A GBAS pseudorange correction simulation method and device based on GPS simulator

Abstract

The present invention provides a GBAS pseudo-range correction simulation method and device based on a GPS simulator, the method comprising: obtaining atmospheric parameter information, glide path, and airport information, generating a user's real-time longitude and latitude and speed according to the glide path and airport information, using ephemeris data to provide satellite position information when the initial time is input, and simulating the generation of a GPS intermediate frequency signal reaching the ground, remodulating the GPS intermediate frequency signal according to the atmospheric parameter information, simulating the GPS intermediate frequency signal disturbed by the atmosphere and outputting it through the GPS radio frequency port, demodulating and processing the GPS intermediate frequency signal disturbed by the atmosphere to obtain a pseudo-range, performing differential processing on the pseudo-range and the actual range, obtaining pseudo-range correction data and packaging it as a VDB message for output. The present invention designs a GLS simulator software architecture composed of a DB simulator and a GPS simulator, takes into account the interference of the atmosphere on the signal, realizes the remodulation of the GPS intermediate frequency signal, and simulates the pseudo-range differential correction data of the VDB signal, so that the VDB simulator has data to fill.

Description

Technical Field

[0001] The present invention relates to the technical field of ground-based augmented simulators, and in particular to a GBAS pseudorange correction simulation method based on a GPS simulator, a GBAS pseudorange correction simulation device based on a GPS simulator, an electronic device and a computer-readable medium. Background Art

[0002] During the approach phase of an aircraft, especially during the descent landing, the positioning accuracy requirement is very high. The ordinary global positioning system (GPS) cannot meet the accuracy requirements of the landing phase of the aircraft due to its integrity, reliability and accuracy. For this reason, an independent error correction system is required to correct the positioning data of the aircraft so that it is possible to meet the accuracy requirements required for landing. The Ground-Based Augmentation Satellite Landing System (GPS Landing System, GLS) is a technology that uses satellites to calculate the positioning of aircraft landing. The Ground-Based Augmentation System (GBAS) is an important part of GLS. It adopts the form of building a ground station on the ground to collect and measure pseudo-ranges within a certain range. The data processor will compare the calculated pseudo-range with the actual distance to calculate the differential correction value, and send this data to the airborne user through the Very-high frequency Data Broadcast (VDB), eliminating the positioning error of GPS in the local area, and providing GPS integrity information, providing precision approach and landing guidance services for the landing of aircraft equipped with corresponding airborne equipment. In addition, the processor sends the final approach path FAS (Final Approach Segment) of each runway, including horizontal and vertical restriction warnings, as well as the atmospheric data model of the local airport to the associated aircraft through VDB.

[0003] Although GBAS technology provides positioning services for aircraft landing, traditional GBAS devices still have many shortcomings: traditional GBAS devices need to set up reference receivers in the field and perform precise positioning calibration, which has high requirements for hardware, sites, and systems. In addition, since the GBAS system relies on actual reference receiver measurement data, it becomes particularly difficult to test and simulate the system without a reference receiver. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a GPS simulator-based GBAS pseudorange correction simulation method and a corresponding GPS simulator-based GBAS pseudorange correction simulation device, an electronic device and a computer-readable medium that overcome the above problems or at least partially solve the above problems.

[0005] The present invention discloses a GBAS pseudorange correction simulation method based on a GPS simulator, wherein the GLS simulator comprises a GPS simulator and a VDB simulator, and the method comprises:

[0006] Get the atmospheric parameter information, glide path, and airport information set by the user;

[0007] Generate the user's real-time latitude, longitude and speed based on the glide path and airport information;

[0008] When the initial time is input, the ephemeris data is used to provide the satellite position information and simulate the generation of GPS intermediate frequency signals reaching the ground;

[0009] According to the atmospheric parameter information, the GPS intermediate frequency signal is remodulated to simulate the GPS intermediate frequency signal interfered by the atmosphere and output through the GPS radio frequency port;

[0010] Demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain a measured pseudorange;

[0011] The pseudorange and actual range of the satellite and the user are differentiated to obtain pseudorange correction data, and the pseudorange correction data is packaged as a VDB message for output.

[0012] Optionally, the atmospheric parameter information includes refractive index, ionospheric residual, and elevation.

