A GNSS multi-mode co-frequency and analog retransmission device

Abstract

The application relates to a GNSS multi-mode same-frequency and analog forwarding device, which comprises a remote / local control module for controlling switching between a same-frequency forwarding mode and an analog forwarding mode; a satellite signal monitoring receiving module for receiving real satellite navigation signals and performing navigation positioning; an analog control module for providing parameters required for analog real navigation based on the real satellite navigation signals; a mathematical analog simulation module for generating satellite observation data and original navigation electric texts according to the parameters required for analog real navigation; a data processing module for preprocessing the satellite observation data and the original navigation electric texts; and a satellite signal generation module for generating final analog satellite navigation signals according to the preprocessed satellite observation data and the original navigation electric texts. The application can realize quasi-seamless connection positioning in indoor or outdoor environments or in the case of satellite navigation signal denial.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation technology, in particular to a GNSS multi-mode same frequency and analog repeater device. BACKGROUND

[0002] Global Navigation Satellite System (GNSS) is a navigation positioning system that can provide all-weather, all-time position, speed and time information for users at any location on the earth's surface or near-earth space. GNSS satellite navigation system has the characteristics of high precision and wide signal coverage range, and is widely used in intelligent transportation, smart agriculture, surveying and mapping, unmanned driving, landslide and other natural geological disaster monitoring fields.

[0003] GNSS has become a universal navigation positioning system, which is widely used in military and civilian fields, but for indoor, tunnel and underground garage places, the received satellite navigation signal strength is too small or even cannot be received due to the blocking of satellite navigation signal, and continuous positioning must rely on indoor satellite navigation technology or other navigation positioning technology.

[0004] In order to solve the above problems, the common positioning technologies mainly include: repeater positioning of forwarding actual satellite navigation signal to indoor, simulator simulation positioning of generating similar satellite navigation signal by equipment, pseudolite positioning, UWB and other positioning. The repeater positioning receives the actual satellite navigation signal without shielding through the satellite signal receiving antenna, and the satellite signal is amplified and purified after being amplified, and then is forwarded by the signal repeater installed in the indoor. Although the repeater positioning is purified, it cannot obtain the real position in the indoor, and the positioning error will be large. The simulator simulation positioning simulates the real position in the indoor through the satellite navigation signal simulator, generates simulated satellite navigation signal, and then transmits the simulated satellite navigation signal through the transmitting antenna. The positioning position of this method is accurate, but the difference between the simulated signal generated by the simulator and the actual satellite navigation signal is large, and the satellite navigation receiver will be in an undefined state for a period of time when switching between the actual navigation signal and the simulated signal. The pseudolite positioning uses pseudolites arranged at different points to emit similar GPS / BDS standard satellite navigation signals to replace the navigation satellites in the air to realize positioning. The working principle of this method is the same as that of GNSS satellite navigation positioning system, but this method needs to arrange different pseudolites, and the construction cost is high, so it is not suitable for wide promotion and application. The UWB and other positioning methods need to modify the hardware of the satellite navigation receiver and develop new positioning technology, which increases the time cost and labor cost. SUMMARY

[0005] The application aims to provide a GNSS multi-mode same-frequency and analog forwarding device to solve the problems in the prior art and improve the high matching reproduction method between satellite navigation analog simulation signals and real satellite navigation signals, so as to realize quasi-seamless positioning in indoor or outdoor or satellite navigation signal denial conditions.

[0006] To achieve the above object, the application provides the following solutions.

[0007] A GNSS multi-mode same-frequency and analog forwarding device comprises:

[0008] A remote / local control module is configured to control the switching between the same-frequency forwarding mode and the analog forwarding mode through a UDP network instruction or a panel button.

[0009] A satellite signal monitoring and receiving module is configured to receive real satellite navigation signals and perform navigation positioning.

[0010] An analog control module is configured to provide parameters required for analog real navigation based on the real satellite navigation signals, wherein the parameters required for analog real navigation include time, position and ephemeris parameters.

