Method and system for navigation mode selection for an aircraft
阅读说明：本技术 用于飞行器的导航模式选择的方法和系统 (Method and system for navigation mode selection for an aircraft ) 是由 万赟 张鹏宇 宗军耀 余亮 王青 刘利朝 于 2021-10-28 设计创作，主要内容包括：本发明公开了一种用于飞行器的导航模式选择的方法,包括：选择多个GNSS源中的一个或多个GNSS源；从惯性基准系统IRS获取IRS导航信息,其中该IRS导航信息包括对飞行器位置的第一估计并且是由惯性基准系统基于飞行器的初始位置和内部实时计算获得的；从所选择的一个或多个GNSS源接收导航信号；基于导航信号获得伪距信息,其中该伪距信息包括所选择的一个或多个GNSS源与飞行器之间的伪距和伪距率；基于伪距信息获得GNSS导航信息,其中该GNSS导航信息包括对飞行器位置的第二估计；基于所选择的一个或多个GNSS源的伪距信息或GNSS导航信息与IRS导航信息组合,以获得飞行器的最终位置。还公开了用于飞行器的导航模式选择的系统。(The invention discloses a method for navigation mode selection of an aircraft, comprising the following steps: selecting one or more of a plurality of GNSS sources; obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of a position of the aircraft and is obtained by the inertial reference system based on an initial position and an internal real-time calculation of the aircraft; receiving navigation signals from the selected one or more GNSS sources; obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft; obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information includes a second estimate of the aircraft position; combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft. A system for navigation mode selection for an aircraft is also disclosed.)
1. A method for navigation mode selection for an aircraft, comprising:
selecting one or more of a plurality of GNSS sources;
obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of the aircraft position and is obtained by the inertial reference system based on an initial position and an internal real-time calculation of the aircraft;
receiving navigation signals from the selected one or more GNSS sources;
obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft;
obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information comprises a second estimate of the aircraft position;
combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft.
2. The method of claim 1, wherein selecting one or more of a plurality of GNSS sources further comprises: selecting one or more of the plurality of GNSS sources based on current location information of the aircraft.
3. The method of claim 1, wherein selecting one or more of the plurality of GNSS sources comprises selecting based on one of the following GNSS source selection modes:
unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source;
the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available;
automatic preferred mode: automatically selecting one or more of the plurality of GNSS sources that perform better.
4. The method of claim 1, wherein the one or more GNSS sources are selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
5. The method of claim 1, wherein combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft further comprises:
combining the IRS navigation information and the pseudorange information in a first navigation mode to obtain a first position of the aircraft;
combining the IRS navigation information and the GNSS navigation information in a second navigation mode to obtain a second position of the aircraft;
selecting either a first position of the first navigation mode or a second position of the second navigation mode as a final position of the aircraft.
6. The method of claim 5, wherein selecting the first position of the first navigation mode or the second position of the second navigation mode comprises:
selecting a first location of the first navigation mode or a second location of the second navigation mode based on a precision or a setting of the first navigation mode and the second navigation mode.
7. The method of claim 5, wherein the first navigation mode and the second navigation mode are implemented under the same software architecture.
8. The method of claim 5, wherein a total number of pseudoranges and a total number of pseudorange rates in the pseudorange information are each greater than or equal to N +3, wherein N represents a number of types of the plurality of GNSS sources, and wherein combining the IRS navigation information and the pseudorange information in a first navigation mode comprises:
selecting N +3 pseudo ranges and N +3 pseudo range rates in the pseudo range information;
performing a close-coupled Kalman filtering algorithm on the selected pseudoranges and pseudorange rates and the IRS navigation information to obtain the first position.
9. The method of claim 5, wherein combining the IRS navigation information and the GNSS navigation information in a second navigation mode comprises:
comparing the accuracy and integrity of the GNSS navigation information;
selecting one of the GNSS navigation information based on the comparison;
performing a pine-combination Kalman filtering algorithm on the selected GNSS navigation information and the IRS navigation information to obtain the second position.
10. A system for navigation mode selection for an aircraft, comprising:
a GNSS source selection module configured to:
selecting one or more of a plurality of GNSS sources;
an acquisition module configured to:
obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of the aircraft position and is obtained by the inertial reference system based on an initial position internal real-time calculation of the aircraft;
receiving navigation signals from the selected one or more GNSS sources;
a position calculation module configured to:
obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft;
obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information comprises a second estimate of the aircraft position;
combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft.
11. The system of claim 10, wherein the GNSS source selection module is further configured to: selecting one or more of the plurality of GNSS sources based on current location information of the aircraft.
12. The system of claim 10, wherein the GNSS source selection module is further configured to select one or more of the plurality of GNSS sources based on one of the following GNSS source selection modes:
unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source;
the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available;
automatic preferred mode: automatically selecting one or more of the plurality of GNSS sources that perform better.