[0013] Optionally, the GPS intermediate frequency signal is remodulated according to the atmospheric parameter information to simulate the GPS intermediate frequency signal interfered by the atmosphere and output through the GPS radio frequency port, including:

[0014] According to the atmospheric parameter information, the atmospheric refraction model and ionosphere model are used to remodulate the GPS intermediate frequency signal to simulate the GPS intermediate frequency signal interfered by the atmosphere;

[0015] Function of PRC caused by atmospheric refraction:

[0016] = (14.588+0.0029611 )-0.3048[0.00586 +294] }c

[0017] Function of PRC caused by atmospheric ionization:

[0018]

[0019] In the formula, : Atmospheric refraction delay error; : ground refractive index; : altitude angle; : speed of light; : ionospheric residual delay; : ionospheric coefficient; : Doppler frequency; : Carrier frequency.

[0020] Optionally, the pseudorange and actual range of the satellite and the user are differentiated to obtain pseudorange correction data, including:

[0021] The calculation formula of pseudorange correction data is obtained according to the pseudorange difference formula:

[0022] ;

[0023] In the formula, : current time; : Parameters defined in the RTCA246 standard are broadcast via VDB; : Pseudorange correction; : Pseudorange correction rate; : Actual distance; : measured pseudorange; : Doppler frequency; : Clock correction; : Ionospheric residual delay.

[0024] Optionally, demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain a measured pseudorange includes:

[0025] The received GPS intermediate frequency signal is converted, filtered and coherently demodulated by using FPGA, and the satellite signal is locked and the pseudorange is measured by combining the ephemeris message and the parameter information set by the user through a serial search algorithm. The serial search algorithm uses the Doppler frequency deviation to bias the received signal.

[0026] Optionally, the method further comprises:

[0027] The satellite position is obtained according to the ephemeris message, and the distance between the satellite position and the user's real-time longitude and latitude is divided by the speed of light to obtain the actual distance between the satellite and the user.

[0028] The present invention also discloses a GBAS pseudorange correction simulation device based on a GPS simulator, characterized in that the GLS simulator includes a GPS simulator and a VDB simulator, and the device includes:

[0029] The user-set parameter information acquisition module is used to obtain the atmospheric parameter information, glide path, and airport information set by the user;

[0030] The user's real-time position and speed calculation module is used to generate the user's real-time latitude, longitude and speed based on the glide path and airport information;

[0031] The signal simulation module is used to provide the satellite position information using the ephemeris data when the initial time is input, and simulate the generation of the GPS intermediate frequency signal reaching the ground;

[0032] The atmospheric interference simulation module is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, simulate the GPS intermediate frequency signal interfered by the atmosphere and output it through the GPS radio frequency port;

[0033] The pseudorange measurement module is used to demodulate the GPS intermediate frequency signal interfered by the atmosphere to obtain the measured pseudorange;

[0034] The differential module is used to differentiate the pseudo-range and the actual range of the satellite and the user to obtain pseudo-range correction data, and to package the pseudo-range correction data into a VDB message for output.

[0035] Optionally, the atmospheric parameter information includes refractive index, ionospheric residual, and elevation.

[0036] Optionally, the atmospheric disturbance simulation module includes:

[0037] The atmospheric interference simulation submodule is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, using the atmospheric refraction model and the ionosphere model, to simulate the GPS intermediate frequency signal interfered by the atmosphere;

[0038] Function of PRC caused by atmospheric refraction:

[0039] = (14.588+0.0029611 )-0.3048[0.00586 +294] }c

[0040] Function of PRC caused by atmospheric ionization:

[0041]

[0042] In the formula, : Atmospheric refraction delay error; : ground refractive index; : altitude angle; : speed of light; : ionospheric residual delay; : ionospheric coefficient; : Doppler frequency; : Carrier frequency.

[0043] Optionally, the differential module includes:

[0044] The differential calculation submodule is used to obtain the calculation formula of the pseudorange correction data according to the pseudorange differential formula:

[0045] ;

[0046] In the formula, : current time; : Parameters defined in the RTCA246 standard are broadcast via VDB; : Pseudorange correction; : Pseudorange correction rate; : Actual distance; : measured pseudorange; : Doppler frequency; : Clock correction; : Ionospheric residual delay.

