CN115712135A

CN115712135A - GNSS/INS vector deep combination system and method

Info

Publication number: CN115712135A
Application number: CN202211484974.2A
Authority: CN
Inventors: 齐巍; 马天翊; 李田; 孟庚; 伍蔡伦; 赵宇娇; 梁志勇; 赵迪
Original assignee: 63921 Troops of PLA; Beijing Institute of Electronic System Engineering
Current assignee: 63921 Troops of PLA; Beijing Institute of Electronic System Engineering
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2023-02-24

Abstract

The application discloses a system and a method for GNSS/INS vector deep combination. The system comprises: the inertial navigation prediction device is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS; the positioning field observation device is communicated with the inertial navigation prediction device and is configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna; and the combined filtering device is communicated with the inertial navigation prediction device and the positioning field observation device, is configured to process the observed quantity to obtain inertial navigation error correction quantity, and sends the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS. According to the method, the satellite navigation pseudo code and carrier signal parameters are accurately generated by using the INS, and the error divergence of the INS is restrained by using the GNSS sensitive positioning field information, so that the problem of contradiction between performance and bandwidth setting in the traditional receiver tracking loop design can be effectively solved.

Description

GNSS/INS vector deep combination system and method

Technical Field

The application relates to the technical field of integrated navigation, in particular to a GNSS/INS vector deep integration system and method.

Background

The Global Navigation Satellite System (GNSS) and the Inertial Navigation System (INS) have strong complementary characteristics, and the combination of the two systems can make up for each other to obtain higher Navigation performance than that of the System which is used alone, so that the GNSS/INS combined Navigation System is researched and applied more and more widely.

The combination of GNSS and INS is generally divided into 3 modes: loose combinations, tight combinations and deep combinations.

The loose combination is the simplest combination mode, the GNSS and the INS work independently, and position and speed information of the GNSS and the INS are utilized to perform data fusion. And the tight combination is relatively complex, the pseudo range and the pseudo range corresponding to the position of the INS are obtained by calculation according to satellite ephemeris information received by the GNSS receiver and position and speed information output by the INS, and then the pseudo range and the pseudo range rate are combined with the pseudo range and the pseudo range rate measured by the GNSS receiver. In the re-loose combination and tight combination mode, the information of the GNSS can inhibit the accumulation of the INS errors, and when the satellite navigation pseudo code and the carrier signal are shielded and cannot work normally, the INS can provide a continuous navigation result.

The deepest combination mode in deep combination gradually becomes the key point of domestic and foreign research along with the improvement of the performance requirements of aviation, aerospace, military and other applications on the navigation system. In addition to performing loose combination and tight combination processing, the deep combination may also assist signal tracking of the receiver by using measurements (acceleration) of the INS or navigation information (position, velocity). The deep combination needs to be deep inside the receiver, relates to the fusion of signal processing layers of the receiver, is more auxiliary than loose combination and tight combination in the aspects of structure or algorithm, and is a combination mode of the GNSS in the deepest layer of the INS. The core link for completing the satellite navigation pseudo code and carrier signal demodulation (acquisition and tracking) in the receiver is a signal tracking loop. The loop continuously identifies the difference between the local replica signal and the received signal, and then adjusts the voltage-controlled oscillator to enable the frequency/phase of the local replica signal to be consistent with the received signal, so as to realize the acquisition/tracking of the signal.

However, the signal tracking loop of the receiver is usually affected by various error sources, including thermal noise, crystal instability, carrier dynamics, and so on. When designing a receiver, a larger loop bandwidth is needed to ensure the dynamic performance of the receiver, however, a larger loop bandwidth generally means that more loop noise is introduced, i.e. the anti-noise or anti-interference performance of the loop and even the sensitivity are sacrificed. Conversely, in order to obtain better anti-noise or anti-interference performance, the loop bandwidth is reduced, so that the dynamic performance of the loop is limited, and the requirements of the dynamic performance of the traditional receiver on the bandwidth and the requirements of the anti-noise and anti-noise performance on the bandwidth have serious contradiction.

In a traditional GNSS receiver, only linear prediction can be carried out on synchronization parameters at the next time, a large error is introduced, and the longer the integration time is, the larger the linear prediction error is. Therefore, in the conventional receiver, when the satellite navigation pseudo code and the carrier signal are shielded and weakened and the linear prediction error cannot be corrected, the tracking loop is quickly unlocked, once the signal quality is affected or the carrier dynamics is too large, the GNSS receiver cannot complete the tracking and locking of the signal, and the whole system cannot work normally. Therefore, the conventional receiver tracking loop design in the prior art has the problem that the performance and the bandwidth are set to be contradictory.

Disclosure of Invention

The embodiments of the present application provide a system and a method for GNSS/INS vector deep combination, so as to solve the problem that the conventional receiver tracking loop design in the prior art has contradictory settings of performance and bandwidth.

In order to achieve the above object, a first aspect of the present application provides a GNSS/INS vector deep combination system, including:

the inertial navigation prediction device is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS;

a positioning field observation device, which is communicated with the inertial navigation prediction device and is configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna;

and the combined filtering device is communicated with the inertial navigation prediction device and the positioning field observation device, is configured to process the observed quantity to obtain inertial navigation error correction quantity, and sends the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS.

In an embodiment of the present application, the inertial navigation prediction device is further configured to correct an accumulated error of the inertial navigation device and the clock unit.

In an embodiment of the present application, an inertial navigation prediction apparatus includes:

the ephemeris extraction module is configured to acquire satellite ephemeris parameters and determine a correction error according to the satellite ephemeris parameters and the signal transmission delay;

the inertial navigation correction module is communicated with the ephemeris extraction module and is configured to correct the accumulated error of the inertial navigation device according to the corrected error;

a clock calibration module, in communication with the ephemeris extraction module, configured to correct the accumulated error of the clock unit based on the corrected error.

In an embodiment of the present application, the inertial navigation prediction apparatus is further configured to:

determining the carrier frequency, carrier phase and code phase of the local satellite navigation pseudo code and carrier signal according to the parameters generated by the INS;

and generating a local satellite navigation pseudo code and a carrier signal according to the carrier frequency, the carrier phase and the code phase.