13. The system of claim 10, wherein the one or more GNSS sources are selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
14. The system of claim 10, wherein the location calculation module further comprises:
a first navigation mode module configured to combine the IRS navigation information and the pseudorange information in a first navigation mode to obtain a first position of the aircraft;
a second navigation mode module configured to combine the IRS navigation information and the GNSS navigation information in a second navigation mode to obtain a second position of the aircraft; and
a selection module configured to select either a first position of the first navigation mode or a second position of the second navigation mode as a final position of the aircraft.
15. The system of claim 14, wherein the selection module is further configured to: selecting a first location of the first navigation mode or a second location of the second navigation mode based on a precision or a setting of the first navigation mode and the second navigation mode.
16. The system of claim 14, wherein the first navigation mode and the second navigation mode are implemented under the same software architecture.
17. The system of claim 14, wherein a total number of pseudoranges and a total number of pseudorange rates in the pseudorange information are each greater than or equal to N +3, wherein N represents a number of types of the GNSS sources, and wherein the first navigation mode module is further configured to:
selecting N +3 pseudo ranges and N +3 pseudo range rates in the pseudo range information;
performing a close-coupled Kalman filtering algorithm on the selected pseudoranges and pseudorange rates and the IRS navigation information to obtain the first position.
18. The system of claim 14, wherein the second navigation mode module is further configured to:
comparing the accuracy and integrity of the GNSS navigation information;
selecting one of the GNSS navigation information based on the comparison;
performing a pine-combination Kalman filtering algorithm on the selected GNSS navigation information and the IRS navigation information to obtain the second position.
19. A computer-readable storage medium storing a computer program for navigation mode selection of an aircraft, the computer program being executable by a processor to perform the method of any one of claims 1-9.
Technical Field
The invention relates to the technical field of Flight Management Systems (FMS), in particular to a method and a System for selecting a navigation mode of an aircraft.
Background
The flight management system FMS is an airborne avionics system for assisting a pilot to complete various tasks from take-off to landing, and can manage, monitor and automatically operate the airplane and realize the automatic flight of the whole flight of the airplane. The FMS is capable of estimating the position of an aircraft in the air by means of onboard autonomous navigation sensors, land-based radio navigation systems and satellite navigation systems. The most widely used satellite navigation system for FMS is currently the GPS system in the united states.
Global Navigation Satellite Systems (GNSS) that have been built and are in use worldwide include GPS in the united states, the beidou Satellite Navigation System (BDS) in china, GLONASS (GLONASS) in russia, and GALILEO (GALILEO) in europe. Although the GPS is most widely applied in the global scope and the related research is most intensive, the research and development of GNSS sources such as BDS and GALILEO fully considers the advantages and disadvantages of the GPS, and theoretically has better navigation accuracy and performance than the GPS in a specific area and under specific conditions. Moreover, a single satellite navigation system is limited by the constellation size, and it is difficult to obtain a navigation position with optimal accuracy and performance. In certain specific areas and conditions, it is difficult for a single satellite navigation source to meet even the navigation positioning requirements. At present, the FMS of the civil aircraft only supports the navigation and positioning function based on the GPS as a single GNSS source, once the conditions of GPS signal quality degradation, multipath effect, man-made interference, signal interruption and the like occur, the positioning accuracy of the aircraft is greatly reduced, and the operation burden and the pressure of a pilot are obviously increased. If the wrong position and speed data are used to directly calculate the guidance instructions, unintended maneuvers of the aircraft will also be initiated.
As more and more countries and regions enforce their respective satellite navigation systems through various policies and regulations, it is becoming more and more the trend that the FMS supports multiple GNSS navigation sources. By adopting the combined positioning of multiple navigation sources, the defect of insufficient coverage of visible stars in a single constellation can be overcome, and meanwhile, the system error and the geometric layout comprehensive calculation based on multiple constellations can be realized, so that the navigation positioning performance is improved. In addition, fault detection can be performed by using redundant pseudo-range information values, and the integrity of the system is improved.
In response to the deficiencies of the prior art in employing a single GNSS source, it is desirable to provide an improved method and system for navigation mode selection for an aircraft.
Disclosure of Invention
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
The invention provides a method for navigation mode selection of an aircraft, comprising: selecting one or more of a plurality of GNSS sources; obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of a position of the aircraft and is obtained by the inertial reference system based on an initial position and an internal real-time calculation of the aircraft; receiving navigation signals from the selected one or more GNSS sources; obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft; obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information includes a second estimate of the aircraft position; combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft.
In some embodiments, selecting one or more of the plurality of GNSS sources further comprises: one or more of the plurality of GNSS sources are selected based on current location information of the aircraft.
In some embodiments, selecting one or more of the plurality of GNSS sources comprises selecting based on one of the following GNSS source selection modes: unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source; the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available; automatic preferred mode: one or more GNSS sources with better performance among the plurality of GNSS sources are automatically selected.
In some embodiments, the one or more GNSS sources are selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
In some embodiments, combining the pseudorange information or the GNSS navigation information with the IRS navigation information based on the selected one or more GNSS sources to obtain the final position of the aircraft further comprises: combining the IRS navigation information and the pseudorange information in a first navigation mode to obtain a first position of the aircraft; combining the IRS navigation information and the GNSS navigation information in a second navigation mode to obtain a second position of the aircraft; the first position of the first navigation mode or the second position of the second navigation mode is selected as the final position of the aircraft.
