CN114295128B - Continuous navigation method and device for low-orbit enhancement and fusion of GNSS and IMU - Google Patents

Abstract

The invention relates to a continuous navigation method and device for low-orbit enhancement and fusion of GNSS and IMU. The method comprises the following steps: s1, capturing, tracking and text resolving are carried out on global satellite navigation signals and low-orbit satellite enhanced signals by utilizing a signal receiving module; s2, passive inertial navigation positioning is carried out by utilizing an inertial measurement unit module; s3, judging whether the satellite navigation signal is captured normally, executing the step S4 during normal capture, otherwise executing the steps S5-S6; s4, fusing an inertial navigation positioning result with a satellite navigation signal by utilizing a combined positioning module to realize combined navigation positioning; s5, processing the low-orbit enhanced signal by using a single-star positioning module to realize single-star positioning of the low-orbit earth satellite; s6, performing long-time coherent integration by using the navigation enhancement module, improving sensitivity and realizing global navigation satellite system positioning in a complex electromagnetic environment. The invention can improve the reliability and the persistence of satellite positioning in a complex electromagnetic environment.

Description

Continuous navigation method and navigation device for low-orbit augmentation, GNSS and IMU integration

Technical field

The invention relates to the technical field of satellite navigation and integrated navigation. It mainly relates to a continuous navigation method and navigation device with low orbit enhancement and GNSS and IMU integration. In particular, it relates to a continuous navigation with low orbit enhancement and GNSS and IMU integration in a complex electromagnetic environment. Methods and navigation devices.

Background technique

Global Navigation Satellite System (GNSS) navigation and positioning is characterized by wide constellation coverage and high positioning accuracy, but the navigation signal is susceptible to interference, and theoretically requires more than four navigation satellites to complete positioning. Inertial Navigation System (INS) navigation and positioning has passive characteristics and stealth, and has high navigation accuracy in a short time. However, due to the limitations of the inherent properties of inertial devices, the accumulation of long-term navigation errors leads to excessive positioning errors. . GNSS/INS integrated navigation technology makes use of the characteristics of the two navigation systems to make up for their respective shortcomings. However, in complex environments such as occlusion and signal interference, the reliability of GNSS positioning is greatly reduced or even unavailable. This requires the introduction of low orbit Enhance the system. Low Earth Orbit (LEO) satellites are used to broadcast enhanced signals, perform single-star positioning when there are insufficient visible stars, and form a single-star/INS combination. At the same time, GNSS is used to assist positioning to cope with the restrictions of complex scenarios.

Taking into account the complexity of navigation and positioning application scenarios and the superiority of low-orbit signals, research on integrated navigation and low-orbit constellations has been ongoing at home and abroad. Tests of low-orbit enhancement performance are also being carried out repeatedly, integrating INS/GNSS/low-orbit enhancement. The combined positioning technology will greatly expand the available scenarios for positioning.

Contents of the invention

In order to improve the reliability and sustainability of satellite positioning in complex electromagnetic environments, the purpose of the present invention is to provide a continuous navigation method and navigation device that enhances low orbit and integrates GNSS and IMU.

In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

The present invention provides a low-orbit enhanced, GNSS and IMU integrated continuous navigation method, including:

S1. Use the satellite navigation signals sent by the global navigation satellite system of the signal receiving module and the low-orbit enhanced signals sent by the low-orbit earth satellites to capture, track and interpret message information;

S2. Use the Inertial Measurement Unit (IMU) module to perform passive inertial navigation positioning and output positioning results;

S3. Use the capture judgment module to determine whether the satellite navigation signal is captured normally. When the satellite navigation signal is captured normally, execute step S4; otherwise, execute steps S5-S6;

S4. Use the combined positioning module to fuse the positioning result with the satellite navigation signal to realize the combined navigation positioning of the inertial navigation system and the global navigation satellite system;

S5. Use the single-satellite positioning module to process the low-orbit enhanced signal, use the positioning information of the inertial navigation system to eliminate positioning ambiguities, and assist in achieving single-star positioning of low-orbit earth satellites;

S6. Use the navigation enhancement module to perform long-term coherent integration of the satellite navigation signal during the acquisition and tracking process based on the single satellite positioning result and the forwarded ephemeris information of the low-orbit enhancement signal to assist in the acquisition and tracking of the satellite navigation signal.