[0011] A mathematical analog simulation module is configured to generate satellite observation data and original navigation messages based on the parameters required for analog real navigation.

[0012] A data processing module is configured to pre-process the satellite observation data and the original navigation messages.

[0013] A satellite signal generation module is configured to generate final analog satellite navigation signals based on the pre-processed satellite observation data and original navigation messages.

[0014] Optionally, the mathematical analog simulation module comprises:

[0015] A first calculation unit is configured to calculate a current satellite position based on the current simulation time, the current position and the ephemeris parameters provided by the analog control module.

[0016] A second calculation unit is configured to calculate error terms based on an error term model, wherein the error terms include ionospheric errors, tropospheric errors and earth rotation errors.

[0017] A third calculation unit is configured to calculate satellite observation data based on the satellite position and the error term information, wherein the satellite observation data includes satellite pseudoranges, carrier phases, pseudorange Dopplers and carrier Dopplers.

[0018] A generation unit is configured to generate original navigation messages based on the content and format of the interface control file of the GNSS satellite navigation system.

[0019] A judging unit is configured to judge the satellite visibility according to the simulation time and the simulation position.

[0020] Optionally, the data processing module comprises:

[0021] A channel management module is configured to switch the satellite signal channel between preset states according to the satellite visibility provided by the mathematical simulation module, so that the visibility state of the satellite signal channel generated finally by simulation is consistent with the real satellite visibility state.

[0022] A plurality of data processing channels are configured to pre-process the satellite observation data and the original navigation message.

[0023] Optionally, the data processing channel comprises:

[0024] An observation data filling sub-module is configured to fill the observation data generated by simulation of the visible satellite into the observation data cache table of the corresponding satellite signal channel according to the satellite visibility state.

[0025] A message filling sub-module is configured to fill the original navigation message into the message cache table of the corresponding satellite signal channel according to the message update identifier of the visible satellite.

[0026] A loop parameter calculation sub-module is configured to initialize the initial values of the code and carrier counts of the satellite signal generation module, and calculate the loop control word of the code loop and the carrier loop, and send the loop control word to the signal generation module.

[0027] A self-closed loop adjustment sub-module is configured to adjust the loop control word of the channel carrier loop and the code loop according to the difference between the pseudo-range obtained according to the current time and the satellite signal channel parameters and the simulation pseudo-range of the current time, and perform closed loop adjustment.

[0028] A frame data management sub-module is configured to calculate the satellite signal transmission time according to the current time and the simulation pseudo-range, calculate the message sub-frame sequence number corresponding to the satellite signal transmission time, and read the message data of the next sub-frame from the message cache table and write the message data into the corresponding sub-frame of the message cache area of the satellite signal generation module.

[0029] Optionally, the satellite signal generation module comprises a plurality of signal generation channels, a digital combiner and a digital-to-analog (DA) conversion sub-module.

[0030] The plurality of signal generation channels correspond to the plurality of data processing channels one-to-one, and one data processing channel and its corresponding signal generation channel constitute a satellite signal channel of a single satellite.

[0031] The digital combiner and the DA conversion sub-module are configured to combine the carrier signals generated by all the signal generation channels, and perform DA conversion on the combined signals to obtain the satellite navigation signal.

[0032] Optionally, the switching between the preset states of each satellite signal channel comprises:

[0033] The switching between the three states of establishment, maintenance and release of each satellite signal channel.

[0034] Optionally, the device further comprises a time and frequency reference module for providing time and frequency reference.

[0035] Optionally, the time and frequency reference module comprises:

[0036] The RTC module is used for real-time updating according to the written real time, and providing real time for the mathematical simulation control module;

[0037] The frequency module is used for providing reference for the frequency driving of the local time and the satellite signal generation module.

[0038] Optionally, the device further comprises a signal power control module for controlling the power of the simulated satellite navigation signal.

