CN101788660A - System, method and equipment for determining whether positioning equipment in space is moved or not - Google Patents

Abstract

The implementation method of the invention provides a system, a method and equipment for determining whether positioning equipment in space is moved or not. The system comprises a label capable of sending ranging signals, positioning equipment and a server, wherein the positioning equipment is configured for acquiring relative coordinates of a position point where the label is positioned relative to the positioning equipment according to the ranging signals of the label; and the server is configured for judging whether the positioning equipment is moved or not according to the relative coordinates, calibration parameters of the positioning equipment and reliable absolute coordinates of the position point in the space. When the system, the method and the equipment are implemented, that whether the positioning equipment is moved or not in real time can be determined accurately and quickly.

Description

System, method and device for determining whether a positioning device in space is moved

Technical Field

The present invention relates to the field of positioning, and in particular, to a system, method and device for determining whether a positioning device in a space is moved.

Background

Location information is a fundamental context for extracting the geographical relationship between a user and the environment to further understand and learn the user's behavior. The importance and the prospect of location-aware applications have led to the design and implementation of systems for providing location information, particularly for use in indoor and urban environments. Currently, positioning systems have been developed for the accurate real-time tracking of people and property in many different applications, which may include a variety of environments, such as offices, healthcare facilities, coal mines, subways, intelligent buildings, and restaurants, to name a few.

Currently, positioning systems are typically based on ultrasound or ultra-wideband radio. They have in common the feature of being able to provide positioning accuracy on the order of centimetres. In some applications of such positioning systems, it is desirable to deploy and calibrate positioning devices in the relevant environment to monitor the position of moving objects in certain areas of Interest (A0I: Area of Interest). Typically, positioning systems are capable of tracking the position of these moving objects in real time to provide some specific location-based services. For example, in an office environment, when a positioning system is deployed, it can track the location of terminals or employees. Thus, location-based access rules may be devised to define a particular "security zone". Access to the confidential information is only allowed within this region, and once outside or beyond, any access to the confidential information is prohibited. The secure area may be a room, a portion of a work area, or even a table.

Fig. 1 shows a schematic diagram of a positioning system in the prior art after it has been arranged and moved. As shown in FIG. 1, taking a room as an example, the device is located, for example, < x₁，y₁，d₁＞-＜x₆，y₆，d₆The positioning devices of > are typically arranged in an array on the roof of the room. These locating devices are calibrated so that the location and behavior of the person or object carrying the tag in the room can be monitored by monitoring the location of the tag. Wherein (x)_i，y_i) Is the location of the ith pointing device in the room, and d_iThen the distance between the ith pointing device and the tag.

However, some positioning devices in the positioning system may be moved by being stolen by an attacker, such as < x in FIG. 1₆，y₆，d₆The calibrated position parameters of the positioning device are inconsistent with the actual position parameters, so that the whole positioning system cannot accurately determine the position represented by the label. As such, the region of interest may not be accurately monitored. In this case, for example, a person who has not been previously authorized to access the computer in the area of interest may now gain access to the computer, creating a security risk, referred to as a mobile attack.

Therefore, there is a particular need in the art for a solution that can determine whether a positioning device is moved.

Disclosure of Invention

It is an object of the present invention to provide a solution for determining whether a positioning device in space is moved.

According to an aspect of the invention, there is provided a system, which may comprise: a tag capable of transmitting a ranging signal; the positioning device is configured to obtain relative coordinates of a position point where the tag is located relative to the positioning device according to the ranging signal from the tag; and the server is configured to judge whether the positioning equipment moves according to the relative coordinates, the calibration parameters of the positioning equipment and the credible absolute coordinates of the position point in the space.

According to another aspect of the present invention, there is provided a method for determining whether a positioning device in a space is moving, the method may include: receiving relative coordinates of a position point in the space relative to the positioning equipment, calibration parameters of the positioning equipment and a credible absolute coordinate of the position point in the space; and judging whether the positioning equipment moves or not according to the relative coordinates, the calibration parameters and the reliable absolute coordinates.

According to another aspect of the present invention, there is provided an apparatus for determining whether a positioning apparatus in a space is moving, the apparatus may include: the receiving device is used for receiving the relative coordinates of the position points in the space relative to the positioning equipment, the calibration parameters of the positioning equipment and the trustable absolute coordinates of the position points in the space; and the judging device is used for judging whether the positioning equipment moves or not according to the relative coordinate, the calibration parameter and the credible absolute coordinate.

The embodiment of the invention has the beneficial effects that whether the positioning equipment moves can be accurately, comprehensively determined in real time, thereby effectively preventing potential movement attack.

Drawings

FIG. 1 shows a schematic diagram of a prior art positioning system arranged and moved;

FIG. 2 shows a schematic view of a room for implementing the invention, as an example;

FIG. 3 shows a schematic view of a positioning apparatus according to an embodiment of the invention;

FIG. 4 shows a three-dimensional schematic of a reference space according to one embodiment of the invention;

FIG. 5 illustrates a simplified two-dimensional view of a reference space according to one embodiment of the invention;

FIG. 6 shows a schematic spatial diagram of a method for calibrating another positioning apparatus based on a calibrated positioning apparatus according to an embodiment of the present invention;

FIG. 7 shows a schematic block diagram of a system for determining whether a positioning device is moved according to an embodiment of the present invention;

FIG. 8 illustrates a flow diagram of a method for determining whether a tag has been moved according to one embodiment of the invention;

FIG. 9 shows a schematic spatial diagram of a method for determining positioning device offsets in accordance with an embodiment of the invention;

FIG. 10 shows a flow diagram of a method for determining whether a positioning device is moved according to another embodiment of the invention;

FIG. 11 shows a schematic diagram representing a change in a parameter after a pointing device has been moved, according to another embodiment of the invention;

FIG. 12 illustrates a schematic spatial diagram for determining whether a pointing device is moving using another calibrated pointing device, according to one embodiment of the present invention;

FIG. 13 shows a block diagram of an apparatus for determining whether a positioning device is moving according to one embodiment of the invention;

FIG. 14 shows a block diagram of a determination device according to an embodiment of the invention; and

fig. 15 shows a block diagram of a determination device according to another embodiment of the present invention.

Detailed Description

First, various terms used in the embodiments of the present invention are briefly described with reference to fig. 2 and 3.

1. A space. The space according to the embodiment of the present invention refers to a space in which an object moves. Such as a room, office, conference room, etc. Fig. 2 shows a schematic view of a space 10, taking a room as an example. It should be understood that embodiments of the present invention are not limited to the quadrilateral rooms shown in fig. 2, but may be any shape.