In an embodiment of the present application, a localization field observation apparatus includes:

the signal module is communicated with the inertial navigation prediction device and is configured to perform coherent integration on the local satellite navigation pseudo code and carrier signal and the satellite navigation pseudo code and carrier signal input by the antenna to obtain a coherent integration accumulated value;

a baseband module, in communication with the signal module and the combined filtering device, configured to process the coherent integration accumulation values through a signal tracking algorithm to obtain measurement values;

a measurement module, in communication with the baseband module and the combined filtering device, configured to determine an observed quantity from the measured value;

and the navigation module is communicated with the measuring module and is configured to carry out positioning and time service according to the observed quantity.

In an embodiment of the present application, the observed quantity includes a carrier frequency error and a phase error, and the combining filter device is further configured to:

processing the carrier frequency error through a frequency locking loop filter to obtain a processed carrier frequency error;

processing the phase error through a phase-locked loop filter to obtain a processed phase error;

and determining the inertial navigation error correction quantity according to the processed carrier frequency error and the processed phase error.

The second aspect of the present application provides a GNSS/INS vector deep combination method, which is applied to a GNSS/INS vector deep combination system, where the GNSS/INS vector deep combination system includes an inertial navigation prediction apparatus, a positioning field observation apparatus, and a combined filtering apparatus, and the method includes:

generating a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS through an inertial navigation prediction device;

determining an observed quantity through a positioning field observation device according to a local satellite navigation pseudo code and carrier signals and antenna satellite navigation pseudo codes and carrier signals input by an antenna;

and processing the observed quantity through the combined filtering device to obtain an inertial navigation error correction quantity, and sending the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS.

In this embodiment, the generating the local satellite navigation pseudo code and the carrier signal according to the parameters generated by the INS includes:

In the embodiment of the present application, determining the observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna comprises:

coherent integration is carried out on the local satellite navigation pseudo code and carrier signal and the satellite navigation pseudo code and carrier signal input by the antenna to obtain a coherent integration accumulated value;

processing the coherent integration accumulated value to obtain a measured value;

the observed quantity is determined from the measured value.

In this embodiment of the present application, the observed quantity includes a carrier frequency error and a phase error, and processing the observed quantity to obtain an inertial navigation error correction amount includes:

Through the technical scheme, the GNSS/INS vector deep combination system comprises an inertial navigation prediction device, a positioning field observation device and a combined filtering device. The inertial navigation prediction device is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS; the positioning field observation device is communicated with the inertial navigation prediction device and is configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna; and the combined filtering device is communicated with the inertial navigation prediction device and the positioning field observation device, is configured to process the observed quantity to obtain inertial navigation error correction quantity, and sends the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS. According to the method, mutual gain between the INS and the GNSS can be realized through a GNSS/INS vector deep combination system, and parameters of satellite navigation pseudo codes and carrier signals are accurately predicted through an inertial navigation prediction device; and the observed quantity is determined through GNSS, and the inertial navigation error correction quantity is further obtained so as to restrain INS error divergence and improve the anti-interference performance and tracking sensitivity of the system.

Additional features and advantages of embodiments of the present application will be described in detail in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the embodiments of the disclosure, but are not intended to limit the embodiments of the disclosure. In the drawings:

FIG. 1 is a schematic structural diagram of a GNSS/INS vector deep integration system according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a GNSS/INS vector deep integration system according to another embodiment of the present application;

FIG. 3 is a schematic structural diagram of a GNSS/INS vector deep integration system according to another embodiment of the present application;

FIG. 4 is a flowchart illustrating a method for GNSS/INS vector deep integration according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a concentrated vector deep combining system according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a carrier tracking loop according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of an INS assisted carrier tracking loop according to an embodiment of the present application;

FIG. 8 is a schematic diagram of tracking satellite carrier-to-noise ratio in a continuous scene according to an embodiment of the present application;

FIG. 9 (a), FIG. 9 (b), FIG. 9 (c) and FIG. 9 (d) are schematic diagrams of error estimation of GNSS/INS vector deep combinations in successive scenarios according to an embodiment of the present invention.

Description of the reference numerals

100. Inertial navigation prediction device 200 positioning field observation device

300. Combined filtering device 101 ephemeris extraction module

102. Inertial navigation correction module 103 clock calibration module

201. Signal module 202 baseband module

203. Measurement module 204 navigation module

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it should be understood that the specific embodiments described herein are only used for illustrating and explaining the embodiments of the present application and are not used for limiting the embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present application, the directional indications are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present application.

Fig. 1 is a schematic structural diagram of a GNSS/INS vector deep combination system according to an embodiment of the present disclosure. As shown in fig. 1, an embodiment of the present application provides a system for GNSS/INS vector deep combination, which may include:

the inertial navigation prediction device 100 is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS;

a positioning field observation device 200, in communication with the inertial navigation prediction device 100, configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna;

the combined filtering device 300, which is in communication with the inertial navigation prediction device 100 and the positioning field observation device 200, is configured to process the observed quantity to obtain an inertial navigation error correction quantity, and send the inertial navigation error correction quantity to the inertial navigation prediction device 100, so that the inertial navigation prediction device 100 corrects the parameter generated by the INS.

In the embodiment of the present application, the GNSS is a global satellite navigation system, and the INS is an inertial navigation system. The deep integration is the deepest integration mode of the GNSS and the INS, and in a deep integration system, signal tracking of a receiver of the GNSS may be assisted by using measurement information or navigation information of the INS. The demodulation of satellite navigation pseudo codes and carrier signals is completed in a receiver, the core link of the demodulation is a signal tracking loop, the signal tracking loop can continuously identify the difference between a local signal and a received signal, and then a voltage-controlled oscillator is adjusted, so that the frequency and the phase of a local replica signal are consistent with the received signal area, and the acquisition and tracking of the signal are realized. Because the signal tracking loop of the receiver is usually affected by various error sources, such as thermal noise, instability of crystal oscillator, carrier dynamics, etc., there is a serious contradiction between the requirement of the dynamic performance of the traditional receiver on the bandwidth and the requirement of the anti-interference and anti-noise performance on the bandwidth. Therefore, it is necessary to implement mutual gain between INS and GNSS by using a vector deep combinatorial system to solve the problem of contradiction between performance and bandwidth setting in the conventional receiver tracking loop design.

In the embodiment of the present application, the GNSS/INS vector deep integration system mainly includes an inertial navigation prediction apparatus 100, a positioning field observation apparatus 200, and an integrated filter apparatus 300. The inertial navigation prediction device 100 is respectively in communication with the localization field observation device 200 and the combined filter device 300, and the localization field observation device 200 can be in communication with the combined filter device 300.