[0039] The present application has the following beneficial effects:

[0040] The present application has two working modes of purification and simulation, and overcomes the shortcomings of the traditional navigation simulator, such as the time and real time being different, the user position and real user position being different, the simulation text and real navigation text being different, and the satellite navigation simulator visible star state and real visible star state being different, etc., so that the satellite navigation simulator simulation signal and the real satellite navigation signal are consistent in time, user position, current time satellite visibility and navigation text, the realness of the satellite navigation simulator simulation signal is improved, the duration of the satellite navigation receiver in the real navigation signal and the satellite navigation simulator simulation signal is greatly shortened, the satellite navigation receiver is switched between the real satellite navigation signal and the satellite navigation simulator simulation signal, the real time and position information can be provided in real time in the case of GNSS satellite navigation signal rejection. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0042] Figure 1 The present application is a GNSS multi-mode same frequency simulation forwarding device system schematic diagram.

[0043] Figure 2 Block diagram of remote / local control module for embodiment of the present application;

[0044] Figure 3 Block diagram of satellite signal detection receiving module for embodiment of the present application;

[0045] Figure 4 Block diagram of simulation control module for embodiment of the present application;

[0046] Figure 5 Block diagram of mathematical simulation module for embodiment of the present application;

[0047] Figure 6 Block diagram of data processing module and satellite signal generation module for embodiment of the present application;

[0048] Figure 7 Flow chart of satellite signal channel establishment, maintenance and release processing for embodiment of the present application;

[0049] Figure 8 Flow chart of satellite signal channel loop adjustment and message data management for embodiment of the present application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0051] In order to make the above objectives, characteristics and advantages of the present application more apparent, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] The embodiment presents a GNSS multi-mode same-frequency and analog forwarding device, comprising:

[0053] A remote / local control module controls the switching between the same-frequency forwarding mode and the analog forwarding mode through UDP network instructions or panel button control.

[0054] A satellite signal monitoring receiving module is used to receive real satellite navigation signals and perform navigation positioning.

[0055] A simulation control module is used to provide parameters required for simulating real navigation based on the real satellite navigation signals of the GNSS multi-mode same-frequency and analog forwarding device; wherein the parameters required for simulating real navigation by the GNSS multi-mode same-frequency and analog forwarding device include time, position and ephemeris parameters.

[0056] The mathematical simulation module is used to simulate the parameters required for real navigation based on GNSS multi-mode co-frequency and simulated transponder devices, and generate satellite observation data and raw navigation messages. The raw navigation messages are generated by arranging time, ephemeris parameters, and ionospheric error parameters according to the message content and format of the GNSS satellite navigation system interface control file.

[0057] The data processing module is used to preprocess satellite observation data and raw navigation messages;

[0058] The satellite signal generation module is used to generate the final simulated satellite navigation signal based on the preprocessed satellite observation data and the original navigation message.

[0059] Specifically, in this embodiment, a GNSS multi-mode co-frequency analog repeater is provided, the system composition of which is as follows: Figure 1 As shown, it mainly includes: simulation control module, mathematical simulation module, data processing module, satellite signal generation module, time and frequency reference module, signal power module, signal co-frequency relay module, satellite signal monitoring and receiving module, and remote / local control module.

[0060] The remote / local control module allows switching between the device's same-frequency relay mode and analog relay mode via a programmable interface or front panel buttons; for example... Figure 2 As shown. The two modes, co-channel relay and analog relay, are selected by the user based on the usage scenario. For example, when no satellite signal is received, the user can switch to analog relay.

[0061] The satellite signal monitoring and receiving module receives real satellite navigation signals and performs navigation and positioning, providing the simulation control module with real-time time, position, ephemeris, almanac, ionospheric, and UTC parameters; such as Figure 3 As shown.

[0062] The simulation control module receives time information to initialize the local time and updates it in real time under the control of the time and frequency reference module, achieving complete synchronization with real time. This provides the mathematical simulation module with the necessary time, position, ephemeris parameters, and other information to simulate real navigation signals. Figure 4 As shown.