In some embodiments, selecting the first position of the first navigation mode or the second position of the second navigation mode comprises: a first location of the first navigation mode or a second location of the second navigation mode is selected based on a precision or a setting of the first navigation mode and the second navigation mode.
In some embodiments, the first navigation mode and the second navigation mode are implemented under the same software architecture.
In some embodiments, the pseudorange totals and the pseudorange rate totals in the pseudorange information are each greater than or equal to N +3, where N represents a number of types of the plurality of GNSS sources, and wherein combining the IRS navigation information and the pseudorange information in the first navigation mode comprises: selecting N +3 pseudo ranges and N +3 pseudo range rates in pseudo range information; a close-coupled kalman filtering algorithm is performed on the selected pseudoranges and pseudorange rates and IRS navigation information to obtain a first position.
In some embodiments, combining IRS navigation information and GNSS navigation information in the second navigation mode comprises: comparing the accuracy and the integrity of the GNSS navigation information; selecting one of the GNSS navigation information based on the comparison; a pine combination Kalman filtering algorithm is performed on the selected GNSS navigation information and the IRS navigation information to obtain a second position.
The present invention also provides a system for navigation mode selection for an aircraft, comprising: a GNSS source selection module configured to: selecting one or more of a plurality of GNSS sources; an acquisition module configured to: obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of a position of the aircraft and is obtained by the inertial reference system based on an initial position internal real-time calculation of the aircraft; receiving navigation signals from the selected one or more GNSS sources; a position calculation module configured to: obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft; obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information includes a second estimate of the aircraft position; combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft.
In some embodiments, the GNSS source selection module is further configured to: one or more of the plurality of GNSS sources are selected based on current location information of the aircraft.
In some embodiments, the GNSS source selection module is further configured to select one or more of the plurality of GNSS sources based on one of the following GNSS source selection modes: unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source; the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available; automatic preferred mode: one or more GNSS sources with better performance among the plurality of GNSS sources are automatically selected.
In some embodiments, the one or more GNSS sources are selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
In some embodiments, the position calculation module further comprises: a first navigation mode module configured to combine the IRS navigation information and the pseudorange information in a first navigation mode to obtain a first position of the aircraft; a second navigation mode module configured to combine the IRS navigation information and the GNSS navigation information in a second navigation mode to obtain a second position of the aircraft; and a selection module configured to select either the first position of the first navigation mode or the second position of the second navigation mode as a final position of the aircraft.
In some embodiments, the selection module is further configured to: a first location of the first navigation mode or a second location of the second navigation mode is selected based on a precision or a setting of the first navigation mode and the second navigation mode.
In some embodiments, the first navigation mode and the second navigation mode are implemented under the same software architecture.
In some embodiments, the pseudorange totals and the pseudorange rate totals in the pseudorange information are each greater than or equal to N +3, where N represents a number of types of GNSS sources, and wherein the first navigation mode module is further configured to: selecting N +3 pseudo ranges and N +3 pseudo range rates in pseudo range information; a close-coupled kalman filtering algorithm is performed on the selected pseudoranges and pseudorange rates and IRS navigation information to obtain a first position.
In some embodiments, the second navigation mode module is further configured to: comparing the accuracy and the integrity of the GNSS navigation information; selecting one of the GNSS navigation information based on the comparison; a pine combination Kalman filtering algorithm is performed on the selected GNSS navigation information and the IRS navigation information to obtain a second position.
The invention also provides a computer-readable storage medium storing a computer program for navigation mode selection of an aircraft, the computer program being executable by a processor to perform the aforementioned method for navigation mode selection of an aircraft.
According to the technical scheme, IRS navigation information is obtained from an inertial reference system IRS, pseudo-range information and GNSS navigation information are obtained based on navigation signals received from one or more selected GNSS sources, a first position and a second position of an aircraft are respectively obtained in a first navigation mode and a second navigation mode based on the information, and the position of one navigation mode is selected as a final position of the aircraft, so that the finally obtained aircraft position is higher in precision and better in navigation performance.
Drawings
The features, nature, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. In the drawings, like reference numerals are used to designate corresponding parts throughout the several views. It is noted that the drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.
Fig. 1 shows a functional architecture diagram of a system for navigation mode selection of an aircraft according to the invention.
FIG. 2 illustrates an exemplary flow diagram of the deep blend mode of the present invention.
FIG. 3 illustrates an exemplary flow chart of a preferred fusion mode of the present invention.
FIG. 4 illustrates an exemplary FMS interactive display interface of the present invention.
FIG. 5 illustrates a flow chart of a method of the present invention for navigation mode selection of an aircraft.
FIG. 6 illustrates a block diagram of a system for navigation mode selection for an aircraft of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with specific embodiments. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the described exemplary embodiments. It will be apparent, however, to one skilled in the art, that the described embodiments may be practiced without some or all of these specific details. In other exemplary embodiments, well-known structures have not been described in detail to avoid unnecessarily obscuring the concepts of the present disclosure. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Meanwhile, the various aspects described in the embodiments may be arbitrarily combined without conflict.