The inertial navigation prediction device 100 is mainly used for generating a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS. The parameters generated by the INS refer to parameters of satellite navigation pseudo codes and carrier signals generated by the INS. In one example, the satellite navigation pseudo code and carrier signal synchronization parameter may be obtained according to a parameter generated by the INS, and further, the local satellite navigation pseudo code and carrier signal may be generated according to the satellite navigation pseudo code and carrier signal synchronization parameter. In another example, the inertial navigation prediction apparatus 100 may generate a local satellite navigation pseudo code and a local satellite navigation carrier signal according to a parameter generated by the INS, the prediction information provided by the INS may be PVCC information, the inertial navigation prediction apparatus 100 may calculate a carrier frequency, a carrier phase, a code phase, and the like according to the PVCC information, and may generate the local satellite navigation pseudo code and the local satellite navigation carrier signal when determining data of the carrier frequency, the carrier phase, the code phase, and the like. The inertial navigation prediction device 100 may communicate with the positioning field observation device 200, and after generating the local satellite navigation pseudo code and the carrier signal, may send the local satellite navigation pseudo code and the carrier signal to the positioning field observation device 200 for further processing.

In the embodiment of the present application, the positioning field observation apparatus 200, i.e. the GNSS receiver, is mainly used for determining the observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna. Specifically, coherent integration is carried out on a local satellite navigation pseudo code and a carrier signal which are locally generated and an antenna satellite navigation pseudo code and a carrier signal which are input by an antenna, after sufficient signal-to-noise ratio gain is obtained, an observed quantity is obtained through error identification processing, and positioning and time service are achieved through the observed quantity. In one example, the main tasks of the GNSS receiver tracking loop are to maintain the code phase and carrier frequency lock of the tracking loop, strip the carrier signal and C/a code information from the intermediate frequency signal, and extract the binary navigation message provided by the satellite. Each channel of the vector tracking loop tracks one satellite, corresponds to one channel preprocessing filter, and is mainly used for estimating estimation error information such as code phase error, carrier frequency error and the like of the tracking loop, and converting the error information into corresponding pseudo range deviation and pseudo range rate deviation information which can be used as an observation signal of a next-stage navigation main filter.

In the embodiment of the present application, the combined filtering device 300 is mainly used for processing the observed quantity to obtain an inertial navigation error correction quantity, and sending the inertial navigation error correction quantity to the inertial navigation prediction device 100, so that the inertial navigation prediction device 100 corrects the parameter generated by the INS. The inertial navigation error correction quantity is coherent data such as inertial navigation error correction information. In one example, the combined filtering device 300 may assist the inertial navigation prediction device 100 to predict the GNSS signal parameters more accurately by inputting the inertial navigation correction information and other related data to the inertial navigation prediction device 100.

Specifically, the combined filtering device 300 inputs the inertial navigation error correction amount to the inertial navigation prediction device 100, the inertial navigation prediction device 100 corrects the parameters generated by the INS through the inertial navigation error correction amount, the INS regenerates the signal parameters of the GNSS and regenerates the local signal by combining the satellite navigation pseudo code and the carrier signal input by the antenna, re-determines the observed quantity, and re-determines the inertial navigation error correction amount according to the observed quantity. And repeating the steps until the local satellite navigation pseudo code and the carrier signal are consistent with the satellite navigation pseudo code and the carrier signal input by the antenna.

In the embodiment of the application, in a GNSS/INS vector deep combination system, the INS can predict the relative motion between the receiver and the satellite by measuring the carrier dynamic, the dynamic stress born by the receiver is greatly reduced, and the loop can stably work under a higher dynamic condition. The inertia auxiliary information is utilized to assist the receiver to track the loop, so that the bandwidth of the loop can be compressed, the noise of the loop is reduced, the carrier-to-noise ratio is improved, and the anti-interference performance of the system is improved; under the action of inertia auxiliary information, the receiver compresses loop bandwidth, reduces loop noise, and provides possibility for prolonging coherent integration time, thereby improving tracking sensitivity.

In the embodiment of the application, mutual gain between the INS and the GNSS is realized through a GNSS/INS vector deep combination system. In terms of the GNSS, the vector deep combination system mainly utilizes INS to provide signal parameters, so that in the scenes of strong noise, weak satellite navigation pseudo codes and carrier signals, the signal-to-noise ratio is improved by a coherent integration method, higher loop gain is obtained, a GNSS receiver can carry out coherent integration for as long as possible, sensitive positioning field information is positioned and timed, the influence of loop noise is reduced, and the anti-noise anti-interference capability and tracking sensitivity are improved. In terms of INS, due to the fact that noise and drift exist in the measurement value of the inertial device, the speed and position results obtained through integration are dispersed along with time, and after the GNSS receiver senses a positioning field, the positioning and time service results can be used for restraining the dispersion of INS errors.

Through the technical scheme, the GNSS/INS vector deep combination system comprises an inertial navigation prediction device 100, a positioning field observation device 200 and a combined filtering device 300. The inertial navigation prediction device 100 is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS; the positioning field observation device 200 is communicated with the inertial navigation prediction device 100 and is configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna; and a combined filtering device 300, which is in communication 300 with the inertial navigation prediction device 100 and the positioning field observation device, and is configured to process the observed quantity to obtain an inertial navigation error correction quantity, and send the inertial navigation error correction quantity to the inertial navigation prediction device 100, so that the inertial navigation prediction device 100 corrects the parameter generated by the INS. According to the method, the mutual gain between the INS and the GNSS can be realized through a GNSS/INS vector deep combination system, and the parameters of the satellite navigation pseudo code and the carrier signal can be accurately predicted through the inertial navigation prediction device 100; and the observed quantity is determined through GNSS, and the inertial navigation error correction quantity is further obtained so as to restrain INS error divergence and improve the anti-interference performance and tracking sensitivity of the system.

In the embodiment of the present application, the inertial navigation prediction apparatus 100 may be further configured to correct the accumulated error of the inertial navigation device and the clock unit.

In this application, the inertial navigation prediction apparatus 100 may also correct the accumulated error of the inertial navigation device and the clock unit. In a GNSS/INS vector deep combination system, the prediction accuracy of an inertial navigation prediction device is related to the accuracy of an inertial device and the accuracy of a clock crystal oscillator. With the aid of the INS, the main error terms of the receiver tracking loop are converted from carrier dynamics induced errors to INS estimation errors and crystal oscillator errors. The crystal oscillator of the receiver is the source of the frequency reference signal of the receiver, and directly influences the performance of the receiver. The level of the inertial device affects the quality of the INS aiding information, which in turn affects the performance of the deep combining system.