[0063] Furthermore, the mathematical simulation module for GNSS multi-mode co-frequency and analog transponder devices includes:

[0064] The first calculation unit is used to perform simulation based on the current simulation time, current position, and ephemeris parameters provided by the simulation control module, and calculate the current satellite position.

[0065] The second calculation unit is used to calculate error terms based on the error term model; wherein, the error terms include: ionospheric error, tropospheric error, and Earth rotation error;

[0066] a third calculation unit, configured to calculate satellite observation data according to the satellite position and the error item information; wherein the satellite observation data comprises satellite pseudo-range, carrier phase, pseudo-range Doppler, and carrier Doppler;

[0067] a generation unit, configured to generate original navigation messages according to the content and format of the messages of the interface control file of the GNSS satellite navigation system;

[0068] a judgment unit, configured to judge satellite visibility according to the simulation time and the simulation position.

[0069] Specifically, in the embodiment, the mathematical simulation module calculates observation data of corresponding satellites according to the current simulation time, the user position, and the ephemeris parameter information, and provides pseudo-range, carrier, Doppler, and other data for the data processing module, and calculates ionosphere, troposphere, and earth rotation error items according to error item models, and calculates pseudo-range, carrier phase, pseudo-range Doppler, carrier Doppler, visibility state, and other information of corresponding satellites, and generates original navigation messages according to the content and format of messages of the interface control file (ICD file), and sends the calculated satellite observation data and the original navigation messages to the data processing module for caching. Figure 5

[0070] Further, the GNSS multi-mode and analog forwarding device data processing module comprises:

[0071] a channel management module, configured to switch each satellite signal channel between preset states according to the satellite visibility identification provided by the mathematical simulation module, so that the visibility state of the finally simulated satellite signal channel is consistent with the real satellite visibility state;

[0072] a multi-channel data processing channel, configured to pre-process satellite observation data and original navigation messages.

[0073] Specifically, in the embodiment, the data processing module comprises a channel management module and n-channel (at least 16 channels for the GPS system, and at least 24 channels for the BDS system) data processing channels. The satellite signal generation module comprises n-channel signal generation channels and a digital combining and digital-analog (DA) conversion module. The n-channel data processing channels and the n-channel signal generation channels correspond to each other one by one, and one data processing channel and its corresponding signal generation channel constitute a satellite signal channel of a satellite, and can simulate output a satellite navigation signal. The data processing module and the satellite signal generation module are as shown in Figure 6

[0074] Further, the switching of each satellite signal channel between preset states comprises:

[0075] ​​Switching between the three states of establishment, maintenance and release of each satellite signal channel.

[0076] Specifically, in the embodiment, the channel management part module implements switching between the three states of establishment, maintenance and release of each satellite signal channel according to the satellite visibility identification provided by the mathematical simulation module, and the processing flow chart is as shown in the figure, so that the visibility state of the satellite signal channel generated by the final simulation is consistent with the real satellite visibility state, thereby ensuring that the simulated satellite navigation signal is consistent with the real satellite navigation signal. Figure 7

[0077] Further, the GNSS multi-mode and simulation forwarding device data processing channel comprises:

[0078] An observation data filling sub-module is configured to fill the observation data generated by the simulation of the visible stars into the observation data buffer table of the corresponding satellite signal channel according to the satellite visibility state;

[0079] A message filling sub-module is configured to fill the original navigation message into the message buffer table of the corresponding satellite signal channel according to the message update identification of the visible stars;

[0080] A loop parameter calculation sub-module is configured to initialize the initial values of the code and carrier count of the satellite signal generation module, and calculate the loop control word of the code loop and the carrier loop, and send the loop control word to the code loop and the carrier loop module of the signal generation module;

[0081] A self-closed loop adjustment sub-module is configured to adjust the loop control word of the channel carrier loop and the code loop according to the difference between the pseudo-range obtained from the current time and the satellite signal channel parameters and the simulation pseudo-range of the current time, and perform closed loop adjustment;

[0082] A frame data management sub-module is configured to calculate the satellite signal transmission time according to the current time and the simulation pseudo-range, calculate the message subframe sequence number corresponding to the satellite signal transmission time, and read the message data of the next subframe from the message buffer table and write the message data into the corresponding subframe of the message buffer area of the satellite signal generation module.