According to one aspect of the present invention, the low-orbit enhanced signal in step S1 modulates two mutually orthogonal message messages using QPSK modulation. The message message includes low-orbit satellite ephemeris parameters and low-orbit satellite clock correction parameters, using To perform single-star positioning; forward BDS satellite ephemeris information for assisted acquisition of global navigation satellite systems.

According to one aspect of the present invention, the signal receiving module is used to receive the satellite navigation signal and resolve it as the input of the combined positioning module;

The signal receiving module is used to perform frequency search and rapid acquisition of the low-orbit enhanced signal under high dynamics, and the pseudo-range information, Doppler information, and low-orbit earth satellite position and speed information at the time of sending the low-orbit enhanced message are solved as all The input of the single satellite positioning module;

The signal receiving module is used to perform message analysis on the low-orbit enhanced signal, and the ephemeris information of the global navigation satellite system is obtained as input to the navigation enhancement module.

According to an aspect of the present invention, the step S4 includes:

Utilize the autonomous positioning information of the inertial navigation system to compress the tracking loop of the satellite navigation signal to assist in the continuous tracking of the satellite navigation signal;

The positioning result is fused with the satellite navigation signal information using a fusion algorithm.

According to an aspect of the present invention, the step S5 includes:

Use the single-star positioning module to process the input information of the signal receiving module and output the single-star positioning result;

Use the positioning information of the inertial navigation system to correct the single-star positioning result and eliminate the single-star positioning ambiguity;

The fusion algorithm is used to fuse information between the positioning results of the inertial navigation system and the single-star positioning results of low-orbit earth satellites.

According to an aspect of the present invention, the step S6 includes:

Use the low-orbit enhanced signal single satellite positioning results assisted by the inertial navigation system as prior information to narrow the frequency and code phase search range during satellite navigation signal acquisition, and perform rapid frequency search and code phase synchronization of satellite navigation signals;

Select the message-free branch of the satellite navigation signal, peel off the sub-code after synchronizing the code phase, perform long-term coherent integration during the acquisition and tracking phase of the satellite navigation signal, and obtain the coherent integration gain.

A low-orbit enhancement, GNSS and IMU fusion continuous navigation device implemented by the low-orbit enhancement, GNSS and IMU fusion continuous navigation method as shown above, including: a signal receiving module, an inertial measurement unit module, a capture judgment module, Combined positioning module, single satellite positioning module and navigation enhancement module.

The signal receiving module is used to capture and track satellite navigation signals sent by global navigation satellite systems and low-orbit enhanced signals sent by low-orbit earth satellites and interpret message information;

The inertial measurement unit module is used for passive inertial navigation positioning and output positioning results;

The capture judgment module is used to determine whether the satellite navigation signal is captured normally. When the satellite navigation signal is captured normally, the captured and tracked signal and the positioning result are output to the combined positioning module. Otherwise, the satellite navigation signal is captured normally. The tracked signal and the positioning result are output to the single-star positioning module;

The combined positioning module is used to fuse the positioning result with the satellite navigation signal to realize combined navigation positioning of the inertial navigation system and the global navigation satellite system;

The single-star positioning module is used to process the low-orbit enhanced signal, use the positioning information of the inertial navigation system to eliminate positioning ambiguities, and assist in achieving single-star positioning of low-orbit earth satellites;

The navigation enhancement module is used to perform long-term coherent integration of the satellite navigation signal based on the single-satellite positioning result and the forwarded ephemeris information in the low-orbit enhancement signal, thereby improving signal acquisition and tracking sensitivity, and achieving a complex electromagnetic environment. Global Navigation Satellite System Positioning.

According to another aspect of the present invention, the signal receiving module includes: a satellite signal down-conversion and baseband processing sub-module and a message interpretation and information processing sub-module.

The satellite signal down-conversion and baseband processing sub-module is used to receive satellite navigation signals sent by global navigation satellite systems and low-orbit enhanced signals sent by low-orbit earth satellites, capture and track the signals, and obtain signal accumulation parameters;

The message calculation and information processing sub-module is used to restore the message bit information based on the signal accumulation parameters, calculate ephemeris parameters, and calculate satellite position and speed information based on the ephemeris parameters.

According to another aspect of the present invention, the combined positioning module is an inertial navigation system and a global navigation satellite system deeply coupled combined navigation and positioning module, which is used to use a fusion algorithm to fuse the positioning results with the satellite navigation signal information, and uses The inertial navigation system autonomously locates information, compresses the tracking loop of the satellite navigation signal, and assists in the continuous tracking of the satellite navigation signal.

