CA2958759A1 - Enhanced positioning method for moving target in mine shaft based on witness nodes under internet of things architecture - Google Patents
Enhanced positioning method for moving target in mine shaft based on witness nodes under internet of things architecture Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/02—Services making use of location information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/02—Services making use of location information
- H04W4/029—Location-based management or tracking services
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/12—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
Abstract
An enhanced positioning method for a moving target in a mine shaft based on witness nodes under an Internet of Things architecture, which belongs to an enhanced positioning method for a moving target in a mine shaft. A moving target moves in a roadway, and is positioned by an existing underground positioning system to obtain an initial positioning coordinate point tp(i); then, the initial positioning coordinate point tp(i) is projected onto a roadway midline to obtain a projection point tp'(i), and an Internet of things management and control platform is used for searching for a sensing node of which the distance from the projection point tp'(i) is within a maximal communication distance range; and finally, the sensing node is used as a witness node, and the obtained initial positioning coordinate point is corrected by means of an enhanced positioning method based on a witness node, so as to enhance the positioning precision of the moving target. The method realizes the effective combination of a positioning system and a sensing node under the Internet of Things architecture, realizes optimization and upgrading of the system without changing the original underground positioning system, and improves the positioning precision of the moving target, thereby having very good practicability and usability.
Description
ENHANCED POSITIONING METHOD FOR MOVING TARGET IN MINE SHAFT
BASED ON WITNESS NODES UNDER INTERNET OF THINGS ARCHITECTURE
Field of the Invention The present invention relates to an enhanced positioning method for a moving target in a mine shaft, in particular to an enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture.
Background Art In the special environment in a coal mine shaft, severe non-line of sight and multi-path fading phenomena exist in wireless signal propagation, and constrain the positioning accuracy of conventional positioning techniques when used in the shaft.
Positioning algorithms can be classified into ranging-based algorithms and non-ranging-based algorithms, depending on whether range measurement is required in the positioning process.
Though non-ranging-based algorithms, such as centroid algorithm, dv-hop algorithm, etc., are simple to implement, these algorithms have poor positioning accuracy, and most algorithms are not suitable for use in long and narrow roadway environments in mine shafts.
Ranging-based algorithms are usually applied for positioning in coal mine shafts, wherein, RSSI-based positioning algorithms are applied most widely owing to their advantages, such as simple principle, and easy hardware implementation, etc. However, since the signal fading in roadways in coal mines are very irregular, it is difficult to set up an appropriate signal attenuation model;
consequently, RSSI-based positioning algorithms don't have high accuracy, and the positioning accuracy varies with time; other common ranging-based algorithms, such as DOA
and TOA, etc., requires the cooperation of high-precision hardware equipment, and their positioning accuracy is not ideal or the cost is high owing to the influences of a variety of conditions.
As can be seen, mine shaft positioning systems solely based on existing positioning algorithms can't meet the requirement for positioning accuracy of production safety in mine shafts. As the Internet of Things for mines is constructed and developed, a large quantity of sensor nodes that have different functions will be deployed in coal mine shafts, to sense, monitor, and pre-alarm, etc., in real time for coal mine environments, production equipment, and production personnel.
Under the Internet of Things architecture, it is a basic function to realize thing-thing interconnection and information communication between different nodes, so that those sensor nodes can provide auxiliary services for positioning systems; in addition, an Internet of Things management and control platform on the ground manages the equipments of the entire mine shaft, the mounting positions of these equipments and sensors are stored in a database, and the platform can coordinate the nodes that don't belong to the positioning system to provide assistance for positioning in shaft.
Contents of the Invention The object of the present invention is to provide an enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture, so as to improve the positioning accuracy without replacing the existing positioning system.
The object of the present invention is attained as follows: the enhanced positioning method for a moving target comprises: positioning a moving target with an existing mine shaft positioning system when the moving target moves in a roadway, and obtaining an initial positioning coordinate point tp(i); then, projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tpt(i), and utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distance bwtween corresponding sensor node and the projection point tpi(i) is within the range of a maximum communication distance; finally, using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target; specifically, the steps are as follows:
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
BASED ON WITNESS NODES UNDER INTERNET OF THINGS ARCHITECTURE
Field of the Invention The present invention relates to an enhanced positioning method for a moving target in a mine shaft, in particular to an enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture.
Background Art In the special environment in a coal mine shaft, severe non-line of sight and multi-path fading phenomena exist in wireless signal propagation, and constrain the positioning accuracy of conventional positioning techniques when used in the shaft.
Positioning algorithms can be classified into ranging-based algorithms and non-ranging-based algorithms, depending on whether range measurement is required in the positioning process.
Though non-ranging-based algorithms, such as centroid algorithm, dv-hop algorithm, etc., are simple to implement, these algorithms have poor positioning accuracy, and most algorithms are not suitable for use in long and narrow roadway environments in mine shafts.