[0083] Specifically, in the embodiment, the data processing channel comprises an observation data filling module, a message filling module, a loop parameter calculation module, a self-closed loop adjustment module and a frame data management module; the observation data filling module fills the observation data generated by the simulation of the visible stars into the observation data buffer table of the corresponding satellite signal channel according to the satellite visibility state; the message filling module fills the original navigation message into the 2D message buffer of the corresponding satellite signal channel to store the latest 2 message packets, and each message packet contains the message data of 5 subframes;

[0084] ​The loop parameter calculation module calculates initial values of code and carrier count of the satellite signal generation channel according to satellite observation data calculated based on current simulation time, user position, and ephemeris, and calculates loop control words of code loop and carrier loop, and sends the loop control words to code loop module and carrier loop module of the signal generation module. The self-closed loop adjustment module adjusts the loop control words according to a difference between the original observation pseudo-range and the simulation pseudo-range latched by the satellite signal channel according to current time, and according to carrier Doppler, code Doppler, and pseudo-range difference. The frame data management module calculates satellite signal transmission time according to current time and simulation pseudo-range, calculates a subframe number corresponding to the satellite signal transmission time, and reads the next subframe data from the text cache table and writes the data into the corresponding subframe of the text cache area of the satellite signal generation module. The above processing flow is as shown in Figure 8 ;

[0085] Specifically, taking the GPS system as an example, in the loop parameter calculation submodule, the calculation method of the accumulated initial values of code and carrier according to the observation data of the corresponding satellite is as follows:

[0086] a) Calculate the current satellite navigation signal transmission time t s :

[0087]

[0088] Where t r is the system simulation time, p is the pseudo-range of the satellite, and c is the speed of light.

[0089] b) Calculate the time t s corresponding to a frame and the subframe number f corresponding to a frame, and then have:

[0090] t = mod(t s , 30), f = round(t / 6.0);

[0091] Where mod represents modulo; round represents rounding.

[0092] c) Calculate the remaining millisecond count t m in a subframe, and calculate the word count w in the subframe:

[0093] t m = (t - f * 6) * 1000, w = round(t m / 600);

[0094] d) Calculate the remaining millisecond count t m in a subframe, and calculate the bit count b in the subframe:

[0095] t m = (t m-w*600), b = round(t m / 20);

[0096] e) Calculate the remaining millisecond count t within a subframe. m And calculate the millisecond count e within the subframe:

[0097] t m =(t m -b*20), e=round(t m );

[0098] f) Calculate the remaining millisecond count t within a subframe. m And calculate the millisecond count (epoch) within the subframe:

[0099] t m =(t m -b*20), epoch=round(t m );

[0100] g) Calculate the remaining millisecond count t within a subframe. m code count value t c And calculate the number of whole code fragments code_ph within the subframe:

[0101] t c =t m *1023, code_ph = round(t c );

[0102] h) Calculate the remaining chip count t within a subframe. m And calculate the code NCO value code_nco:

[0103]

[0104] Where, N code The word length (number of bits) of the NCO counter.

[0105] i) Calculate the signal transmission time t s Carrier integer cycle number carr_cnt and carrier NCO value carr_nco:

[0106]

[0107] Where cr is the carrier phase value, in meters; λ is the carrier wavelength, N carr The word length (number of bits) of the carrier NCO.

[0108] The calculation methods for the loop control words of the code loop and carrier loop are as follows:

[0109] a) Calculate the loop control word carr_m of the code loop according to code_doppler:

[0110]

[0111] Where, N nco is the word length (bit number) of the loop control word, F s is the channel rate; r adj is the self-closed loop adjustment amount.

