GPS deception method based on SDR platform analog signal

Abstract

The invention discloses a GPS deception method based on SDR platform analog signals. The method comprises the following steps: determining the state of a GPS deception signal and deception target signal receiver based on an SDR platform and GPS-SDR-SIM software; a satellite position and a deception target position are determined based on the ephemeris data file and the initial motion parameters, signal propagation time is obtained based on the satellite position and the deception target position, and the signal propagation time is time when a satellite signal is transmitted to a deception target signal receiver; obtaining an initial phase, a carrier frequency and a code frequency of the GPS deception signal, and obtaining a transmission time difference of the GPS deception signal based on the signal propagation time; the phase difference of the GPS deception signal is obtained through a carrier phase formula, and the phase difference is converted into a corresponding I / Q signal sample. According to the method, the defects of an existing GPS deception method are at least overcome, the influence of the multipath effect and wall reflection on the GPS deception signal is reduced, and the possibility that real GPS data transmission is interrupted and unstable is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of GPS signal processing, and in particular to a GPS spoofing method based on SDR platform simulation signals. Background Art

[0002] GPS signal spoofing is a technical means of misleading the target receiver by forging or tampering with navigation signals. Its role in intelligence acquisition, strategic countermeasures and network information warfare is becoming increasingly prominent. Mastering GPS signal spoofing technology and its defense strategies can effectively enhance the country's offensive and defensive capabilities in electronic warfare, help identify and suppress enemy information attacks, and protect national interests. In addition, studying the principles and defense mechanisms of GPS spoofing interference can also provide technical support for the navigation anti-interference design of modern military equipment, thereby enhancing the reliability and stability of key systems.

[0003] Existing GPS spoofing technology still faces many challenges in practical applications. For example, due to the multipath effect, wall reflection and environmental changes, the fake signal transmission process may be unstable or interrupted, resulting in reduced spoofing effect.

[0004] Based on this, a new technical solution is needed. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a GPS spoofing method based on an SDR platform analog signal to at least solve the problems existing in the existing GPS spoofing technology.

[0006] The embodiment of the present invention provides the following technical solutions:

[0007] The embodiment of the present invention provides a GPS spoofing method based on an SDR platform simulation signal, comprising:

[0008] Initialize the initial parameters of the SDR platform and GPS-SDR-SIM software, and obtain the satellite's ephemeris data file and the initial motion parameters of the spoofed target;

[0009] Determine the status of the GPS spoofing signal and the spoofing target signal receiver based on the SDR platform and the GPS-SDR-SIM software;

[0010] Determine the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and obtain the signal propagation time based on the satellite position and the spoofed target position, wherein the signal propagation time is the time for the satellite signal to be transmitted to the spoofed target signal receiver;

[0011] Acquire the initial phase, carrier frequency, and code frequency of the GPS spoofing signal, and acquire the transmission time difference of the GPS spoofing signal based on the signal propagation time, wherein the transmission time difference is the time difference between the GPS spoofing signal and the reference signal transmitted by the satellite to the spoofing target signal receiver;

[0012] Based on the initial phase, the carrier frequency, the code frequency and the transmission time difference, obtain the phase difference of the GPS spoofing signal through a carrier phase formula, and convert the phase difference into a corresponding I / Q signal sample;

[0013] The GPS spoofing signal formed by the I / Q signal samples is transmitted to the mobile device to form signal spoofing.

[0014] Further, the obtaining of GPS spoofing signals includes:

[0015] The GPS spoofing signal is modulated based on a carrier wave of a first frequency and a second frequency, and the GPS spoofing signal includes a binary offset carrier wave and a pseudo-random noise code.

[0016] Furthermore, the obtaining of GPS spoofing signals also includes:

[0017] Acquire the signal amplitude and phase of the GPS spoofing signal through the satellite C / A code and satellite navigation data;

[0018] Acquire a carrier frequency through the carriers of the first frequency and the second frequency;

[0019] The binary offset carrier is obtained based on the signal amplitude, the phase, and the carrier frequency.

[0020] Furthermore, the obtaining of GPS spoofing signals also includes:

[0021] Acquire a satellite C / A code, and acquire an M sequence based on the satellite C / A code;

[0022] The pseudo-random noise code is obtained based on the C / A code and the M sequence.

