Environment Adaptive Navigation Device and Method for Low Earth Orbit Navigation Enhancement

Abstract

The present invention relates to an environment adaptive navigation device suitable for low-earth orbit navigation augmentation, comprising: a GNSS / low-earth orbit satellite signal receiving antenna for receiving GNSS signals or low-earth orbit satellite signals; a radio frequency module for performing low-noise amplification and down-conversion processing on GNSS signals or low-earth orbit satellite signals and outputting digital intermediate frequency signals; a system-level navigation chip for performing acquisition and tracking, synchronization decoding, and positioning and timing on the digital intermediate frequency signals; a clock management module for providing a sampling clock signal for the radio frequency module and a baseband operating clock signal for the system-level navigation chip; and a power supply module for providing power for the GNSS / low-earth orbit satellite signal receiving antenna, the clock management module, the radio frequency module, and the system-level navigation chip. The present invention can receive and process GNSS satellite signals and low-earth orbit satellite signals. When the GNSS signals cannot be normally acquired, a low-earth orbit satellite signal assistance strategy is enabled to quickly acquire weak GNSS navigation star signals and complete GNSS navigation positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite communication and navigation, and in particular to an environment adaptive navigation device and method suitable for low-earth orbit navigation enhancement. Background Art

[0002] In recent years, with the comprehensive application of satellite navigation in various industries, higher requirements have been put forward for the GNSS satellite navigation system, such as higher performance in system integrity, anti-jamming, high-precision navigation, etc. Therefore, various satellite systems for improving satellite navigation performance have emerged, such as augmentation systems, low-earth orbit satellite systems, etc.

[0003] The development of low-earth orbit communication satellites is rapid. Due to the low orbit altitude of low-earth orbit satellites, high landing power, and the low operating cost of low-earth orbit microsatellites, the research on low-earth orbit satellite systems has gradually increased. The low-earth orbit satellite communication system can be widely applied to various fields such as mobile communication, Internet, navigation enhancement, target monitoring, etc. Among them, the research on low-earth orbit satellites in the direction of satellite navigation anti-jamming is also becoming more and more in-depth. Whether in the military field or the civilian field, how to quickly capture the navigation star signal in various complex environments has always been a difficult point. Many traditional capture algorithms are either complex and resource-consuming or difficult to apply in practice, and in general, the effects are not ideal.

[0004] The existing low-earth orbit satellite systems attempt to forward the GNSS navigation star message information synchronously through the low-earth orbit satellite system, so as to assist various navigation devices to obtain the GNSS navigation star signal. However, there is no such navigation device that can effectively solve how the navigation device realizes the reception and processing of low-earth orbit satellite signals and how to correctly apply the navigation star information assisted by low-earth orbit navigation enhancement. Summary of the Invention

[0005] To overcome the defects in the above-mentioned prior art, the purpose of the present invention is to provide an environment adaptive navigation device and method suitable for low-earth orbit navigation enhancement, which can receive and process low-earth orbit satellite signals, and quickly capture and stably track weak GNSS signals in the case of weak GNSS signals or interference. At the same time, it can also capture normal GNSS satellite signals, so as to achieve precise GNSS navigation and positioning.

[0006] To achieve the above-mentioned invention purpose, the technical solution of the present invention is as follows:

[0007] The present invention provides an environment adaptive navigation device suitable for low-earth orbit navigation enhancement, including: a GNSS / low-earth orbit satellite signal receiving antenna, a radio frequency module, a system-level navigation chip, a clock management module, and a power supply module.

[0008] The GNSS / low-earth orbit satellite signal receiving antenna is used to receive GNSS signals and low-earth orbit satellite signals.

[0009] The radio frequency module is used to perform low-noise amplification and down-conversion processing on the GNSS signal or the low-earth orbit satellite signal, and output a digital intermediate frequency signal;

[0010] The system-level navigation chip is used to capture and track, synchronize and decode, and position and time the digital intermediate frequency signal;

[0011] The clock management module is used to provide a sampling clock signal for the radio frequency module and a baseband working clock signal for the system-level navigation chip;

[0012] The power supply module is used to provide power for the GNSS / low-earth orbit satellite signal receiving antenna, the clock management module, the radio frequency module, and the system-level navigation chip.