Ranging-based algorithms are usually applied for positioning in coal mine shafts, wherein, RSSI-based positioning algorithms are applied most widely owing to their advantages, such as simple principle, and easy hardware implementation, etc. However, since the signal fading in roadways in coal mines are very irregular, it is difficult to set up an appropriate signal attenuation model;
consequently, RSSI-based positioning algorithms don't have high accuracy, and the positioning accuracy varies with time; other common ranging-based algorithms, such as DOA
and TOA, etc., requires the cooperation of high-precision hardware equipment, and their positioning accuracy is not ideal or the cost is high owing to the influences of a variety of conditions.
As can be seen, mine shaft positioning systems solely based on existing positioning algorithms can't meet the requirement for positioning accuracy of production safety in mine shafts. As the Internet of Things for mines is constructed and developed, a large quantity of sensor nodes that have different functions will be deployed in coal mine shafts, to sense, monitor, and pre-alarm, etc., in real time for coal mine environments, production equipment, and production personnel.
Under the Internet of Things architecture, it is a basic function to realize thing-thing interconnection and information communication between different nodes, so that those sensor nodes can provide auxiliary services for positioning systems; in addition, an Internet of Things management and control platform on the ground manages the equipments of the entire mine shaft, the mounting positions of these equipments and sensors are stored in a database, and the platform can coordinate the nodes that don't belong to the positioning system to provide assistance for positioning in shaft.
Contents of the Invention The object of the present invention is to provide an enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture, so as to improve the positioning accuracy without replacing the existing positioning system.
The object of the present invention is attained as follows: the enhanced positioning method for a moving target comprises: positioning a moving target with an existing mine shaft positioning system when the moving target moves in a roadway, and obtaining an initial positioning coordinate point tp(i); then, projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tpt(i), and utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distance bwtween corresponding sensor node and the projection point tpi(i) is within the range of a maximum communication distance; finally, using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target; specifically, the steps are as follows:
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
(2) projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tpr(i);
(3) obtaining a maximum search radius dõkõ, of sensor node, when a maximum transmitting power Põ of the sensor node is known;
(4) utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distances between the corresponding sensor node and the projection point is within the range of a maximum communication distance (i.e., the maximum search radius dõ,õx), and logging the number n of the sensor nodes and the coordinates of the sensor nodes;
(5) using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes, to obtain a final positioning coordinate point rp(i).
The enhanced positioning method based on witness node comprises the following steps:
=
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(1) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step 1 is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and sp(2) respectively, and their coordinates are (x,/, y,i) and (xo, yo);
b. if n>=2, two sensor nodes that are at the nearest distances to tp'(i) are used as witness nodes, the two witness nodes are denoted as sp1(1) and sp42) respectively, and their coordinates are (xii, ya) and (2c,2, y,2) respectively;
step 2: calculating the distances d,(1) and d1(2) from the projection point tp'(i) to the witness nodes sp,(1) and sp1(2) respectively; calculating a line ii passing through sp,(i) and sp,(2):
Xi¨Yr xi1)+Ya xit , a line /2 passing through sp1(1) and parallel to the center line of the roadway, and a line /3 passing through sp,(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to ro meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius da, searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d,G), j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by ro m in each time, i.e., iteratively searching for the moving target in radius (ddi) -countXr0), till the witness nodes can't find the moving target or a condition (d,C) m X ro < ro) is met in the 'nth search cycle, where, count---,1, m; d10) > niX ro; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the M(h search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp,C), i.e., within a range constituted by annuli (1) and (2); in that case, the following formula (I) is met:
R2 = (x¨ x,1)2 ty¨ yv ( r = (x- x, j)2 +(y¨v)2 r2 S(x¨xii)2 +(y¨ y11)2 R2 ( ) where, R=di(j) - (m - 1) X ro, r = c/a - m X ro;
b. if the criterion (di(j) - m X ro < ro) is met, it indicates that the moving target is within a range of a minimum circle in radius (61,0 - m X ro) centering on sp,a); in that case, the following formula (2) is met:
(X¨ x) )1 +(v¨ y0)2 rz (2) where, r = (14)- mX ro;
case 2: if the witness nodes can't find the moving target within the search area in radius dia), adjusting the transmitting power so that the search radius is outwardly expanded by ro meter in each time, i.e., iteratively searching for the moving target in radius (diG) +
countXro), till the witness nodes finds the moving target in the /nth search cycle or no witness node is found within the range dmax, where, count=1, m; (d,a) + m x ro) < m is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the Mrh search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
= ( x )2. + ( y ¨ yt, )2 r = (x ¨ + ( y y; I )2 (i) r'2 (x¨ x)2 -1- (y ¨ y R.2 ( 3 ) where, R'=dia) + rriX ro, e=c11(j) 4- (M-i) X ro;
b. if no witness node is found within the range clõ,, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d,(j)+mxr) >dõ,õ ( 4) step 4: correcting the initial positioning point tp(i) based on the two witness nodes:
'after iterative search is carried out for sp,(1) and sp,(2), analyzing the types of sp,(1) and sp,(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp,(1) and sp,(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp,(1) and sp1(2) belongs to the type a in the case 1 and the other of sp1(1) and sp,(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius dõ,õ if there is an intersection region at a side, the area scope of the moving target can be determined, and the line 12 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is = closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp,(2) and outside of a circle centering on sp41) in radius dõ,, rp'(i) can be calculated in the same way;
(3) in other cases except the above-mentioned cases, the moving target is within an intersection area centering on sp,(1) and sp,(2), and the line 1, has two intersecting points with the boundary of the intersection area; in that case, calculating a middle point rp'(i) between the two intersecting points; if there is no intersection between the search result areas of spi(1) and sp,(2), an inner arc in a result annular area at the right side of the left witness node and an inner arc in a result annular area at the left side of the right witness node are taken, the line // has one intersecting point with the two arcs respectively, and a middle point rp'(i) between the two intersecting points is calculated;
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i).