[0023] Further, the determining the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and acquiring the signal propagation time based on the satellite position and the spoofed target position includes:

[0024] A satellite position and a spoofed target position are determined based on the ephemeris data file and the initial motion parameters, a pseudorange is acquired based on the satellite position and the spoofed target position, and a signal propagation time is acquired based on the pseudorange.

[0025] Furthermore, based on the pseudorange, a phase subtraction method is used to obtain a distance between the satellite and the spoofed target signal receiver, and the signal propagation time is obtained through the distance between the satellite and the spoofed target signal receiver.

[0026] Further, obtaining the signal propagation time also includes:

[0027] The pseudorange is obtained based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. The calculation formula of the pseudorange is as follows:

[0028] ρ measured =ρ+c·(δt iono +δt tro +δt sat +δt rec );

[0029] Among them, δt iono is the ionospheric delay, δt tro is the tropospheric delay, δt sat is the satellite clock error; δt rec is the receiver clock error.

[0030] Furthermore, the carrier phase formula is:

[0031]

[0032] Among them, φ s is the initial phase, f carr is the carrier frequency, f code is the code frequency, and Δt is the transmission time difference.

[0033] Further, after converting the phase difference into a corresponding I / Q signal sample, the method further includes:

[0034] Storing the I / Q signal samples in a buffer;

[0035] Based on the propagation delay caused by the electron density change in the ionosphere, obtaining the total path delay of the GPS spoofing signal from the satellite position to the spoofing target signal receiver position;

[0036] A GPS spoofing signal formed of the I / Q signal samples is transmitted to a mobile device based on the total path delay.

[0037] Further, transmitting the GPS spoofing signal formed by the I / Q signal sample to the mobile device includes:

[0038] The GPS spoofing signal is optimized using a random mutation hill climbing algorithm.

[0039] Compared with the prior art, the at least one technical solution adopted in the embodiment of the present invention can achieve the following beneficial effects:

[0040] The present invention discloses a GPS spoofing method based on an SDR platform simulation signal. The method comprises the following steps: initializing the initial parameters of the SDR platform and GPS-SDR-SIM software, and obtaining the satellite ephemeris data file and the initial motion parameters of the spoofing target; determining the status of the GPS spoofing signal and the spoofing target signal receiver based on the SDR platform and the GPS-SDR-SIM software; determining the satellite position and the spoofing target position based on the ephemeris data file and the initial motion parameters, and obtaining the signal propagation time based on the satellite position and the spoofing target position, wherein the signal propagation time is the time for the satellite signal to be transmitted to the spoofing target signal receiver; obtaining the initial phase, carrier frequency and code frequency of the GPS spoofing signal, and obtaining the transmission time difference of the GPS spoofing signal based on the signal propagation time, wherein the transmission time difference is the time difference between the GPS spoofing signal and the reference signal transmitted from the satellite to the spoofing target signal receiver; obtaining the phase difference of the GPS spoofing signal through a carrier phase formula based on the initial phase, carrier frequency, code frequency and transmission time difference, and converting the phase difference into a corresponding I / Q signal sample; and transmitting the GPS spoofing signal formed by the I / Q signal sample to a mobile device to form a signal spoofing. The present invention decomposes GPS spoofing signals into stages, solves them stage by stage, and integrates multi-stage constraints, thereby being able to simply decompose complex tasks into stages, thereby reducing the difficulty of generating GPS spoofing signals and making GPS signal application scenarios more flexible, ensuring that the generated GPS signals can complete the deception of civilian equipment at the fastest speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 It is a flow chart of a GPS spoofing method based on SDR platform simulation signal according to an embodiment of the present invention;

[0043] Figure 2 The present invention is a schematic diagram of an application scenario of a GPS spoofing method based on an SDR platform simulating signal according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0045] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0046] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0047] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0049] Based on this, this specification embodiment proposes a processing solution: Figures 1-2As shown, a GPS spoofing method based on SDR platform simulation signal of the present invention is carried out by determining that the software and hardware equipment environment has been prepared; obtaining real-time ephemeris file data through NASA, and determining the simulated user motion trajectory file or coordinate position; generating static or dynamic I\Q samples through instructions, and the SDR platform sends the simulated sample signal through instructions, so as to achieve the use of SDR to simulate GPS spoofing signals to deceive and interfere with GPS, and the present application can reduce the influence of multipath effects and wall reflections on GPS spoofing signals by simulating GPS signal samples, sending SDR signals and replacing the real GPS signals to be received, thereby reducing the possibility of real GPS data transmission interruption and signal instability.

