CN114353803A - Indoor and outdoor positioning coordinate reference frame conversion method - Google Patents
Indoor and outdoor positioning coordinate reference frame conversion method Download PDFInfo
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- CN114353803A CN114353803A CN202210005042.9A CN202210005042A CN114353803A CN 114353803 A CN114353803 A CN 114353803A CN 202210005042 A CN202210005042 A CN 202210005042A CN 114353803 A CN114353803 A CN 114353803A
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Abstract
The invention discloses a method for converting an indoor and outdoor positioning coordinate reference frame, which comprises the following steps: step one, selecting a coordinate origin O, and establishing an indoor local coordinate system; step two, carrying out indoor positioning and storing indoor local area coordinates of historical positioning points; step three, when the user changes from indoor to outdoor, obtaining local coordinates through indoor positioning and obtaining ECEF coordinates through outdoor GNSS positioning for n continuous positioning points, wherein n is more than or equal to 2; step four, establishing a coordinate transformation equation; subtracting the coordinate conversion equations pairwise to obtain a single difference equation; step six, solving the longitude and latitude of the origin O
And a true north deviation angle theta of the local coordinate system; step seven, calculating the ECEF coordinate of the origin O; and step eight, calculating to obtain the ECEF coordinates of the indoor historical positioning points. The method can accurately calibrate the indoor true north azimuth deviation of the user, simplifies the solving process through the single difference equation, and realizes fast coordinate in indoor and outdoor integrated positioningAnd (4) fast conversion.
Description
Technical Field
The invention relates to the fields of Indoor Positioning (Indoor Positioning), Location-based Service (LBS) and the like, in particular to a conversion method of an Indoor and outdoor Positioning coordinate reference frame.
Background
Statistically, over 80% of the time of modern urban populations spent in indoor environments, indoor location service needs have become increasingly widespread and important. Based on the indoor position information, the system can provide abundant and various position-Based services (LBS) for common people and various professionals under various scenes such as markets, parking lots, libraries, conference exhibition halls, office buildings, hospitals, schools, museums and the like, and can improve the social productivity and promote the economic development and simultaneously ensure the property and life safety of people. With the development of technology and the upgrading of industry, the navigation positioning technology and the related position information service thereof begin to expand from outdoor to indoor, and the seamless continuous positioning of indoor and outdoor becomes an important future development direction.
However, the coordinate and position information is expressed under a certain specific spatial reference frame, and a scientific and reasonable coordinate reference frame system is an important premise for realizing ideal indoor and outdoor seamless, continuous high-precision positioning and service.
In the outdoors, a Global Navigation Satellite System (GNSS) represented by a GPS is a main outdoor positioning means, and positioning and display of a GNSS user are performed in a geodetic coordinate System. Specifically, the geodetic coordinate system may be an Earth ellipsoid coordinate system (represented by longitude, latitude, and geodetic height), or an Earth-Centered Earth-Fixed coordinate system (ECEF) (represented by a right-handed rectangular coordinate system). Typical ECEF Coordinate systems include the United states WGS-84(World geographic System 1984) Coordinate System, the China 2000 national Geodetic Coordinate System (China geographic Coordinate System 2000, CGCS2000), and the like. The earth ellipsoid coordinate system and the earth center earth fixed coordinate system can be converted through known earth ellipsoid parameters, unknown parameters are not involved, and the method is equivalent to the user.
In the indoor environment, because GNSS signals are blocked and rejected, technologies such as Ultra-Wide Band (UWB), BlueTooth (BlueTooth), Wi-Fi, Inertial Navigation System (INS), Visual Odometer (VO), and Visual Inertial Odometer (VIO) are mainly used for positioning at present. Also, since it is difficult to establish a geodetic coordinate system using GNSS positioning, indoor positioning generally establishes and uses a local coordinate system based on east, north, and sky directions. This local coordinate system is essentially a perpendicular standing-center rectangular coordinate system in geodetics, and it usually selects a certain position as the origin O (the origin does not need to have special requirements or meanings), and uses the perpendicular direction of the O point as the Z axis (pointing to the zenith as positive), the meridian direction as the X axis (pointing to the north as positive), and the Y axis is perpendicular to the X, Z axis (pointing to the east as positive) to form a left-hand rectangular coordinate system, as shown in fig. 1 of the specification.
For the respective independent positioning, the geodetic coordinate system in the outdoor environment and the local coordinate system in the indoor environment can respectively meet the respective use requirements. However, for the indoor and outdoor integrated seamless positioning, the same coordinate reference frame is often needed to be used outdoors and indoors, so that operations such as map display and path planning are facilitated.
When a user first locates outdoors and then enters indoors from outdoors, the outdoor geodetic coordinate system frame can be naturally introduced and extended indoors, so that the geodetic coordinate system is directly adopted for locating indoors, or a conversion relation between an indoor local area coordinate system and an outdoor geodetic coordinate system is established.