Single GNSS source based positioning (e.g., GPS) is susceptible to interference, affecting positioning accuracy and reliability. Therefore, it is necessary to further extend the navigation functions of BDS, GLONASS and GALILEO based on GPS, and to comprehensively utilize multiple GNSS sources to achieve more accurate and reliable positioning.
The invention provides an improved method and system for selecting a navigation mode of an aircraft, which overcomes the defects of a conventional positioning method and realizes higher precision and more reliable positioning.
Fig. 1 shows a functional architecture diagram of a system 100 for navigation mode selection for an aircraft of the present invention.
For ease of illustration, fig. 1 shows two GNSS sources, GPS and BDS. It should be understood that the solution of the present invention is applicable to existing GNSS sources including GPS, BDS, GLONASS and GALILEO as well as to new GNSS sources that may be built up in the future.
As shown in fig. 1, the system 100 may select a GNSS source. Specifically, the invention proposes the following three GNSS source selection modes: (1) unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source; (2) the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available; (3) automatic preferred mode: one or more GNSS sources with better performance among the plurality of GNSS sources are automatically selected.
In an embodiment where there are two GNSS sources, i.e. GPS and BDS, the GNSS source selection mode can be further subdivided into the following five modes (not shown in the figure): (1) select only the GPS mode: only selecting a GPS as a unique GNSS source, directly warning a pilot when the GPS is unavailable without automatically switching to a BDS, and allowing the BDS to be adopted as the GNSS source only after the pilot confirms; (2) selection of only BDS mode: only selecting the BDS as a unique GNSS source, directly warning the pilot when the BDS is unavailable without automatically switching to the GPS, and allowing the GPS to be adopted as the GNSS source only after the confirmation of the pilot; (3) preferentially selecting the GPS mode: the method comprises the steps of preferentially selecting a GPS as a GNSS source, and automatically switching to a BDS without pilot confirmation when the GPS is unavailable; (4) preferential selection of BDS mode: the BDS is preferentially selected as a GNSS source, and when the BDS is unavailable, the BDS is automatically switched to the GPS without confirmation of a pilot; (5) automatic preferred mode: one or more GNSS sources in the GPS and BDS that perform better are automatically selected.
By default, the system 100 employs an "auto-prefer mode" to select a GNSS source. In an auto-opt mode, the system 100 may select one or more of the plurality of GNSS sources based on current location information of the aircraft. In some embodiments, the corresponding selection of different geographical location information and GNSS sources may be stored in a database, and the system 100 may select an appropriate GNSS source by querying the database. In an alternative embodiment, a GNSS source selection rule may be preset that states that an aircraft at a particular geographic location will select one or more particular GNSS sources. In such embodiments, the system 100 may select the GNSS source through the preset rule. Alternatively, the pilot may manually select one of the modes via the FMS interactive display interface (e.g., by entering human-machine interaction information on the interface). It should be noted that the manual selection by the pilot has the highest priority.
To obtain the position of the aircraft, the System 100 needs to obtain IRS navigation information from an Inertial Reference System (IRS), wherein the IRS navigation information includes a first estimate of the aircraft position and is obtained by the Inertial Reference System based on an initial position of the aircraft and an internal real-time calculation. Specifically, the IRS navigation information includes aircraft position and velocity obtained based on an inertial reference system. In addition, the system 100 also acquires corresponding navigation signals from the GPS receiver and the BDS receiver.
After acquiring the above information, the system 100 performs position calculation based on the information and the signal. The system 100 may obtain pseudorange information based on the navigation signals and obtain GNSS navigation information based on the pseudorange information. In particular, the pseudorange information includes pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft, and the GNSS navigation information includes aircraft position and velocity obtained based on the GNSS sources.
Subsequently, the system 100 may obtain the position of the aircraft based on the pseudorange information or the GNSS navigation information combined with the IRS navigation information for the selected one or more GNSS sources. In the present invention, the above information can be combined in two navigation modes: a depth blend mode (also referred to herein as a "first navigation mode") and a preferred blend mode (also referred to herein as a "second navigation mode"). In particular, IRS navigation information and pseudorange information may be combined in a deep hybrid mode to obtain a first position of the aircraft, while IRS navigation information and GNSS navigation information may be combined in a preferred fusion mode to obtain a second position of the aircraft. Detailed procedures regarding the depth blending mode and the preferred fusion mode will be illustrated in fig. 2 and 3.
The system 100 may then compare and select the deep hybrid mode and the preferred fusion mode. For example, the first location of the hybrid-depth mode or the second location of the preferred blend mode may be selected as the final location of the aircraft based on the accuracy or settings of the hybrid-depth mode and the preferred blend mode. Preferably, the associated navigational capabilities of the first and second locations may be compared and the location of the first and second locations having the better navigational capability is selected as the final location of the aircraft for output and display based on the comparison.
For example, the final position of the aircraft may be output to the FMS guidance function module to implement the FMS auto-guidance function. At the same time, the final position of the aircraft may also be displayed on the FMS interactive display interface to provide relevant information to the pilot.