2. Spatial feature location points. The spatial feature location point is a location point for determining a space. For example, in a room-exemplified space 10 as shown in fig. 2, the spatial feature location points may be room corner location points 11, 12, and 13. In principle, any location point within the space may be selected as a spatial feature location point as long as the space can be determined. It should be understood that when the room is other polygonal shapes, such as a hexagon, the top location point of the polygon may be used as the characteristic location point. If the room is other irregular shapes, at least three location points on the perimeter of the room can be used to fit a polygon, so that rooms of other shapes can be treated like a polygon.

3. Positioning apparatus (POD: Positioning on 0ne Device). A positioning apparatus according to an embodiment of the present invention is an apparatus for determining coordinates of a position point in space. Fig. 3 shows an example of a positioning apparatus used in an embodiment of the present invention. As shown in FIG. 3, the positioning device employed in embodiments of the present invention is a sensor array having a plurality of leaf node locations. The number of leaf node points is at least two, i.e. the positioning device comprises at least two leaf node point sensors and one sensor in the middle. Generally, the more leaf node positions, the higher the positioning accuracy. The positioning device shown in fig. 3 has 6 leaf node positions. In particular applications, as shown in FIG. 3, a locating device 14 is typically disposed at the top of space 10, which is capable of transmitting ranging signals to or receiving ranging signals from target location points in space 10.

In the present invention, only the receiving function of the positioning apparatus is used. The positioning device itself may have a calculation function for performing a correlation calculation based on the received ranging signals. Alternatively, the positioning device may be connected to a remote server or dedicated computing device by wired or wireless means, such that the ranging signal based correlation calculations are performed at the remote server or dedicated computing device.

The coordinates of the target location point in space can be generally obtained using conventional triangulation or coordinate transformation methods based on ranging signals received by the positioning device from the target location point. The structure and function of the positioning device itself is known in the art and will not be described in further detail herein.

4. Absolute coordinate system. In the embodiment of the present invention, a coordinate system in which one position point in space is used as a coordinate home position point is referred to as an absolute coordinate system. Any one of the characteristic position points in space can be used as a home position point of the absolute coordinate system. For example, in the space 10 shown in fig. 2, the feature position point 11 is set as a home position point of the absolute coordinate system. Of course, it will be understood by those skilled in the art that the selection of one of the feature location points as the home location point is merely convenient for calculation, and is not required. If the other position points are taken as the coordinate home position points, the absolute coordinate system described above can be obtained by a simple translation. This is well known to those skilled in the art and will therefore not be described in detail here.

5. Relative to a coordinate system. In the present invention, a coordinate system in which the positioning apparatus itself is a home position point is referred to as a relative coordinate system. The home position point of the relative coordinates is the center position point of the pointing device, and the X-axis direction is the first sensor (not shown) of the pointing device. The "first sensor" referred to herein may be defined at the time of initial configuration of the manufacturing of the pointing device. When the X-axis is defined, the direction perpendicular to and in the plane of the positioning apparatus is defined as the Y-axis.

When the positioning apparatus is calibrated, there may be a certain angle θ between the relative coordinate system and the absolute coordinate system, which is referred to as a setting angle of the positioning apparatus in the absolute coordinate system in the present invention, such as the POD angle 18 shown in fig. 2. In this way, the position parameters of the position of the positioning apparatus in space (the POD position 17 shown in fig. 2) include the absolute coordinates of the positioning apparatus in the absolute coordinate system and the setting angle θ.

6. And (4) a label. The tag in the embodiment of the present invention refers to a tag capable of transmitting a ranging signal, such as a radio frequency tag. In the invention, the tag can be placed at a position point in space, so that the relative coordinate or the absolute coordinate of the position point can be obtained by receiving the ranging signal sent by the tag through the positioning equipment. The form of the ranging signal may be various and may include, but is not limited to, ultrasonic, infrared, laser, radio frequency, ultra wideband pulsed, doppler, and sonic, among others. In addition, determining the relative coordinates or absolute coordinates of a location point by a locating device and a tag is known in the art and will not be described herein.

7. A region of interest and a region of interest feature location point. An area of interest refers to a geographic area that a user characterizes for particular application needs (e.g., security purposes). The region of interest is located in space. For example, in a "secure desktop" application, the desktop is defined as a region of interest. Access to confidential information is only allowed within this region of interest, and once outside or beyond the region of interest, any access to the confidential information is prohibited. Region of interest feature location points are those location points that can be used to characterize a region of interest. Fig. 2 shows the region of interest 15 and the region of interest feature location points 16.

The following first describes how to initially calibrate a positioning apparatus according to one embodiment of the present invention with reference to the accompanying drawings.

Specifically, according to one embodiment of the present invention, three spatial feature location points in space (shown as reference spatial feature location points in FIG. 2) are first selected and tags capable of transmitting ranging signals are placed on these feature location points in order to determine the relative coordinates of the three spatial feature location points with respect to the positioning device itself. Alternatively, the relative coordinates of the spatial feature location points may be determined by placing a label at each spatial feature location point. In addition, optionally, a tag may be placed successively at the selected spatial feature position point to determine the relative coordinates of the spatial feature position point.

Next, a positioning device may be provided in the space. The pointing device may be located anywhere in space. Alternatively, the positioning device is arranged at the top of the space and is arbitrary at the time of initial arrangement, i.e. it can be arranged anywhere at the top. Then, the positioning device can acquire the relative coordinates of the spatial feature position points relative to the positioning device itself according to the ranging signals from the tags.

For example, the positioning device uses the center of the positioning device as a coordinate home position point, and the relative coordinates of the three sensors of the positioning device relative to the positioning device are determined. Then, the three sensors can obtain the distance from the spatial feature position point to each sensor according to the ranging signal from the tag at the spatial feature position point. And finally, obtaining the relative coordinates of each spatial characteristic position point relative to the positioning equipment by using the distance from the spatial characteristic position point to each sensor and the relative coordinates of each sensor according to a traditional triangulation algorithm (such as a minimum mean square error algorithm). It should be understood that obtaining the relative coordinates of each spatial feature location point with respect to the positioning device itself through conventional triangulation algorithms is known in the art and will not be described in detail herein.

Then, through corresponding calculation, the position parameters of the positioning device in the space can be automatically calculated, so as to complete the automatic calibration of the positioning device, which will be described in detail later. Alternatively, the position parameters may include absolute coordinates (x, y, z) of the pointing device in space and a set angle θ of the pointing device in space. The position parameters of the positioning device that have been calibrated are referred to as calibration parameters of the positioning device in the present invention.

How to obtain the position parameters of the positioning device in the space according to the acquired relative coordinates of the three reference spatial feature position points is described below by taking a quadrangular room as an example in conjunction with fig. 4 and 5.

As shown in fig. 4, the relative coordinates of the three reference spatial feature position points on the ground are (x)₁，y₁，z₁)，(x₂，y₂，z₂) And (x)₃，y₃，z₃) Where these relative coordinates are already known with the pointing device and the tag. Characteristic location point (x)₁，y₁，z₁) Is defined as the home position point (0, 0, 0) of the reference space absolute coordinate system. The length (1), width (w), height (h) of the room, absolute coordinates (x, y, z) of the positioning apparatus, and the set angle θ of the POD are unknown numbers.