When the first positioning of the user occurs indoors, we can first use the local coordinate system for positioning. Once the user enters or exits from the indoor space to the outdoor space, the position point information under the indoor local coordinate system and the outdoor geodetic coordinate system can be obtained simultaneously, and therefore the relation between the indoor coordinate system and the outdoor coordinate system is established. Once the relation is established, all historical position points in the previous indoor positioning process can be further converted into a geodetic coordinate system, so that a uniform spatial position reference datum is established.
However, this method has limitations and difficulties in practical use. It is known that in order to establish an accurate local coordinate system, the azimuth angle (also called heading angle) of the user relative to the true north direction needs to be obtained. Currently, only a few technical means such as magnetometers and INSs can obtain true north azimuth in an outdoor environment where GNSS signals cannot be used. However, the magnetometer is poor in accuracy, generally ranges from several degrees to tens of degrees, and is susceptible to the influence of objects such as metal and electromagnetism; INS equipment with true north alignment capability is very expensive, with prices varying from tens of thousands of rmb to millions of rmb, and cannot be applied to user terminals such as smart phones and wearable devices in low-cost and mass production. Thus, when positioning occurs initially indoors, the local coordinate system established by the user is actually difficult to accurately align with the true north direction, but has some fixed deviation from the true north direction. If the navigation positioning activity of the user is always performed in an indoor environment (for example, by using the above-mentioned technical means such as UWB, BlueTooth, Wi-Fi, VO, VIO, etc.), it will not generally affect the user. However, once the user goes in and out from the outdoors and needs to establish a connection with the outdoor geodetic coordinate system, it is difficult to determine the conversion relationship between the indoor and outdoor coordinate systems, or significant errors are brought to the conversion result, and finally the positioning performance and the use experience of the user are affected.
Disclosure of Invention
In view of this, the embodiment of the present invention provides a method for converting an indoor and outdoor positioning coordinate reference frame, which is used to solve the problem that an accurate conversion relationship cannot be established with an outdoor geodetic coordinate system due to the fact that the true north direction of a user in an indoor environment is unknown.
In order to achieve the above object, the present invention provides a method for converting an indoor and outdoor positioning coordinate reference frame, comprising:
step one, selecting a certain indoor position point as a coordinate origin O to establish an indoor local coordinate system, and recording the coordinates of a geocentric and geostationary coordinate system of the coordinate origin O as (X)O，YO，ZO) The geodetic longitude and latitude coordinates are
The deviation angle of the coordinate axis in the north direction of the local coordinate system relative to the true north direction of the earth is recorded as theta,
wherein the local coordinate system forms a left-hand rectangular coordinate system by taking the perpendicular direction of the point O as a Z axis and the pointing zenith as positive, the meridian direction as an X axis and the pointing north as positive, the Y axis is vertical to the X, Z axis and the pointing east as positive,
the geocentric coordinate system is a United states WGS-84 coordinate system or a China CGCS-2000 coordinate system;
secondly, developing indoor positioning in the local area coordinate system and storing coordinate values of historical positioning points in the indoor local area coordinate system;
step three, when the user positioning environment is changed from indoor to outdoor, the n continuous positioning points P are usedi(i-1, 2, … n) even if its coordinates in the local coordinate system are obtained using indoor positioning techniques
And obtaining the coordinates of the earth core in the earth core earth fixed coordinate system by using an outdoor GNSS positioning technology
Wherein n is more than or equal to 2;
step four, for each positioning point PiEstablishing a coordinate transformation equation of the form:
thus, n coordinate transformation equations are obtained in total;
step five, subtracting the coordinate transformation equations in the step four from each other to obtain n-1 single difference equations with the following forms:
step six, the single difference equation in the step five is simultaneously established, and the longitude and latitude coordinates of the coordinate origin O are obtained through solving
And the deviation angle θ of the local coordinate system;
seventhly, the longitude and latitude coordinates of the coordinate origin O are obtained
Substituting the deviation angle theta of the local coordinate system into the coordinate conversion equation in the step four, and calculating to obtain the geocentric coordinate system coordinate (X) of the origin OO，YO，ZO)；
And step eight, calculating the coordinates of the geocentric coordinate system of the historical positioning points in the step two by using the coordinate conversion equation in the step four.
By utilizing the indoor and outdoor positioning coordinate reference frame conversion method provided by the invention, the true north azimuth deviation of a user in an indoor positioning environment can be accurately calibrated on the premise of not increasing any hardware equipment and cost, and the local coordinates of indoor positioning points are quickly converted into an outdoor geodetic coordinate system, so that the unification of the indoor and outdoor positioning coordinate reference frames is realized; in the process, the calculation and solution process is further simplified by a method of constructing a single difference equation. Therefore, the difficult problem of coordinate conversion in indoor and outdoor integrated positioning of a user is effectively solved.