The pilot may view the information on the FMS interactive display interface for reference and may also select GNSS sources through the FMS interactive display interface.
FIG. 2 illustrates an exemplary flow diagram 200 of the deep blend mode of the present invention. Wherein the steps in the dashed box represent optional steps. For ease of illustration, fig. 2 shows two GNSS sources, GPS and BDS.
At 202, navigation signals are received from each of the GPS and BDS. Specifically, GPS navigation signals are received from GPS satellites by a GPS receiver on the aircraft and BDS navigation signals are received from BDS satellites by a BDS receiver on the aircraft.
At 204, pseudorange information is obtained based on the navigation signals, wherein the pseudorange information includes pseudoranges and pseudorange rates between the receiver (i.e., the aircraft) and the GNSS source.
For example, a GPS receiver may receive navigation signals from GPS satellites. Assuming that the GPS satellite and the GPS receiver are in the same time system, the propagation time of the navigation signal from the GPS satellite to the GPS receiver can be known, and thus the transmission distance, i.e., the pseudo range, is calculated from the radio wave transmission speed, and the pseudo range rate is calculated. Pseudoranges and pseudorange rates between a BDS receiver and BDS satellites may be obtained in the same manner.
To calculate the aircraft position, 3 pseudoranges need to be used to locate the spatial coordinates. Meanwhile, since the system time may have a certain error, a time-dependent variable needs to be introduced for calibration, and accordingly, one satellite and its pseudorange need to be added for each GNSS source. Thus, the total number of pseudoranges in the pseudorange information needs to be greater than or equal to N +3, where N represents the number of types of GNSS sources. Similarly, the total number of pseudorange rates needs to be greater than or equal to N + 3. In the presence of both GPS and BDS types of GNSS sources (N = 2), both the pseudorange totals and the pseudorange rate totals need to be greater than or equal to 5.
At 206, pseudorange information for the GPS and BDS is normalized. Since different GNSS sources may employ different geographical coordinate systems and navigation capability definitions, their information may not be directly available for combination. There is therefore a need to unify the information of pseudorange information based on different GNSS sources to bring it to the same coordinate system and performance definition.
At 208, it is determined whether the GNSS source selection mode is the "auto-preferred mode". If the mode is "auto-prefer mode" (yes at 208), pseudorange information for one or more GNSS sources in the GPS and BDS that perform better is automatically selected (210).
In various embodiments, N +3 pseudoranges and N +3 pseudorange rates may be selected from all pseudorange information for the one or more GNSS sources, where N represents a number of types of the one or more GNSS sources. For example, in the case of selecting two GNSS sources, GPS and BDS, 5 pseudoranges and 5 pseudorange rates may be selected from all pseudorange information, where 3 pseudoranges are used for spatial positioning and 2 pseudoranges are used for calibrating the GPS and BGS sources. In a preferred embodiment, the 5 pseudoranges with the best performance (e.g., 5 pseudoranges with the best three-dimensional position accuracy factor (PDOP)) and 5 pseudorange rates may be selected from all pseudorange information. Different criteria may be used to select pseudorange information or a different number of pseudorange information (e.g., greater than 5) may be selected in different embodiments.
If the GNSS source selection mode is not the "auto-prefer mode" (NO at 208), then a determination is made at 212 as to whether the GNSS source selection mode is the "prefer mode". If in "prioritized mode" (yes at 212), the pseudorange information for one of the GPS and BDS is prioritized (214).
In the case of GPS, preference may be given to 4 pseudoranges (3 pseudoranges for spatial positioning and 1 pseudorange for calibrating the GPS source) and 4 pseudorange rates in the GPS pseudorange information. When GPS is not available, the pseudorange information may be automatically switched to select the BDS.
Similarly, in the case where the selection of the BDS is preferred, 4 pseudoranges and 4 pseudorange rates in the pseudorange information of the BDS may be preferred. When the BDS is not available, it may automatically switch to selecting pseudorange information for GPS.
If the GNSS source selection mode is not the "preferred selection mode" (NO at 212), then a determination is made at 216 as to whether the GNSS source selection mode is the "unique selection mode". If the mode is "uniquely selected" (YES at 216), the pseudorange information for only one of the GPS and BDS is selected (218).
In the case of only selecting GPS, 4 pseudoranges (3 pseudoranges for spatial positioning and 1 pseudorange for calibrating the GPS source) and 4 pseudorange rates in the GPS pseudorange information may be selected. When GPS is not available, an alert message is issued to the aircraft without automatically switching to pseudorange information for the selected BDS.
Similarly, in the case where only the BDS is selected, 4 pseudoranges and 4 pseudorange rates in the pseudorange information of the BDS may be selected. When the BDS is not available, a warning message is issued to the aircraft without automatically switching to selecting pseudorange information for GPS.
After obtaining the required pseudorange information, method 200 proceeds to 220. At 220, a tight combined Kalman filtering is performed on the selected pseudorange information (i.e., the selected pseudoranges and pseudorange rates) and IRS navigation information (obtained from the IRS) (i.e., an aircraft position and velocity obtained based on the IRS) to obtain a first position of the aircraft, wherein the first position has an associated navigation performance.