Beneficial effects: With the technical solution described above, the enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture in the present invention positions a moving target with a mine shaft positioning system when the moving target moves in a roadway, so as to obtain an initial positioning coordinate point tp(i); then, projects the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i), and utilizes an Internet of Things management and control platform to search for sensor nodes wherein the distance between the corresponding sensor node and the projection point tp1(i) is within the range of a maximum communication distance; finally, uses the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target.
Under the guideline of Internet of Things architecture, an initial positioning value is provided for =
the moving target by an existing positioning system. In view that the preliminary positioning result may not be accurate, other nodes that know the accurate positions thereof are required as witnesses to prove whether the moving target is at the position obtained in the preliminary positioning result; accordingly, the nodes that can provide proof are witness nodes. Utilizing these sensor nodes as witness nodes, whether the positioning result obtained with the positioning system is accurate or not is judged. If the positioning accuracy is low, operating commands are sent via an Internet of Things management and control platform on the ground to the witness nodes, so as to correct the positioning result and improve the positioning accuracy.
Advantages: Under Internet of Things architecture, the method provided in the present invention effectively incorporates a positioning system and sensor nodes, realizes system optimization and upgrade without changing the existing mine shaft positioning system, so as to improve the positioning accuracy of the moving target. The method provided in the present invention has high practicability and high usability.
Description of the Drawings Fig. 1 is a flow chart of the entire algorithm in the present invention;
Fig. 2 is a schematic diagram of the enhanced algorithm in the present invention, when the nearest witness node and the second nearest witness node finally can find and can't find the moving target;
Fig. 3 is a schematic diagram of the enhanced algorithm in the present invention, when the nearest witness node and the second nearest witness node finally can't find and can find the moving target;
Fig. 4 is a partial schematic diagram of the enhanced algorithm in the present invention, in the case that both witness nodes can finally find the moving target.
Embodiments Hereunder an example of the present invention will be further described with reference to the accompanying drawings.
The enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture comprises: positioning a moving target with an existing mine shaft positioning system when the moving target moves in a roadway, and obtaining an initial positioning coordinate point tp(i); then, projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i), and utilizing an Internet of Things management and control platform to search for sensor nodes wherein the
The enhanced positioning method based on witness node comprises the following steps:
=
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(1) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step 1 is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and sp(2) respectively, and their coordinates are (x,/, y,i) and (xo, yo);
b. if n>=2, two sensor nodes that are at the nearest distances to tp'(i) are used as witness nodes, the two witness nodes are denoted as sp1(1) and sp42) respectively, and their coordinates are (xii, ya) and (2c,2, y,2) respectively;
step 2: calculating the distances d,(1) and d1(2) from the projection point tp'(i) to the witness nodes sp,(1) and sp1(2) respectively; calculating a line ii passing through sp,(i) and sp,(2):
Xi¨Yr xi1)+Ya xit , a line /2 passing through sp1(1) and parallel to the center line of the roadway, and a line /3 passing through sp,(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to ro meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius da, searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d,G), j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by ro m in each time, i.e., iteratively searching for the moving target in radius (ddi) -countXr0), till the witness nodes can't find the moving target or a condition (d,C) m X ro < ro) is met in the 'nth search cycle, where, count---,1, m; d10) > niX ro; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the M(h search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp,C), i.e., within a range constituted by annuli (1) and (2); in that case, the following formula (I) is met:
R2 = (x¨ x,1)2 ty¨ yv ( r = (x- x, j)2 +(y¨v)2 r2 S(x¨xii)2 +(y¨ y11)2 R2 ( ) where, R=di(j) - (m - 1) X ro, r = c/a - m X ro;
b. if the criterion (di(j) - m X ro < ro) is met, it indicates that the moving target is within a range of a minimum circle in radius (61,0 - m X ro) centering on sp,a); in that case, the following formula (2) is met:
(X¨ x) )1 +(v¨ y0)2 rz (2) where, r = (14)- mX ro;
case 2: if the witness nodes can't find the moving target within the search area in radius dia), adjusting the transmitting power so that the search radius is outwardly expanded by ro meter in each time, i.e., iteratively searching for the moving target in radius (diG) +
countXro), till the witness nodes finds the moving target in the /nth search cycle or no witness node is found within the range dmax, where, count=1, m; (d,a) + m x ro) < m is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the Mrh search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
= ( x )2. + ( y ¨ yt, )2 r = (x ¨ + ( y y; I )2 (i) r'2 (x¨ x)2 -1- (y ¨ y R.2 ( 3 ) where, R'=dia) + rriX ro, e=c11(j) 4- (M-i) X ro;
b. if no witness node is found within the range clõ,, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d,(j)+mxr) >dõ,õ ( 4) step 4: correcting the initial positioning point tp(i) based on the two witness nodes:
'after iterative search is carried out for sp,(1) and sp,(2), analyzing the types of sp,(1) and sp,(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp,(1) and sp,(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp,(1) and sp1(2) belongs to the type a in the case 1 and the other of sp1(1) and sp,(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius dõ,õ if there is an intersection region at a side, the area scope of the moving target can be determined, and the line 12 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is = closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp,(2) and outside of a circle centering on sp41) in radius dõ,, rp'(i) can be calculated in the same way;
(3) in other cases except the above-mentioned cases, the moving target is within an intersection area centering on sp,(1) and sp,(2), and the line 1, has two intersecting points with the boundary of the intersection area; in that case, calculating a middle point rp'(i) between the two intersecting points; if there is no intersection between the search result areas of spi(1) and sp,(2), an inner arc in a result annular area at the right side of the left witness node and an inner arc in a result annular area at the left side of the right witness node are taken, the line // has one intersecting point with the two arcs respectively, and a middle point rp'(i) between the two intersecting points is calculated;
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i).