First the z-coordinate of the positioning device, i.e. the height (h) of the positioning device, is determined. Typically, since the roof and the floor are parallel, the positioning device has a height h, i.e. z ═ h ═ z₁＝z₂＝z₃. However, considering possible errors, for example due to uneven ground, the z-coordinate is calculated as z-h (z-h)₁+z₂+z₃)/3。

When z is computed, the remaining problem is to solve the remaining unknowns in two-dimensional space.

Fig. 5 shows a schematic diagram of calculating the above-described unknowns (e.g., the length (l), width (w) of a room, absolute coordinates (x, y) of a POD, and angle θ of the POD) in a two-dimensional space according to the present invention.

As shown in fig. 5, the solid line represents an absolute coordinate system in the present invention, and the dotted line represents a relative coordinate system with the positioning apparatus as the home position point in the present invention. The angle between the two coordinate systems, i.e. the setting angle of the positioning device, is θ.

From fig. 5, using a conventional coordinate transformation, the following equation set (1) can be derived:

x₁cos(θ)-y₁sin(θ)+x＝0

x₁sin(θ)+y₁cos(θ)+y＝0

x₂cos(θ)-y₂sin(θ)+x＝l

x₂sin(θ)+y₂cos(θ)+y＝w (1)

x₃cos(θ)-y₃sin(θ)+x＝l

x₃sin(θ)-y₃cos(θ)+y＝0

(x₁-x₃)²+(y₁-y₃)²＝l²

(x₂-x₃)²+(y₂-y₃)²＝w²

it will be appreciated by those skilled in the art that if more reference spatial feature location points are employed, the number of equations in equation set (1) will be increased, i.e., the number of rows in the coefficient matrix will be increased. This is well known to those skilled in the art and will not be described here.

Solving this system of equations (1) yields the absolute coordinates (x, y) and angle θ of the pointing device and the length 1 and width w of the reference space, as follows:

$l=\sqrt{{(x_1-x_3)}^2+{(y_1-y_3)}^2}---\left(2\right)$

$w=\sqrt{{(x_2-x_3)}^2+{(y_2-y_3)}^2}---\left(3\right)$

$x=(x_1^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009100039532E0000032.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-x_1{x}_3-y_1{y}_3)/l---\left(4\right)$

$y=x_3^2+y_3^2-x_2{x}_3-y_2{y}_3/w---\left(5\right)$

<math><mrow><mi>&theta;</mi><mo>=</mo><mi>ac</mi><mi>sin</mi><mrow><mo>(</mo><mfrac><mrow><msub><mi>y</mi><mn>3</mn></msub><mi>x</mi><mo>-</mo><msub><mi>x</mi><mn>1</mn></msub><mi>y</mi></mrow><mrow><msub><mi>x</mi><mn>1</mn></msub><msub><mi>x</mi><mn>3</mn></msub><mo>+</mo><msub><mi>y</mi><mn>3</mn></msub><msub><mi>y</mi><mn>1</mn></msub></mrow></mfrac><mo>)</mo></mrow><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>6</mn><mo>)</mo></mrow></mrow></math>

this allows to obtain the dimensions of the reference space and the position parameters of the positioning device in the reference space, such as the absolute coordinates (x, y, z) of the positioning device and the setting angle θ, so that the determination of the dimensions of the full space and the calibration of the positioning device are automatically performed to obtain the calibration parameters of the positioning device.

It will be appreciated that once the locating device is calibrated, it can use existing triangulation algorithms to directly derive the absolute coordinates of any location point in space in that space. In addition, the absolute coordinates of an arbitrary position point in space can also be obtained by conversion between the relative coordinates and the absolute coordinates. That is, the relative coordinates of the position point in the space with respect to the positioning apparatus itself are first obtained, and then the absolute coordinates of the position point are obtained through conventional coordinate conversion.

In the above example, the procedure for calibrating a positioning device according to the invention is described by selecting three spatial feature location points. However, the invention is not limited to the implementation of three spatial feature location points. In certain implementations, only one or two spatial feature location points may be used to calibrate the pointing device. For example, when the pointing device is placed on top of a room, it may be made to have its own X-axis (e.g., the direction of the first sensor) relative to the coordinate system parallel to the X-axis of the spatial absolute coordinate system. In this case, the set angle θ of the pointing device is practically zero. At this time, the home position point of the absolute coordinate system is set to one corner of the house, that is, the absolute coordinate of the corner of the house is (0, 0, 0). The relative coordinates of the corner with respect to the pointing device can be obtained by the pointing device. Typically, as indicated above, the Z-axis coordinate of the pointing device is equal to the Z-axis coordinate value of the angle relative to the relative coordinates of the pointing device. Then, in a two-dimensional plane, according to the relative coordinates and the absolute coordinates of the corner, the X-axis coordinates and the Y-axis coordinates of the absolute coordinates of the positioning equipment can be obtained through translation transformation of a common coordinate system. Specific variations are known in the art and will not be described in detail herein.

It will be appreciated that the more spatial feature location points that are selected, the greater the number of equations that are derived from the coordinate transformation, and thus the more accurate the location parameters of the pointing device are determined in accordance with the present invention.

The above only describes the process of calibrating the positioning device in a quadrangular room. However, it should be understood that the above embodiments are not limited to the space of a quadrangular room. If the space is in other irregular shapes, three position points on the periphery of the space can be used for fitting a polygon, so that the space in other shapes can be treated like the space in a polygon.

According to another embodiment of the present invention, when a plurality of PODs are provided in a space, after one POD is calibrated according to the above method, another POD may also be calibrated. For convenience of description, the POD that has been calibrated is referred to as a first positioning apparatus (POD1), and the POD to be calibrated is referred to as a second positioning apparatus (POD 2).

Fig. 6 shows a schematic diagram for calibrating a second positioning apparatus (POD2) from a calibrated first positioning apparatus (POD1) according to another embodiment of the invention.

In fig. 6, the POD1 has been calibrated according to equation set (1). To calibrate POD2, according to this embodiment, it is necessary to first determine the coverage areas of POD1 and POD2 and ensure that the two PODs have overlapping coverage areas. As shown in fig. 6, the coverage area of POD1 is referred to as the first coverage area, while POD2 has the second coverage area, both with overlapping coverage areas. There are several ways to determine overlapping coverage areas, for example, a POD2 may be located approximately 6 meters apart, knowing that a POD has a coverage area radius of 4 meters at 3 m. Alternatively, it may be determined whether a particular location is in an overlapping coverage area by detecting whether both POD1 and POD2 are able to detect a tag at that location at the same time.

