information returned by the IF modulation subsystem ; The intermediate frequency modulation subsystem and the radio frequency subsystem are connected by orthogonal I and Q analog intermediate frequency signals, and are also connected through the I2C interface to control the frequency point and power of the radio frequency output signal; in addition, an external frequency standard is provided The dedicated multi-output clock drive circuit is used for each IF modulation board and RF up-conversion circuit of each frequency point to ensure the clock homology of all IF and RF circuits; The host computer subsystem includes: a human-computer interaction graphical interface module, which is used to receive user configuration and data input, display and output the processing results of the background software module in data and graphics, and provide communication control functions with the hardware signal generator ; Time coordinate system conversion module, used for the operation of conversion between commonly used time and coordinate systems, including conversion between navigation system time and UTC time, conversion between geodetic coordinates and earth-centered earth-fixed coordinate system, earth-centered earth-fixed Conversion between coordinates and horizon/geographical coordinate system, conversion between agreement coordinate system between WGS84 and CGS2000, conversion between agreement coordinate system between Beijing 54 and CGS2000, wherein the navigation system time includes: BD2 system time, GPS system time , Galileo system; the carrier trajectory calculation module is used to generate the carrier trajectory according to the typical carrier movement model, and allows the user to configure the carrier trajectory or provide trajectory files; the satellite position calculation and visible satellite timetable generation module is used for Select the satellite to be simulated according to the status of the navigation satellites working normally in the defined constellation, calculate the satellite position at the simulation time from the ephemeris/almanac file or the uplink injection information source file; select the satellite whose elevation angle is greater than the minimum shading angle according to the carrier position, and generate visible Satellite timetable; the table corresponds to the time update rate of the carrier motion data, and gives the PRN number of each visible satellite at each simulated receiving epoch, and the position of the phase center of each visible satellite antenna at the corresponding launch time; the navigation message The configuration and generation module is used to generate the navigation message bit stream of each visible satellite in the simulation period according to the space segment/user interface control file of the selected navigation system and the user's reconfiguration information on the navigation message frame structure on the graphical interface; error And the signal state calculation module, used to calculate the propagation delay in vacuum according to the user position at each simulation epoch and the satellite position including the ephemeris error, the simulation calculation includes the relativistic effect error of the satellite clock error and the earth rotation error, and the simulation calculation Signal amplitude fading in space propagation and delay errors including ionospheric delay, tropospheric delay, and multipath error, and then obtain the corresponding signal state at the time of signal transmission, including signal power, pseudo code phase, code rate, carrier phase, carrier Doppler Le frequency and its rate of change; the interference simulation module is used to calculate and generate the interference signal state control parameters according to the interference type and parameters selected and configured by the user on the interface; the data binding and modulation card communication module is used to transfer The calculated navigation message, signal state parameters and various control parameters are packaged into a frame, sent to the modulation card through the PCI-E interface, and receive the status information returned by the modulation card; the baseband data generation module is used to configure and generate the navigation message The navigation message generated by the module and the signal state parameters generated by the error and signal state calculation module are written into the file according to the specified format to form a baseband data file; the measurement result recording and analysis module is used to record the data generated by the upper computer software simulation, including Carrier motion state, satellite motion state, and satellite signal state at a certain update rate State, the data used for training and verification of each simulation model, the data is for analysis and playback after the event, and at the same time supports the complete reproduction of the test environment, receives the data fed back by the receiver under test, and compares and analyzes it with the corresponding recorded data, so as to give the Evaluation of the entire closed-loop measurement effect; The intermediate frequency modulation subsystem adopts the form of three PCI-E boards, and the structure and function of the three boards are the same, and each board can at least generate I and Q orthogonal analog intermediate frequency signals of two frequency points, or