[0047] Optionally, the pseudorange measurement module includes:

[0048] The pseudorange measurement submodule is used to use FPGA to perform frequency conversion, filtering and coherent demodulation on the received GPS intermediate frequency signal, lock the satellite signal and measure the pseudorange through a serial search algorithm combined with the ephemeris message and the parameter information set by the user. The serial search algorithm uses the Doppler frequency deviation to bias the received signal.

[0049] Optionally, the device further comprises:

[0050] The actual distance calculation module is used to obtain the satellite position according to the ephemeris message, and divide the distance between the satellite position and the user's real-time longitude and latitude by the speed of light to obtain the actual distance between the satellite and the user.

[0051] The present invention also discloses an electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0052] The memory is used to store computer programs;

[0053] The processor is used to implement the GBAS pseudorange correction simulation method based on the GPS simulator as described in the present invention when executing the program stored in the memory.

[0054] The present invention also discloses one or more computer-readable media, on which instructions are stored. When executed by one or more processors, the processors execute the GPS simulator-based GBAS pseudorange correction simulation method as described in the present invention.

[0055] The present invention includes the following advantages:

[0056] The GBAS pseudo-range correction simulation method based on the GPS simulator of the present invention obtains the atmospheric parameter information, glide path, and airport information set by the user, generates the user's real-time longitude and latitude, and speed according to the glide path and airport information, uses the ephemeris data to provide the satellite's position information when the initial time is input, and simulates the generation of the GPS intermediate frequency signal reaching the ground, re-modulates the GPS intermediate frequency signal according to the atmospheric parameter information, simulates the GPS intermediate frequency signal interfered by the atmosphere and outputs it through the GPS radio frequency port, demodulates the GPS intermediate frequency signal interfered by the atmosphere, measures the pseudo-range of the satellite and the user, and differentiates the pseudo-range and the actual range of the satellite and the user to obtain the pseudo-range correction data, and packages the pseudo-range correction data into a VDB message for output. The present invention takes into account the interference of the atmosphere on the signal, realizes the re-modulation of the GPS intermediate frequency signal, highly simulates the signal transmission situation in the actual environment, solves the problem of realizing automatic simulation and generation of pseudo-range differential correction data without the measurement of the reference receiver, enables the satellite landing simulator (GLS) to run completely (GPS+GBAS+FAS), and solves the problem of incomplete functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flowchart of the steps of a GBAS pseudorange correction simulation method based on a GPS simulator provided by an embodiment of the present invention;

[0058] Figure 2 It is a schematic diagram of a ground-based enhanced simulation device based on software radio provided by an embodiment of the present invention;

[0059] Figure 3 : is a schematic diagram of a GLS simulator simulating GBAS pseudorange correction provided by an embodiment of the present invention;

[0060] Figure 4 is a schematic diagram of GBAS environment simulation provided by an embodiment of the present invention;

[0061] Figure 5 It is a schematic diagram of generating a GPS intermediate frequency signal simulating atmospheric interference provided by an embodiment of the present invention;

[0062] Figure 6 It is a schematic diagram of demodulation of a GPS intermediate frequency signal simulated by atmospheric interference provided by an embodiment of the present invention;

[0063] Figure 7 It is a schematic diagram of simulating GPS intermediate frequency signal satellite capture provided by an embodiment of the present invention;

[0064] Figure 8 is a schematic diagram of pseudorange differential simulation provided by an embodiment of the present invention;

[0065] Fig. 9It is a structural block diagram of a GBAS pseudorange correction simulation device based on a GPS simulator provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0067] Reference Figure 1 , shows a flowchart of a method for simulating GBAS pseudorange correction based on a GPS simulator provided in an embodiment of the present invention, which may specifically include the following steps:

[0068] Step 101, obtaining atmospheric parameter information, glide path, and airport information set by the user;

[0069] Step 102, generating the user's real-time latitude, longitude, and speed according to the glide path and airport information;

[0070] Step 103, when the initial time is input, the ephemeris data is used to provide the satellite position information, and the GPS intermediate frequency signal reaching the ground is simulated and generated;

[0071] Step 104, remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, simulate the GPS intermediate frequency signal interfered by the atmosphere and output it through the GPS radio frequency port;

[0072] Step 105, demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain a measured pseudorange;

[0073] Step 106, differentially calculate the pseudorange and actual range of the satellite and the user to obtain pseudorange correction data, and package the pseudorange correction data into a VDB message for output.