To calibrate the POD2, the absolute coordinates (x) of the POD2 in the room need to be calculated₂₀，y₂₀，z₂₀) And the angle θ of the POD2₂₀. Two location points (referred to as overlapping coverage area location points for convenience of description) are selected in the overlapping coverage area, and tags (referred to as overlapping coverage area tags for convenience of description) are respectively placed at the two selected location points, for example, to transmit ranging signals (referred to as overlapping coverage area ranging signals for convenience of description). The POD1 can thus obtain the relative coordinates of the two overlapping coverage area position points in its own coordinate system, and the absolute coordinates of the two overlapping coverage area position points after coordinate transformation are, for example, (x)₁₁，y₁₁，z₁₁) And (x)₁₂，y₁₂，z₁₂). Of course, the POD1 may also directly obtain the absolute coordinates of the two overlapping coverage area location points through triangulation algorithms. Obtaining absolute coordinates of a target object (e.g., a location point in space) by a calibrated pointing device is known in the art and will not be described herein.

At the same time, POD2 may obtain the relative coordinates of these two overlapping coverage area feature location points in its own coordinate system as, for example, (x)₂₁，y₂₁，z₂₁) And (x)₂₂，y₂₂，z₂₂). It can be seen that since the POD1 has been calibrated, the absolute coordinates of the two overlapping coverage area location points are known. This is achieved byIn addition, since the POD2 is also installed on, for example, a roof, z of the POD2₂₀＝h＝(z₁+z₂+z₃)/3. Thereby, the coordinates (x) of POD2 are compared₂₀，y₂₀，z₂₀) And an angle theta₂₀Is simplified into two-dimensional coordinates.

By conventional coordinate transformation, the absolute coordinates of POD2 in this reference space can be calculated by the following system of equations:

<math><mrow><mfenced open='{' close=''><mtable><mtr><mtd><msub><mi>x</mi><mn>21</mn></msub><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>-</mo><msub><mi>y</mi><mn>21</mn></msub><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>x</mi><mn>20</mn></msub><mo>=</mo><msub><mi>x</mi><mn>11</mn></msub></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>21</mn></msub><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>y</mi><mn>21</mn></msub><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>y</mi><mn>20</mn></msub><mo>=</mo><msub><mi>y</mi><mn>11</mn></msub></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>22</mn></msub><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>-</mo><msub><mi>y</mi><mn>22</mn></msub><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>x</mi><mn>20</mn></msub><mo>=</mo><msub><mi>x</mi><mn>12</mn></msub></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>22</mn></msub><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>y</mi><mn>22</mn></msub><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow><mo>+</mo><msub><mi>y</mi><mn>20</mn></msub><mo>=</mo><msub><mi>y</mi><mn>12</mn></msub></mtd></mtr></mtable></mfenced><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>7</mn><mo>)</mo></mrow></mrow></math>

from equation set (7), the following matrix calculation can be derived:

<math><mrow><mfenced open='[' close=']'><mtable><mtr><mtd><msub><mi>x</mi><mn>21</mn></msub></mtd><mtd><mo>-</mo><msub><mi>y</mi><mn>21</mn></msub></mtd><mtd><mn>1</mn></mtd><mtd><mn>0</mn></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>21</mn></msub></mtd><mtd><msub><mi>x</mi><mn>21</mn></msub></mtd><mtd><mn>0</mn></mtd><mtd><mn>1</mn></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>22</mn></msub></mtd><mtd><mo>-</mo><msub><mi>y</mi><mn>22</mn></msub></mtd><mtd><mn>1</mn></mtd><mtd><mn>0</mn></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>22</mn></msub></mtd><mtd><msub><mi>x</mi><mn>22</mn></msub></mtd><mtd><mn>0</mn></mtd><mtd><mn>1</mn></mtd></mtr></mtable></mfenced><mfenced open='[' close=']'><mtable><mtr><mtd><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>20</mn></msub></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>20</mn></msub></mtd></mtr></mtable></mfenced><mo>=</mo><mfenced open='[' close=']'><mtable><mtr><mtd><msub><mi>x</mi><mn>11</mn></msub></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>11</mn></msub></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>12</mn></msub></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>12</mn></msub></mtd></mtr></mtable></mfenced><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>8</mn><mo>)</mo></mrow></mrow></math>

solving the matrix can obtain the absolute coordinates of the second positioning equipment and the setting angle theta₂₀：

<math><mrow><mfenced open='[' close=']'><mtable><mtr><mtd><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mn>20</mn></msub><mo>)</mo></mrow></mtd></mtr><mtr><mtd><msub><mi>x</mi><mn>20</mn></msub></mtd></mtr><mtr><mtd><msub><mi>y</mi><mn>20</mn></msub></mtd></mtr></mtable></mfenced><mo>=</mo><msup><mrow><mo>(</mo><msup><mi>A</mi><mi>T</mi></msup><mi>A</mi><mo>)</mo></mrow><mrow><mo>-</mo><mn>1</mn></mrow></msup><msup><mi>A</mi><mi>T</mi></msup><mi>b</mi><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>9</mn><mo>)</mo></mrow></mrow></math>

Wherein,

$A=\left[\begin{array}{cccc}{x}_{21}& -y_{21}& 1& 0\\ y_{21}& x_{21}& 0& 1\\ x_{22}& -y_{22}& 1& 0\\ y_{22}& x_{22}& 0& 1\end{array}\right],b=\left[\begin{array}{c}{x}_{11}\\ y_{11}\\ x_{12}\\ {\mathrm{<figure-callout\; id="12"\; label="y"\; filenames="H2009100039532E0000021.png"\; state="\{\{state\}\}">y</figure-callout>}}_{12}\end{array}\right]$

therefore, the absolute coordinates of the POD2 to be calibrated and the setting angle thereof can be calculated, so that the calibration of the POD2 is completed, and the calibration parameters of the POD2 are obtained.

It is noted that the number of selected overlapping coverage area location points may be more than two, which will increase the number of rows of the above coefficient matrix, and the calculation procedure is the same as the above calculation procedure. Selecting more overlapping coverage area characteristic position points is beneficial to improving the positioning precision.

Still further, more PODs may be progressively targeted using the above method and based on the targeted PODs, thereby covering a larger area. And will not be described in detail herein. It should be appreciated that in the above embodiments, the procedure for calibrating a positioning device according to the invention has been described by selecting two overlap region location points. However, embodiments of the invention are not limited to two overlapping coverage area location points. In certain implementations, the positioning device may also be calibrated using only one overlapping coverage area location point. For example, when a first pointing device has been calibrated to calibrate a second pointing device, the X-axis of the second pointing device may be set to be parallel to the X-axis of the first pointing device. In this case, the setting angle of the second pointing device is the same as the device angle of the first pointing device, a known quantity. At this time, the calibrated first positioning device is used for obtaining the absolute coordinates of a position point of the overlapping coverage area, and the relative coordinates of the position point relative to the second positioning device are obtained through the second positioning device. Then, the absolute coordinates of the second positioning device can be obtained through ordinary coordinate transformation.