[0013] According to one aspect of the present invention, the clock management module includes: an oven-controlled crystal oscillator and a frequency synthesizer,

[0014] The oven-controlled crystal oscillator is used to provide a high-precision and stable reference clock signal for the frequency synthesizer;

[0015] The frequency synthesizer is used to adjust the reference clock signal into a sampling clock signal and output a baseband working clock signal at the same time.

[0016] According to one aspect of the present invention, the radio frequency module includes: a local oscillator generation module, a mixing module, a low-pass filter, and an AD sampling module,

[0017] The local oscillator generation module is used to generate a local oscillator signal based on the sampling clock signal;

[0018] The mixing module is used to mix the GNSS signal and the low-earth orbit satellite signal with the corresponding local oscillator signals respectively;

[0019] The low-pass filter is used to filter out the high-frequency part of the mixed signal and leave a low-frequency analog intermediate frequency signal;

[0020] The AD sampling module is used to sample the analog intermediate frequency signal under the drive of the sampling clock signal to generate a digital intermediate frequency signal.

[0021] According to one aspect of the present invention, the system-level navigation chip includes: a baseband processing module and a signal processing module,

[0022] The baseband processing module includes a capture module and a tracking module,

[0023] The capture module is used to capture the GNSS signal and the low-earth orbit satellite signal;

[0024] The tracking module is used to complete the loop tracking processing, synchronization processing, and decoding processing of the GNSS signal and the LEO satellite signal, calculate the observables of the GNSS signal and the LEO satellite signal, and output the observable information, time information, and message information of the GNSS signal and the LEO satellite signal;

[0025] The signal processing module includes a single satellite positioning module and a GNSS navigation positioning module.

[0026] The single satellite positioning module is used to output rough position and velocity information according to the observable information, time information, and message information of the LEO satellite signal;

[0027] The GNSS navigation positioning module is used to achieve GNSS navigation positioning according to the observable information, time information, and message information of the GNSS signal.

[0028] According to one aspect of the present invention, the observable information of the GNSS signal and the LEO satellite signal both include pseudorange observables and Doppler observables.

[0029] An environment adaptive navigation method suitable for LEO navigation enhancement implemented by using the environment adaptive navigation device suitable for LEO navigation enhancement as described above includes:

[0030] S1. Receive the GNSS signal and the LEO satellite signal by using the GNSS / LEO satellite signal receiving antenna;

[0031] S2. When the GNSS signal is a strong signal, perform acquisition tracking, synchronization, decoding, and observable calculation on the GNSS signal to achieve GNSS signal navigation positioning. When the GNSS signal is a weak signal, execute steps S3 - S4;

[0032] S3. Process the LEO satellite signal to achieve acquisition tracking, synchronization, decoding, observable calculation, and single satellite positioning calculation of the LEO satellite signal;

[0033] S4. Use the processed LEO satellite signal to assist the GNSS weak signal for fast acquisition and stable tracking to achieve GNSS signal navigation positioning.

[0034] According to another aspect of the present invention, the step S3 includes:

[0035] S31. Use the RF module to perform low - noise amplification and down - conversion processing on the LEO satellite signal, and output a digital intermediate - frequency signal;

[0036] S32. Use the clock management module to provide a sampling clock signal for the RF module and a baseband working clock signal for the system - level navigation chip;

[0037] S33. Use the system-level navigation chip to capture, track, synchronize and decode the co-directional and orthogonal signals of the digital intermediate frequency signal to obtain the navigation message information and time information of the low-orbit satellite and the navigation message information and time information of the GNSS navigation star;

[0038] S34. Calculating the observed value of the low-orbit satellite signal according to the navigation message information of the low-orbit satellite;

[0039] S35. Using the single-star positioning module of the system-level navigation chip to obtain positioning and timing results based on the observed values;

[0040] S36. Calculate the phase and Doppler information of the GNSS navigation star based on the positioning and timing results and the navigation message information of the GNSS navigation star.