Beneficial effects: With the technical solution described above, the enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture in the present invention positions a moving target with a mine shaft positioning system when the moving target moves in a roadway, so as to obtain an initial positioning coordinate point tp(i); then, projects the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i), and utilizes an Internet of Things management and control platform to search for sensor nodes wherein the distance between the corresponding sensor node and the projection point tp1(i) is within the range of a maximum communication distance; finally, uses the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target.
Under the guideline of Internet of Things architecture, an initial positioning value is provided for =
the moving target by an existing positioning system. In view that the preliminary positioning result may not be accurate, other nodes that know the accurate positions thereof are required as witnesses to prove whether the moving target is at the position obtained in the preliminary positioning result; accordingly, the nodes that can provide proof are witness nodes. Utilizing these sensor nodes as witness nodes, whether the positioning result obtained with the positioning system is accurate or not is judged. If the positioning accuracy is low, operating commands are sent via an Internet of Things management and control platform on the ground to the witness nodes, so as to correct the positioning result and improve the positioning accuracy.
Advantages: Under Internet of Things architecture, the method provided in the present invention effectively incorporates a positioning system and sensor nodes, realizes system optimization and upgrade without changing the existing mine shaft positioning system, so as to improve the positioning accuracy of the moving target. The method provided in the present invention has high practicability and high usability.
Description of the Drawings Fig. 1 is a flow chart of the entire algorithm in the present invention;
Fig. 2 is a schematic diagram of the enhanced algorithm in the present invention, when the nearest witness node and the second nearest witness node finally can find and can't find the moving target;
Fig. 3 is a schematic diagram of the enhanced algorithm in the present invention, when the nearest witness node and the second nearest witness node finally can't find and can find the moving target;
Fig. 4 is a partial schematic diagram of the enhanced algorithm in the present invention, in the case that both witness nodes can finally find the moving target.
Embodiments Hereunder an example of the present invention will be further described with reference to the accompanying drawings.
The enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture comprises: positioning a moving target with an existing mine shaft positioning system when the moving target moves in a roadway, and obtaining an initial positioning coordinate point tp(i); then, projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i), and utilizing an Internet of Things management and control platform to search for sensor nodes wherein the
6 distance bwtween corresponding sensor node and the projection point tp'(i) is within the range of a maximum communication distance; finally, using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target; specifically, the steps are as follows:
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
(2) projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i);
(3) obtaining a maximum search radius d,,, of sensor node, when a maximum transmitting power P. of the sensor node is known;
(4) utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distances between the corresponding sensor node and the projection point is within the range of a maximum communication distance (i.e., the maximum search radius and logging the number n of the sensor nodes and the coordinates of the sensor nodes;
(5) using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes, to obtain a final positioning coordinate point rp(i).
The entire process of the algorithm is shown in Fig. I.
The enhanced positioning method based on witness node comprises the following steps:
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(I) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step I is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and spi(2) respectively, and their coordinates are (x,i, yil) and (x1.2, y12);
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
(2) projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i);
(3) obtaining a maximum search radius d,,, of sensor node, when a maximum transmitting power P. of the sensor node is known;
(4) utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distances between the corresponding sensor node and the projection point is within the range of a maximum communication distance (i.e., the maximum search radius and logging the number n of the sensor nodes and the coordinates of the sensor nodes;
(5) using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes, to obtain a final positioning coordinate point rp(i).
The entire process of the algorithm is shown in Fig. I.