[0050] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0051] like Figures 1-2 As shown, a GPS spoofing method based on SDR platform simulation signal of the present invention can be applied to a custom GPS signal spoofing interference method, such as spoofing of civil GPS signals, and the method includes:

[0052] Step S102: Initialize the initial parameters of the SDR platform and GPS-SDR-SIM software, and obtain the satellite's ephemeris data file and the initial motion parameters of the spoofed target.

[0053] Among them, the SDR (software defined radio) platform can flexibly configure the frequency, repetition and phase of the modulated signal for use in hardware generation tools for GPS spoofing signals.

[0054] Among them, GPS-SDR-SIM is a software used to generate simulated GPS signals, and supports the simulation processing of ephemeris data files and signal sample generation. Its initial parameters include geometric factors, ionospheric correction factors, phase parameters, etc.

[0055] Among them, the ephemeris data file includes real-time satellite orbit information, which is used to calculate the position and path of the satellite at a specific time.

[0056] Among them, the initial motion parameters are used to record the current position, speed, direction and other information of the deceived target, which is used to provide a basis for the subsequent adjustment of signal parameters.

[0057] Step S102 defines the initial conditions for generating a GPS spoofing signal, which includes a simulated environment, a dynamic target state, etc., to facilitate the subsequent generation of a GPS spoofing signal.

[0058] Step S104: Determine the status of the GPS spoofing signal and the spoofed target signal receiver based on the SDR platform and the GPS-SDR-SIM software.

[0059] The parameters of the GPS spoofing signal can be adjusted according to the status of the spoofed target signal receiver (such as frequency and time synchronization requirements).

[0060] Specifically, obtaining GPS spoofing signals includes:

[0061] Step S102a: modulating a GPS spoofing signal based on the carrier waves of the first frequency and the second frequency, wherein the GPS spoofing signal includes a binary offset carrier wave and a pseudo-random noise code.

[0062] For example, carriers with L1 and L2 frequencies are used for modulation, and the frequencies of the carriers are 1575.42 MHz and 1227.6 MHz respectively, and the modulation method is a binary offset carrier.

[0063] Furthermore, the process of obtaining the binary offset carrier is as follows:

[0064] Acquire the signal amplitude and phase of GPS spoofing signals through satellite C / A codes and satellite navigation data;

[0065] Acquire a carrier frequency through carriers of a first frequency and a second frequency;

[0066] Get a binary offset carrier based on signal amplitude, phase, and carrier frequency.

[0067] The calculation formula of binary offset carrier is as follows:

[0068] S(t)=A·cos(2πf C t+φ);

[0069] Where A is the amplitude, f c is the carrier frequency and φ is the phase.

[0070] Furthermore, the process of obtaining the pseudo-random noise code is as follows:

[0071] Obtain satellite C / A code, and obtain M sequence based on the satellite C / A code;

[0072] A pseudo-random noise code is obtained based on the C / A code and the M sequence.

[0073] Step S104 is used to modulate the GPS spoofing signal into a demodulatable legitimate signal and reduce the risk of the receiver detecting or rejecting the GPS spoofing signal.

[0074] Step S106: determine the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and obtain the signal propagation time based on the satellite position and the spoofed target position. The signal propagation time is the time it takes for the satellite signal to be transmitted to the spoofed target signal receiver.

[0075] Specifically, determining the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and acquiring the signal propagation time based on the satellite position and the spoofed target position includes:

[0076] The satellite position and the spoofed target position are determined based on the ephemeris data file and the initial motion parameters, and the pseudorange is obtained based on the satellite position and the spoofed target position, and the signal propagation time is obtained based on the pseudorange.

[0077] The calculation formula of pseudorange is:

[0078]

[0079] Where p is the pseudorange from the satellite to the receiver, (x s ,y s ) is the position of the satellite, and (x, y) is the position of the receiver.

[0080] Among them, in this application, the broadcast ephemeris data can be used to determine the satellite position and satellite velocity parameters at a specific time through Kepler's equations and Newton's law of gravity.

[0081] Furthermore, based on the pseudo-range, the distance between the satellite and the spoofed target signal receiver is obtained by using the phase subtraction method, and the signal propagation time is obtained by using the distance between the satellite and the spoofed target signal receiver.