Drawings
FIG. 1 is a schematic diagram of an indoor local area coordinate system;
FIG. 2 is a flow chart of the method for converting indoor and outdoor positioning coordinate reference frames according to the present invention
Detailed Description
For a better understanding of the technical aspects of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings. Embodiments of the present disclosure are described in further detail below with reference to the figures and the detailed description, but the present disclosure is not limited thereto.
The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
Aiming at the problems existing in the current indoor and outdoor integrated positioning, the invention provides a conversion method of an indoor and outdoor positioning coordinate reference frame, which comprises the following steps:
step one, selecting a certain indoor position point as a coordinate origin O to establish an indoor local coordinate system, and recording the coordinates of a geocentric and geostationary coordinate system of the coordinate origin O as (X)O，YO，ZO) The geodetic longitude and latitude coordinates are
And recording the deviation angle of the coordinate axis in the north direction of the local coordinate system relative to the true north direction of the earth as theta.
The local coordinate system is essentially a perpendicular standing center rectangular coordinate system in geodetics, and generally a left-hand rectangular coordinate system is formed by taking the perpendicular direction of an O point as a Z axis (pointing to the zenith as positive), the meridian direction as an X axis (pointing to the north as positive), and the Y axis being perpendicular to an X, Z axis (pointing to the east as positive), as shown in the attached figure 1 of the specification. Of course, we can also choose to point north as the Y-axis and east as the X-axis, which have no effect on the user's actual usage. In addition, the selection of the origin O of the local coordinate system also generally has no special requirement, and a user can select any point in an indoor positioning environment as the origin of the local coordinate system of the user.
The earth-centered earth-fixed (ECEF) Coordinate System may be the WGS-84 Coordinate System in the united states, or the CGCS2000 Coordinate System in China, or the BeiDou Coordinate System (BDCS) in China, or the like. Among them, WGS84 is a coordinate system established in the united states for use of GPS, established by observing data from satellite observation stations throughout the world, and has the geometrical meaning: the origin of the coordinate system is located in the earth centroid, the Z-axis points to the protocol earth Pole (CTP) direction defined by the Bureau International de l' heart (BIH) 1984.0, the X-axis points to the intersection point of the zero-degree meridian plane of BIH1984.0 and the equator of the CTP, and the Y-axis is determined by the right-hand rule. CGCS2000 is the latest national geodetic coordinate system in China at present, and the origin is the mass center of the whole earth including the ocean and the atmosphere; the Z axis points to the direction of the earth reference pole of an epoch 2000.0 from the origin, the pointing direction of the epoch is calculated by an initial pointing direction with an epoch 1984.0 given by the International time office, the directional time evolution ensures that no residual global rotation is generated relative to the earth crust, the X axis points to the intersection point of the Greenwich mean reference meridian and the earth equatorial plane (the epoch 2000.0) from the origin, and the Y axis, the Z axis and the X axis form a right-hand orthogonal coordinate system. The definition of BDCS conforms to the International Earth Rotation Service (IERS) specification, and is consistent with the CGCS2000 definition (with identical Earth reference ellipsoid parameters).
And secondly, developing indoor positioning in the local area coordinate system, and storing coordinate values of the historical positioning points in the indoor local area coordinate system. The method of the present invention is not limited by specific indoor positioning techniques and systems. In an indoor environment, a user may select to use Ultra-wideband (UWB), BlueTooth (BlueTooth), Wi-Fi, Visual Odometer (VO), Visual-Inertial odometer (VIO), and the like.
Step three, when the user positioning environment is changed from indoor to outdoor, the n continuous positioning points P are usedi(i-1, 2, … n) even if its coordinates in the local coordinate system are obtained using indoor positioning techniques
And obtaining the coordinates of the earth core in the earth core earth fixed coordinate system by using an outdoor GNSS positioning technology
Wherein n is more than or equal to 2.
Specifically, when the indoor positioning technology used by the user is an inertial navigation system, a visual odometer, or a visual inertial odometer, the positioning point P may be obtained by dead reckoningiCoordinates in the local coordinate system. And when the indoor positioning technology used by the user is Ultra-Wide Band (UWB), BlueTooth (BlueTooth), or Wi-Fi, the signal is required to be able to extend and cover a part of the area transitioning from indoor to outdoor, so as to ensure that the user can obtain the coordinates of the indoor coordinate system and the coordinates of the outdoor coordinate system in the part of the transition area at the same time.
Step four, for each positioning point PiEstablishing a coordinate transformation equation of the form:
thus, n coordinate conversion equations are obtained in total.