The enhanced positioning method based on witness node comprises the following steps:
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(I) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step I is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and spi(2) respectively, and their coordinates are (x,i, yil) and (x1.2, y12);
7 b. if n>=2, two sensor nodes that are at the nearest distances to tp'(i) are used as witness nodes, the two witness nodes are denoted as spi(1) and sp,(2) respectively, and their coordinates are (xii, y,i) and (xi2, yo) respectively;
step 2: calculating the distances d,(1) and d,(2) from the projection point tpt(i) to the witness nodes spi(1) and sp,(2) respectively; calculating a line // passing through spi(i) and spi(2):
V -y., x -x 11 s2 , a line 12 passing through spi(1) and parallel to the center line of the roadway, and a line 13 passing through sp1(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to ro meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius did), searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d,O, j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by ro m in each time, i.e., iteratively searching for the moving target in radius (diN -countX ro), till the witness nodes can't find the moving target or a condition (da m X ro < ro) is met in the mil' search cycle, where, count=1, m; cl(1) > inX ro; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the mth search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (I) and (2); in that case, the following formula (1) is met:
+ ( v ¨ v (11) r = (x¨x,2)2 + (y ¨ N)' (2) (X¨ x 4)2 + v ¨ y )2 :5-R2 (I) where, R=diN -(m-1) X ro, r = 4.0 - rn X ro;
b. if the criterion (d,0) - m X ro < ro) is met, it indicates that the moving target is within a range of a minimum circle in radius (d,(i) - m X ro) centering on spi0); in that case, the following formula (2) is met:
(x x,) )2 + y ¨ )2 5 r2 ( 2 ) where, r d,02- mXro;
case 2: if the witness nodes can't find the moving target within the search area in radius d,a),
step 2: calculating the distances d,(1) and d,(2) from the projection point tpt(i) to the witness nodes spi(1) and sp,(2) respectively; calculating a line // passing through spi(i) and spi(2):
V -y., x -x 11 s2 , a line 12 passing through spi(1) and parallel to the center line of the roadway, and a line 13 passing through sp1(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to ro meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius did), searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d,O, j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by ro m in each time, i.e., iteratively searching for the moving target in radius (diN -countX ro), till the witness nodes can't find the moving target or a condition (da m X ro < ro) is met in the mil' search cycle, where, count=1, m; cl(1) > inX ro; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the mth search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (I) and (2); in that case, the following formula (1) is met:
+ ( v ¨ v (11) r = (x¨x,2)2 + (y ¨ N)' (2) (X¨ x 4)2 + v ¨ y )2 :5-R2 (I) where, R=diN -(m-1) X ro, r = 4.0 - rn X ro;
b. if the criterion (d,0) - m X ro < ro) is met, it indicates that the moving target is within a range of a minimum circle in radius (d,(i) - m X ro) centering on spi0); in that case, the following formula (2) is met:
(x x,) )2 + y ¨ )2 5 r2 ( 2 ) where, r d,02- mXro;
case 2: if the witness nodes can't find the moving target within the search area in radius d,a),
8 adjusting the transmitting power so that the search radius is outwardly expanded by ro meter in each time, i.e., iteratively searching for the moving target in radius (40 +
countXr0), till the witness nodes finds the moving target in the mth search cycle or no witness node is found within the range dm, where, count=?, m; (d,C) + m X ro) < ?I is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the Mt h search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
R'2 = ( x ¨ xi/ )2 ( y ¨ yt, )2 (4) r'2 = (x )2 + ( y )2 (4) r'' 5(x¨x)2 +(y¨ )2 R (3) where, R'=d,a) + m X 7.0, r'=c11(j) + (m-1) X ro;
b. if no witness node is found within the range dm, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d,(j)+mxrp) (4) step 4: correcting the initial positioning point tp(i) based on the two witness nodes:
after iterative search is carried out for sp,(1) and sp1(2), analyzing the types of sp,(1) and sp1(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp,(1) and sp,(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp,(1) and sp,(2) belongs to the type a in the case 1 and the other of sp,(1) and sp,(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius d,õõõ, if there is an intersection region at a side, the area scope of the moving target can be determined, and the line 12 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp,(2) and outside of a circle centering on sp1(1) in radius dõ,,õ rp'(i) can be calculated in the same way;
countXr0), till the witness nodes finds the moving target in the mth search cycle or no witness node is found within the range dm, where, count=?, m; (d,C) + m X ro) < ?I is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the Mt h search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on spa, i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
R'2 = ( x ¨ xi/ )2 ( y ¨ yt, )2 (4) r'2 = (x )2 + ( y )2 (4) r'' 5(x¨x)2 +(y¨ )2 R (3) where, R'=d,a) + m X 7.0, r'=c11(j) + (m-1) X ro;
b. if no witness node is found within the range dm, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d,(j)+mxrp) (4) step 4: correcting the initial positioning point tp(i) based on the two witness nodes:
after iterative search is carried out for sp,(1) and sp1(2), analyzing the types of sp,(1) and sp1(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp,(1) and sp,(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp,(1) and sp,(2) belongs to the type a in the case 1 and the other of sp,(1) and sp,(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius d,õõõ, if there is an intersection region at a side, the area scope of the moving target can be determined, and the line 12 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp,(2) and outside of a circle centering on sp1(1) in radius dõ,,õ rp'(i) can be calculated in the same way;
9 (3) in other cases except the above-mentioned cases, the moving target is within an intersection area centering on sp,(1) and sp,(2), and the line ii has two intersecting points with the boundary of the intersection area; in that case, calculating a middle point rp'(i) between the two intersecting points; if there is no intersection between the search result areas of sp,(1) and sp,(2), an inner arc in a result annular area at the right side of the left witness node and an inner arc in a result annular area at the left side of the right witness node are taken, the line ii has one intersecting point with the two arcs respectively, and a middle point rp'(i) between the two intersecting points is calculated;
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i), as shown in Figs. 2, 3, 4.