In one example, the ins may use a high-precision inertial device and a high-precision clock oscillator, which accurately generate satellite navigation pseudo code and carrier signal synchronization parameters over a long period of time, but at a high cost and large volume. In another example, the INSS may use a low-precision inertial device and a low-precision clock oscillator, which may reduce cost and volume, but may accurately generate the satellite navigation pseudo code and carrier signal synchronization parameters only in a short time. In practical application, if the observed quantity of the GNSS can be used for correcting errors of the inertial device and the clock crystal oscillator in a short time, the system can be ensured to operate with high precision for a long time, and therefore, the inertial device and the clock crystal oscillator can be selected according to practical application scenes.

Fig. 2 is a schematic structural diagram of a system for GNSS/INS vector deep integration according to another embodiment of the present application. As shown in fig. 2, the inertial navigation prediction apparatus 100 may include:

an ephemeris extraction module 101 configured to obtain satellite ephemeris parameters and determine a correction error according to the satellite ephemeris parameters and the signal transmission delay;

an inertial navigation correction module 102, in communication with the ephemeris extraction module 101, configured to correct an accumulated error of the inertial navigation device according to the corrected error;

the clock calibration module 103, in communication with the ephemeris extraction module 101, is configured to correct the accumulated error of the clock unit based on the corrected error.

In the embodiment of the present application, the inertial navigation prediction apparatus 100 may include an ephemeris extraction module 101, an inertial navigation correction module 102, and a clock calibration module 103. The ephemeris extraction module 101 is mainly configured to obtain satellite ephemeris parameters, and determine a correction error according to the satellite ephemeris parameters and the signal transmission delay. In an example, the ephemeris extraction module 101 may provide information of a satellite clock bias, an ionosphere, a troposphere, and an earth rotation, so as to improve the accuracy of predicting the GNSS synchronization parameters, calculate the satellite clock bias, the ionosphere, the troposphere, and the earth rotation, and obtain a correction error after calculation according to the satellite ephemeris parameters and the signal transmission delay. The inertial navigation correction module 102 and the clock calibration module 103 may respectively perform an accumulated error of the inertial navigation device and an accumulated error of the clock unit according to the corrected error. In another example, the inertial navigation system and the clock may be corrected for the error, and then parameters generated by the INS may be corrected according to the inertial navigation system and the clock, and finally converted into GNSS synchronization parameters.

In an embodiment of the present application, the inertial navigation prediction apparatus 100 may be further configured to:

Specifically, the satellite signal transmitting time, the satellite position, the satellite speed, the satellite clock bias and the pseudo range are iteratively calculated according to the receiver time and the ephemeris file; the period of the C/A ranging code of the L1 frequency band of the GPS signal is 1ms and is aligned with the satellite clock by a whole second, so that the pseudo code phase can be calculated according to the signal transmitting time, and the unit of the pseudo code phase is a code chip. Calculating carrier rate and carrier phase under the condition of neglecting the satellite Zhong Piao; and calculating the signal amplitude according to the carrier-to-noise ratio estimation result. Finally, the local signal can be generated under the condition that the signal amplitude, the code phase, the carrier frequency and the carrier phase on tracking are determined.

Fig. 3 is a schematic structural diagram of a GNSS/INS vector deep combination system according to yet another embodiment of the present application. As shown in fig. 3, the localization field observing apparatus 200 may include:

a signal module 201, in communication with the inertial navigation prediction apparatus 100, configured to perform coherent integration on the local satellite navigation pseudo code and the carrier signal and the satellite navigation pseudo code and the carrier signal input by the antenna to obtain a coherent integration accumulated value;

a baseband module 202, in communication with the signal module 201 and the combined filtering apparatus 300, configured to process the coherent integration accumulation values through a signal tracking algorithm to obtain measurement values;

a measurement module 203, in communication with the baseband module 202 and the combined filtering device 300, configured to determine an observed quantity from the measured values;

the navigation module 204, in communication 203 with the metrology module, is configured to locate and time based on the observations.

In the embodiment of the present application, the positioning field observation device 200, i.e. the GNSS receiver, specifically divides the GNSS receiver into 4 levels of signal, baseband, measurement, and navigation according to the processing flow of the satellite navigation pseudo code and the carrier signal, and considering the compatibility problem of different GNSS navigation algorithms, that is, the positioning field observation device 200 may include a signal module 201, a baseband module 202, a measurement module 203, and a navigation module 204.

In this embodiment, the positioning field observation device 200 receives the local satellite navigation pseudo code and the carrier signal generated by the inertial navigation prediction device 100, acquires an antenna input signal, correlates and coherently accumulates the local signal and the signal input by the antenna through the signal module 201 to obtain a coherent integration accumulated value, and further performs signal tracking algorithm processing on the coherent integration accumulated value through the baseband module 202 to obtain a measured value. The measured value refers to a carrier frequency, a carrier phase, a code phase, and the like. The baseband module 202 inputs the measured value to the measurement module 203, and the measurement module 203 can realize navigation message mediation, determine the observed quantity according to the measured value, and input the observed quantity to the combined filtering device for further processing. In the embodiment of the application, in a loop structure of a GNSS/INS vector deep combination, after a baseband I/Q signal passes through a phase discriminator, an obtained code phase tracking error and a carrier phase tracking error are used as observed quantities of a channel preprocessing filter. The channel preprocessing filter utilizes the code tracking error, the carrier frequency change rate error and the like as state quantities, the code tracking error and the carrier tracking error are coupled together and mutually assisted, and the change of the carrier frequency and the code phase can be estimated and predicted more accurately.

In the embodiment of the present application, the navigation module 204 may obtain the observed quantity output by the measurement layer 203, and further implement positioning and time service functions according to the observed quantity.

In one example, the localization field observation device 200 receives a local signal generated by the inertial navigation prediction device 100, acquires an antenna input signal, correlates and coherently accumulates the local signal and the antenna input signal to obtain a sufficient signal-to-noise ratio gain, senses localization field information, and processes an accumulation result through a frequency discriminator and a code phase discriminator to obtain a carrier frequency error and a code phase error.