[0074] The present invention designs a GLS simulator, which is composed of a GPS simulator and a VDB simulator combined with a GPS local demodulator. The intermediate frequency signal emitted by the GPS simulator is re-modulated and output through the atmospheric parameters provided by the VDB simulator. One channel is frequency-converted and directly outputs the GPS radio frequency, and the other channel is re-modulated. The GPS signal is demodulated in the FPGA to measure the pseudo-range. The pseudo-range and the actual distance generated by the ephemeris are differentiated, and the obtained correction data is packaged by the VDB simulator to generate a message, which is modulated and output through the intermediate frequency signal transceiver radio frequency.

[0075] GLS simulator software is used for ground-based augmentation simulation devices based on software radio, referring to Figure 2The ground-based augmentation simulation device based on software radio is implemented with modular hardware, including a PXIe chassis (including a controller, an intermediate frequency signal transceiver), a display (touch screen), RF components, and a front panel interface; the user customizes the configuration of the generated GPS and VDB messages through the display or the programmable network port, and the intermediate frequency signal transceiver generates the modulation signal. The GPS intermediate frequency signal is transmitted from the intermediate frequency signal transceiver 1 to the intermediate frequency signal transceiver 2 to simulate the GPS receiving signal. The two intermediate frequencies are up-converted to the L1 RF to output the GPS RF, and up-converted to the very high frequency to output the VDB RF.

[0076] The user can set the VDB message based on the technical requirements of Class I precision approach. The VDB message can include message 1, message 2 and message 4. The parameters of message 2 and message 4 can be directly or indirectly obtained through user settings, such as the refractive index and ionospheric residual of message 2, and the airport, runway and glide path angle of message 4. Message 1 is a GBAS message used to calibrate positioning errors. The data volume is huge and changes all the time.

[0077] VDB message 4 simulates the real-time glide path, and the positioning and speed are transmitted to the GPS simulator. The satellite position can be obtained according to the ephemeris message file, and the distance between the position set by the user interface is divided by the speed of light to obtain the actual distance, satellite altitude angle, and relative speed between satellite users; VDB message 2 inputs the atmospheric error parameters, and these parameters can be used to generate GPS intermediate frequency signals that simulate the atmospheric parameter errors.

[0078] Specifically, refer to Figure 3 , schematic diagram of GBAS pseudorange correction simulation by GLS simulator. First, the atmospheric parameter information for VDB message is set, which may include refractive index, ionospheric residual, and elevation, and program control is performed under local operation to simulate the precision approach environment including glide path, airport information, etc. Subsequently, the user's real-time latitude, longitude and speed are generated according to the glide path and airport information of VDB. At the initial time, satellite information is provided through ephemeris to simulate the GPS intermediate frequency signal reaching the ground. This signal will be remodulated by the algorithm model of the atmospheric parameter information of the VDB message, and the RF output will be performed through the GPS device to simulate the GPS intermediate frequency signal after atmospheric interference. After that, the simulated GPS intermediate frequency signal is demodulated to measure the pseudorange. Finally, the VDB simulator uses the difference between the calculated pseudorange and the actual distance as the correction amount, and combines other relevant information to complete the entire simulation process in the form of VDB RF output and message output, so as to provide it to the GBAS system for further processing and application.

[0079] In general, the GBAS pseudorange correction simulation method based on the GPS simulator of the present invention can accurately simulate the propagation characteristics of GPS signals in a complex atmospheric environment and provide effective pseudorange correction data, which is helpful to improve the navigation accuracy and reliability of the GBAS system.

[0080] In one embodiment of the present invention, the GPS intermediate frequency signal is remodulated according to the atmospheric parameter information, the GPS intermediate frequency signal interfered by the atmosphere is simulated and outputted through the GPS radio frequency port, including:

[0081] According to the atmospheric parameter information, the atmospheric refraction model and ionosphere model are used to remodulate the GPS intermediate frequency signal to simulate the GPS intermediate frequency signal interfered by the atmosphere;

[0082] Function of PRC caused by atmospheric refraction:

[0083] = (14.588+0.0029611 )-0.3048[0.00586 +294] }c

[0084] Function of PRC caused by atmospheric ionization:

[0085]

[0086] In the formula, : Atmospheric refraction delay error; : ground refractive index; : altitude angle; : speed of light; : ionospheric residual delay; : ionospheric coefficient; : Doppler frequency; : Carrier frequency.