[0112] b) Calculate the loop control word carr_m of the carrier loop according to code_doppler:

[0113]

[0114] The satellite signal generation module extracts the subframe data of the text and processes it into a text bit stream with a width of 1ms and caches it, and calculates the initial position of the navigation text bit. According to the satellite signal transmission time t s , the calculation method of the starting bit b0 position of the navigation text of a satellite is as follows:

[0115] a) Calculate the satellite signal transmission time t s Use the subframe data packet text of the first subframe;

[0116] b) Calculate the ms count in the satellite text;

[0117] b0 = mod(t s *1000, B);

[0118] Where, B is the millisecond count length of the navigation text bit.

[0119] Further, the GNSS multi-mode same frequency and analog forwarding device satellite signal generation module comprises a multi-channel signal generation channel, a digital combiner and a digital analog DA conversion submodule;

[0120] The multi-channel GNSS multi-mode same frequency and analog forwarding device signal generation channel corresponds to the multi-channel GNSS multi-mode same frequency and analog forwarding device data processing channel one by one, and one data processing channel and its corresponding signal generation channel constitute a satellite signal channel of a satellite;

[0121] The digital combiner and the digital analog DA conversion submodule are used to complete the merging of the carrier signals generated by all signal generation channels, and DA conversion of the merged signals to obtain satellite navigation signals.

[0122] Specifically, in the embodiment, the satellite signal generation module generates radio frequency signals according to the satellite navigation data processed by the data processing module; the satellite signal generation module includes a text buffer, a code ring module and a carrier ring module, a digital combiner and a digital-to-analog (DA) conversion module; wherein the text buffer extracts text subframe data and processes it into a text bit stream with a width of 1 ms and stores it; the code ring module is composed of a second-order accumulator and modulates the corresponding text bit stream in the text buffer to a pseudo code according to the loop control word of the corresponding satellite data processing channel; the carrier ring module is composed of a third-order accumulator and modulates the pseudo code to a carrier for spread spectrum according to the loop control word of the corresponding satellite data processing channel; the digital combiner and the DA conversion module combine the carrier signals generated by all signal generation channels and perform DA conversion on the combined signals to obtain satellite navigation signals. The n signal generation channels correspond to n text buffers, code ring modules and carrier ring modules respectively. Each signal generation channel includes a text buffer, a code ring module and a carrier ring module.

[0123] After the signal generation channel completes loop parameter and control word calculation, and the signal generation module completes text filling and text starting position calculation, the channel has a start condition. Under the control of the time and frequency reference module, at the whole second moment, the channel is started according to the prepared parameters to ensure that the navigation signal generated by the channel is highly consistent with the real navigation signal.

[0124] After the channel is started, the signal generation module modulates the corresponding text in the text buffer to the pseudo code generated by the second-order code ring module; then the pseudo code is modulated to the carrier composed of the third-order carrier ring module for spread spectrum processing; finally, digital combining and DA conversion are performed to complete the combination of the carrier signals generated by all signal generation channels, and satellite navigation signals are obtained after DA conversion.

[0125] Further, the GNSS multi-mode same frequency and analog forwarding device further comprises a time and frequency reference module for providing time and frequency reference.

[0126] Further, the time and frequency reference module of the GNSS multi-mode same frequency and analog forwarding device comprises:

[0127] The RTC module is used for real-time updating according to the real time written, and provides real time for the mathematical simulation control module of the GNSS multi-mode same frequency and analog forwarding device;

[0128] The frequency module is used for providing a reference for the local time and the frequency driving of the satellite signal generation module of the GNSS multi-mode same frequency and analog forwarding device.

[0129] Further, the GNSS multi-mode same-frequency and analog repeater device further comprises a signal power control module configured to control the power of the analog satellite navigation signal of the GNSS multi-mode same-frequency and analog repeater device.

[0130] The embodiment also provides a method for reproducing satellite navigation signals based on GNSS satellite navigation simulator time and position synchronization, which can realize quasi-seamless positioning in the case of GNSS satellite navigation signal denial.