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i), as shown in Figs. 2, 3, 4.
Claims (2)
1. An enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture, comprising: positioning a moving target with an existing mine shaft positioning system when the moving target moves in a roadway, and obtaining an initial positioning coordinate point tp(i); then, projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i), and utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distance bwtween corresponding sensor node and the projection point tp'(i) is within the range of a maximum communication distance; finally, using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes to improve the positioning accuracy of the moving target; specifically, the steps are as follows:
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
(2) projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i);
(3) obtaining a maximum search radius d max of sensor node, when a maximum transmitting power P max of the sensor node is known;
(4) utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distances between the corresponding sensor node and the projection point is within the range of a maximum communication distance (i.e., the maximum search radius d max), and logging the number n of the sensor nodes and the coordinates of the sensor nodes;
(5) using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes, to obtain a final positioning coordinate point rp(i).
(1) obtaining an initial positioning coordinate point tp(i) of a moving target with a mine shaft positioning algorithm when the moving target moves in a roadway and communicates with the mine shaft positioning system;
(2) projecting the initial positioning coordinate point tp(i) to the center line of the roadway, so as to obtain a projection point tp'(i);
(3) obtaining a maximum search radius d max of sensor node, when a maximum transmitting power P max of the sensor node is known;
(4) utilizing an Internet of Things management and control platform to search for sensor nodes wherein the distances between the corresponding sensor node and the projection point is within the range of a maximum communication distance (i.e., the maximum search radius d max), and logging the number n of the sensor nodes and the coordinates of the sensor nodes;
(5) using the sensor nodes as witness nodes to correct the obtained initial positioning coordinate point with an enhanced positioning method based on witness nodes, to obtain a final positioning coordinate point rp(i).
2. The enhanced positioning method for a moving target in a mine shaft based on witness nodes under Internet of Things architecture according to claim 1, wherein, the enhanced positioning method based on witness node comprises the following steps:
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(1) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step 1 is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and sp i(2) respectively, and their coordinates are (xi1, yi1) and (xi2, .yi2);
b. if n>=2, two sensor nodes that are at the nearest distances to tp'(i) are used as witness nodes, the two witness nodes are denoted as sp i(1) and sp i(2) respectively, and their coordinates are (x i1, y i1) and (x i2, y i2) respectively;
step 2: calculating the distances di(1) and di(2) from the projection point tp'(i) to the witness nodes sp i(1) and sp i(2) respectively; calculating a line l i passing through sp i(i) and sp i(2):
, a line l2 passing through sp i(1) and parallel to the center line of the roadway, and a line l3 passing through sp i(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to r0 meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius d i(j), searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d i(j), j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by r0 m in each time, i.e., iteratively searching for the moving target in radius (d i(j) - countX r0), till the witness nodes can't find the moving target or a condition (d i(j) - m X r0 <
r0) is met in the m th search cycle, where, count=1, ..., m; d i(j) > m X r0; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the m th search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp i(j), i.e., within a range constituted by annuli (1) and (2); in that case, the following formula (1) is met:
R2 =(x¨ x ij)2 +(y ¨ y ij)2 (1) r2 = (x¨x ij)2 +(y ¨ y )2 (2) r2 <= (x¨ x ii)2 +(y ¨ y ii)2 <= R2 (1) where, R=d i(j) - (m - I) X r0, r = d i(j) - m X r0;
b. if the criterion (d1(j) - m X r0 < r0) is met, it indicates that the moving target is within a range of a minimum circle in radius (d i(j) - mXr0) centering on sp i(j); in that case, the following formula (2) is met:
(x-x ij)2 +(y - y ij)2 <= r2 (2) where, r = d i(j)- m X r0;
case 2: if the witness nodes can't find the moving target within the search area in radius d i(j), adjusting the transmitting power so that the search radius is outwardly expanded by r0 meter in each time, i.e., iteratively searching for the moving target in radius (d i(j) + countXr0), till the witness nodes finds the moving target in the m th search cycle or no witness node is found within the range d max, where, count=1,..., m; (d i(j) + m X r0) < d max; m is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the m th search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp i(j), i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
R'2 = (x ¨x ij)2 + (y ¨ y ij)2 (3) r '2 = (x¨x ij)2 +(y - y ij)2 (4) r'2 <= (x¨ x ij)2 + (y ¨ y ij)2<= R'2 (3 ) where, R'=d i(j) + m X r0, r'=d i(j) + (m-1) X r0;
b. if no witness node is found within the range d max, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d i(j)+ m x r~) > d max ( 4) step 4. correcting the initial positioning point tp(i) based on the two witness nodes:
after iterative search is carried out for sp i(1) and sp i(2), analyzing the types of sp i(1) and sp i(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp i(1) and sp i(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp i(1) and sp i(2) belongs to the type a in the case 1 and the other of sp i(1) and sp i(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius d max, if there is an intersection region at a side, the area scope of the moving target can be determined, and the line .intg.2 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp 1(2) and outside of a circle centering on sp,(1) in radius d max, rp'(i) can be calculated in the same way;
(3) in other cases except the above-mentioned cases, the moving target is within an intersection area centering on sp,(1) and sp,(2), and the line .intg.1 has two intersecting points with the boundary of the intersection area; in that case, calculating a middle point rp'(i) between the two intersecting points; if there is no intersection between the search result areas of sm(1) and sp,(2), an inner arc in a result annular area at the right side of the left witness node and an inner arc in a result annular area at the left side of the right witness node are taken, the line 11 has one intersecting point with the two arcs respectively, and a middle point rp'(i) between the two intersecting points is calculated;
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i).