[0087] In one embodiment of the present invention, the pseudorange and the actual range of the satellite and the user are differentiated to obtain pseudorange correction data, including:

[0088] The calculation formula of pseudorange correction data is obtained according to the pseudorange difference formula:

[0089] ;

[0090] In the formula, : current time; : Parameters defined in the RTCA246 standard are broadcast via VDB; The time difference between the two signals received by the receiver, the modified Z count: indicates the applicability time of all parameters in the message. The modified Z count determines the reference time of all parameters in the message; : Pseudorange correction; : Pseudorange correction rate; : Actual distance; : measured pseudorange; : Doppler frequency; : Clock correction; : Ionospheric residual delay.

[0091] In one embodiment of the present invention, demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain the measured pseudorange includes:

[0092] The received GPS intermediate frequency signal is converted, filtered and coherently demodulated by using FPGA, and the satellite signal is locked and the pseudorange is measured by combining the ephemeris message and the parameter information set by the user through a serial search algorithm. The serial search algorithm uses the Doppler frequency deviation to bias the received signal.

[0093] In one embodiment of the present invention, the method further comprises:

[0094] The satellite position is obtained according to the ephemeris message, and the distance between the satellite position and the user's real-time longitude and latitude is divided by the speed of light to obtain the actual distance between the satellite and the user.

[0095] set up : Actual distance; : measured pseudorange; : Pseudorange correction; : Pseudorange correction rate; : Atmospheric refraction delay error; : ionospheric residual delay; : ground refractive index; : aircraft refractive index; : Clock correction; : Doppler frequency; is the altitude angle; : atmospheric pressure; Temperature;

[0096] Reference Figure 4 , simulating GBAS environment.

[0097] According to the formula for calculating pseudorange difference:

[0098]

[0099] We can get: ;

[0100] The atmospheric refraction model is as follows:

[0101] = (14.588+0.0029611 )-0.3048[0.00586 +294] }c

[0102] A simplified model can also be introduced:

[0103]

[0104] However, the aircraft and the ground station are not at the same altitude, and the refractive index is different, so the model is introduced:

[0105]

[0106] Since the higher the altitude, the lower the temperature and the lower the atmospheric pressure, the first variable can be omitted:

[0107]

[0108] In the formula, is the ionospheric coefficient, , , , ,

[0109] Ionosphere Model:

[0110]

[0111]

[0112] Among them, the speed of light c and the carrier frequency ϖ are constants, is the standard deviation of the normal distribution associated with the residual ionospheric uncertainty of spatial decorrelation. This parameter, combined with the satellite altitude angle, the radius of the earth, and the user speed, can calculate the ionospheric difference. Finally, the function is obtained:

[0113]

[0114] in, , , It is the VDB message user input. , , , is calculated, , It is obtained from the ephemeris message. =1575.42MHz, the Doppler frequency calculation formula is known to be:

[0115]

[0116] Reference Figure 5 , a schematic diagram of simulating the generation of GPS intermediate frequency signals. Through this model, the independent variable is By adjusting the dependent variable t, the GPS intermediate frequency signal simulating atmospheric interference can be generated:

[0117]

[0118] One channel of GPS intermediate frequency signal is converted and output, and the other channel needs to be demodulated and tracked for measurement. Although the pseudorange differential formula has been determined ; However, in the actual GBAS, there are other unsimulated interferences that cause Therefore, the present invention utilizes the difference between the clocks of the intermediate frequency transceiver 1 and the intermediate frequency transceiver 2 and the actual transmission of the intermediate frequency signal to further simulate the GBAS system environment.

[0119] Serial search has the advantages of simple algorithm and less resources occupied by hardware operation. However, traditional serial search requires satellite-by-satellite phase-by-phase Doppler search, which is extremely inefficient. Therefore, the present invention uses a GPS simulator with known ephemeris messages and user-set parameters. When performing serial search, only known enabled satellites are searched, and the received intermediate frequency signal is offset to the baseband signal using the known Doppler frequency deviation, which greatly reduces the search time.

[0120] Reference Figure 6 , based on local analog GPS demodulation.