[0082] Furthermore, obtaining the signal propagation time also includes:

[0083] The pseudorange is obtained based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. The pseudorange calculation formula is as follows:

[0084] ρ measured =ρ+c·(δt iono +δt tro +δt sat +δt rec );

[0085] Among them, δt iono is the ionospheric delay, δt tro is the tropospheric delay, δt sat is the satellite clock error; δt rec is the receiver clock error.

[0086] Step S106 can obtain the signal propagation time according to the distance between the satellite and the receiver, and correct the signal propagation time by taking into account factors such as multipath effects, ionosphere, and tropospheric delay, so as to obtain accurate signal propagation time, provide necessary input for the subsequent calculation of phase difference, time offset, and transmission time difference, and make the spatiotemporal properties of the GPS spoofing signal consistent with the real signal.

[0087] Step S108, obtain the initial phase, carrier frequency, and code frequency of the GPS spoofing signal, and obtain the transmission time difference of the GPS spoofing signal based on the signal propagation time. The transmission time difference is the time difference between the GPS spoofing signal and the reference signal transmitted by the satellite to the spoofed target signal receiver.

[0088] The initial phase is the seven points of the GPS spoofing signal waveform, the carrier frequency is the transmission frequency of the set signal, and the code frequency is the frequency of the pseudo-random noise code.

[0089] The transmission time difference is the difference between the timestamp of the GPS spoofing signal and the timestamp of the real satellite signal. The present application adjusts the time attribute of the GPS spoofing signal to form a small time offset to ensure that the GPS spoofing signal is captured first.

[0090] Step S108 can ensure that the physical properties (such as phase and frequency) of the GPS spoofing signal are consistent with the expectations of the target receiver, and enable the GPS spoofing signal to attract the target receiver to lock with a higher priority.

[0091] Step S110: Based on the initial phase, carrier frequency, code frequency and transmission time difference, the phase difference of the GPS spoofing signal is obtained by using a carrier phase formula, and the phase difference is converted into a corresponding I / Q signal sample.

[0092] Furthermore, the carrier phase formula is:

[0093]

[0094] Among them, φ s is the initial phase, f carr is the carrier frequency, f code is the code frequency, and Δt is the transmission time difference.

[0095] The carrier phase formula can be used to calculate the phase difference between the GPS spoofing signal and the real signal, and then the orthogonal modulation technology is used to map the phase difference into digital sampling values ​​of the I channel (in-phase component) and the Q channel (orthogonal component). The I / Q signal sample is the basic format of the signal transmitted by the SDR device.

[0096] Furthermore, the present application may first acquire satellite navigation data, and then divide it into five subframes, each subframe containing 10 words, and each word containing 25 bits; based on the carrier, C / A code and satellite navigation data, the final I / Q signal sample is generated, and the formula for calculating the I / Q signal sample is as follows:

[0097] I(t)=A·CA_code[t]·Data[t]

[0098] Q(t)=A·CA_code[t]·Data[t];

[0099] Where A is the amplitude, A·CA_code[t] is the C / A code, and Data[t] is the satellite navigation data.

[0100] Step S110 is used to convert the signal description of the mathematical model clock into a digital signal that can actually be transmitted.

[0101] Furthermore, after converting the phase difference into a corresponding I / Q signal sample, the method further includes:

[0102] Step S111a: store the I / Q signal samples in a buffer.

[0103] The I / Q signal samples are digital representations obtained through calculation, which are modulated GPS spoofing signals.

[0104] Specifically, on the SDR platform, all signal transmissions must go through digital sampling, buffer storage, hardware forwarding and other links.

[0105] The function of the buffer is to temporarily store the generated I / Q signal samples to prepare for subsequent modulation and transmission, and to avoid signal loss or delay caused by mismatch between signal generation speed and transmission speed.

[0106] Step S111b: based on the propagation delay caused by the electron density change in the ionosphere, the total path delay of the GPS spoofing signal from the satellite position to the spoofed target signal receiver position is obtained.

[0107] Among them, ionospheric delay is an important source of error in the GPS signal propagation process. When the GPS signal passes through the Earth's ionosphere, the uneven distribution of electron density affects the signal propagation speed, resulting in additional propagation delay.

[0108] The total path delay can be solved based on the ionospheric delay and pseudorange to obtain the total path delay that meets the mission requirements.