step 1: judging which of the following conditions is met by the number n of sensor nodes;
(1) if n=0, it indicates there is no witness node near the moving target, and it is unable to correct the initial positioning coordinate point tp(i); in that case, it is unnecessary to carry out the processing in the following steps; instead, the result is outputted directly, i.e., tp(i) is the final positioning coordinate point rp(i);
(2) if n>=1, the step 1 is handled in the following two cases:
a. if n=1, it indicates there is one witness node near the moving target; in that case, a base station that is at the nearest distance to the moving target in the Internet of Things management and control platform is used as another witness node, the two witness nodes are denoted as sp,(1) and sp i(2) respectively, and their coordinates are (xi1, yi1) and (xi2, .yi2);
b. if n>=2, two sensor nodes that are at the nearest distances to tp'(i) are used as witness nodes, the two witness nodes are denoted as sp i(1) and sp i(2) respectively, and their coordinates are (x i1, y i1) and (x i2, y i2) respectively;
step 2: calculating the distances di(1) and di(2) from the projection point tp'(i) to the witness nodes sp i(1) and sp i(2) respectively; calculating a line l i passing through sp i(i) and sp i(2):
, a line l2 passing through sp i(1) and parallel to the center line of the roadway, and a line l3 passing through sp i(2) and parallel to the center line of the roadway;
setting the positioning accuracy range of the moving target to r0 meter;
step 3: adjusting the transmitting power of the witness nodes, determining a search area in radius d i(j), searching for the moving target, and handling in either of the following cases depending on whether the moving target is found:
case 1: if the witness nodes find the moving target within the search area in radius d i(j), j=1, 2, adjusting the transmitting power so that the search radius is inwardly compressed by r0 m in each time, i.e., iteratively searching for the moving target in radius (d i(j) - countX r0), till the witness nodes can't find the moving target or a condition (d i(j) - m X r0 <
r0) is met in the m th search cycle, where, count=1, ..., m; d i(j) > m X r0; m is the total number of iteration search cycles:
a. if the witness nodes can't find the moving target in the m th search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp i(j), i.e., within a range constituted by annuli (1) and (2); in that case, the following formula (1) is met:
R2 =(x¨ x ij)2 +(y ¨ y ij)2 (1) r2 = (x¨x ij)2 +(y ¨ y )2 (2) r2 <= (x¨ x ii)2 +(y ¨ y ii)2 <= R2 (1) where, R=d i(j) - (m - I) X r0, r = d i(j) - m X r0;
b. if the criterion (d1(j) - m X r0 < r0) is met, it indicates that the moving target is within a range of a minimum circle in radius (d i(j) - mXr0) centering on sp i(j); in that case, the following formula (2) is met:
(x-x ij)2 +(y - y ij)2 <= r2 (2) where, r = d i(j)- m X r0;
case 2: if the witness nodes can't find the moving target within the search area in radius d i(j), adjusting the transmitting power so that the search radius is outwardly expanded by r0 meter in each time, i.e., iteratively searching for the moving target in radius (d i(j) + countXr0), till the witness nodes finds the moving target in the m th search cycle or no witness node is found within the range d max, where, count=1,..., m; (d i(j) + m X r0) < d max; m is the total number of iteration search cycles:
a. if the witness nodes finds the moving target in the m th search cycle, it indicates that the moving target is within a range constituted by concentric annuli centering on sp i(j), i.e., within a range constituted by annuli (3) and (4); in that case, the following formula (3) is met:
R'2 = (x ¨x ij)2 + (y ¨ y ij)2 (3) r '2 = (x¨x ij)2 +(y - y ij)2 (4) r'2 <= (x¨ x ij)2 + (y ¨ y ij)2<= R'2 (3 ) where, R'=d i(j) + m X r0, r'=d i(j) + (m-1) X r0;
b. if no witness node is found within the range d max, it indicates the moving target can't be found within the maximum expansion range; in that case, the following formula (4) is met:
(d i(j)+ m x r~) > d max ( 4) step 4. correcting the initial positioning point tp(i) based on the two witness nodes:
after iterative search is carried out for sp i(1) and sp i(2), analyzing the types of sp i(1) and sp i(2) directed to the step 3 and correcting the initial positioning point;
(1) if both sp i(1) and sp i(2) belong to the type b in the case 2, the witness nodes can't play a role, and tp(i) is the final positioning coordinate point rp(i);
(2) if one of sp i(1) and sp i(2) belongs to the type a in the case 1 and the other of sp i(1) and sp i(2) belongs to the type b in the case 2, then, only one witness node can find the target node and plays the role of "witness" truly, in the case that the moving target is within the range of double annuli centering on sp1(1) and outside of a circle centering on sp,(2) in radius d max, if there is an intersection region at a side, the area scope of the moving target can be determined, and the line .intg.2 has two intersecting points with the boundary of the area of the moving target; in that case, a middle point rp'(i) between the two intersecting points is calculated; otherwise, there are two intersection areas; in that case, a shadow area that is closer to the initial positioning value is selected as the area of the moving target, and rp'(i) is obtained in the same way;