Beneficial effects:

According to the solution of the present invention, a combination of low-orbit enhanced signal, GNSS system and INS system is used. Compared with the traditional GNSS/INS integrated navigation system, the navigation method and device of the present invention can operate in the presence of electromagnetic interference and cause GNSS satellite navigation. In scenarios where signals cannot be positioned normally, low-orbit enhancement information is used to perform long-term coherent integration of GNSS satellite navigation signals to obtain additional coherent integration gain, thereby assisting the capture and tracking of GNSS satellite navigation signals and improving the sensitivity and accuracy of signal capture. Anti-interference ability.

According to one solution of the present invention, the present invention can directly use LEO satellites for single-star positioning without relying on GNSS navigation and positioning, and at the same time obtain user dynamics with INS positioning, further improving single-star positioning accuracy, and realizing scenarios where GNSS satellite navigation signals are completely unavailable. positioning.

According to one solution of the present invention, the GNSS/INS integrated navigation mode and the low-orbit signal-assisted GNSS mode can be operated simultaneously. According to the judgment result of the acquisition judgment module on the channel GNSS satellite navigation signal acquisition situation, the channel acquisition positioning mode is optimized, and the lifting device Adaptability enables continuous positioning in complex electromagnetic environments.

Description of drawings

Figure 1 schematically represents a flow chart of a low-orbit augmentation, GNSS and IMU integrated continuous navigation method according to an embodiment of the present invention;

Figure 2 schematically shows the structural diagram of a low-orbit enhanced, GNSS and IMU integrated continuous navigation device according to an embodiment of the present invention;

Figure 3 schematically shows the physical structure of a low-orbit enhanced, GNSS and IMU integrated continuous navigation device according to an embodiment of the present invention.

Detailed ways

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

According to the concept of the present invention, the low-orbit enhanced, continuous navigation method and navigation device integrating GNSS and IMU of the present invention can receive GNSS satellites in a complex electromagnetic environment and in a scenario where GNSS satellite navigation signals can be normally received, captured and tracked. Navigation signals are deeply coupled with INS to achieve integrated navigation and positioning of GNSS and INS. In the case of electromagnetic interference and GNSS satellite navigation signals cannot be received normally, on the one hand, it can receive low-orbit enhanced signals (or low-orbit navigation enhanced signals) and perform combined positioning with INS to complete positioning without relying on GNSS. Positioning work of satellite navigation signals; on the other hand, a priori information is generated from the combined positioning of low-orbit navigation enhanced signals and INS, which assists the long-term coherent integration of GNSS satellite navigation signals to obtain coherent integration gain, which improves the method of the present invention to a certain extent. and the device’s capture sensitivity and anti-interference performance for GNSS satellite navigation signals.

As shown in Figure 1, the low-orbit enhanced, GNSS and IMU integrated continuous navigation method of this embodiment includes:

S1. Use the signal receiving module to capture, track and interpret the message information of satellite navigation signals sent by global navigation satellite systems and low-orbit enhanced signals sent by low-orbit earth satellites;

S2. Use the inertial measurement unit module to perform passive inertial navigation positioning and output positioning results;

S3. Use the capture judgment module to determine whether the satellite navigation signal is captured normally. When the satellite navigation signal is captured normally, execute step S4; otherwise, execute steps S5~S6;

S4. Use the combined positioning module to fuse the inertial navigation positioning results with satellite navigation signals to realize the combined navigation and positioning of the inertial navigation system and the global navigation satellite system;

S5. Use the single-satellite positioning module to process low-orbit enhanced signals, use the positioning information of the inertial navigation system to eliminate positioning ambiguities, and assist in achieving single-star positioning of low-orbit earth satellites;

S6. Use the navigation enhancement module to perform long-term coherent integration of satellite navigation signals based on the single-satellite positioning results and the forwarded ephemeris information of the low-orbit enhanced signal, assisting the capture and tracking of the global navigation satellite system, and realizing global navigation in complex electromagnetic environments. Satellite system positioning.

According to an embodiment of the present invention, the above-mentioned low-orbit enhanced signal modulates the mutually orthogonal I and Q message information in the QPSK modulation method. The message information includes low-orbit earth satellite status information required for single-star positioning, and global navigation satellites. The system assists in capturing the required satellite ephemeris information. The I branch specifically includes low-orbit satellite ephemeris parameters and low-orbit satellite clock correction parameters; the Q branch specifically includes the forwarded BDS satellite ephemeris information.