The carrier frequency error represents a speed domain error, and is an error caused by the INS speed and inaccuracy of the receiver Zhong Piao when the external auxiliary frequency is calculated; the code phase error represents the position domain error, which is the error in calculating the aiding code phase due to the INS position and inaccuracy in the receiver Zhong Piao.

In the embodiment of the present application, the prediction information generated by the INS has a certain correlation with the carrier frequency error and the code phase error. If the PVCC information generated by the INS is accurate, the carrier frequency error and the code phase error are zero; otherwise, the carrier frequency error and the code phase error are not zero, and the PVCC information generated by the INS has errors. As a result, the carrier frequency error and the code phase error reflect the accuracy with which the INS generates PVCC information, and therefore, the accuracy with which the INS generates information can be determined from the carrier frequency error and the code phase error.

In the embodiment of the present application, the carrier error may be regarded as a pseudo-range rate error, the code phase error may be regarded as a pseudo-range error, and the carrier error and the code phase error are regarded as an observed quantity output by the positioning field observation device 200, and the positioning field observation device 200 inputs the observed quantity into the combined filter device 300 for further processing.

In one example, multipath error compensation and signal integrity analysis processing are required to be performed on the observed quantity, so as to eliminate unhealthy satellites, and available satellites are selected and channel allocation is performed according to satellite elevation angles and carrier-to-noise ratios on the basis of the unhealthy satellites.

In the embodiment of the present application, the observed quantity includes a carrier frequency error and a phase error, and the combined filtering apparatus 300 may be further configured to:

In the embodiment of the present application, a phase-locked loop generally includes a phase detector, a loop filter, and a voltage-controlled oscillator, where the phase-locked loop filter is a filter in a phase-locked loop component. The frequency-locked loop is an automatic frequency fine-tuning circuit which is used dynamically, is a typical automatic control loop, and is mainly used for replacing a phase-locked loop as a tracking filter to track large dynamic parameter targets such as satellites and the like or signals with rapidly changed phases. In the embodiment of the application, the carrier frequency error is processed by the frequency-locked loop filter, the phase error is processed by the phase-locked loop filter, and the two are correspondingly added, so that the frequency-locked loop auxiliary phase-locked loop can be realized.

Fig. 4 is a flowchart illustrating a method for GNSS/INS vector deep integration according to an embodiment of the present disclosure. As shown in fig. 4, a second aspect of the present application provides a method for GNSS/INS vector deep combination, which is applied to a system for GNSS/INS vector deep combination, where the system for GNSS/INS vector deep combination includes an inertial navigation prediction apparatus, a positioning field observation apparatus, and a combined filtering apparatus, and the method may include the following steps:

step 401, generating a local satellite navigation pseudo code and a carrier signal according to parameters generated by an INS through an inertial navigation prediction device;

step 402, determining an observed quantity according to a local satellite navigation pseudo code and carrier signal and an antenna satellite navigation pseudo code and carrier signal input by an antenna through a positioning field observation device;

and step 403, processing the observed quantity through the combined filtering device to obtain an inertial navigation error correction quantity, and sending the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS.

In the embodiment of the present application, the parameters generated by the INS refer to parameters of satellite navigation pseudo codes and carrier signals generated by the INS. In one example, the satellite navigation pseudo code and carrier signal synchronization parameter may be obtained according to a parameter generated by the INS, and further, the local satellite navigation pseudo code and carrier signal may be generated according to the satellite navigation pseudo code and carrier signal synchronization parameter. In another example, the inertial navigation prediction device may generate a local satellite navigation pseudo code and a carrier signal according to a parameter generated by the INS, the prediction information provided by the INS may be PVCC information, the inertial navigation prediction device may calculate a carrier frequency, a carrier phase, a code phase, and the like according to the PVCC information, and the local satellite navigation pseudo code and the carrier signal may be generated under the condition that data such as the carrier frequency, the carrier phase, the code phase, and the like is determined. The inertial navigation prediction device can be communicated with the positioning field observation device, and after the local satellite navigation pseudo code and the carrier signal are generated, the local satellite navigation pseudo code and the carrier signal can be sent to the positioning field observation device for further processing.

In the embodiment of the application, coherent integration is performed on the local satellite navigation pseudo code and carrier signal generated locally and the antenna satellite navigation pseudo code and carrier signal input by the antenna through the positioning field observation device, after sufficient signal-to-noise ratio gain is obtained, an observed quantity is obtained through error identification processing, and the observed quantity is further input to the combined filtering device for further processing. And carrying out combined filtering processing on the observed quantity through a combined filtering device to obtain an inertial navigation error correction quantity, and sending the inertial navigation error correction quantity to an inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS. The inertial navigation error correction quantity is coherent data such as inertial navigation error correction information. In one example, the combination filtering device inputs the inertial navigation correction information and other related data to the inertial navigation prediction device, so that the INS can be assisted to predict the signal parameters of the GNSS more accurately.

In the embodiment of the application, the INS can predict the relative motion between the receiver and the satellite by measuring the carrier dynamics, the dynamic stress born by the receiver is greatly reduced, and the loop can stably work under a higher dynamic condition. The inertia auxiliary information is utilized to assist the receiver in tracking the loop, so that the bandwidth of the loop can be compressed, the noise of the loop is reduced, the carrier-to-noise ratio is improved, and the anti-interference performance of the system is improved; under the action of inertia auxiliary information, the receiver compresses loop bandwidth, reduces loop noise, and provides possibility for prolonging coherent integration time, thereby improving tracking sensitivity.

In this embodiment, the generating the local satellite navigation pseudo code and carrier signal according to the parameters generated by the INS may include:

Specifically, satellite signal emission time, satellite position, satellite speed, satellite clock bias and pseudo range are iteratively calculated according to receiver time and an ephemeris file; the period of the C/A ranging code of the L1 frequency band of the GPS signal is 1ms and is aligned with the satellite clock by a whole second, so that the pseudo code phase can be calculated according to the signal transmitting time, and the unit of the pseudo code phase is a code chip. Calculating carrier rate and carrier phase under the condition of neglecting the satellite Zhong Piao; and calculating the signal amplitude according to the carrier-to-noise ratio estimation result. Finally, the local signal can be generated under the condition that the signal amplitude, the code phase, the carrier frequency and the carrier phase on tracking are determined.

In this embodiment, determining the observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna may include:

the observed quantity is determined from the measured value.