[0121] A is the amplitude, i is the satellite number, n is the number of satellites used, is the GPS signal, ϖ is the intermediate frequency, and f is the Doppler frequency. is the altitude angle, is the intermediate frequency phase, the intermediate frequency signal expression generated by the GPS simulator can be obtained as:

[0122]

[0123]

[0124] In the formula, is an I-channel signal, which represents the RF signal after the baseband signal is modulated by the carrier; It is the Q-channel signal, which represents the RF signal after the baseband signal is modulated by the carrier.

[0125] The model is used for abnormal simulation, where is the phase difference from the signal to the intermediate frequency transceiver 2, is the offset of the model, but the receiving end and the transmitting end are not absolutely identical:

[0126]

[0127]

[0128] In the formula, To simulate atmospheric interference, the I-channel signal is affected by delay, amplitude, frequency deviation, phase, multipath, etc. In order to add atmospheric interference to the simulation, the Q-path signal is affected in terms of time delay, amplitude, frequency deviation, phase, multipath, etc.

[0129] Known , and perform frequency deviation to 0 frequency:

[0130]

[0131] The low-frequency interference is caused by the frequency deviation, which is also the error generated by the non-simultaneous reception and transmission. The local C / A code of the i-th satellite is generated locally for coherence:

[0132]

[0133] Where k is the code phase of the i-th satellite. When the local C / A code and the received C / A code are in phase, k= When , the local C / A code signal resonates with the i-th satellite, and the amplitude value is the largest. On the contrary, the two signals are orthogonal, and the multiplication amplitude is approximately equal to 0:

[0134]

[0135] The same logic can be applied to Q path:

[0136]

[0137] Add two ways:

[0138]

[0139] The phase perturbation follows a zero-mean Gaussian distribution:

[0140]

[0141] In the formula, yes The square of the standard deviation of is the standard deviation.

[0142] Adding a code loop filter to eliminate phase disturbance and noise can obtain:

[0143]

[0144] From this formula, we can see that the carrier loop phase detector is no longer needed. When the maximum value is obtained, k is the phase among the 1023 captured C / A codes. The locked phase enters the code tracking program to determine whether it is within the advance, synchronization, and lag codes. Since the satellite and the user have relative speed, the distance from the satellite to the user changes all the time, resulting in phase changes. The threshold is the upper and lower limits of the phase change per unit time. When the threshold is exceeded, the phase code is estimated and output using the three pre-locked advance, synchronization, and lag states; when the threshold is not exceeded, the measured value, that is, the pseudorange, is output, and the difference between the measured value and the estimated value is fed back into the code loop filter. The estimated value is due to the relative speed between the satellite and the user, which is roughly the same in a short period of time. GPS serial demodulation takes time to search, and the result of the solution is slow to respond. Therefore, it is necessary to use its phase change speed to estimate (based on the demodulation time) the current phase estimate. The experimental results are as follows Figure 7 .

[0145] By differentiating the measured pseudorange with the actual range in the GPS simulator, the required correction parameters can be obtained. The simulation effect is as follows: Figure 8 .

[0146] The present invention is based on a PXIe chassis and uses modular hardware. A single device can realize all functions of the ground and satellite ends of the GLS system. It has the advantages of arbitrary modification of longitude and latitude, small device size, and easy construction of the test environment. In addition, a new algorithm architecture for differential correction is designed, such as a code tracking loop based on known GPS parameters, which reduces the time of phase locking and the resources occupied by hardware operations, while simulating the errors caused by actual environmental reception.

[0147] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0148] Reference Fig. 9 , shows a structural block diagram of a GBAS pseudorange correction simulation device based on a GPS simulator provided in an embodiment of the present invention, which may specifically include the following modules:

[0149] The user-set parameter information acquisition module is used to obtain the atmospheric parameter information, glide path, and airport information set by the user;

[0150] The user's real-time position and speed calculation module is used to generate the user's real-time latitude, longitude and speed based on the glide path and airport information;

[0151] The signal simulation module is used to provide the satellite position information using the ephemeris data when the initial time is input, and simulate the generation of the GPS intermediate frequency signal reaching the ground;

[0152] The atmospheric interference simulation module is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, simulate the GPS intermediate frequency signal interfered by the atmosphere and output it through the GPS radio frequency port;

[0153] The pseudorange measurement module is used to demodulate the GPS intermediate frequency signal interfered by the atmosphere to obtain the measured pseudorange;

[0154] The differential module is used to differentiate the pseudo-range and the actual range of the satellite and the user to obtain pseudo-range correction data, and to package the pseudo-range correction data into a VDB message for output.

