CN108917793A - The INS calibration system and method assisted using GNSS and DTM - Google Patents

Abstract

The invention provides an INS calibration system and method assisted by GNSS and DTM, belonging to the technical field of INS calibration. The combined positioning module returns a combined positioning performance indicator parameter I _t to the INS calibration module. The INS calibration module judges whether the positioning result calculated by the combined positioning module is available through the parameter I _t . If not, the INS calibration module will provide it at time t+1 The new set set _t+1 is given to the INS calibration module, and continues to initialize the INS motion state until the positioning result indicated by the combined positioning module is available. The present invention can quickly and accurately initialize INS motion state parameters when GNSS recovery is available, avoiding the occurrence of GNSS/INS combined positioning error accumulation caused by long-term limitation of satellite signals, and improving the usability and accuracy of subsequent combined positioning. Accuracy is conducive to the safe and reliable operation of trains.

Description

INS calibration system and method assisted by GNSS and DTM

technical field

The invention relates to the technical field of inertial navigation system (INS) calibration, in particular to an INS calibration method assisted by a satellite navigation system (GNSS) and a digital track map (DTM).

Background technique

The combined positioning technology based on GNSS and INS combines the advantages of the continuity of INS positioning and the non-cumulative error of GNSS positioning, and can provide a continuous and high-precision solution for train positioning in the railway field. Affected by occlusions such as urban canyons and tunnels, GNSS positioning will be unavailable during train operation. Long-term satellite signal limitations will lead to the accumulation of GNSS/INS combined positioning errors, which will eventually lead to positioning divergence. How to quickly and accurately initialize INS motion state parameters when GNSS is available again will have an important impact on the usability and accuracy of subsequent combined positioning.

Contents of the invention

The purpose of the present invention is to provide an INS calibration method assisted by GNSS and DTM that can quickly and accurately complete the INS initialization positioning after the GNSS is available again, so as to solve the technical problems in the above-mentioned background technology.

In order to achieve the above object, the present invention has taken the following technical solutions:

On the one hand, the present invention provides an INS calibration system assisted by GNSS and DTM, the system includes a GNSS receiver, DTM and INS, and is characterized in that it also includes a combined positioning module and an INS calibration module;

The combined positioning module is used to provide the combined positioning performance indicator parameter I _t for the INS calibration module, and complete the recombined positioning of GNSS and INS;

The INS calibration module is used to obtain the train position r ^t _gnss provided by GNSS, the train speed v ^t _gnss and the attitude information ψ _t stored in the DTM, and determine the set set _t ={r _t ,v _t ,ψ _t }.

On the other hand, an INS calibration method assisted by GNSS and DTM provided by the present invention includes the following process steps:

Step S110: when the GNSS positioning is restored, obtain the train position r ^t _gnss and train speed v ^t _gnss provided by GNSS at time t;

Step S120: map the train position r ^t _gnss and train speed v ^t _gnss to the DTM database, and obtain the train position r _t and train speed v _t at time t provided by DTM;

Step S130: Collect the posture information ψ _t of the train stored in the DTM at the position r _t , and obtain the set set _t ={r _t , v _t ,ψ _t };

Step S140: Take the time t as the starting point, combine set _t to calibrate and initialize the train position, train speed and train attitude information of the INS, and restart the combined positioning of GNSS/INS.

Further, the step S140 includes:

The combined positioning module returns a combined positioning performance indicator parameter I _t to the INS calibration module. The INS calibration module judges whether the positioning result calculated by the combined positioning module is available through the parameter I _t . If not, the INS calibration module will provide a new one at time t+1. The set set _t+1 is given to the INS calibration module, and continues to initialize the INS motion state until the positioning result indicated by the combined positioning module is available.

Further, I _t depends on the specific combined positioning algorithm. When the extended Kalman filter is used in the combined positioning module, I _t represents the error covariance matrix

Further, when I _t represents the error covariance matrix when using Do a chi-square test:

If it fails to pass the test, it is determined that the positioning result is not available, and if it passes the test, it is determined that the positioning result is available; wherein, for A matrix of elements on the diagonal.

Beneficial effects of the present invention: When GNSS recovery is available, INS motion state parameters can be initialized quickly and accurately, avoiding the occurrence of GNSS/INS combined positioning error accumulation caused by long-term limitation of satellite signals, and improving subsequent combined positioning The availability and accuracy of the train are conducive to the safe and reliable operation of the train.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description, or may be learned by practice of the invention.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

FIG. 1 is a schematic diagram of a recovery scene after GNSS signal occlusion in a train positioning environment according to an embodiment of the present invention.

Fig. 2 is a functional block diagram of the INS calibration using the GNSS and DTM assisted INS calibration system according to the embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or modules having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

Those skilled in the art will understand that unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of said features, integers, steps, operations, elements and/or modules, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, modules, and/or groups thereof.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as herein explain.

In order to facilitate the understanding of the embodiments of the present invention, the following will further explain and illustrate by taking specific embodiments as examples in conjunction with the accompanying drawings, and the embodiments do not constitute a limitation to the embodiments of the present invention.

Those skilled in the art should understand that the accompanying drawing is only a schematic diagram of an embodiment, and the components or devices in the accompanying drawings are not necessarily necessary for implementing the present invention.

Example

Embodiments of the present invention provide a method and system for INS calibration assisted by GNSS and DTM. As shown in FIG. 1 , the GNSS signal occlusion area will cause the normal GNSS/INS combined positioning results to gradually diverge, and the INS loses its own motion status. Effective tracking, eventually leading to unavailable INS.