In the embodiment of the application, the positioning field observation device receives the local satellite navigation pseudo code and the carrier signal generated by the inertial navigation prediction device, acquires an antenna input signal, correlates and coherently accumulates the local signal and the signal input by the antenna through the signal module to obtain a coherent integration accumulated value, and performs signal tracking algorithm processing on the coherent integration accumulated value through the baseband module to obtain a measured value. The measured value refers to a carrier frequency, a carrier phase, a code phase, and the like. The baseband layer inputs the measured value to the measuring layer, and the measuring layer can realize navigation message mediation and determine the observed quantity according to the measured value. In the embodiment of the application, the observed quantities, namely the carrier frequency error and the code phase error, in the loop structure of the GNSS/INS vector deep combination, the baseband I/Q signal passes through a phase discriminator, and the obtained code phase tracking error and carrier phase tracking error are used as the observed quantities of the channel preprocessing filter. The channel preprocessing filter utilizes the code tracking error, the carrier frequency change rate error and the like as state quantities, the code tracking error and the carrier tracking error are coupled together and mutually assisted, and the change of the carrier frequency and the code phase can be estimated and predicted more accurately.

In this embodiment of the present application, the observed quantity includes a carrier frequency error and a phase error, and processing the observed quantity to obtain an inertial navigation error correction quantity may include:

Through the technical scheme, the GNSS/INS vector deep combination system comprises an inertial navigation prediction device, a positioning field observation device and a combined filtering device. The inertial navigation prediction device is configured to generate a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS; the positioning field observation device is communicated with the inertial navigation prediction device and is configured to determine an observed quantity according to the local satellite navigation pseudo code and carrier signal and the antenna satellite navigation pseudo code and carrier signal input by the antenna; and the combined filtering device is communicated with the inertial navigation prediction device and the positioning field observation device, is configured to process the observed quantity to obtain inertial navigation error correction quantity, and sends the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS. According to the method, mutual gain between the INS and the GNSS can be realized through a GNSS/INS vector deep combination system, and parameters of satellite navigation pseudo codes and carrier signals are accurately predicted through the INS; and the observed quantity is determined through GNSS, and the inertial navigation error correction quantity is further obtained so as to restrain INS error divergence and improve the anti-interference performance and tracking sensitivity of the system.

In an embodiment of the present application, a system for GNSS/INS vector deep combination may include the following:

the ephemeris extraction in the inertial navigation prediction device mainly provides satellite clock bias, an ionosphere, a troposphere and earth rotation information, is used for improving the prediction precision of GNSS synchronous parameters, calculates the satellite clock bias, the ionosphere, the troposphere and the earth rotation, and obtains a correction error after calculation according to the satellite ephemeris parameters and signal transmission delay. And the inertial navigation and clock correction error is used for correcting the predicted pseudo range and pseudo range rate, and finally converted into the GNSS synchronization parameter. The inertial navigation prediction precision is related to the precision of an inertial device and the precision of a clock crystal oscillator, and the high-precision inertial device and the high-precision crystal oscillator are used, so that the satellite navigation pseudo code and carrier signal synchronous parameters can be accurately predicted for a long time, but the cost is high and the size is large; on the contrary, the low-precision inertial device and the low-precision crystal oscillator are used, the satellite navigation pseudo code and carrier signal synchronous parameters can be accurately predicted in a short time, the size is small, the cost is low, and if the GNSS observation value can be used for correcting errors of the inertial device and the crystal oscillator in a short time, the long-time high-precision operation of the system can be ensured. In engineering, the inertial device and the crystal oscillator can be selected according to application scenes.

The positioning field observation device needs to perform multi-path error compensation and signal integrity analysis processing on the observed quantity so as to eliminate unhealthy satellites, selects available satellites and distributes channels according to satellite elevation angles and carrier-to-noise ratios on the basis, and the sensitive positioning field information can be treated by being summarized as a signal estimation problem. According to the processing flow of satellite navigation pseudo codes and carrier signals and considering the compatibility problems of different GNSS navigation algorithms, the GNSS receiver is specifically divided into 4 layers of a signal layer, a baseband layer, a measurement layer and a navigation layer. The signal layer inputs intermediate frequency sampling points to realize coherent integration and output a coherent integration accumulated value; the input of the baseband layer is a coherent integration I/Q value, a signal tracking algorithm is realized, and the measured values of carrier frequency, carrier phase, code phase and the like are output; the measurement layer demodulates the navigation message, extracts pseudo range and pseudo range rate observed quantity and outputs the pseudo range rate observed quantity; the navigation layer realizes navigation and time service functions.

And the combined filtering device is used for carrying out low-pass filtering by using an Extended Kalman Filter (EKF) according to the inertial navigation prediction deviation to obtain an inertial navigation error correction quantity and correcting the inertial navigation state error. In a deep combination system, the relative motion between a receiver and a satellite can be predicted by measuring the carrier dynamics through inertial navigation, the dynamic stress born by the receiver is greatly reduced, and a loop can stably work under a high dynamic condition. The inertia auxiliary information is utilized to assist the receiver to track the loop, so that the bandwidth of the loop can be compressed, the noise of the loop is reduced, the carrier-to-noise ratio is improved, and the anti-interference performance of the system is improved; under the action of inertia auxiliary information, the receiver compresses loop bandwidth, reduces loop noise, and provides possibility for prolonging coherent integration time, thereby improving tracking sensitivity. With the aid of the INS, the main error terms of the receiver tracking loop are converted from carrier dynamics induced errors to INS estimation errors and crystal oscillator errors. The crystal oscillator of the receiver is the source of the frequency reference signal of the receiver, and directly influences the performance of the receiver. The level of the inertial device affects the quality of the INS aiding information, which in turn affects the performance of the deep combining system. A navigation filter in a GNSS/INS deep combination vector tracking loop of vector tracking estimates the positioning error of the INS by using the output of a pre-filter as an observed quantity, and then controls the generation of a local signal by using a code Doppler and carrier Doppler estimated value which is obtained by the calculation of an INS navigation solution after error correction.

In an embodiment of the present application, a method for GNSS/INS vector deep combination may include the following steps:

the method comprises the following steps that step 1, an inertial navigation prediction module provides satellite navigation pseudo codes and carrier signal synchronous parameters to generate local satellite navigation pseudo codes and carrier signals, and the inertial navigation prediction module mainly comprises ephemeris, an inertial sensor (IMU) and a clock.