[0155] Optionally, the atmospheric parameter information includes refractive index, ionospheric residual, and elevation.

[0156] Optionally, the atmospheric disturbance simulation module includes:

[0157] The atmospheric interference simulation submodule is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, using the atmospheric refraction model and the ionosphere model, to simulate the GPS intermediate frequency signal interfered by the atmosphere;

[0158] Function of PRC caused by atmospheric refraction:

[0159] = (14.588+0.0029611 )-0.3048[0.00586 +294] }c

[0160] Function of PRC caused by atmospheric ionization:

[0161]

[0162] In the formula, : Atmospheric refraction delay error; : ground refractive index; : altitude angle; : speed of light; : ionospheric residual delay; : ionospheric coefficient; : Doppler frequency; : Carrier frequency.

[0163] Optionally, the differential module includes:

[0164] The differential calculation submodule is used to obtain the calculation formula of the pseudorange correction data according to the pseudorange differential formula:

[0165] ;

[0166] In the formula, : current time; : Parameters defined in the RTCA246 standard are broadcast via VDB; : Pseudorange correction; : Pseudorange correction rate; : Actual distance; : measured pseudorange; : Doppler frequency; : Clock correction; : Ionospheric residual delay.

[0167] Optionally, the pseudorange measurement module includes:

[0168] The pseudorange measurement submodule is used to use FPGA to perform frequency conversion, filtering and coherent demodulation on the received GPS intermediate frequency signal, lock the satellite signal and measure the pseudorange through a serial search algorithm combined with the ephemeris message and the parameter information set by the user. The serial search algorithm uses the Doppler frequency deviation to bias the received signal.

[0169] Optionally, the device further comprises:

[0170] The actual distance calculation module is used to obtain the satellite position according to the ephemeris message, and divide the distance between the satellite position and the user's real-time longitude and latitude by the speed of light to obtain the actual distance between the satellite and the user.

[0171] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0172] In addition, an embodiment of the present invention further provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus 404.

[0173] Memory, used to store computer programs;

[0174] The processor is used to implement the GBAS pseudorange correction simulation method based on the GPS simulator as described in the above embodiment when executing the program stored in the memory.

[0175] The communication bus mentioned in the above terminal can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0176] The communication interface is used for communication between the above terminal and other devices.

[0177] The memory may include a random access memory (RAM) or a non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0178] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0179] In another embodiment of the present invention, a computer-readable storage medium is provided, in which instructions are stored. When the computer-readable storage medium is executed on a computer, the computer executes the GBAS pseudorange correction simulation method based on the GPS simulator described in the above embodiment.

[0180] In another embodiment of the present invention, a computer program product including instructions is provided. When the computer is run on the computer, the computer executes the GBAS pseudorange correction simulation method based on the GPS simulator described in the above embodiment.

[0181] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0182] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A GBAS pseudorange correction simulation method based on a GPS simulator, characterized in that: The GLS simulator includes a GPS simulator and a VDB simulator, and the method includes: Get the atmospheric parameter information, glide path, and airport information set by the user; Generate the user's real-time latitude, longitude and speed based on the glide path and airport information; When the initial time is input, the ephemeris data is used to provide the satellite position information and simulate the generation of GPS intermediate frequency signals reaching the ground; According to the atmospheric parameter information, the GPS intermediate frequency signal is remodulated to simulate the GPS intermediate frequency signal interfered by the atmosphere and output through the GPS radio frequency port; Demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain a measured pseudorange; Differentiate the pseudorange and actual range of the satellite and the user to obtain pseudorange correction data, and package the pseudorange correction data into a VDB message for output; According to the atmospheric parameter information, the GPS intermediate frequency signal is remodulated to simulate the GPS intermediate frequency signal interfered by the atmosphere and output through the GPS RF port, including: According to the atmospheric parameter information, the atmospheric refraction model and ionosphere model are used to remodulate the GPS intermediate frequency signal to simulate the GPS intermediate frequency signal interfered by the atmosphere; Function of PRC caused by atmospheric refraction: Function of PRC caused by atmospheric ionization: Where P t : atmospheric refraction delay error; N s : ground refractive index; θ i : altitude angle; c: speed of light; P io : ionospheric residual delay; σ io : ionospheric coefficient; f i : Doppler frequency; Carrier frequency; Difference the pseudo-range and actual range of the satellite and the user to obtain pseudo-range correction data, including: The calculation formula of pseudorange correction data is obtained according to the pseudorange difference formula: P(t)=PRC+RRC(t-t zcount )=P c -P n -P t -cΔT i -ΔP io ; Where, t: current time; t zcount : Parameters defined in the RTCA246 standard, broadcast through VDB; PRC: pseudorange correction; RRC: pseudorange correction rate; P c : Actual distance; P n : measured pseudorange; f i : Doppler frequency; ΔT i : Clock correction; ΔP io : Ionospheric residual delay.