[0041] According to another aspect of the present invention, the process of obtaining the GNSS navigation star phase in step S36 includes:

[0042] S3611. Use the navigation message information and time information of the GNSS navigation star to obtain the position and speed of the GNSS navigation star;

[0043] S3612. Calculate a rough pseudorange ρ1 according to the position of the GNSS navigation star and the position of the navigation device;

[0044] S3613. Considering the influence of the ionosphere, troposphere and satellite clock error, the pseudorange ρ1 is corrected to obtain a corrected pseudorange ρ2;

[0045] S3614. Calculate a rough propagation time T1 according to the pseudorange ρ2;

[0046] S3615. Repeat the steps S3611 to S3614 to obtain the accurate propagation time T2, and combine the reception time of the navigation device to obtain the transmission time T S , thereby obtaining the initial code phase.

[0047] According to another aspect of the present invention, the process of obtaining the GNSS navigation star Doppler information in step S36 includes:

[0048] S3621. Obtain the position velocity of the GNSS navigation star after iteration in the calculation method of the accurate phase of the GNSS navigation star;

[0049] S3622. Calculate a rough Doppler D1 based on the position velocity of the GNSS navigation star and the position velocity information of the navigation device;

[0050] S3623. Consider the influence of the clock drift of the navigation device, correct the rough Doppler D1, and obtain the accurate Doppler D2.

[0051] Advantageous effects:

[0052] According to the solution of the present invention, it is compatible with normal GNSS signal processing and low-earth orbit satellite signal processing. When the GNSS signal is strong, normal GNSS navigation and positioning can be carried out. When the GNSS signal is weak or there is interference resulting in the inability to normally capture the GNSS signal, the low-earth orbit satellite assistance strategy is enabled, and the low-earth orbit satellite information is used to assist the rapid capture and stable tracking of the GNSS navigation satellite signal. After obtaining the observables, GNSS navigation and positioning are completed. Thus, adaptive rapid navigation and positioning under different signal environment conditions are realized.

[0053] The present invention realizes the reception and processing of low-earth orbit satellite signals, synchronously processes the I / Q two-channel telegram information, accurately obtains the low-earth orbit satellite telegram information and the GNSS navigation satellite telegram information, realizes the rough positioning and timing of the navigation device, and accurately calculates the initial phase and Doppler information of the GNSS navigation satellite, realizes the rapid capture of the GNSS navigation satellite signal, uses the long-time coherent integration method to realize the rapid capture of weak signals and the stable tracking of weak signals, and finally realizes GNSS navigation and positioning.

[0054] The present invention provides a high-performance navigation device for application scenarios where the GNSS navigation satellite signal is weak or there is interference, and can be widely applied to different application scenarios such as military and civilian. At the same time, the present invention is not only applicable to ground navigation, but can also be extended to various navigation application terminals such as sea, land, and air, improving the GNSS navigation and positioning ability in complex environments.

[0055] The present invention adopts a hardware platform based on an SoC navigation chip, realizing miniaturization and low power consumption while improving the processing speed of the navigation device. Description of the drawings

[0056] Figure 1 Schematic diagram showing the structure of an environment-adaptive navigation device for low-earth orbit navigation enhancement according to an embodiment of the present invention;

[0057] Figure 2 Schematic block diagram showing the principle of an environment-adaptive navigation device for low-earth orbit navigation enhancement according to an embodiment of the present invention;

[0058] Figure 3 Schematic flowchart showing an environment-adaptive navigation method for low-earth orbit navigation enhancement according to an embodiment of the present invention;

[0059] Figure 4 Schematic flowchart showing the low-earth orbit satellite signal processing of an environment-adaptive navigation method for low-earth orbit navigation enhancement according to an embodiment of the present invention;

[0060] Figure 5 Flowchart of the GNSS navigation star initial phase calculation method for the environment - adaptive navigation method of low - orbit navigation enhancement showing an embodiment of the present invention;

[0061] Figure 6 Flowchart of the calculation method for the GNSS navigation star Doppler information of the environment - adaptive navigation method of low - orbit navigation enhancement showing an embodiment of the present invention. Detailed implementation manners

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0063] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners. The implementation manners cannot be elaborated one by one here, but the implementation manners of the present invention are not limited to the following embodiments.