Accordingly, as described in conjunction with fig. 2-6, those skilled in the art can understand the concepts of relative coordinates, absolute coordinates, coordinate transformation, etc. and how to calibrate one or more positioning devices to obtain calibration parameters of the positioning devices.

The method for determining whether a calibrated pointing device in space is moving according to an embodiment of the present invention will be described in detail below. FIG. 7 shows a schematic diagram of a system 100 for determining whether a calibrated position of a device in space is moving, according to one embodiment of the present invention.

As shown in fig. 7, the system 100 includes a tag 110 capable of transmitting ranging signals, which is placed at a location point in space; a locating device 120 located in the space, wherein the locating device 120 is configured to acquire relative coordinates of the location point with respect to the locating device 120 according to the ranging signal from the tag 110; and a server 130 configured to determine whether the positioning device 120 moves according to the relative coordinates of the location point in the space with respect to the positioning device 120, the trustable absolute coordinates of the location point in the space, and the calibration parameters of the positioning device 120.

The positioning device 120 may have been calibrated in advance by using the method described in the foregoing embodiment, that is, the calibration parameters of the positioning device 120 may be obtained in advance by using the method described in the foregoing embodiment. Of course, other methods known in the art may be used to calibrate the positioning apparatus 120 in advance, i.e., obtain calibration parameters of the positioning apparatus 120. The calibration parameters may be pre-stored.

In an embodiment of the invention, the trustable absolute coordinates are reliable absolute coordinates of the location point in space. The trustable absolute coordinates of the location point can be obtained, for example, by a locating device that is calibrated and determined to have not moved.

A method for determining whether the pointing device 120 is moving according to one embodiment of the present invention is described below with reference to fig. 8.

As shown in fig. 8, at step S210, the relative coordinates of a location point in the space with respect to positioning device 120 are received; at step S220, calculating absolute coordinates of the location point in the space according to the calibration parameters of the positioning apparatus 120 and the relative coordinates; and determining whether movement of the pointing device 120 has occurred based on the trustable absolute coordinates and the calculated absolute coordinates at step S230.

The specific implementation of step 210-230 is described below.

For step 210, a location point in space may be selected and a tag placed at the location point whose trusted absolute coordinates have been obtained and stored. When it is required to detect whether positioning device 120 moves, positioning device 120 first receives the ranging signal of the tag, and obtains the relative coordinates of the location point with respect to positioning device 120 from the ranging signal.

The choice of location point is arbitrary and according to a preferred embodiment of the invention the location point may be located in the space, e.g. in a corner of a room, for ease of calculation.

Optionally, to prevent malicious behavior by an attacker, the tag may be hidden, referred to herein as a hidden tag. The term "hiding" includes, for example, implanting the tag into, for example, a wall or randomly placing the tag at any point in the space. For example, when locating device 120 is calibrated, a number of location points may be randomly selected in space, and locating device 120 calculates the trustable absolute coordinates of these location points, which are then stored. If it is suspected that the pointing device 120 has been moved, the tag may be relocated to a previous location to determine if the pointing device 120 has moved according to the embodiment shown in FIG. 8. This has the advantage that since the selection of characteristic location points is random, an attacker cannot know exactly which location points were initially selected at all and thus cannot destroy the hidden tag. In conjunction with the above description, it will be understood by those skilled in the art that the term "hidden" does not include only visual hiding, but encompasses any means by which an attacker cannot know where the tag is located.

Of course, the placement of the tag is only one embodiment, and the invention is not limited in this way, but can be measured by any other known method, for example by hand.

Then, for step 220, the absolute coordinates of the location point in space are calculated based on the calibration parameters of the positioning device 120 and the obtained relative coordinates of the positioning device 120. The process of calculating absolute coordinates is described below in conjunction with fig. 9.

Let the positioning device 120, e.g. a POD, have a calibration parameter of (x) in this space_P，y_P，z_P，θ_P) Wherein (x)_P，y_P，z_P) Is the absolute coordinate of the POD center position in the reference space and θ P is the above-mentioned calibrated POD angle, which parameters can be obtained, for example, by equations (4) - (6) above.

As shown in fig. 9, four hidden tags are set in the reference space, and the absolute coordinates calculated first are (x) respectively₁，y₁，z₁)(x₄，y₄，z₄). These four coordinates can be stored as trusted absolute coordinates. For convenience of description, the coordinates are referred to as calibration coordinates.

If it is suspected that the positioning device has been moved, the hidden tag absolute coordinates may first be calculated by the following system of equations, referred to herein as suspect absolute coordinates (x)_i’，y_i’)：

<math><mrow><mfenced open='{' close=''><mtable><mtr><mtd><msup><msub><mi>x</mi><mi>i</mi></msub><mo>&prime;</mo></msup><mo>=</mo><msub><mi>x</mi><mi>P</mi></msub><mo>+</mo><msup><msub><mi>x</mi><mi>ri</mi></msub><mo>&prime;</mo></msup><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mi>P</mi></msub><mo>)</mo></mrow><mo>-</mo><msup><msub><mi>y</mi><mi>ri</mi></msub><mo>&prime;</mo></msup><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mi>P</mi></msub><mo>)</mo></mrow></mtd></mtr><mtr><mtd><msup><msub><mi>y</mi><mi>i</mi></msub><mo>&prime;</mo></msup><mo>=</mo><msub><mi>y</mi><mi>P</mi></msub><mo>+</mo><msup><msub><mi>x</mi><mi>ri</mi></msub><mo>&prime;</mo></msup><mi>sin</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mi>P</mi></msub><mo>)</mo></mrow><mo>+</mo><msup><msub><mi>y</mi><mi>ri</mi></msub><mo>&prime;</mo></msup><mi>cos</mi><mrow><mo>(</mo><msub><mi>&theta;</mi><mi>P</mi></msub><mo>)</mo></mrow></mtd></mtr></mtable></mfenced><mi>i</mi><mo>=</mo><mn>1,2</mn><mo>,</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>,</mo><mi>n</mi><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>10</mn><mo>)</mo></mrow></mrow></math>

Wherein (x)_ri’，y_ri') is the relative coordinate of the covert label currently sensed by the locating device relative to the locating device, where r represents relative, i represents the index of the covert label, and n represents the number of covert labels. It can be seen that equation (10) is actually similar to the calculation of equation (7).

It is noted here that the calculation of the z coordinate is omitted here, since the positioning device can directly sense the z coordinate.

Since the calculation of equation (10) is at the nominal coordinates (x) of the pointing device 120_P，y_P，z_P) Calculated for reference, so that if the locating device 120 is moved without the tag being moved, there will be an inconsistency between the suspect absolute coordinates of the calculated tag and the previously stored trusted absolute coordinates, whereas if the locating device 120 is not moved, the suspect absolute coordinates will remain consistent with the previously stored trusted absolute coordinates.