Step 2, calculating the clock bias of the satellite, the ionosphere, the troposphere and the earth rotation, and obtaining a correction error after calculation according to the ephemeris parameters of the satellite and the signal transmission delay;

step 3, the principle and the flow of calculating the synchronization parameters of the satellite navigation pseudo code and the carrier signal according to the PVCC information are as follows:

1) According to the time of the receiver and the ephemeris file, iteratively calculating the satellite signal transmitting time, the satellite position, the satellite speed, the satellite clock bias and the pseudo range;

2) The GPS L1C/A ranging code period is 1ms and is aligned with the satellite clock in whole second, so that the pseudo code phase (the unit is a code chip) can be calculated according to the signal transmitting time;

3) Neglecting a satellite Zhong Piao, calculating a carrier frequency and a carrier phase;

4) Calculating signal amplitude according to the carrier-to-noise ratio estimation result;

5) The satellite signal can be generated by knowing the signal amplitude, code phase, carrier frequency and carrier phase on tracking.

Step 4, the positioning field observation module performs coherent integration by using the satellite navigation pseudo code and carrier signal generated locally and the satellite navigation pseudo code and carrier signal input by the antenna, so that after enough signal-to-noise ratio gain is obtained, positioning field information can be sensitive, an observed quantity is obtained after error identification, and positioning and time service are realized by using the observed quantity;

and 5, multipath error compensation and signal integrity analysis processing are carried out on the observed quantity, unhealthy satellites are removed, and available satellites are selected and channels are distributed according to satellite elevation angles and carrier-to-noise ratios on the basis.

Step 6, according to the satellite navigation pseudo code and carrier signal processing flow and considering the compatibility problems of different GNSS navigation algorithms, the GNSS receiver is specifically divided into 4 layers of a signal layer, a baseband layer, a measurement layer and a navigation layer;

step 7, inputting the observed quantities of the signal layer, the baseband layer, the measurement layer, the navigation layer and the like into a combined filtering module;

step 8, the combined filtering module performs low-pass filtering by using an Extended Kalman Filter (EKF) according to inertial navigation prediction deviation given after a sensitive positioning field to obtain inertial navigation error correction, corrects inertial navigation state error, and can be treated by being reduced to a control problem;

and 9, the combined filtering module inputs related data such as error correction information and the like to the inertial navigation module to assist inertial navigation to predict more accurately.

Fig. 5 is a schematic structural diagram of a concentrated vector deep combining system according to an embodiment of the present application. As shown in fig. 5, in an embodiment, the GNSS and the INS form a large loop to realize the tracking of the satellite navigation pseudo code and the carrier signal and the correction of the INS error, and the work flow of the GNSS/INS vector deep combination system is as follows:

the GNSS calculates carrier frequency, carrier phase and code phase according to the PVCC information generated by the INS and generates a local signal. And then, the local signal and the signal input by the antenna are correlated and coherently accumulated, and the accumulated structure passes through a frequency discriminator and a code phase discriminator to obtain a carrier frequency error and a code phase error.

The carrier frequency error represents a speed domain error, and is an error caused by inaccuracy of the INS speed and the receiver Zhong Piao when the external auxiliary frequency is calculated;

the code phase error represents the position domain error, which is the error caused by inaccuracy of the INS position and receiver clock bias when calculating the auxiliary code phase.

If the PVCC information predicted by the INS is accurate, the carrier frequency error and the code phase error are zero, otherwise, the carrier frequency error and the code phase error reflect the accuracy of the PVCC information generated by the INS.

In the GNSS/INS vector deep combination system, the carrier frequency error may be referred to as u pseudo range rate error, the phase error may be referred to as pseudo range error, and the carrier frequency error and the code phase error may be referred to as combined filtered observed quantity. And after the observed quantity is subjected to combined filtering processing, updating INS errors and receiver clock errors, and predicting PVCC information again by using the updated INS information and receiver clock information to start the next cycle.

Fig. 6 is a schematic structural diagram of a carrier tracking loop according to an embodiment of the present application. In a specific embodiment, as shown in fig. 6, in the implementation of the carrier tracking loop, in case the INS assistance information is invalid, the switch dials down, using a wide bandwidth loop filter for carrier tracking. And under the condition that the INS auxiliary information is effective, the switch is dialed up, and a narrow-bandwidth loop filter is used.

In the aspect of combined filtering, the higher the filtering frequency is, the greater the effect of the GNSS on INS error correction is, the greater the noise introduced into the INS is, and the independence of the INS is easily damaged. Conversely, the lower the filtering frequency, the less obvious the INS error correction effect. Therefore, the filtering frequency should be selected in a trade-off in practical applications.

Fig. 7 is a schematic structural diagram of an INS assisted carrier tracking loop according to an embodiment of the present application. As shown in fig. 7, in a specific embodiment of the present application, in a GNSS carrier tracking loop design after INS assistance information is introduced, input intermediate frequency data is correlated with local data, and coherent data is processed by an a & D (accumulation and zero clearing) module to obtain an in-phase-path accumulated value and an orthogonal-path accumulated value within coherent integration time.

The resulting accumulated value is then processed by a frequency and phase detector. Specifically, a frequency error is obtained after the frequency detector processes the frequency error, and a high-frequency component is filtered by an FLL filter; the phase detector processes the signal to obtain a phase error, and the phase error is filtered by a PLL filter to remove high-frequency components. The two correspondences are added to realize the FLL-assisted PLL. The loop filtering result is then correlated with INS assisted Doppler f _ext Adding to obtain carrier frequency f _carr An input Numerically Controlled Oscillator (NCO) generates a local carrier for generating local data.

By the technical scheme, the INS assists the Doppler f _ext The introduction of the FLL auxiliary PLL removes most of receiver dynamic stress, and the FLL auxiliary PLL loop only needs to process the dynamic stress caused by residual dynamic, thermal noise and clock jitter, so that the bandwidth of a loop filter can be narrowed, and under the condition that the noise spectrum density is not changed, the noise fixed frequency resolution entering the loop can be effectively reduced, and the integration time length and the tracking sensitivity are determined.

In another embodiment of the present application, taking the position estimation of the GNSS/INS vector deep combination system in a low-dynamic continuous scene as an example, the simulation inertial device index is set with reference to ADIS16477-2, and the simulation inertial device index is performed in the low-dynamic continuous scene, which includes static, acceleration, deceleration, and turning motions.