[0064] According to the concept of the present invention, on the one hand, it can be compatible with the processing of normal GNSS signals and low - orbit satellite signals. When the GNSS signal is strong, the low - orbit navigation enhancement environment - adaptive navigation device of the present invention can directly perform navigation positioning on the normal GNSS signal; when the GNSS signal is weak or there is interference resulting in the inability to normally capture the GNSS signal, the low - orbit satellite assistance strategy is enabled, and the low - orbit satellite information is used to assist the rapid capture and stable tracking of the GNSS navigation star signal. After obtaining the observables, GNSS navigation positioning is completed. Thus, adaptive rapid navigation positioning under different signal environment conditions is realized. On the other hand, it can also realize the reception and processing of low - orbit satellite signals. Synchronously process the in - phase I / quadrature Q two - path telegram information, accurately obtain the low - orbit satellite telegram information and the GNSS navigation star telegram information, realize the rough positioning and timing of the navigation device, and accurately calculate the initial phase and Doppler information of the GNSS navigation star, realize the rapid capture of the GNSS navigation star signal, use the long - time coherent integration method to realize the rapid capture of weak GNSS signals and the stable tracking of weak signals, and finally realize GNSS navigation positioning.

[0065] Such as Figure 1As shown in the figure, the environment-adaptive navigation device for low-orbit navigation enhancement in this embodiment includes: a GNSS / low-orbit satellite signal receiving antenna, a radio frequency module, a system-on-chip (SoC) navigation chip, a clock management module, and a power supply module. The GNSS / low-orbit satellite signal receiving antenna is used to receive GNSS signals and low-orbit satellite signals; the radio frequency module is used to perform low-noise amplification and down-conversion processing on the GNSS signals or the low-orbit satellite signals, and output digital intermediate frequency signals; the system-level navigation chip is used to perform acquisition and tracking, synchronization decoding, and positioning and timing on the digital intermediate frequency signals; the clock management module is used to provide a sampling clock signal for the radio frequency module and a baseband working clock signal for the system-level navigation chip; the power supply module is used to provide power for the GNSS / low-orbit satellite signal receiving antenna, the clock management module, the radio frequency module, and the system-level navigation chip.

[0066] As Figure 2 shown in the figure, the clock management module includes: a temperature-controlled crystal oscillator and a frequency synthesizer. The temperature-controlled crystal oscillator is used to provide a high-precision and stable reference clock signal for the frequency synthesizer; the frequency synthesizer is used to adjust the reference clock signal into a sampling clock signal and output a baseband working clock signal at the same time. The clock management module uniformly generates an AD sampling clock signal and a baseband working clock signal for the SoC navigation chip from the reference clock, realizing clock homology.

[0067] The radio frequency module includes: a local oscillator generation module, a mixing module, a low-pass filter, and an AD sampling module. The local oscillator generation module is used to generate a local oscillator signal based on the sampling clock signal; the mixing module is used to mix the GNSS signals, low-orbit satellite signals with the local oscillator signal; the low-pass filter is used to filter out the high-frequency part of the mixed signal and leave the low-frequency analog intermediate frequency signal; the AD sampling module is used to sample the analog intermediate frequency signal under the drive of the sampling clock signal to generate a digital intermediate frequency signal.

[0068] The system-level navigation chip (SoC navigation chip) includes: a baseband processing module and a signal processing module. The baseband processing module includes an acquisition module and a tracking module. The acquisition module is used to acquire GNSS signals and low-orbit satellite signals; the tracking module is used to calculate the pseudorange observables and Doppler observables of the GNSS signals and low-orbit satellite signals, and output the time information and message information of the GNSS signals and low-orbit satellite signals, realizing the tracking of the GNSS signals and low-orbit satellite signals. The signal processing module includes a single-satellite positioning module and a GNSS navigation positioning module. The single-satellite positioning module is used to output rough position and speed information according to the pseudorange observables, Doppler observables, time information, and message information of the low-orbit satellite signals of weak GNSS signals; the GNSS navigation positioning module is used to realize GNSS navigation positioning according to the pseudorange observables, Doppler observables, time information, and message information of the GNSS signals.

[0069] As Figure 3As shown in the figure, this embodiment also implements the following environment - adaptive navigation method for low - earth - orbit navigation enhancement by using the above - mentioned device, including:

[0070] S1. Use the GNSS / low - earth - orbit satellite signal receiving antenna to receive GNSS signals and low - earth - orbit satellite signals;

[0071] S2. When the GNSS signal is a strong signal, perform acquisition, tracking, synchronization, decoding, and observable solution of the GNSS signal to achieve the navigation and positioning of the GNSS signal. When the GNSS signal is a weak signal, execute steps S3 - S4;

[0072] S3. Process the low - earth - orbit satellite signal to achieve acquisition, tracking, synchronization, decoding, observable solution, and single - satellite positioning solution of the low - earth - orbit satellite signal;

[0073] S4. Use the processed low - earth - orbit satellite signal to assist the GNSS weak signal for fast acquisition and stable tracking to achieve the navigation and positioning of the GNSS signal.