According to an embodiment of the present invention, the above-mentioned step S1 includes: using the signal receiving module to receive the satellite navigation signal sent by the global navigation satellite system, solving the signal, and inputting it as a combined positioning module; using the signal receiving module to receive the broadcast of the low-orbit earth satellite The low-orbit enhanced signal is used to perform frequency search and rapid acquisition of the low-orbit enhanced signal under high dynamics, and the pseudo-range information, Doppler information, and low-orbit earth satellite position and velocity information at the time when the low-orbit enhanced message is sent are solved. As the input of the single-satellite positioning module; the signal receiving module is used to perform message analysis on the low-orbit enhanced signal to obtain the ephemeris information of the global navigation satellite system, which is used as the input of the navigation enhancement module. The signal receiving module here can be composed of a GNSS antenna and related hardware.

According to an embodiment of the present invention, the above step S4 includes: using a fusion algorithm to fuse the positioning result with the GNSS satellite navigation signal information; using the inertial navigation system autonomous positioning information to compress the tracking loop of the GNSS satellite navigation signal to assist the GNSS satellite Continuous tracking of navigation signals. Positioning accuracy and system robustness can be improved through fusion algorithms.

According to an embodiment of the present invention, the above step S5 includes: using the single-star positioning module to process the module input information and output the single-star positioning result; using the positioning information of the inertial navigation system to correct the single-star positioning result and eliminate the single-star positioning result. Fuzzy value; use the fusion algorithm to fuse the positioning results of the inertial navigation system and the single-star positioning results of low-orbit earth satellites to optimize the positioning results.

According to an embodiment of the present invention, the above step S6 includes: using the low orbit enhanced signal single satellite positioning result assisted by the inertial navigation system as a priori information, after narrowing the frequency and code phase search range during the GNSS satellite navigation signal acquisition process, Fast frequency search and code phase synchronization of GNSS satellite navigation signals can ensure that after the coherent integration time is extended, GNSS satellite navigation signal acquisition can still be completed during the LEO satellite transit; select the message-free branch of the GNSS satellite navigation signal and code phase synchronization After stripping the sub-code, long-term coherent integration is performed during the acquisition and tracking phase of the GNSS satellite navigation signal, and the coherent integration gain is obtained to improve the acquisition sensitivity and anti-interference performance of the GNSS satellite navigation signal.

According to an embodiment of the present invention, as shown in Figure 2, this embodiment utilizes the above-mentioned low-orbit enhancement, GNSS and IMU fusion continuous navigation method to implement a low-orbit enhancement, GNSS and IMU fusion continuous navigation device, including: signal reception Module 201, inertial measurement unit module 202, capture judgment module 203, combined positioning module 204, single satellite positioning module 205 and navigation enhancement module 206.

Among them, the signal receiving module 201 is used to capture and track GNSS satellite navigation signals and low-orbit enhanced signals broadcast by low-orbit earth satellites and to interpret message information; the inertial measurement unit module 202 is used for passive inertial navigation positioning and output positioning results; The capture judgment module 203 is used to determine whether the GNSS satellite navigation signal is captured normally. When the GNSS satellite navigation signal is captured normally, the captured and tracked signal and positioning result will be output to the combined positioning module 204. Otherwise, the tracked signal and positioning result will be captured. Output to the single-star positioning module 205; the combined positioning module 204 is used to fuse the positioning results with the GNSS satellite navigation signal to realize the combined navigation and positioning of the inertial navigation system and the global navigation satellite system; the single-star positioning module 205 is used to receive input according to the signal module The information is used to perform single-star positioning of low-orbit earth satellites, use the positioning information of the inertial navigation system to correct the single-star positioning results, and fuse the single-star positioning results with the inertial navigation positioning results; the navigation enhancement module 206 is used to based on the single-star positioning results, It also uses the forwarded ephemeris information in the low-orbit enhanced signal to complete long-term coherent integration during the acquisition and tracking process of GNSS satellite navigation signals, assisting the acquisition and tracking of GNSS satellite navigation signals.

According to an embodiment of the present invention, the signal receiving module 201 includes: a satellite signal down-conversion and baseband processing sub-module and a message interpretation and information processing sub-module. Among them, the satellite signal down-conversion and baseband processing sub-modules are used to receive satellite navigation signals sent by global navigation satellite systems and low-orbit enhanced signals sent by low-orbit earth satellites, capture and track the signals, and obtain signal accumulation parameters. The message calculation and information processing sub-module is used to restore the message bit information according to the signal accumulation parameters, solve the ephemeris parameters, and calculate the satellite positioning information based on the ephemeris parameters.