if the moving target is within double annuli centering on sp 1(2) and outside of a circle centering on sp,(1) in radius d max, rp'(i) can be calculated in the same way;
(3) in other cases except the above-mentioned cases, the moving target is within an intersection area centering on sp,(1) and sp,(2), and the line .intg.1 has two intersecting points with the boundary of the intersection area; in that case, calculating a middle point rp'(i) between the two intersecting points; if there is no intersection between the search result areas of sm(1) and sp,(2), an inner arc in a result annular area at the right side of the left witness node and an inner arc in a result annular area at the left side of the right witness node are taken, the line 11 has one intersecting point with the two arcs respectively, and a middle point rp'(i) between the two intersecting points is calculated;
step 5: projecting rp'(i) to the center line of the roadway; thus, the projection point on the center line is the final positioning coordinate point rp(i).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510037300.1A CN104540101B (en) | 2015-01-23 | 2015-01-23 | Mine moving target enhancing localization method based on witness's node under Internet of Things framework |
| CN201510037300.1 | 2015-01-23 | ||
| PCT/CN2015/099316 WO2016115961A1 (en) | 2015-01-23 | 2015-12-29 | Enhanced positioning method for moving target in mine shaft based on witness nodes under internet of things architecture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
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| CA2958759C CA2958759C (en) | 2020-06-30 |
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| CA2958759A Expired - Fee Related CA2958759C (en) | 2015-01-23 | 2015-12-29 | Enhanced positioning method for moving target in mine shaft based on witness nodes under internet of things architecture |
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| CN (1) | CN104540101B (en) |
| CA (1) | CA2958759C (en) |
| WO (1) | WO2016115961A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113505858A (en) * | 2021-08-24 | 2021-10-15 | 中煤科工集团重庆研究院有限公司 | Method for identifying underground illegal operation area of coal mine based on massive activity track inversion |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104540101B (en) * | 2015-01-23 | 2018-06-12 | 中国矿业大学 | Mine moving target enhancing localization method based on witness's node under Internet of Things framework |
| CN113784282B (en) * | 2021-08-31 | 2023-08-15 | 北京京诚瑞达电气工程技术有限公司 | Wireless positioner calibration method and device |
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| US4814087A (en) * | 1987-10-09 | 1989-03-21 | Separation Dynamics, Inc. | Fuel delivery system |
| CN102196560B (en) * | 2011-05-24 | 2013-10-09 | 国电南京自动化股份有限公司 | Method for positioning high-accuracy nodes in Zigbee network |
| CN102427450B (en) * | 2011-11-14 | 2014-12-10 | 郑州赛金电气有限公司 | Mine emergency communication system |
| CN202560325U (en) * | 2012-05-11 | 2012-11-28 | 黑龙江科技学院 | Underground multiple-data monitor system for coal mine |
| CN102932256A (en) * | 2012-10-31 | 2013-02-13 | 中国矿业大学(北京) | Positioning and routing method based on DV-Hop (Distance Vector-Hop) positioning mechanism |
| CN103491627B (en) * | 2013-08-03 | 2016-08-10 | 东北大学 | A kind of closely real-time accurate positioning method of integrated many algorithms |
| CN103778415B (en) * | 2014-01-21 | 2017-05-17 | 蔺全录 | Mine personnel iris checking-in and tracking and positioning method and system |
| CN203984410U (en) * | 2014-06-27 | 2014-12-03 | 中国矿业大学 | Coal mine down-hole personnel monitoring wireless receiving substation |
| CN104540101B (en) * | 2015-01-23 | 2018-06-12 | 中国矿业大学 | Mine moving target enhancing localization method based on witness's node under Internet of Things framework |
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- 2015-12-29 WO PCT/CN2015/099316 patent/WO2016115961A1/en active Application Filing
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113505858A (en) * | 2021-08-24 | 2021-10-15 | 中煤科工集团重庆研究院有限公司 | Method for identifying underground illegal operation area of coal mine based on massive activity track inversion |
| CN113505858B (en) * | 2021-08-24 | 2023-04-18 | 中煤科工集团重庆研究院有限公司 | Method for identifying underground coal mine illegal operation area based on massive activity track inversion |
Also Published As
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| CN104540101A (en) | 2015-04-22 |
| CN104540101B (en) | 2018-06-12 |
| WO2016115961A1 (en) | 2016-07-28 |
| CA2958759C (en) | 2020-06-30 |
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