2. The method according to claim 1, characterized in that: The atmospheric parameter information includes refractive index, ionospheric residual, and elevation.

3. The method according to claim 1, characterized in that Demodulating the GPS intermediate frequency signal interfered by the atmosphere to obtain a measured pseudorange, including: The received GPS intermediate frequency signal is converted, filtered and coherently demodulated by using FPGA, and the satellite signal is locked and the pseudorange is measured by combining the ephemeris message and the parameter information set by the user through a serial search algorithm. The serial search algorithm uses the Doppler frequency deviation to bias the received signal.

4. The method according to claim 1, characterized in that: The method further comprises: The satellite position is obtained according to the ephemeris message, and the distance between the satellite position and the user's real-time longitude and latitude is divided by the speed of light to obtain the actual distance between the satellite and the user.

5. A GBAS pseudorange correction simulation device based on a GPS simulator, characterized in that: The GLS simulator includes a GPS simulator and a VDB simulator, and the device includes: The user-set parameter information acquisition module is used to obtain the atmospheric parameter information, glide path, and airport information set by the user; The user's real-time position and speed calculation module is used to generate the user's real-time latitude, longitude and speed based on the glide path and airport information; The signal simulation module is used to provide the satellite position information using the ephemeris data when the initial time is input, and simulate the generation of the GPS intermediate frequency signal reaching the ground; The atmospheric interference simulation module is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, simulate the GPS intermediate frequency signal interfered by the atmosphere and output it through the GPS radio frequency port; The pseudorange measurement module is used to demodulate the GPS intermediate frequency signal interfered by the atmosphere to obtain the measured pseudorange; A differential module is used to differentiate the pseudo-range and actual range of the satellite and the user to obtain pseudo-range correction data, and to package the pseudo-range correction data into a VDB message for output; The atmospheric disturbance simulation module comprises: The atmospheric interference simulation submodule is used to remodulate the GPS intermediate frequency signal according to the atmospheric parameter information, using the atmospheric refraction model and the ionosphere model, to simulate the GPS intermediate frequency signal interfered by the atmosphere; Function of PRC caused by atmospheric refraction: Function of PRC caused by atmospheric ionization: Where P t : atmospheric refraction delay error; N s : ground refractive index; θ i : altitude angle; c: speed of light; P io : ionospheric residual delay; σ io : ionospheric coefficient; f i : Doppler frequency; Carrier frequency; The differential module comprises: The differential calculation submodule is used to obtain the calculation formula of the pseudorange correction data according to the pseudorange differential formula: P(t)=PRC+RRC(t-t zcount )=P c -P n -P t -cΔT i -ΔP io ; Where, t: current time; t zcount : Parameters defined in the RTCA246 standard, broadcast through VDB; PRC: pseudorange correction; RRC: pseudorange correction rate; P c : Actual distance; P n : measured pseudorange; f i : Doppler frequency; ΔT i : Clock correction; ΔP io : Ionospheric residual delay.

6. The device according to claim 5, characterized in that The atmospheric parameter information includes refractive index, ionospheric residual, and elevation.

7. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; The memory is used to store computer programs; The processor is used to implement the GPS simulator-based GBAS pseudorange correction simulation method as described in any one of claims 1 to 4 when executing the program stored in the memory.

8. One or more computer-readable media having instructions stored thereon, which, when executed by one or more processors, enable the processors to execute the GPS simulator-based GBAS pseudorange correction simulation method according to any one of claims 1 to 4.

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