[0074] When the GNSS signal is strong, the acquisition module first acquires the GNSS signal. After acquiring the GNSS signal, it transfers to the tracking module for tracking. The tracking module outputs observables such as the pseudorange and Doppler of the GNSS satellite, as well as time information and telemetry information to the GNSS navigation and positioning module. Through the above - mentioned normal processes of acquisition, tracking, synchronization, decoding, and positioning, the accurate navigation and positioning of the GNSS signal are achieved. When the GNSS signal is weak, the acquisition module and the tracking module sequentially acquire, track, synchronize, and decode the low - earth - orbit satellite signal. The I channel outputs observables such as the pseudorange and Doppler of the low - earth - orbit satellite signal to the single - satellite positioning module, and at the same time, the Q channel outputs the GNSS navigation message and time information relayed by the low - earth - orbit satellite. The single - satellite positioning module realizes rough positioning and velocity measurement based on observables such as the pseudorange and Doppler of the low - earth - orbit satellite. At this time, only the position and velocity of the low - earth - orbit satellite are roughly positioned. Then, the acquisition module uses the rough position and velocity of the navigation device and the GNSS navigation message and time information relayed by the low - earth - orbit satellite to assist in acquiring the GNSS signal. The tracking module completes the tracking process of the GNSS weak signal through long - time coherent integration of the GNSS signal, performs observable solution, and then outputs the solved observables to the GNSS navigation and positioning module, finally achieving the accurate navigation and positioning of the GNSS signal.

[0075] As Figure 4 shown, the above step S3 specifically includes: S31. Use the radio frequency module to perform low - noise amplification and down - conversion processing on the low - earth - orbit satellite signal and output a digital intermediate - frequency signal;

[0076] S32. Use the clock management module to provide a sampling clock signal for the radio frequency module and a baseband working clock signal for the system - level navigation chip;

[0077] S33. Use the system-level navigation chip to capture, track, synchronize, and decode the in-phase and quadrature signals of the digital intermediate-frequency signal, respectively obtaining the navigation message information and time information of the low-earth orbit satellite, as well as the navigation message information and time information of the GNSS navigation star;

[0078] S34. Calculate the observables of the low-earth orbit satellite signal based on the navigation message information of the low-earth orbit satellite;

[0079] S35. Use the single-satellite positioning module of the system-level navigation chip to obtain the positioning and timing result according to the observables;

[0080] S36. Calculate the phase and Doppler information of the GNSS navigation star based on the positioning and timing result and the navigation message information of the GNSS navigation star.

[0081] As Figure 5 shown, the process of obtaining the GNSS navigation star phase in step S36 above is as follows:

[0082] S3611. Use the navigation message information and time information of the GNSS navigation star to calculate the position P of the GNSS navigation star s ;

[0083] S3612. Calculate the rough pseudorange ρ1 according to the GNSS navigation star position P s and the navigation device position P r : ρ1 = ||Pr - Ps|| / c, where c is the speed of light;

[0084] S3613. Considering the influence of the ionosphere Δt T , troposphere Δt I and satellite clock error Δt S , correct the pseudorange ρ1, and calculate the corrected pseudorange ρ2 according to the formula ρ2 = ρ1 + (Δt T +Δt I +Δt S )*c;

[0085] S3614. Calculate the rough propagation time T1 according to the pseudorange ρ2, T1 = ρ2 / c;

[0086] S3615. Repeat the iterative steps S3611 - S3614 to obtain the accurate propagation time T2, and combine the reception time T of the navigation device R to obtain the transmission time T S , T S = T R - T2, and obtain the initial code phase according to the transmission time T S ;

[0087] As Figure 6As shown, the process of obtaining GNSS navigation star Doppler information in the above step S36 is as follows: S3621. Obtain the accurate position and velocity of the GNSS navigation star obtained after iteration in the calculation method of the accurate phase of the GNSS navigation star;

[0088] S3622. According to the position and velocity information of the GNSS navigation star and the navigation device, and based on the relative position (d x , d y , d z ) information and the relative velocity (d vx , d vy , d vz ) information of the GNSS navigation star and the navigation device, calculate the rough Doppler D1 of the GNSS satellite, which is:

[0089] λ is the GNSS carrier wavelength;

[0090] S3623. Consider the influence Δd of the clock drift of the navigation device, correct the rough Doppler D1, and calculate the corrected accurate Doppler D2 according to the formula D2 = D1 + Δd.