[0131] Step one: send a command to switch to the same-frequency repeater mode through a remote control interface or a front panel button, receive the real GNSS satellite navigation signal by the satellite signal monitoring and receiving module, obtain the current real time and position information, the ephemeris of all visible satellites, the almanac, the ionosphere and the UTC parameter information, initialize the local information according to the current time, position and satellite ephemeris parameter information obtained by the satellite signal monitoring and receiving module by the simulation control module, write the time information into the RTC clock chip, and store the position and satellite parameter information into the FLASH memory;

[0132] Step two: in the case of indoor signal or GNSS satellite signal denial, send a command to switch to the analog repeater mode through a remote control interface or a front panel button, and perform analog simulation.

[0133] The satellite position, velocity and clock error information are calculated by the mathematical analog simulation module according to the current simulation time, current position and ephemeris parameters provided by the simulation control module.

[0134] The observation error term is calculated by the mathematical analog simulation module according to the ionosphere, the troposphere, the earth rotation and the relativistic effect.

[0135] The satellite visibility is calculated according to the current position and the satellite position.

[0136] The original observation data are generated, and the navigation message data of the satellite are generated in the specified format of the ICD file at the message update time.

[0137] Step three: the channel management module periodically traverses all satellites according to the satellite visibility generated by the mathematical analog simulation module to perform channel data management.

[0138] For the visible satellite, it is judged whether the satellite is allocated a channel. For the satellite without allocated channel, the corresponding satellite signal channel is established, the channel initialization operation is performed on the newly established satellite signal channel according to the observation data, the loop control word is converted, and the original navigation message data are cached. For the satellite with allocated channel, the observation data generated by the mathematical analog simulation module are cached, and the original navigation message is updated according to the message update identifier.

[0139] The satellite signal generation channel is driven by the accumulation of the channel control word according to the code stream and the calculated message starting position, and the message bit stream of the message buffer is modulated onto the pseudo code; at the same time, the carrier loop control word modulates the pseudo code onto the carrier;

[0140] The channel management module calculates the pseudo range according to the original measurement information latched by the satellite signal channel, calculates the current simulation time pseudo range difference, and adjusts the channel loop control word in a closed loop;

[0141] According to the calculated satellite navigation signal transmission time, the next subframe message data in the current time corresponding to the message cache is extracted and written into the message buffer area of the corresponding signal generation channel.

[0142] Step four, the channel management module starts the satellite signal channel at the front edge of the real satellite navigation signal second pulse signal; and when the satellite changes from visible to invisible state, the satellite signal channel of the allocated channel is released, and the satellite signal channel parameters are zero processed.

[0143] The embodiment has two working modes of purification forwarding and simulation forwarding, overcomes the shortcomings of the traditional navigation simulator that the time is not synchronized with the real time, the user position is not synchronized with the real user position, the simulation message is not consistent with the real navigation message, and the visible satellite state of the satellite navigation simulator is not consistent with the real visible satellite state, and the like, can make the satellite navigation simulator simulation signal consistent with the real satellite navigation signal in time, user position, current time satellite visibility, and navigation message, improves the authenticity of the satellite navigation simulator simulation signal, greatly shortens the duration of the indefinite position state of the satellite navigation receiver when switching between the real navigation signal and the satellite navigation simulator simulation signal, realizes the quasi-seamless switching of the satellite navigation receiver between the real satellite navigation signal and the satellite navigation simulation signal, and can provide real-time time and position information in the case of GNSS satellite navigation signal denial.