After calculating the suspicious absolute coordinates (x) of the hidden label_i’，y_i') may be determined whether the pointing device is moving in a number of ways.

For example, optionally, the error of the calculated absolute coordinates and the trustable absolute coordinates is counted, and if the error is larger than a predetermined threshold, it is determined that the positioning device has moved.

The error described herein includes various criteria such as directly calculating the average of the differences between the suspect absolute coordinates and the trustable absolute coordinates, calculating the mean square error between the suspect absolute coordinates and the trustable absolute coordinates, and calculating the covariance between the two, etc. For example, the process of calculating the mean square error is shown in equation (11):

<math><mrow><mi>&delta;</mi><mo>=</mo><munderover><mi>&Sigma;</mi><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></munderover><mfrac><msqrt><msup><mrow><mo>(</mo><msup><msub><mi>x</mi><mi>i</mi></msub><mo>&prime;</mo></msup><mo>-</mo><msub><mi>x</mi><mi>i</mi></msub><mo>)</mo></mrow><mn>2</mn></msup><mo>+</mo><msup><mrow><mo>(</mo><msup><msub><mi>y</mi><mi>i</mi></msub><mo>&prime;</mo></msup><mo>-</mo><msub><mi>y</mi><mi>i</mi></msub><mo>)</mo></mrow><mn>2</mn></msup></msqrt><mi>n</mi></mfrac><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>11</mn><mo>)</mo></mrow></mrow></math>

it is noted that equation (11) only shows the two-dimensional case, since in most cases the height of the positioning device does not change, and therefore the calculation of the most z-coordinate can be omitted. Of course, it is easy for those skilled in the art to extend this equation (11) into three dimensions.

It should be noted that the selection of the threshold value may be determined according to actual needs, and the smaller the threshold value, the higher the sensitivity of the method, but the slight interference may be considered as the movement of the positioning device. On the other hand, the larger the threshold, the lower the sensitivity of the method and the possible motion attacks may be missed.

It is noted that, in addition to the above judgment criteria, other parameters may be adopted as the judgment criteria. Alternatively, an average value may be employed as the judgment criterion. For example, the difference between the suspicious absolute coordinates and the trustable absolute coordinates of a plurality of location points may be summed and then averaged as a determination criterion. Further alternatively, the determination may be made in a weighted manner. The weighted object may be a parameter, such as an x-coordinate, or a pointing device. For example, in the case of multiple positioning devices, certain positioning devices may be given greater weight, and even if the positioning devices slightly move, the movement may have a significant effect on the MSE or other determination criteria, so that the movement determination for the certain positioning devices is more sensitive.

In view of the above description, the present invention only provides some judgment criteria by way of example, but the present invention is not limited to these judgment criteria, and any method known in the art that can reflect the fluctuation situation of data can be used.

According to another embodiment of the present invention, it is also possible to determine whether the pointing device is moved by calculating exactly the amount of movement of the pointing device. A method of determining whether the pointing device 120 is moving according to another embodiment of the present invention is described below with reference to fig. 10.

As shown in fig. 10, at step S310, the relative coordinates of the location point in the space with respect to the positioning device are received; at step S320, receiving the trusted absolute coordinates of the location point and calibration parameters of the positioning device; step S330, calculating the movement amount of the positioning equipment through coordinate transformation according to the relative coordinate, the trustable absolute coordinate and the calibration parameter of the positioning equipment, and at step S340, if the movement amount is larger than a preset threshold value, determining that the positioning equipment moves. The implementation of steps S310-S340 is described in detail below in conjunction with fig. 11 and 12.

It will be appreciated that as the positioning apparatus, for example the POD, moves, its originally calibrated parameters, including coordinates and angles, may change, as shown in figure 11. The POD source is providedThe orientation parameter calibrated first is (x)_P，y_P，z_P，θ_P) And the orientation parameter after the change of the orientation parameter is (X)_P+Δx_P，y_P+Δy_P，Z_P+ΔZ_P，θ_P+Δθ_P) Then if the offset (Δ x) can be calculated_P，Δy_P，Δz_P，Δθ_P) It may be determined whether the positioning device is moving.

Here, the pairs Δ z are still ignored_POf course, those skilled in the art can easily extend to three-dimensional calculations.

For three unknowns, at least three equations are required to solve for them, and since each location point can give two equations, at least two location points are required to determine the offset of the positioning device.

Let it be assumed that N location points, or N hidden tags, are selected and that the initial absolute coordinates, i.e. the trusted absolute coordinates, of these feature location points can be expressed as (x) respectively₁，y₁)、(x₂，y₂)...(x_N，y_N). Accordingly, if movement of the positioning apparatus is suspected, the relative coordinates (x) of the N position points with respect to the positioning apparatus can be obtained using the positioning apparatus_r1，y_r1)、(x_r2，y_r2)...(x_rN，y_rN)。

By coordinate transformation, the offset (Δ x) of the orientation parameter of the positioning device can be calculated_P，Δy_P，Δz_P，Δθ_P). The specific calculation process is shown as equation set (12):

it can be seen that the system of equations (12) has a total of 2N equationsEquation, therefore, when N is equal to 2, the offset amount (Δ x) can be calculated_P，Δy_P，Δθ_P)。

Similarly, according to an example of the present invention, it may be determined whether the positioning device is moving by comparing the offset with a certain threshold, as with an error, such as MSE, as the decision criterion. An offset that exceeds the particular threshold is considered to have moved.

It should be understood that in the case where the pointing device is moved, if it is determined that the set angle of the pointing device is not changed, the amount of movement of the pointing device can be determined through one location point.

In the above, the trustable absolute coordinates are reliable absolute coordinates in which at least one position point is stored in advance. According to another embodiment of the invention, the trusted absolute coordinates may be obtained by another positioning device that has been determined to have not moved, having an overlapping coverage area with the positioning device 120. That is, the system of FIG. 7 may also include another positioning system that has been calibrated and confirmed that no movement has occurred.

According to this embodiment of the invention, the location point is in the overlapping coverage area of the pointing device 120 and the other pointing device, which has been calibrated and determined to be unmoved, and wherein the trustable absolute coordinates of the location point are obtainable by the other pointing device.

A specific implementation of the above embodiment is described below in conjunction with fig. 12.

As shown in fig. 12, two positioning devices with overlapping coverage areas are shown, such as POD1 and POD2, where POD1 is assumed to have been calibrated and determined to be unmoved. At this time, since the POD1 has been calibrated, it can obtain the absolute coordinates of any position point within the footprint of the POD1 directly or indirectly through coordinate transformation, and the absolute coordinates are trusted.