[0091] The accurate code phase and Doppler of the GNSS navigation star are input to the acquisition module. The frequency searcher of the acquisition module quickly completes frequency locking according to the accurate Doppler shift information. The code correlator of the acquisition module quickly completes the correlation with the local code according to the accurate initial code phase, enables the tracking module, and realizes the fast acquisition and tracking of the GNSS navigation star signal;

[0092] The accurate phase of the GNSS navigation star is input to the acquisition module. The code correlator of the acquisition module performs long-time coherent integration according to the accurate initial code phase and the message information. At the same time, the tracking module also performs long-time coherent integration to realize the acquisition and stable tracking of the weak GNSS navigation star signal;

[0093] Solve the GNSS navigation star signal under stable tracking to obtain observable information such as pseudorange and Doppler;

[0094] Perform positioning calculation according to the GNSS navigation star observables combined with the navigation star message information;

[0095] Through the above work process, complete the GNSS navigation positioning under weak signals.

[0096] The above is only one embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An environment - adaptive navigation device applicable to low - earth - orbit navigation enhancement, characterized in that, It includes: GNSS / Low Earth Orbit (LEO) satellite signal receiving antenna, radio frequency module, system-level navigation chip, clock management module, and power supply module. The GNSS / LEO satellite signal receiving antenna is used to receive GNSS signals and LEO satellite signals. The radio frequency module is used to perform low-noise amplification and down-conversion processing on the GNSS signal or the LEO satellite signal, and output a digital intermediate frequency signal. The system-level navigation chip is used to perform acquisition and tracking, synchronization and decoding, and positioning and timing on the digital intermediate frequency signal. The clock management module is used to provide a sampling clock signal for the radio frequency module and a baseband working clock signal for the system-level navigation chip. The power supply module is used to provide power for the GNSS / LEO satellite signal receiving antenna, the clock management module, the radio frequency module, and the system-level navigation chip. When the GNSS signal is a strong signal, perform acquisition and tracking, synchronization, decoding, and observable solution on the GNSS signal to achieve navigation and positioning of the GNSS signal. When the GNSS signal is a weak signal, process the LEO satellite signal to achieve acquisition and tracking, synchronization, decoding, observable solution, and single-satellite positioning solution of the LEO satellite signal, and use the processed LEO satellite signal to assist the GNSS weak signal for fast acquisition and stable tracking to achieve navigation and positioning of the GNSS signal. Among them, processing the LEO satellite signal specifically includes: S31. Use the radio frequency module to perform low-noise amplification and down-conversion processing on the LEO satellite signal, and output a digital intermediate frequency signal. S32. Use the clock management module to provide a sampling clock signal for the radio frequency module and a baseband working clock signal for the system-level navigation chip. S33. Use the system-level navigation chip to perform acquisition and tracking, synchronization, and decoding on the in-phase and quadrature two-way signals of the digital intermediate frequency signal to obtain the navigation message information and time information of the LEO satellite and the navigation message information and time information of the GNSS navigation star respectively. S34. Calculate the observables of the LEO satellite signal according to the navigation message information of the LEO satellite. S35. Use the single-satellite positioning module of the system-level navigation chip to obtain the positioning and timing result according to the observables. S36. Calculate the accurate phase and Doppler information of the GNSS navigation star according to the positioning and timing result and the navigation message information of the GNSS navigation star. The observable information of the GNSS signal and the LEO satellite signal both includes pseudorange observables and Doppler observables. The process of obtaining the phase of the GNSS navigation star includes: S3611. Calculate the position P and velocity of the GNSS navigation star using the navigation message information and time information of the GNSS navigation star s and speed; S3612. According to the position P of the GNSS navigation star s and the position P of the navigation device r calculate the pseudo-range ρ1: ρ1 = ||Pr - Ps|| / c, where c is the speed of light; Consider the ionospheric Δt T , tropospheric Δt I and satellite clock error Δt S to correct the pseudorange ρ1. Calculate the corrected pseudorange ρ2 according to ρ2 = ρ1 + (Δt T + Δt I + Δt S ) * c; S3614. Calculate the rough propagation time T1 according to the pseudorange ρ2, T1 = ρ2 / c. Repeat and iterate the steps S3611 to S3614 to obtain an accurate propagation time T2, and combine it with the reception time T of the navigation device R The transmission time T can be obtained S , T S = T R - T2. Based on the transmission time T S The initial code phase is obtained; The process of obtaining the Doppler information of the GNSS navigation star in step S36 includes: S3621. Obtain the position and velocity of the GNSS navigation star obtained after iteration in the calculation method of the GNSS navigation star phase. S3622. Calculate the GNSS satellite Doppler D1 based on the position and velocity information of the GNSS navigation stars and the position and velocity information of the navigation device, according to the relative position (d x , d y , d z ) information between the GNSS navigation stars and the navigation device and the relative velocity (d vx , d vy , d vz ) information between the GNSS navigation stars and the navigation device, where D1 is: λ is the GNSS carrier wavelength; S3623. Consider the influence of the clock drift Δd of the navigation device, correct the Doppler D1, and calculate the corrected Doppler D2 according to D2 = D1 + Δd.