I, Q quadrature analog IF signal of at least one frequency point plus an interfering I, Q quadrature analog IF signal, the circuit on each board includes a PCI-E bridge chip, a DSP, an FPGA, and a SRAM , a FLASH, two digital upconverters DUC, two digital-to-analog converters DAC, two signal conditioning modules, and a PRM module; the PCI-E board is controlled by a state machine in the FPGA for its working timing; use The PCI-E bridge chip realizes the bridge between the PCI-E bus and the local bus; the data sent by the upper computer subsystem is stored in the SRAM, and the DSP reads and analyzes the control commands, messages and signal status parameters, and calculates the signal status control word and stores it in the In SRAM; FPGA reads control parameters from SRAM and completes spread spectrum modulation, subcarrier modulation suitable for GalileoE1B signal, quadrature carrier modulation, and multi-channel digital combination. The dedicated PRM module is generated; the digital up-converter completes the digital up-conversion from low intermediate frequency to intermediate frequency, the digital-to-analog converter completes the digital-to-analog conversion, and the signal conditioning module is composed of a low-pass filter, amplifier and power splitter to complete the output of the analog intermediate frequency Signal conditioning. 2. satellite navigation signal simulator according to claim 1, is characterized in that, described navigation signal simulator is based on the design concept of software radio, can be to B1I, B1Q, B2I, B2Q, B3I, B3Q signal of BD2 system And GPSL1C/A code signal and GalileoE1B signal of various systems are simulated, including mathematical simulation and physical simulation. 3. satellite navigation signal simulator according to claim 1, is characterized in that, described navigation signal simulator has three stages of real-time signal output interfaces, comprising: RF-level signal output: Simulate the multi-system and multi-channel satellite signal reaching the antenna of the receiver, and output it through the N-type interface and SMA interface of the RF subsystem at the same time; where the N-type interface is connected to the antenna, and the SMA interface is connected to the coaxial cable; Analog intermediate frequency level signal output: simulate the analog intermediate frequency signal of each signal of each system, which is used as the simulation, test and verification signal of the analog intermediate frequency input terminal of the corresponding receiver, and output through the SMA interface of the intermediate frequency modulation subsystem; Baseband-level observations and message data output: simulate the message parameters and original observations input to the receiver information processing unit, and output them in the form of data files through the host computer subsystem; the message parameters include: satellite ephemeris and star clock in the message , ionospheric parameters, almanac, and difference and integrity information; the original observations include: pseudorange, carrier Doppler, carrier phase, and Δpseudorange. 4. satellite navigation signal simulator according to claim 1, it is characterized in that, described navigation signal simulator can be provided with different systems and signal forms on the upper computer graphical interface, the various errors that are superimposed on the signal are set, Set the dynamic parameters and trajectory of the carrier, set the output power of each satellite signal, set the frame structure of the BD2D1 code and D2 code message; set the output signal form; and precisely control the output signal according to the above settings. 5. satellite navigation signal simulator according to claim 1, it is characterized in that, described intermediate frequency modulation subsystem adopts DDS technology to carry out digital waveform synthesis; Adopt low intermediate frequency digital quadrature carrier modulation system to guarantee in limited DDS Under the clock rate and multi-bandwidth requirements, all signal forms can be uniformly realized to avoid spectrum aliasing and large spurious components; outputting I and Q two-way analog IF signals to the RF subsystem for quadrature up-conversion can suppress image components The production reduces the requirement on the radio frequency filter. 6. satellite navigation signal simulator according to claim 1, is characterized in that, described radio frequency subsystem adopts quadrature modulation mode to up-convert analog intermediate frequency signal to specified frequency point; Communicate with the host computer to obtain user configuration information to control the output signal frequency and power. 7. satellite navigation signal simulator according to claim 1, is characterized in that, described radio frequency subsystem adopts radio frequency switch matrix to realize for simulated B1/B2/B3/L1/E1 radio frequency signal and simulated Interference signals or external interference signals can be combined and combined for output; the combined signal is then divided into two channels through a power divider, one is directly connected to the SMA interface for coaxial cable output, and the other is connected to the N-type interface after passing through the amplifier. The output is transmitted by the antenna of the corresponding frequency band to provide two kinds of RF test signal output, wired and wireless.