At this time, in order to determine whether POD2 has moved, a position point may be selected in the overlapping coverage area of POD1 and POD2, POD1 acquires absolute coordinates of the position point as trusted absolute coordinates, and POD2 acquires relative coordinates of the position point with respect to the POD2, so that whether POD2 has moved or not may be determined using the method shown in fig. 8 and 10, based on the absolute coordinates determined by POD1, the relative coordinates of the position point with respect to POD2, and the calibration parameters of POD2 obtained in advance.

Preferably, whether the POD2 has moved is calculated by selecting multiple location points in the overlapping coverage area. This can improve the judgment accuracy.

Methods of selecting multiple location points are various, for example, by simultaneously placing multiple tags in the overlapping coverage area so that POD1 and POD2 can receive the coordinates of the characteristic location points represented by these tags. Preferably, according to this embodiment, this object is achieved by using a mobile tag, i.e. a tag that is mobile in the overlapping coverage area. As the mobile tag moves, a series of data reflecting the characteristic location points experienced by the mobile tag may be obtained.

Each POD can obtain a tuple (POD) of the mobile tag relative to itself, provided that the mobile tag moves in an overlapping coverage area_ID，rpos，t]Where podID is the index of the POD, rpos is the relative position of the mobile tag with respect to the POD, and t is the current time. Over time, a sequence of this tuple can be obtained, [ pod ]₁，rpos₁₁，t₁]，[pod₂，rpos₂₁，t₁]，[pod₁，rpos₁₂，t₂]，[pod₂，rpos₂₂，t₂]，...，[pod₁，rpos_1k，t_k]，[pod₂，rpos_2k，t_k]Where k denotes the number of time position points, the tuple [ pod ]₁，rpos_1k，t_k]Is shown at t_kAt the moment the mobile tag is relative toRelative position rpos of POD1_1kSimilarly, the tuple [ pod ]₂，rpos_2k，t_k]Is shown at t_kTime of day the relative position rpos of the mobile tag with respect to the POD2_2k. It can thus be seen that for two PODs, a total of 2k tuples are available. Further, from the above description, it can be appreciated that since POD1 is determined to have not moved, the location of the move tag determined by the tuple to which POD1 corresponds is trusted.

Let (x)_jrt’，y_irt') is the relative coordinate of the moving tag with respect to the jth POD at time t, where r represents relative. Thus, for each POD, the absolute coordinates (x) of the mobile tag_jt，y_jt) Can be obtained by equation set (13):

wherein (x)_Pj，y_Pj，θ_Pj) Is the original orientation parameter of the jth POD which has been calibrated, and can be stored in advance. It will be appreciated that the calculation of the z coordinate is omitted here and can be readily extended to three dimensions by those skilled in the art if desired.

The trustable absolute coordinates that can be calculated from the trustable POD1 given these location points are (x)_1t，y_1t) And the suspicious absolute coordinates of the corresponding feature location point calculated by the POD2 are (x)_2t’，y_2t'). Then, the Mean Square Error (MSE) between them may be calculated, for example, by equation (14) to determine whether POD2 has moved:

<math><mrow><mi>&delta;</mi><mo>=</mo><munderover><mi>&Sigma;</mi><mrow><mi>t</mi><mo>=</mo><mn>1</mn></mrow><mi>k</mi></munderover><mfrac><msqrt><msup><mrow><mo>(</mo><msup><msub><mi>x</mi><mrow><mn>2</mn><mi>t</mi></mrow></msub><mo>&prime;</mo></msup><mo>-</mo><msub><mi>x</mi><mrow><mn>1</mn><mi>t</mi></mrow></msub><mo>)</mo></mrow><mn>2</mn></msup><mo>+</mo><msup><mrow><mo>(</mo><msup><msub><mi>y</mi><mrow><mn>2</mn><mi>t</mi></mrow></msub><mo>&prime;</mo></msup><mo>-</mo><msub><mi>y</mi><mrow><mn>1</mn><mi>t</mi></mrow></msub><mo>)</mo></mrow><mn>2</mn></msup></msqrt><mi>k</mi></mfrac><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>14</mn><mo>)</mo></mrow></mrow></math>

after POD2 is determined to be secure, POD3, POD4 (not shown), and the like may be determined in sequence until all PODs are determined.

Alternatively, in the case of multiple PODs, the method described in equation set (12) may also be employed to determine the specific offset to which a suspect POD has moved, in which case the various coordinates of the desired location point are provided by moving the tag, and will not be described in detail herein.

According to yet another embodiment of the invention, the user may also be alerted when it is detected that the positioning device is moved. The manner of the alarm includes, but is not limited to, an audible alarm, a flashing alarm signal, and the like. The user may also be provided with orientation parameters specific to each pointing device graphically or in a table via the display, so that the user can determine whether the pointing device has been moved based on these orientation parameters.

In addition, according to another embodiment of the present invention, the method shown in fig. 8 and the method shown in fig. 10 are combined. That is, it is first determined whether the positioning device is moving according to the method shown in fig. 8. In the case where it is determined that the pointing device is moving, the amount of movement of the pointing device in space is determined according to the method shown in FIG. 10. Optionally, the positioning apparatus is recalibrated based on the obtained amount of movement.

Further, according to another embodiment of the present invention, as shown in fig. 13, there is provided an apparatus 400 for determining whether a positioning apparatus in a space is moved, the apparatus 400 may include: receiving means 410 for receiving relative coordinates of a location point in the space with respect to the positioning apparatus, calibration parameters of the positioning apparatus, and trustable absolute coordinates of the location point in the space; and a determining device 420, configured to determine whether the positioning apparatus moves according to the relative coordinate, the calibration parameter, and the trustable absolute coordinate.

As shown in fig. 14, in an example, the determining means 420 may include: absolute coordinate calculation means 510 for calculating the absolute coordinate of the position point in the space according to the calibration parameter and the relative coordinate; error statistics means 520 for counting the errors of said calculated absolute coordinates and said trustable absolute coordinates, and determining means 530 for determining that said positioning device is moving if said errors are larger than a predetermined threshold.

As shown in fig. 15, in another example, the determining means 420 may include: movement amount calculating means 610 for calculating a movement amount of the positioning device according to the relative coordinates, the calibration parameters and the trustable absolute coordinates, and determining means 620 for determining that the positioning device is moved if the movement amount is larger than a predetermined threshold.

According to another example of the present invention, the example shown in fig. 14 and the example shown in fig. 15 may be combined. That is, it is first determined whether the positioning apparatus is moved according to the example shown in fig. 14. In the case where it is determined that the pointing device has moved, the amount of movement of the pointing device in space is determined in accordance with the example shown in fig. 15. Optionally, the positioning apparatus is recalibrated based on the obtained amount of movement.