2. The device according to claim 1, wherein The clock management module includes: an oven-controlled crystal oscillator and a frequency synthesizer, The oven-controlled crystal oscillator is used to provide a high-precision and stable reference clock signal for the frequency synthesizer; The frequency synthesizer is used to adjust the reference clock signal into a sampling clock signal and output a baseband working clock signal at the same time.

3. The device according to claim 1 or 2, characterized in that, The radio frequency module includes: a local oscillator generation module, a mixing module, a low-pass filter, and an AD sampling module, The local oscillator generation module is used to generate a local oscillator signal based on the sampling clock signal; The mixing module is used to mix the GNSS signal and the low-earth orbit satellite signal with the corresponding local oscillator signals respectively; The low-pass filter is used to filter out the high-frequency part of the mixed signal and leave a low-frequency analog intermediate-frequency signal; The AD sampling module is used to sample the analog intermediate-frequency signal under the drive of the sampling clock signal to generate a digital intermediate-frequency signal.

4. The device according to claim 1, characterized in that, The system-level navigation chip includes: a baseband processing module and a signal processing module, The baseband processing module includes a capture module and a tracking module, The capture module is used to capture the GNSS signal and the low-earth orbit satellite signal; The tracking module is used to complete the loop tracking processing, synchronization processing, and decoding processing of the GNSS signal and the low-earth orbit satellite signal, and calculate the observables of the GNSS signal and the low-earth orbit satellite signal, and output the observable information, time information, and message information of the GNSS signal and the low-earth orbit satellite signal; The signal processing module includes a single-satellite positioning module and a GNSS navigation positioning module, The single-satellite positioning module is used to output rough position and speed information according to the observable information, time information, and message information of the low-earth orbit satellite signal; The GNSS navigation positioning module is used to implement GNSS navigation positioning according to the observable information, time information, and message information of the GNSS signal.

5. A low-earth orbit navigation enhanced environment adaptive navigation method implemented by using a low-earth orbit navigation enhanced environment adaptive navigation device as described in any one of claims 1 to 4, including: S1. Receive the GNSS signal and the low-earth orbit satellite signal by using a GNSS / low-earth orbit satellite signal receiving antenna; S2. When the GNSS signal is a strong signal, perform capture tracking, synchronization, decoding, and observable calculation on the GNSS signal to achieve GNSS signal navigation positioning. When the GNSS signal is a weak signal, execute steps S3 to S4; S3. Process the low-earth orbit satellite signal to achieve capture tracking, synchronization, decoding, observable calculation, and single-satellite positioning calculation of the low-earth orbit satellite signal; S4. Use the processed low-earth orbit satellite signal to assist the GNSS weak signal for fast capture and stable tracking to achieve GNSS signal navigation positioning.

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