As shown in Figure 2, the embodiment of the present invention provides a system for INS calibration assisted by GNSS and DTM. After the train passes through the occluded area, the calibration of the INS is completed by triggering the "INS calibration module", thus providing the "combined positioning module" Provide effective initial parameters to ensure the continuity and reliability of subsequent combined positioning results.

The above system includes GNSS receiver, DTM and INS, and also includes combined positioning module and INS calibration module;

The combined positioning module is used to provide the combined positioning performance indicator parameter I _t for the INS calibration module, and complete the recombined positioning of GNSS and INS;

The INS calibration module is used to obtain the train position r ^t _gnss provided by GNSS, the train speed v ^t _gnss and the attitude information ψ _t stored in the DTM, and determine the set set _t ={r _t ,v _t ,ψ _t }.

When the above system is used for INS calibration, when the train passes through the signal occlusion area, the GNSS signal starts to recover, and when the GNSS positioning is recovered, the train position r ^t _gnss and the train speed v ^t _gnss provided by the GNSS are obtained at time t;

Then map the train position r ^t _gnss and train speed v ^t _gnss to the DTM database, and obtain the train position r _t and train speed v _t at the moment t provided by DTM;

Then collect the attitude information ψ _t of the train stored in the DTM at the position _rt , and obtain the set

set _t = {r _t ,v _t ,ψ _t };

Finally, starting from time t, combined with the set set _t to calibrate and initialize the train position, train speed and train attitude information of INS, the combined positioning of GNSS/INS is restarted.

In an embodiment of the present invention, the combined positioning module returns a combined positioning performance indicator parameter I _t to the INS calibration module, and the INS calibration module judges whether the positioning result calculated by the combined positioning module is available through the parameter I _t , if not, the INS calibration module A new set set _t+1 will be provided to the INS calibration module at time t+1, and the INS motion state will continue to be initialized until the positioning result indicated by the combined positioning module is available.

In practical applications, I _t depends on the specific combined positioning algorithm, for example, when the extended Kalman filter is used in the combined positioning module, I _t represents the error covariance matrix When I _t represents the error covariance matrix when using Do a chi-square test:

If it fails to pass the test, it is determined that the positioning result is not available, and if it passes the test, it is determined that the positioning result is available; wherein, for A matrix of elements on the diagonal.

In summary, the INS calibration method assisted by GNSS and DTM described in the embodiment of the present invention can quickly and accurately initialize the INS motion state parameters when the GNSS recovery is available, avoiding the long-term limitation of satellite signals This leads to the accumulation of GNSS/INS combined positioning errors, which improves the availability and accuracy of subsequent combined positioning, and is conducive to the safe and reliable operation of trains.

It can be seen from the above description of the implementation manners that those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art can be embodied in the form of software products, and the computer software products can be stored in storage media, such as ROM/RAM, disk , CD, etc., including several instructions to make a computer device (which may be a personal computer, server, or network device, etc.) execute the methods described in various embodiments or some parts of the embodiments of the present invention.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (5)

1. A kind of INS calibration system utilizing GNSS and DTM assistance, comprises GNSS receiver, DTM and INS, is characterized in that, also comprises combined positioning module and INS calibration module; The combined positioning module is used to provide the combined positioning performance indicator parameter I _t for the INS calibration module, and complete the recombined positioning of GNSS and INS; The INS calibration module is used to obtain the train position r ^t _gnss provided by GNSS, the train speed v ^t _gnss and the attitude information ψ _t stored in the DTM, and determine the set set _t ={r _t ,v _t ,ψ _t }. 2. A kind of INS calibration method utilizing GNSS and DTM assistance, is characterized in that, comprises following flow process step: Step S110: when the GNSS positioning is restored, obtain the train position r ^t _gnss and train speed v ^t _gnss provided by GNSS at time t; Step S120: map the train position r ^t _gnss and train speed v ^t _gnss to the DTM database, and obtain the train position r _t and train speed v _t at time t provided by DTM; Step S130: Collect the posture information ψ _t of the train stored in the DTM at the position r _t , and obtain the set set _t ={r _t , v _t ,ψ _t }; Step S140: Take the time t as the starting point, combine set _t to calibrate and initialize the train position, train speed and train attitude information of the INS, and restart the combined positioning of GNSS/INS. 3. The INS calibration method utilizing GNSS and DTM assistance according to claim 2, wherein the step S140 comprises: The combined positioning module returns a combined positioning performance indicator parameter I _t to the INS calibration module. The INS calibration module judges whether the positioning result calculated by the combined positioning module is available through the parameter I _t . If not, the INS calibration module will provide a new one at time t+1. The set set _t+1 is given to the INS calibration module, and continues to initialize the INS motion state until the positioning result indicated by the combined positioning module is available. 4. utilize the INS calibration method that GNSS and DTM are assisted according to claim 3, it is characterized in that, It _depends on concrete combined positioning algorithm, when extended _Kalman filtering is used for combined positioning module, It represents error Covariance matrix Px ⁺ . 5. utilize GNSS and DTM assisted INS calibration method according to claim 4, it is characterized in that, when I _t represents error covariance matrix P _k ⁺ , use Do a chi-square test: If it fails to pass the test, it is determined that the positioning result is not available, and if it passes the test, it is determined that the positioning result is available; wherein, is a matrix composed of elements on the P _k ⁺ diagonal.