In one example of the present embodiment, the position point is a fixed point whose absolute coordinates have been determined in advance; and a tag capable of transmitting a ranging signal is placed at the location point, and the relative coordinates are acquired by the positioning device according to the ranging signal from the tag. Optionally, the tag may be hidden.

In one example of this embodiment, the location points are randomly in an overlapping coverage area of the positioning device and another positioning device that has been calibrated and determined to be not moving. A tag capable of transmitting a ranging signal is placed at the location point, the relative coordinates are obtained by the locating device from the ranging signal from the tag, and the trusted absolute coordinates are obtained by the other locating device from the ranging signal from the tag. Optionally, the tag is movable in the overlapping coverage area.

According to another example of the present invention, the example shown in fig. 14 and the example shown in fig. 15 may be combined. That is, it is first determined whether the positioning apparatus is moved according to the example shown in fig. 14. In the case where it is determined that the pointing device has moved, the amount of movement of the pointing device in space is determined in accordance with the example shown in fig. 15. Optionally, the positioning apparatus is recalibrated based on the obtained amount of movement.

It is noted that the device 400 may be integrated in the positioning device or may be implemented in a remote server or computer connected to the positioning device via a communication link. Moreover, the device 400 may be implemented in various ways, such as hardware, software, firmware, and combinations thereof.

The methods and apparatus of the present invention may be implemented in software, hardware, or a combination of software and hardware. The hardware portion may be implemented using dedicated logic; the software portions may be stored in a memory for execution by a suitable instruction execution system, such as a microprocessor, Personal Computer (PC), or mainframe.

The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art.

Therefore, the embodiments were chosen and described in order to best explain the principles of the invention and its practical application, and to enable others of ordinary skill in the art to understand the invention for various modifications and various embodiments with the understanding that they are within the scope of the invention as defined by the appended claims.

Claims (21)

1. A system, comprising:

a tag capable of transmitting a ranging signal;

the positioning equipment is configured to obtain the relative coordinates of the position point where the label is located relative to the positioning equipment according to the ranging signals from the label; and

the server is configured to judge whether the positioning equipment moves according to the relative coordinates, the calibration parameters of the positioning equipment and the credible absolute coordinates of the position point in the space.

2. The system of claim 1, wherein the server is further configured to:

calculating the absolute coordinates of the position point in the space according to the relative coordinates and the calibration parameters;

counting the error of said calculated absolute coordinates from said trustable absolute coordinates, an

Determining that the positioning device is moving if the error is greater than a predetermined threshold.

3. The system of claim 1 or 2, wherein the server is further configured to:

calculating the amount of movement of the positioning device in the space based on the relative coordinates, the calibration parameters and the trustable absolute coordinates, an

If the amount of movement is greater than a predetermined threshold, it is determined that the pointing device has moved.

4. The system of claim 3, wherein the positioning apparatus is recalibrated as a function of the amount of movement.

5. The system of claim 1, wherein the calibration parameters include absolute coordinates and set angles that the positioning apparatus has calibrated in the space.

6. The system of claim 1, wherein the location point is a fixed point whose absolute coordinates have been determined in advance.

7. The system of claim 1, further comprising another locating device that has been calibrated and determined to be unmoved, wherein the location points are randomly in an overlapping coverage area of the locating device and another locating device, and the trustable absolute coordinates are obtained by the other locating device from ranging signals from the tags.

8. A method for determining whether a positioning device in space is moving, comprising:

receiving relative coordinates of a location point in the space relative to the positioning device, calibration parameters of the positioning device, and trusted absolute coordinates of the location point in the space; and

and judging whether the positioning equipment moves or not according to the relative coordinate, the calibration parameter and the dependable absolute coordinate.

9. The method of claim 8, wherein determining whether the positioning device is moving further comprises:

calculating the absolute coordinates of the position point in the space according to the calibration parameters and the relative coordinates;

counting the error of said calculated absolute coordinates from said trustable absolute coordinates, an

Determining that the positioning device is moving if the error is greater than a predetermined threshold.

10. The method of claim 8 or 9, wherein determining whether the positioning device is moving further comprises:

calculating the movement of the positioning device according to the relative coordinates, the calibration parameters and the trustable absolute coordinates, an

If the amount of movement is greater than a predetermined threshold, it is determined that the pointing device has moved.

11. The method of claim 10, wherein the positioning apparatus is recalibrated as a function of the amount of movement.

12. The method of claim 8, wherein the calibration parameters include absolute coordinates and set angles of the positioning device calibrated in the space.

13. The method of claim 8, wherein the location point is a fixed point whose absolute coordinates have been determined in advance.

14. The method of claim 13, wherein a tag capable of transmitting a ranging signal is placed at the location point, and the relative coordinates are obtained by the positioning device from the ranging signal from the tag.

15. The method of claim 8, wherein,

the location points are randomly in an overlapping coverage area of the positioning device and another positioning device, the other positioning device having been calibrated and determined to be not moving,

a tag capable of transmitting a ranging signal is placed at the location point,

the relative coordinates are obtained by the positioning device from ranging signals from the tags, an

The trusted absolute coordinates are obtained by the other locating device from ranging signals from the tag.

16. An apparatus for determining whether a positioning device in a space is moving, comprising:

receiving means, configured to receive relative coordinates of a location point in the space with respect to the positioning apparatus, calibration parameters of the positioning apparatus, and trustable absolute coordinates of the location point in the space; and

and the judging device is used for judging whether the positioning equipment moves or not according to the relative coordinate, the calibration parameter and the dependable absolute coordinate.

17. The apparatus of claim 16, wherein the determining means further comprises:

absolute coordinate calculation means for calculating an absolute coordinate of the position point in the space based on the calibration parameter and the relative coordinate;

error counting means for counting the error of said calculated absolute coordinates and said trustable absolute coordinates, an

First determining means for determining that the positioning device is moving if the error is greater than a predetermined threshold.

18. The apparatus according to claim 16 or 17, wherein the determining means further comprises:

a movement amount calculation device for calculating a movement amount of the positioning apparatus based on the relative coordinates, the calibration parameters and the trustable absolute coordinates, an

Second determining means for determining that the positioning device has moved if the amount of movement is greater than a predetermined threshold.

19. The apparatus of claim 18, wherein the positioning apparatus is recalibrated in accordance with the amount of movement.

20. The apparatus of claim 16, wherein the location point is a fixed point whose absolute coordinates have been determined in advance; and a tag capable of transmitting a ranging signal is placed at the location point, and the relative coordinates are acquired by the positioning device according to the ranging signal from the tag.

21. The apparatus of claim 16, wherein,

the location points are randomly in an overlapping coverage area of the positioning device and another positioning device, the other positioning device having been calibrated and determined to be not moving,

a tag capable of transmitting a ranging signal is placed at the location point,

the relative coordinates are obtained by the positioning device from ranging signals from the tags, an

The trusted absolute coordinates are obtained by the other locating device from ranging signals from the tag.

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