The maximum acceleration of the acceleration and deceleration stage is 1g, the jerk is 1g/s, the maximum speed is 80m/s, the centripetal acceleration of the turning stage is 1.6g, and the track time is 120s.

Under a low dynamic scene, the position, speed, attitude, angular velocity, acceleration curve and other parameter information of the track are set in advance in a simulation mode, the parameter output of the vector deep combination is carried out under the same condition, and errors are compared and analyzed to evaluate the performance advantage of the vector deep combination system.

In the simulation parameters of the gyroscope, the zero offset stability is 2.5 degrees/h, the angle random walk is 0.15 degrees/v/h, the initial zero offset is [0.1,0.2,0.3] °/s, and the sampling period is 100Hz.

In the simulation parameters of the accelerometer, the zero offset stability is 13 mug, the random walk speed is 0.037 m/s/v h, the initial zero offset is [ -2,2, -3] mg, and the sampling period is 100Hz.

Fig. 8 is a schematic diagram of tracking a carrier-to-noise ratio of a satellite in a continuous scene according to an embodiment of the present application. As shown in fig. 8, in a specific embodiment, in a low dynamic continuous scene, the position, velocity, attitude, and accelerometer zero offset estimation of the vector deep combination system are estimated through different tracking satellite carrier-to-noise ratios. The noise ratios of the tracking Wei Xingzai are all above the reference range of 37dB/Hz when continuous and uninterrupted.

And according to the data, outputting information such as the position, the speed, the attitude, the accelerometer zero offset estimation and the like of the GNSS/INS vector depth combination system through simulation, and carrying out error analysis on the information.

Fig. 9 (a) -9 (d) are schematic diagrams of error estimation of GNSS/INS vector deep combinations in continuous scenes according to an embodiment of the present application. As shown in fig. 9, fig. 9 (a) is a schematic diagram of the number of position errors, fig. 9 (b) is a schematic diagram of the number of velocity errors, fig. 9 (c) is a schematic diagram of the number of attitude errors, and fig. 9 (d) is a schematic diagram of the estimated null value of the accelerometer. In a specific embodiment, in the position error analysis, single and composite error estimates are made from altitude, longitude and latitude, respectively.

In the velocity error analysis, single and composite error estimation is performed from the ground-direction velocity error, the east-direction velocity error, and the north-direction velocity error, respectively.

In the attitude error analysis, single and comprehensive error estimation is carried out from a rolling angle, a pitch angle and a heading angle respectively.

In the accelerometer zero offset estimation error analysis, single and comprehensive error estimation is performed from x, y and z axes respectively.

According to simulation analysis results, the positioning precision is better than 1m and the speed measurement precision is better than 0.005m/s in the low dynamic scene vector depth combination mode. Therefore, the GNSS/INS vector deep combination system can realize the mutual gain between the INS and the GNSS, and accurately predict the parameters of the satellite navigation pseudo code and the carrier signal through the INS; and the observed quantity is determined through GNSS, and the inertial navigation error correction quantity is further obtained so as to restrain INS error divergence, improve the anti-interference performance and tracking sensitivity of the system and further improve the navigation positioning precision.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). The memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A system for GNSS/INS vector deep combining, the system comprising:

a positioning field observation device, in communication with the inertial navigation prediction device, configured to determine an observed quantity from the local satellite navigation pseudo-code and carrier signal and an antenna satellite navigation pseudo-code and carrier signal input by an antenna;

and the combined filtering device is communicated with the inertial navigation prediction device and the positioning field observation device, is configured to process the observed quantity to obtain an inertial navigation error correction quantity, and sends the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS.

2. The system of claim 1, wherein the inertial navigation prediction unit is further configured to correct accumulated error of inertial navigation devices and clock units.

3. The system of claim 2, wherein the inertial navigation prediction unit comprises:

the satellite ephemeris system comprises a ephemeris extraction module, a signal transmission delay module and a satellite ephemeris module, wherein the ephemeris extraction module is configured to acquire satellite ephemeris parameters and determine a correction error according to the satellite ephemeris parameters and the signal transmission delay;

an inertial navigation correction module, in communication with the ephemeris extraction module, configured to correct an accumulated error of the inertial navigation device according to the corrected error;

a clock calibration module, in communication with the ephemeris extraction module, configured to correct an accumulated error of the clock unit based on the corrected error.

4. The system of claim 1, wherein the inertial navigation prediction device is further configured to:

and generating the local satellite navigation pseudo code and the carrier signal according to the carrier frequency, the code phase and the carrier phase.

5. The system of claim 1, wherein the localization field observation device comprises:

a baseband module, in communication with the signal module and the combined filtering device, configured to process the coherent integration accumulation value through a signal tracking algorithm to obtain a measurement value;

a metrology module, in communication with the baseband module and the combined filtering device, configured to determine an observation from the measurement;

6. The system of claim 1, wherein the observations comprise a carrier frequency error and a phase error, the combined filtering device further configured to:

processing the carrier frequency error through a frequency-locked loop filter to obtain a processed carrier frequency error;

7. A GNSS/INS vector deep combination method is applied to a GNSS/INS vector deep combination system, and the GNSS/INS vector deep combination system comprises an inertial navigation prediction device, a positioning field observation device and a combination filtering device, and the method comprises the following steps:

generating a local satellite navigation pseudo code and a carrier signal according to the parameters generated by the INS through the inertial navigation prediction device;

determining an observed quantity according to the local satellite navigation pseudo code and carrier signal and an antenna satellite navigation pseudo code and carrier signal input by an antenna through the positioning field observation device;

and processing the observed quantity through the combined filtering device to obtain inertial navigation error correction quantity, and sending the inertial navigation error correction quantity to the inertial navigation prediction device so that the inertial navigation prediction device corrects the parameters generated by the INS.

8. The method of claim 7, wherein generating the local satellite navigation pseudo code and carrier signal based on the INS generated parameters comprises:

9. The method of claim 8, wherein determining the observations from the local satellite navigation pseudo-code and carrier signal and the antenna satellite navigation pseudo-code and carrier signal of the antenna input comprises:

performing coherent integration on the local satellite navigation pseudo code and carrier signal and the satellite navigation pseudo code and carrier signal input by the antenna to obtain a coherent integration accumulated value;

and determining an observed quantity according to the measured value.

10. The method of claim 8, wherein the observed quantities include a carrier frequency error and a phase error, and wherein processing the observed quantities to obtain an inertial navigation error correction comprises: