JP2001056899A - Moving direction detecting device for object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the moving direction of an object while using a single GPS receiver by discriminating the moving direction of the object on the basis of the lowering tendency of the reception level of a radio wave, which is transmitted from a GPS satellite, to be received by a receiving means installed in the traveling area of the object and the position information of the GPS satellite. SOLUTION: A GPS receiver 6 transmits each of reception information such as the elevation angle and azimuth angle of the satellite and the reception level of the radio wave from the orbit information of the GPS satellite, which receives the radio wave, to radio equipment 7. On the basis of each of information such as the elevation angle and azimuth angle of each GPS satellite and the reception level inputted from the GPS receiver 6 through radio equipment 7 and 8, a computer 9 discriminates the moving direction of an airplane from the lowering tendency of the reception level of each GPS satellite. In this case, based on the input information, the moving direction is determined from the moving tendency of an airplane position, which is estimated on a plane coordinate system with the install position of the GPS receiver 6 as an origin, on the plane coordinate system and on the basis of the compared result of the reception level information and a set threshold value, the presence of the airplane is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving direction detecting device for an object which can detect the moving direction of the object with only one GPS receiver.

[0002]

2. Description of the Related Art Conventionally, as a device for detecting objects such as various vehicles and ground-based aircraft, devices utilizing electric, magnetic, optical, or ultrasonic waves are generally used. In the detection method of these detection devices, a transmission device and a reception device are arranged opposite to each other in a detection area, a signal wave transmitted from the transmission device is affected by a vehicle or an aircraft, and a reception signal on the reception device side is set in advance. When the threshold level is changed, a detection signal of a vehicle or an aircraft is generally generated.

[0003] When detecting the moving direction of an object such as a vehicle or an aircraft on the ground, the above-described object detection device is conventionally used. That is, the above-described object detection device is
A plurality of objects are arranged at intervals along the moving path of the object, and the moving direction of the object is detected from the order of generation of the detection signals of each object detecting device.

[0004]

However, in the conventional moving direction detecting device described above, at least two object detecting devices are required, and each object detecting device requires a transmitting device and a receiving device. , The cost will be higher.
In addition, for example, in an optical or ultrasonic object detection device, etc., since the transmission and reception device is installed above the running surface of the object,
It may become a ground protrusion, which may hinder traffic of vehicles and aircraft.

[0005] The applicant has disclosed an object detection apparatus using a GPS receiver in International Publication WO97 / 4337. This object detection method has an advantage that there is no need for a transmission device only with a GPS receiver, and there is no ground protrusion since the GPS receiver can be buried underground. Although an object movement direction detection technique using this object detection device is also shown, a plurality of GPs
Using the S receiver, the moving direction is detected based on the reception order of the GPS receiver.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive object movement direction detecting device capable of detecting an object movement direction using only one GPS receiver. Aim.

[0007]

In order to achieve the above object, an object moving direction detecting apparatus according to the first aspect of the present invention is provided in a traveling area of the object and is capable of receiving a radio wave transmitted from a GPS satellite. And a moving direction of an object is determined on the basis of the number of receiving units and the receiving information of the plurality of GPS satellites received by the plurality of GPS satellites. And a direction determining means.

[0008] In this configuration, one receiving unit receives radio waves from a plurality of GPS satellites. If the radio wave is interrupted by the movement of the object, the reception level will decrease. Therefore, if the installation position of the receiving means is the center, G in the same direction as the object
The reception level from the PS satellite decreases. Therefore, the direction determining means determines the direction of the object based on the tendency of the reception level of radio waves from a plurality of GPS satellites to decrease and the position information of each GPS satellite.

[0009] Specifically, the direction judging means, based on information on elevation, azimuth and reception level of the plurality of GPS satellites obtained at regular intervals, as described in claim 2,
Position estimating means for estimating the object position with respect to the installation position of the receiving means at regular intervals, and the position of the object with respect to the installing position of the receiving means based on the moving tendency of the object position at regular intervals estimated by the position estimating means. Direction determining means for determining a moving direction.

[0010] The position estimating means may be as follows.
Satellite position calculating means for calculating a coordinate position of each GPS satellite in an xy plane coordinate system having an installation position of the receiving means as an origin, based on elevation information and azimuth information of each of the plurality of GPS satellites; The x and y coordinate components of each GPS satellite calculated by the satellite position calculating means are weighted based on the respective reception levels, and the respective GPS satellites are weighted.
Coordinate position conversion means for converting the coordinate position of the satellite into a coordinate position representing the positional relationship between each GPS satellite and the object, and gravity center calculation means for calculating the center of gravity of each coordinate position obtained by the coordinate position conversion means. It is configured to estimate the calculated center of gravity position as an object position with respect to the installation position of the receiving means,
The direction determining means stores a predetermined number of pieces of center-of-gravity position data calculated by the center-of-gravity calculating means at regular time intervals while updating the earliest data with the latest data, and stores movement data of the center of gravity position. Storage means; and x, y of a predetermined number of respective centroid position data stored in the movement data storage means.
A direction calculating unit that sets a direction from the coordinate position calculated by adding the coordinate components to the origin as a moving direction of the object.