[0109] Step S111b is used to simulate the delay experienced by the real satellite signal during the propagation process, so that the GPS spoofing signal has a higher spoofing effect and prevents the target receiver from identifying the GPS spoofing signal by detecting the abnormality of ionospheric delay.

[0110] Step S111c: transmitting a GPS spoofing signal formed by I / Q signal samples to the mobile device based on the total path delay.

[0111] Specifically, when transmitting the signal, the calculated total path delay is used as the time attribute of the GPS spoofing signal and superimposed on the timestamp of the I / Q signal to dynamically adjust the signal transmission time to ensure that the GPS spoofing signal perceived by the target receiver arrives earlier than the real signal.

[0112] Step S111c achieves signal deception on the target receiver by successfully generating and transmitting a highly simulated GPS pseudo signal; simulates the path propagation delay characteristics of the real signal, improves the concealment and reliability of the pseudo signal; enhances the adaptability of the GPS deception signal in complex environments, and improves the deception efficiency.

[0113] Step S112: transmitting a GPS spoofing signal formed by the I / Q signal samples to the mobile device to form signal spoofing.

[0114] The generated I / Q signal samples are loaded into the SDR buffer, and the operating frequency, transmission gain and power of the SDR device are configured to ensure that the GPS spoofing signal can suppress the real signal so that the GPS spoofing signal covers the real signal.

[0115] Further, transmitting the GPS spoofing signal formed by the I / Q signal sample to the mobile device includes:

[0116] Optimizing GPS spoofing signals using random mutation hill climbing algorithm.

[0117] Specifically, the optimization strategy for solving the random mutation hill climbing algorithm to improve the receiver acceptance efficiency is as follows:

[0118] Determine the population size N, randomly generate N initial solutions {x1, x2, ..., x N}, each solution expresses a candidate solution;

[0119] Determine a fitness function f(x) to evaluate the quality of each solution. For example, for a minimization problem, the fitness function may be f(x) = -g(x), where g(x) is the objective function;

[0120] According to the algorithm, the solution selects a part of the solutions from the current population as parents through the selection operator (such as roulette selection, tournament selection, etc.);

[0121] Based on the selected parent generation, mutation is performed to generate a new solution. Assuming that each solution xx is a vector, the mutation operation can be implemented by the following formula x′=x+N(0,σ 2 );

[0122] x' is the new solution after mutation, x is the parent solution, N(0,σ 2 ) has a mean of 0 and a variance of σ 2 Gaussian noise;

[0123] Determine the global optimal solution strategy.

[0124] Furthermore, in some cases, a crossover operation can be used to combine features of two parent solutions.

[0125] For example, x1 and x2 are two parent solutions, β is a random number in the interval [0,1] and the uniform crossover can be expressed as: x′=(1-β)x1+βx2.

[0126] Furthermore, the newly generated solution is compared with the solutions in the current population, and the better solution is selected according to the fitness function to be replaced in the next generation;

[0127] Repeat the steps of selecting operators to replace until the stopping condition is met (such as reaching the maximum number of iterations or the quality of the solution is no longer significantly improved);

[0128] Furthermore, the optimal solution obtained is the approximate global optimal solution to the problem.

[0129] In a specific embodiment of the present application, Figure 2 As shown, the latest ephemeris data can be acquired through the acquisition and processing device, and then a custom GPS signal can be generated. After the acquisition and processing device sends the custom GPS signal to the radio device, the radio device sends a simulated GPS signal to deceive the mobile device.

[0130] The specific steps of the present invention include reading the ephemeris file, inputting the user's location name (or latitude and longitude, altitude), and sampling rate and other information, and then generating a binary file through software. The generated file complies with the I / Q sampling data format, specifically the SC16 format, and transmits signals through the SDR platform to achieve the task of deceiving the mobile device.

[0131] Compared with the prior art, the technical solution of the present invention aims at the scenario of deceiving the signals of civilian GPS devices, solves the problem of GPS signals generated by software-defined radio technology to deceive the GPS signals of civilian devices, and adopts a method of decomposing the simulated GPS signals into stages, solving them stage by stage, and fusing multi-stage constraints. The beneficial effects that can be achieved include at least: it can simply decompose complex tasks into stages, provide a solution method and layout strategy for the problem of SDR generating custom GPS signals to deceive civilian devices, and support the needs of space mission planning; it can quickly and accurately generate a path map passing through the specified user trajectory, solving the problem of deceiving GPS signals; it can make the application scenarios of GPS signals more flexible, and ensure that the generated GPS signals can complete the deception of civilian devices at the fastest speed.

[0132] In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the product embodiment described later, since it corresponds to the method, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment.

[0133] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A GPS spoofing method based on SDR platform simulation signal, characterized in that: include: Initialize the initial parameters of the SDR platform and GPS-SDR-SIM software, and obtain the satellite's ephemeris data file and the initial motion parameters of the spoofed target; Determine the status of the GPS spoofing signal and the spoofing target signal receiver based on the SDR platform and the GPS-SDR-SIM software; Determine the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and obtain the signal propagation time based on the satellite position and the spoofed target position, wherein the signal propagation time is the time for the satellite signal to be transmitted to the spoofed target signal receiver; Acquire the initial phase, carrier frequency, and code frequency of the GPS spoofing signal, and acquire the transmission time difference of the GPS spoofing signal based on the signal propagation time, wherein the transmission time difference is the time difference between the GPS spoofing signal and the reference signal transmitted by the satellite to the spoofing target signal receiver; Based on the initial phase, the carrier frequency, the code frequency and the transmission time difference, obtain the phase difference of the GPS spoofing signal through a carrier phase formula, and convert the phase difference into a corresponding I / Q signal sample; The GPS spoofing signal formed by the I / Q signal samples is transmitted to the mobile device to form signal spoofing.

2. The GPS spoofing method according to claim 1, characterized in that: The obtaining of GPS spoofing signals comprises: The GPS spoofing signal is modulated based on a carrier wave of a first frequency and a second frequency, and the GPS spoofing signal includes a binary offset carrier wave and a pseudo-random noise code.

3. The GPS spoofing method according to claim 2, characterized in that: The obtaining of GPS spoofing signals also includes: Acquire the signal amplitude and phase of the GPS spoofing signal through the satellite C / A code and satellite navigation data; Acquire a carrier frequency through the carriers of the first frequency and the second frequency; The binary offset carrier is obtained based on the signal amplitude, the phase, and the carrier frequency.

4. The GPS spoofing method according to claim 2, characterized in that: The obtaining of GPS spoofing signals also includes: Acquire a satellite C / A code, and acquire an M sequence based on the satellite C / A code; The pseudo-random noise code is obtained based on the C / A code and the M sequence.

5. The GPS spoofing method according to claim 1, characterized in that: The determining of the satellite position and the spoofed target position based on the ephemeris data file and the initial motion parameters, and acquiring the signal propagation time based on the satellite position and the spoofed target position comprises: A satellite position and a spoofed target position are determined based on the ephemeris data file and the initial motion parameters, a pseudorange is acquired based on the satellite position and the spoofed target position, and a signal propagation time is acquired based on the pseudorange.

6. The GPS spoofing method according to claim 5, characterized in that: Based on the pseudo-range, the distance between the satellite and the spoofed target signal receiver is obtained by using a phase subtraction method, and the signal propagation time is obtained by using the distance between the satellite and the spoofed target signal receiver.

7. The GPS spoofing method according to claim 6, characterized in that: Acquiring the signal propagation time further includes: The pseudorange is obtained based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. The calculation formula of the pseudorange is as follows: r measured =ρ+c·(δt iono +δt tro +δt sat +δt rec ); Among them, δt iono is the ionospheric delay, δt tro is the tropospheric delay, δt sat is the satellite clock error; δt rec is the receiver clock error.

8. The GPS spoofing method according to claim 1, characterized in that: The carrier phase formula is: Among them, φ s is the initial phase, f carr is the carrier frequency, f code is the code frequency, and Δt is the transmission time difference.

9. The GPS spoofing method according to claim 1, characterized in that: After converting the phase difference into a corresponding I / Q signal sample, the method further includes: Storing the I / Q signal samples in a buffer; Based on the propagation delay caused by the electron density change in the ionosphere, obtaining the total path delay of the GPS spoofing signal from the satellite position to the spoofing target signal receiver position; A GPS spoofing signal formed of the I / Q signal samples is transmitted to a mobile device based on the total path delay.

10. The GPS spoofing method according to claim 1, characterized in that: Transmitting the GPS spoofing signal formed by the I / Q signal sample to the mobile device includes: The GPS spoofing signal is optimized using a random mutation hill climbing algorithm.

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