At 222, the first position is output.
The depth hybrid mode in fig. 2 adopts pseudo-range information and close-combination kalman filtering, and has complex algorithm, large calculation amount, higher positioning accuracy and stronger positioning reliability.
Fig. 3 illustrates an exemplary flow chart 300 of a preferred fusion mode of the present invention. Wherein the steps in the dashed box represent optional steps. For ease of illustration, fig. 3 shows two GNSS sources, GPS and BDS.
At 302, navigation signals are received from each of the GPS and BDS, similar to 202 in fig. 2.
At 304, pseudorange information is obtained based on the navigation signals, similar to 204 in FIG. 2.
At 306, GNSS navigation information is obtained based on the pseudorange information, wherein the GNSS navigation information includes a position and a velocity of the aircraft obtained based on the GNSS source.
For a GPS source, the GPS receiver receives navigation signals from three GPS satellites and obtains three pseudorange information. Based on the known positions of these three GPS satellites, a triangular pyramid with the GPS receiver as the vertex can be constructed in space to calculate the three-dimensional coordinates xyz of the receiver (i.e., the spatial position of the aircraft). GNSS navigation information based on BDS sources may be obtained in a similar manner.
At 308, the GNSS navigation information is normalized. In particular, the GNSS navigation information based on GPS sources and the GNSS navigation information based on BDS sources are normalized to fit the same coordinate system and performance definition.
At 310, it is determined whether the GNSS source selection mode is the "auto-preferred mode". If the mode is "auto-prefer mode" (YES at 310), one of the GNSS navigation information of the GNSS source or sources having the better performance in the GPS and BDS is automatically selected (312). In a preferred embodiment, the accuracy and integrity of the GNSS navigation information may be compared and a GNSS navigation information with optimal navigation performance may be selected based on the comparison. In other embodiments, one of the GNSS navigation information may be selected based on other factors.
If the GNSS source selection mode is not the "auto-prefer mode" (NO at 310), then a determination is made at 314 as to whether the GNSS source selection mode is the "prefer mode". If in the "prefer mode" (YES at 314), GNSS navigation information for one of the GPS and BDS is preferentially selected (316).
In the case of the preference of the GPS, the GNSS navigation information of the GPS is preferentially selected. When GPS is not available, a switch may be automatically made to select GNSS navigation information for the BDS.
Similarly, in the case of preferentially selecting the BDS, GNSS navigation information of the BDS is preferentially selected. When the BDS is not available, the GNSS navigation information for the GPS may be automatically switched to be selected.
If the GNSS source selection mode is not the "preferred selection mode" (NO at 314), then a determination is made at 318 as to whether the GNSS source selection mode is the "unique selection mode". If the mode is "uniquely selected" (YES at 318), GNSS navigation information for only one of the GPS and BDS is selected (320).
In the case where only the GPS is selected, GNSS navigation information of the GPS is selected. When GPS is not available, a warning message is sent to the aircraft without automatically switching to GNSS navigation information for the BDS.
Similarly, in the case where only the BDS is selected, the GNSS navigation information of the BDS is selected. When the BDS is not available, warning information is sent to the aircraft without automatically switching to the GNSS navigation information for selecting the GPS.
After obtaining the desired GNSS navigation information, the method 300 may proceed to 322. At 322, a pine-combination Kalman filter is performed on the selected GNSS navigation information (i.e., the position and velocity of the aircraft obtained based on the GNSS source) and the IRS navigation information (obtained from the IRS) (i.e., the position and velocity of the aircraft obtained based on the IRS) to obtain a second position of the aircraft, wherein the second position has an associated navigation capability.
At 324, the second position is output.
The preferred fusion mode of fig. 3 employs GNSS navigation information based on GNSS sources and pine-combination kalman filtering, and the algorithm is relatively simple, has limited interference rejection capability and low positioning accuracy, but can further extend land-based radio navigation information to form FMS position calculation for integrated IRS, GNSS and land-based radio navigation.
FIG. 4 illustrates an exemplary FMS interactive display interface 400 of the present invention.
The top half of the FMS interactive display interface 400 shows four types of GNSS data, respectively:
GPS: predicted aircraft position and associated navigation performance assuming GPS as a single GNSS source;
BDS: predicted aircraft position and associated navigation performance assuming the BDS as a single GNSS source;
MODE 1: predicted aircraft position and associated navigation performance in deep hybrid MODE (shown as "MODE 1" in the figure) assuming GPS and BDS sources as GNSS sources;
MODE 2: the predicted aircraft position and associated navigation performance in the preferred fusion MODE (shown as "MODE 2" in the figure) assuming GPS and BDS sources as GNSS sources.
The Position information is given in the "Position" column in the form of uniform latitude and longitude, and the navigation performance is given in the "Perf" column in the form of Actual Navigation Performance (ANP) in units of nautical miles.
It should be noted that the above information is the predicted aircraft position for the system assuming different GNSS sources and different navigation modes, and not the actual position of the aircraft. This information is mainly used as a reference (e.g., for the pilot to use in selecting GNSS sources).
The lower half of the FMS interactive display interface 400 is a GNSS source selection interface, including AUTO-preferred mode (shown as "AUTO"), GPS (shown as "GPS") and BDS (shown as "BDS"). In the event that the "GPS" option is selected, the interface 400 may further display sub-options of "GPS-preferred" and "GPS-unique"; in the case of selecting the "BDS" option, the interface 400 may further display sub-options of "BDS priority" and "BDS unique" so as to correspond to the aforementioned "priority selection mode" and "unique selection mode". For clarity, the sub-options described above are not shown in the figures.
By default, the system employs AUTO preference mode (AUTO). Additionally, the pilot may manually select a particular GNSS source. It should be noted that only one of "AUTO", "GPS-preferred", "GPS-unique", "BDS-preferred", and "BDS-unique" can be selected at any one time.
Upon selection of a particular GNSS source selection mode, the corresponding aircraft location and associated navigation capabilities are automatically updated and displayed after the corresponding fields for pilot awareness and reference.
If the GNSS source selection mode is selected manually by the pilot, the pilot may need to click an execute button (EXEC) to effect the selection after manually selecting one of the GNSS source selection modes (e.g., by clicking an icon on the interface).
It should be noted that the FMS interactive display interface 400 of fig. 4 is merely exemplary. In different implementations, different interfaces may be employed to display the various items of information in FIG. 4. For example, in some implementations, five options, "AUTO," "GPS preferred," "GPS unique," "BDS preferred," and "BDS unique" may be displayed simultaneously on the interface.
FIG. 5 illustrates a flow chart of a method 500 for navigation mode selection for an aircraft of the present invention.
The method 500 begins at 502. At 502, one or more of a plurality of GNSS sources are selected.
The one or more GNSS sources may be selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
In some embodiments, one or more of the plurality of GNSS sources may be selected based on current location information of the aircraft.
At 504, IRS navigation information is acquired from the inertial reference system IRS, wherein the IRS navigation information includes a first estimate of the aircraft position and is obtained by the inertial reference system based on the initial position and the internal real-time calculations of the aircraft.
At 506, navigation signals are received from the selected one or more GNSS sources.
At 508, pseudorange information is obtained based on the navigation signals, wherein the pseudorange information includes pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft.
In various embodiments, the total number of pseudoranges and the total number of pseudorange rates in the pseudorange information are each greater than or equal to N +3, where N represents the number of types of GNSS sources.
At 510, GNSS navigation information is obtained based on the pseudorange information, wherein the GNSS navigation information includes a second estimate of the aircraft position.
At 512, the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources is combined with the IRS navigation information to obtain a final position of the aircraft.
In particular, IRS navigation information and pseudorange information may be combined in a first navigation mode to obtain a first position of the aircraft. Preferably, N +3 pseudoranges and N +3 pseudorange rates of the pseudorange information may be selected, and a close-coupled kalman filtering algorithm may be performed on the selected pseudoranges and pseudorange rates and the IRS navigation information to obtain the first position. Meanwhile, the IRS navigation information and the GNSS navigation information may be combined in a second navigation mode to obtain a second position of the aircraft. Preferably, the accuracy and integrity of the GNSS navigation information may be compared, one of the GNSS navigation information may be selected based on the comparison, and a loose combination Kalman filtering algorithm may be performed on the selected GNSS navigation information and the IRS navigation information to obtain the second position.
In a preferred embodiment, the first position of the first navigation mode or the second position of the second navigation mode may be selected as the final position of the aircraft based on the accuracy or settings of the first navigation mode and the second navigation mode.
According to the method, the information from various GNSS sources is adopted, and the depth mixed mode based on pseudo-range information and the optimal fusion mode based on GNSS navigation information are utilized to generate the aircraft position with higher precision and better navigation performance, so that the combined positioning of the various GNSS sources is realized, and the positioning precision and reliability are improved.
While the steps of method 500 are described in a particular order for the sake of simplicity, it is to be understood that the order of the steps is illustrative and not limiting. In some embodiments, the steps of method 500 may be performed in a different order. For example, while the step of obtaining IRS navigation information from the inertial reference system IRS (504) is shown in fig. 5 as occurring before the steps of obtaining pseudorange information and GNSS navigation information (508 and 510), in other embodiments the step of obtaining IRS navigation information from the inertial reference system IRS may occur after the steps of obtaining pseudorange information and GNSS navigation information. In further embodiments, the step of obtaining IRS navigation information from the inertial reference system IRS may also occur in parallel with the step of obtaining pseudorange information and GNSS navigation information.
FIG. 6 illustrates a block diagram of a system 600 for navigation mode selection for an aircraft of the present invention. Wherein the modules in the dashed box represent optional modules.
As shown in FIG. 6, the system 600 may include a GNSS source selection module 602, an acquisition module 604, a position calculation module 606, an output module 608, and a display module 610. Each of these modules may be connected to or communicate with each other, directly or indirectly, over one or more buses 612.