Here, more than 2 coordinate conversion equations (n ≧ 2) are established because there is (X) in the coordinate conversion equationsO，YO，ZO) And a total of four degrees of freedom (ECEF coordinates (X)O，YO，ZO) And geodetic latitude and longitude coordinates (X)O，YO，ZO) Inter-convertible) so that four unknowns cannot be solved using only single epoch observation data.
Step five, directly developing and solving the coordinate transformation equation established in the step four is more complex, so that the coordinate transformation equation is subtracted from each other two by two to obtain n-1 single difference equations with the following forms:
thus, common to the coordinate conversion equations is eliminated by the single difference processing between the equations
And partially, thereby facilitating the expansion of the equations and the solution of unknowns.
Step six, simultaneously establishing each single difference equation in the step five, and solving to obtain the longitude and latitude coordinate of the coordinate origin O
And the deviation angle theta of the local coordinate system.
Seventhly, the longitude and latitude coordinates of the coordinate origin O are obtained
Substituting the deviation angle theta of the local coordinate system into the coordinate conversion equation in the step four, and calculating to obtain the geocentric coordinate system coordinate (X) of the origin OO，YO，ZO)。
And step eight, calculating the coordinates of the geocentric coordinate system of the historical positioning points in the step two by using the coordinate conversion equation in the step four. Therefore, the indoor historical positioning point is converted from the indoor local coordinate to the outdoor geodetic coordinate.
By utilizing the indoor and outdoor positioning coordinate reference frame conversion method provided by the invention, the true north azimuth deviation of a user in an indoor positioning environment can be accurately calibrated on the premise of not increasing any hardware equipment and cost, and the local coordinates of indoor positioning points are quickly converted into an outdoor geodetic coordinate system, so that the unification of the indoor and outdoor positioning coordinate reference frames is realized; in addition, in the process, the calculation and solution process is further simplified by a method of constructing a single difference equation. Therefore, the difficult problem of coordinate conversion in indoor and outdoor integrated positioning of a user is effectively solved.
While the embodiments of the present invention have been described in detail, the present invention is not limited to these specific embodiments, and those skilled in the art can make various modifications and modifications of the embodiments based on the concept of the present invention, which fall within the scope of the present invention as claimed.
Claims (1)
1. A method for converting indoor and outdoor positioning coordinate reference frames comprises the following steps:
step one, selecting a certain indoor position point as a coordinate origin O to establish an indoor local coordinate system, and recording the coordinates of a geocentric and geostationary coordinate system of the coordinate origin O as (X)O，YO，ZO) The geodetic longitude and latitude coordinates are
The deviation angle of the coordinate axis in the north direction of the local coordinate system relative to the true north direction of the earth is recorded as theta,
wherein the local coordinate system forms a left-hand rectangular coordinate system by taking the perpendicular direction of the point O as a Z axis and the pointing zenith as positive, the meridian direction as an X axis and the pointing north as positive, the Y axis is vertical to the X, Z axis and the pointing east as positive,
the geocentric geostationary coordinate system is a United states WGS-84 coordinate system, or China CGCS2000 coordinate system, or China BDCS coordinate system;
secondly, developing indoor positioning in the local area coordinate system and storing coordinate values of historical positioning points in the indoor local area coordinate system;
step three, when the user positioning environment is changed from indoor to outdoor, the n continuous positioning points P are usedi(i-1, 8, … n) even if its coordinates in the local coordinate system are obtained using indoor positioning techniques
And obtaining the coordinates of the earth core in the earth core earth fixed coordinate system by using an outdoor GNSS positioning technology
Wherein n is more than or equal to 2;
step four, for each positioning point PiEstablishing a coordinate transformation equation of the form:
thus, n coordinate transformation equations are obtained in total;
step five, subtracting the coordinate transformation equations in the step four from each other to obtain n-1 single difference equations with the following forms:
step six, the single difference equation in the step five is simultaneously established, and the longitude and latitude coordinates of the coordinate origin O are obtained through solving
And the deviation angle θ of the local coordinate system;
seventhly, the longitude and latitude coordinates of the coordinate origin O are obtained
Substituting the deviation angle theta of the local coordinate system into the coordinate conversion equation in the step four, and calculating to obtain the geocentric coordinate system coordinate (X) of the origin OO，YO，ZO)；
And step eight, calculating the coordinates of the geocentric coordinate system of the historical positioning points in the step two by using the coordinate conversion equation in the step four.
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| CN116996606A (en) * | 2023-09-26 | 2023-11-03 | 东莞信宝电子产品检测有限公司 | Indoor Wi-Fi positioning performance evaluation method of smart phone |
| CN116996606B (en) * | 2023-09-26 | 2024-01-09 | 东莞信宝电子产品检测有限公司 | Indoor Wi-Fi positioning performance evaluation method of smart phone |
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