According to an embodiment of the present invention, the combined positioning module 204 is an INS and GNSS deeply coupled combined navigation and positioning module, which is used to use a fusion algorithm to fuse positioning results with GNSS satellite navigation signal information, and to use the inertial navigation system autonomous positioning information to perform GNSS The tracking loop of the satellite navigation signal is compressed to assist the continuous tracking of the GNSS satellite navigation signal.

According to an embodiment of the present invention, the single-star positioning module 205 implements a single-star positioning module for the INS-assisted LEO satellite, and is used to perform single-star positioning based on the input LEO satellite pseudorange information, Doppler information, and satellite position and speed information. And output the positioning results; and used to use the inertial navigation system to obtain the carrier motion status, eliminate single-star positioning fuzzy values and correct the single-star positioning results; and use the fusion algorithm to fuse the inertial navigation positioning information and single-star positioning results, and Positioning results are further optimized.

According to an embodiment of the present invention, the navigation enhancement module 206 uses the low-orbit enhancement signal single satellite positioning result assisted by the inertial navigation system as a priori information to narrow the frequency and code phase search range during the GNSS satellite navigation signal acquisition process before performing the GNSS satellite search. Fast frequency search and code phase synchronization of navigation signals. And select the non-message information branch of the GNSS satellite navigation signal, peel off the sub-code after code phase synchronization, and perform long-term coherent integration during the acquisition and tracking phase of the GNSS satellite navigation signal to obtain the coherent integral gain.

According to an embodiment of the present invention, as shown in Figure 3, the low-orbit enhanced, GNSS and IMU integrated continuous navigation entity device in a complex electromagnetic environment includes: a signal receiver 301, an IMU inertial device 302, a combined positioner 303, Single star locator 304 and navigation enhanced locator 305. The signal receiver 301 captures and tracks GNSS satellite navigation signals and LEO low-orbit enhanced signals, performs message interpretation and calculates ephemeris parameters. The IMU inertial device 302 performs inertial navigation positioning through the inertial device. The combined positioner 303 feeds back the positioning result output by the IMU inertial device 302 to the signal receiver 301, assists in loop tracking of GNSS satellite navigation signals, and outputs the positioning result through information fusion. The single-star locator 304 receives the low-orbit enhanced signal ephemeris calculation result output by the signal receiver 301, performs single-star positioning processing, and fuses it with the inertial navigation positioning result output by the IMU inertial device 302 to improve positioning accuracy. The navigation enhancement locator 305 receives the positioning result output by the single-star locator 304, assists the long-term coherent integration of GNSS satellite navigation signals in the acquisition and tracking process, and improves the acquisition and tracking sensitivity.

The above description is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. A low-rail-augmentation, GNSS-and-IMU-fusion continuous navigation method comprising:

s1, capturing and tracking a satellite navigation signal sent by a global navigation satellite system and a low-orbit enhancement signal sent by a low-orbit earth satellite by utilizing a signal receiving module, and resolving text information;

s2, passive inertial navigation positioning is performed by using the inertial measurement unit module, and a positioning result is output;

s3, judging whether the satellite navigation signal is captured normally or not by utilizing a capture judging module, executing a step S4 when the satellite navigation signal is captured normally, otherwise executing steps S5-S6;

s4, fusing an inertial navigation positioning result with the satellite navigation signal by utilizing a combined positioning module to realize combined navigation positioning of an inertial navigation system and a global navigation satellite system;

s5, processing the low-orbit enhancement signal by using a single-star positioning module, removing a positioning fuzzy value by using positioning information of the inertial navigation system, and assisting in realizing single-star positioning of the low-orbit earth satellite;

s6, performing long-time coherent integration on the satellite navigation signals by utilizing a navigation enhancement module according to a single-satellite positioning result and the forwarded ephemeris information of the low-orbit enhancement signals, and realizing global navigation satellite system positioning in a complex electromagnetic environment.

2. The method according to claim 1, wherein the low-orbit augmentation signal of step S1 modulates two paths of message information orthogonal to each other in a QPSK modulation manner, the message information including low-orbit satellite ephemeris parameters and low-orbit satellite clock correction parameters for single-satellite positioning, and forwarded BDS satellite ephemeris information for assisted acquisition of the global navigation satellite system.