In various embodiments of the invention, the GNSS source selection module 602 may be configured to: one or more of the plurality of GNSS sources are selected. In some embodiments, the one or more GNSS sources are selected from the following satellite navigation sources: global positioning system GPS, beidou satellite navigation system BDS, GLONASS, GALILEO.
In some embodiments, the GNSS source selection module 602 may be further configured to: one or more of the plurality of GNSS sources are selected based on current location information of the aircraft.
In some embodiments, the GNSS source selection module 602 may be further configured to select one or more of the plurality of GNSS sources based on one of the following GNSS source selection modes: unique selection mode: selecting only one of the plurality of GNSS sources and issuing an alert message when the selected one GNSS source is unavailable without automatically switching to another available GNSS source; the preferential selection mode: preferentially selecting one of the plurality of GNSS sources and automatically switching to another available GNSS source when the selected one GNSS source is not available; automatic preferred mode: one or more GNSS sources with better performance among the plurality of GNSS sources are automatically selected.
The acquisition module 604 may be configured to: obtaining IRS navigation information from an inertial reference system IRS, wherein the IRS navigation information includes a first estimate of a position of the aircraft and is obtained by the inertial reference system based on an initial position and an internal real-time calculation of the aircraft; navigation signals are received from the selected one or more GNSS sources.
The location calculation module 606 may be configured to: obtaining pseudorange information based on the navigation signals, wherein the pseudorange information comprises pseudoranges and pseudorange rates between the selected one or more GNSS sources and the aircraft; obtaining GNSS navigation information based on the pseudorange information, wherein the GNSS navigation information includes a second estimate of the aircraft position; combining the pseudorange information or the GNSS navigation information based on the selected one or more GNSS sources with the IRS navigation information to obtain a final position of the aircraft.
The output module 608 may be configured to output the final position of the aircraft. For example, the final position of the aircraft may be output to an FMS guidance function module (not shown in fig. 6) to implement the FMS auto-guidance function.
The display module 610 may be configured to display the final position of the aircraft. For example, the final position of the aircraft may be displayed on an FMS interactive display interface (e.g., 400 in fig. 4) to provide relevant information to the pilot for reference.
As shown, the location calculation module 606 can further include a first navigation mode module 614, a second navigation mode module 616, a selection module 618.
The first navigation mode module 614 may be configured to: the IRS navigation information and the pseudorange information are combined in a first navigation mode to obtain a first position of the aircraft.
In some embodiments, the total number of pseudoranges and the total number of pseudorange rates in the pseudorange information are each greater than or equal to N +3, where N represents a number of types of GNSS sources, and the first navigation mode module 614 may be further configured to: selecting N +3 pseudo ranges and N +3 pseudo range rates in pseudo range information; a close-coupled kalman filtering algorithm is performed on the selected pseudoranges and pseudorange rates and IRS navigation information to obtain a first position.
The second navigation mode module 616 may be configured to: combining the IRS navigation information and the GNSS navigation information in a second navigation mode to obtain a second position of the aircraft.
In some embodiments, the second navigation mode module 616 may be further configured to: comparing the accuracy and the integrity of the GNSS navigation information; selecting one of the GNSS navigation information based on the comparison; a pine combination Kalman filtering algorithm is performed on the selected GNSS navigation information and the IRS navigation information to obtain a second position.
The selection module 618 may be configured to: the first position of the first navigation mode or the second position of the second navigation mode is selected as the final position of the aircraft.
In some embodiments, the selection module 618 may be further configured to: a first location of the first navigation mode or a second location of the second navigation mode is selected based on a precision or a setting of the first navigation mode and the second navigation mode.
In a preferred embodiment, the first navigation mode and the second navigation mode are implemented under the same software architecture. The first navigation mode and the second navigation mode can be realized under the same software architecture, so that the bottom layer pseudo range information and the upper layer position information of the GNSS navigation information can be used and selected at the same time, and the availability and the selection synchronism of the navigation information are improved.
It should be appreciated that FIG. 6 illustrates only one exemplary configuration of a system for navigation mode selection for an aircraft. In other examples, the system of the present invention may be implemented in different ways. For example, one or more modules may be added or omitted, or multiple modules may be combined or integrated. For example, the first navigation mode module and the second navigation mode module may be combined into a single module.
The system of the invention generates the FMS position with higher precision and better navigation performance by adopting the information from various GNSS sources and utilizing the depth mixed mode based on pseudo-range information and the optimal fusion mode based on GNSS navigation information, thereby realizing the combined positioning of various GNSS sources and improving the positioning precision and reliability.
The detailed description set forth above in connection with the appended drawings describes examples and is not intended to represent all examples that may be implemented or fall within the scope of the claims. The terms "example" and "exemplary" when used in this specification mean "serving as an example, instance, or illustration," and do not mean "superior or superior to other examples.
Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, usage of such phrases may not refer to only one embodiment. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more. The term "some" means one or more unless specifically stated otherwise. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims.
It is also noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged.
While various embodiments have been illustrated and described, it is to be understood that the embodiments are not limited to the precise configuration and components described above. Various modifications, substitutions, and improvements apparent to those skilled in the art may be made in the arrangement, operation, and details of the devices disclosed herein without departing from the scope of the claims.