[0144] The above-described embodiments are only descriptions of the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A GNSS multi-mode co-frequency and analog transponder device, characterized in that, include: The remote / local control module controls the switching between same-frequency forwarding mode and analog forwarding mode via UDP network commands or panel buttons; The satellite signal monitoring and receiving module is used to receive real satellite navigation signals and perform navigation and positioning. The simulation control module is used to provide parameters required for simulating real navigation based on the real satellite navigation signals; wherein the parameters required for simulating real navigation include: time, position, and ephemeris parameters; The mathematical simulation module is used to generate satellite observation data and raw navigation messages based on the parameters required for simulating real navigation. The data processing module is used to preprocess satellite observation data and raw navigation messages; The satellite signal generation module is used to generate the final simulated satellite navigation signal based on the preprocessed satellite observation data and the original navigation message; The mathematical simulation module includes: The first calculation unit is used to perform simulation based on the current simulation time, current position, and ephemeris parameters provided by the simulation control module, and calculate the current satellite position. The second calculation unit is used to calculate error terms based on the error term model; wherein, the error terms include: ionospheric error, tropospheric error, and Earth rotation error; The third calculation unit is used to calculate satellite observation data based on satellite position and error term information; wherein, the satellite observation data includes: satellite pseudorange, carrier phase, pseudorange Doppler, and carrier Doppler; The generation unit is used to arrange and generate the original navigation message according to the message content and format of the GNSS satellite navigation system interface control file; The judgment unit is used to determine satellite visibility based on the simulation time and simulation location.

2. The GNSS multi-mode co-frequency and analog relay device according to claim 1, characterized in that, The data processing module includes: The channel management module is used to switch between preset states of each satellite signal channel based on the satellite visibility identifier provided by the mathematical simulation module, so that the visibility state of the satellite signal channel generated by the final simulation is consistent with the actual satellite visibility state. Multiple data processing channels are used to preprocess satellite observation data and raw navigation messages.

3. The GNSS multi-mode co-frequency and analog transponder device according to claim 2, characterized in that, The data processing channel includes: The observation data filling submodule is used to fill the observation data generated by the simulation of visible stars into the observation data cache table of the corresponding satellite signal channel according to the satellite visibility status. The message filling submodule is used to fill the original navigation message into the message cache table of the corresponding satellite signal channel based on the message update identifier of the visible satellite; The loop parameter calculation submodule is used to initialize the initial values ​​of the code and carrier counts of the satellite signal generation module, calculate the loop control words of the code loop and carrier loop, and send the loop control words to the signal generation module. The self-closed-loop adjustment submodule is used to adjust the loop control words of the channel carrier loop and code loop based on the difference between the pseudorange obtained from the current time and the satellite signal channel parameters and the simulated pseudorange at the current time, thereby performing closed-loop adjustment. The frame data management submodule is used to calculate the satellite signal transmission time based on the current time and the simulated pseudorange, calculate the message subframe number corresponding to the satellite signal transmission time, and read the message data of the next subframe from the message cache table and write it into the corresponding subframe in the message cache area of ​​the satellite signal generation module.

4. The GNSS multi-mode co-frequency and analog relay device according to claim 3, characterized in that, The satellite signal generation module includes: a multi-channel signal generation channel, a digital combiner, and a digital-to-analog (DA) converter submodule; Each of the multiple signal generation channels corresponds one-to-one with the multiple data processing channels, and one data processing channel and its corresponding signal generation channel constitute the satellite signal channel of a single satellite. The digital combiner and digital-to-analog (DA) converter submodule are used to combine the carrier signals generated by all signal generation channels and perform DA conversion on the combined signals to obtain satellite navigation signals.

5. The GNSS multi-mode co-frequency and analog relay device according to claim 2, characterized in that, Switching between preset states for each satellite signal channel includes: Switching between the three states of establishing, maintaining, and releasing each satellite signal channel.

6. The GNSS multi-mode co-frequency and analog relay device according to claim 1, characterized in that, The device further includes a time-frequency reference module for providing time and frequency references.

7. The GNSS multi-mode co-frequency and analog transponder device according to claim 6, characterized in that, The time-frequency reference module includes: The RTC module is used to update in real time based on the actual time written, providing the mathematical simulation module with the actual time. The frequency module is used to provide a reference for local time and the frequency drive of the satellite signal generation module.

8. The GNSS multi-mode co-frequency and analog relay device according to claim 1, characterized in that, The device further includes a signal power control module for controlling the power of the simulated satellite navigation signal.

Images