3. The method according to claim 1, wherein the step S1 comprises:

the signal receiving module is used for receiving and resolving the satellite navigation signals and is used as the input of the combined positioning module;

the signal receiving module is used for carrying out frequency searching and quick capturing under high dynamic state on the low-orbit enhanced signal, and calculating pseudo-range information, doppler information and low-orbit earth satellite position and speed information at the time of low-orbit enhanced message sending, which are used as the input of the single-star positioning module;

and performing text calculation on the low-orbit enhanced signal by using the signal receiving module to acquire ephemeris information of the global navigation satellite system as input of the navigation enhancing module.

4. The method according to claim 1, wherein the step S4 comprises:

compressing a tracking loop of the satellite navigation signal by utilizing autonomous positioning information of an inertial navigation system to assist continuous tracking of the satellite navigation signal;

and carrying out information fusion on the positioning result and the satellite navigation signal by using a fusion algorithm.

5. The method according to claim 1, wherein the step S5 comprises:

processing the information input by the signal receiving module by utilizing the single-star positioning module, and outputting a single-star positioning result;

correcting the single-star positioning result by utilizing the positioning information of the inertial navigation system, and eliminating the single-star positioning fuzzy value;

and carrying out information fusion on the positioning result of the inertial navigation system and the single-star positioning result of the low-orbit earth satellite by using a fusion algorithm.

6. The method according to claim 1, wherein the step S6 comprises:

using the low-orbit enhanced signal single-star positioning result assisted by the inertial navigation system as priori information, reducing the frequency and code phase searching range in the capturing process of the satellite navigation signal, and carrying out quick frequency searching and code phase synchronization of the satellite navigation signal;

selecting a non-text information branch of the satellite navigation signal, stripping subcodes after code phase synchronization, performing long-time coherent integration in the capturing and tracking stages of the satellite navigation signal, and obtaining coherent integration gain.

7. A low-rail enhanced, GNSS and IMU fused sustained navigation apparatus implemented using the low-rail enhanced, GNSS and IMU fused sustained navigation method of any of claims 1 to 6, comprising: the system comprises a signal receiving module (201), an inertial measurement unit module (202), a capture judging module (203), a combined positioning module (204), a single-star positioning module (205) and a navigation enhancing module (206);

the signal receiving module (201) is used for capturing, tracking and text information resolving a satellite navigation signal sent by a global navigation satellite system and a low-orbit enhancement signal sent by a low-orbit earth satellite;

the inertial measurement unit module (202) is used for passive inertial navigation positioning and outputting a positioning result;

the capturing judging module (203) is configured to judge whether the satellite navigation signal is captured normally, when the satellite navigation signal is captured normally, output a captured tracking signal and the positioning result to the combined positioning module (204), otherwise output a captured tracking signal and the positioning result to the single-star positioning module (205);

the combined positioning module (204) is used for fusing the positioning result with the satellite navigation signal to realize combined navigation positioning of an inertial navigation system and a global navigation satellite system;

the single-star positioning module (205) is used for carrying out single-star positioning of the low-orbit earth satellite according to the information input by the signal receiving module, correcting a single-star positioning result by utilizing positioning information of an inertial navigation system, and fusing the single-star positioning result with the inertial navigation positioning result;

the navigation enhancement module (206) is used for completing long-time coherent integration of the satellite navigation signal capturing and tracking process according to a single-star positioning result and by utilizing the forwarded ephemeris information of the low-orbit enhancement signal, and assisting capturing and tracking of the satellite navigation signal.

8. The apparatus of claim 7, wherein the signal receiving module (201) comprises: a satellite signal down-conversion and baseband processing sub-module and an electric text resolving and information processing sub-module;

the satellite signal down-conversion and baseband processing submodule is used for receiving satellite navigation signals sent by a global navigation satellite system and low-orbit enhancement signals sent by low-orbit earth satellites, capturing and tracking the signals, and obtaining signal accumulation parameters;

the message resolving and information processing sub-module is used for recovering message bit information according to the signal accumulation quantity parameter, resolving ephemeris parameters and calculating satellite position and speed information according to the ephemeris parameters.

9. The apparatus of claim 7, wherein the combined positioning module (204) is a combined navigation positioning module of inertial navigation system and global navigation satellite system, and is configured to fuse the positioning result with the satellite navigation signal information by using a fusion algorithm, and compress a tracking loop of the satellite navigation signal by using autonomous positioning information of the inertial navigation system, so as to assist continuous tracking of the satellite navigation signal.