According to a fourth aspect of the present invention, there is provided an object detecting means for detecting the presence or absence of an object based on a comparison result between the reception level of the radio wave in the receiving means and a preset threshold value,
The direction calculation means may set a direction from the calculated coordinate position toward the origin to a movement direction of the object when a detection signal indicating presence of an object is input from the object detection means.

According to a fifth aspect of the present invention, the direction determining means determines the direction using a radio wave from a GPS satellite having a predetermined elevation angle or more. In such a configuration, the influence of a building or the like on the ground can be reduced, so that the reliability of the direction determination can be improved.

According to a sixth aspect of the present invention, there is provided a display device for displaying a moving direction of an object based on a result of the determination by the direction determining means. With this configuration, a human can visually check the moving direction of the object.

According to a seventh aspect of the present invention, the object is an aircraft, and the receiving means is installed near an end of the taxiway on the runway side to determine whether the aircraft enters or exits the runway.

[0015] With this configuration, it is possible to determine the entry / exit of the aircraft to / from the runway.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to the determination of the moving direction of an aircraft will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of the present embodiment.
In FIG. 1, 1 is a runway, 2 is a taxiway, 3 is a tarmac,
Reference numeral 4 denotes a control tower. The taxiway 2 is connected to the runway 1 at four points A1 to A4, for example, as shown in FIG.
Is provided. One GPS receiver 6 is provided between the stop bar 5 and the runway 1. Each G
A radio 7 is connected to each of the PS receivers 6.

On the control tower 4 side, there are a radio 8 for receiving information from each radio 7 and an aircraft detecting means for detecting the presence or absence of an aircraft as an object based on the information from the radio 8. Computer 9 having software and a function of a direction determining means for determining the traveling direction of the aircraft in software
And a display device 10 as display means for displaying a result of the direction determination by the computer 9 and the like.

As shown in FIG. 2, each of the GPS receivers 6 has a receiving antenna 6A for receiving a radio wave from a GPS satellite.
And a receiver main body 6B for converting reception information such as an azimuth angle, an elevation angle, a reception level and the like into a transmission signal and outputting the transmission signal to the radio device 7, is housed in a hard cover 6C, and a cover 6C for receiving radio waves. It is buried in the taxiway 2 with its upper surface exposed to the ground surface. 6D is a cable in which a power supply line to the receiver main body 6B and a signal transmission line to the wireless device 7 are integrated.

The GPS satellites used in the Global Positioning System (GPS) have a total of 24 GPS satellites, each of four orbits in six orbits having an inclination of 55 degrees with respect to the equatorial plane at about 20,000 km above the earth. Orbit information such as the elevation angle and azimuth angle of each satellite is transmitted from all the GPS satellites for a fixed time, for example, every second. Therefore, the GPS receiver 6
Transmits, to the wireless device 7, information on the elevation angle, the azimuth angle, and the reception level of the radio wave from the orbit information of the GPS satellite that has received the radio wave. The GPS receiver 6 constantly receives radio waves from about eight GPS satellites.

The computer 9 receives each GPS satellite on the basis of information on the elevation angle, azimuth angle and reception level of each GPS satellite input from the GPS receiver 6 via the radios 7 and 8.
The moving direction of the aircraft is determined from the decreasing tendency of the reception level of the S satellite. Specifically, as will be described later with reference to the flowchart of FIG. 4, based on the input information, the aircraft position is estimated in a plane coordinate system whose origin is the installation position of the GPS receiver 6, and the estimated aircraft position is determined. The moving direction of the object is determined from the moving tendency in the plane coordinate system. Further, as shown in a flowchart of FIG. 6 described later, the presence / absence of an aircraft is detected based on a comparison result between the reception level information and a preset threshold.

For example, as shown in FIG. 3, the display device 10 displays a runway (RUNWAY) and A1 to A4 indicating four end portions of a taxiway. An arrow for display is displayed.

Next, the flow of detecting the moving direction of the aircraft according to the present embodiment in the computer 9 will be described with reference to the flowchart of FIG. In step 1 (S1 in the figure, the same applies hereinafter), based on the received elevation angle θ and azimuth angle α, each GPS satellite in the xy plane coordinate system whose origin is the installation position of the GPS receiver 6 is set. Find coordinates. Here, in the plane coordinate system, the north-south direction is the y-axis, the east-west direction is the x-axis, and the direction from south to north and west to east is positive. This step 1 corresponds to satellite position calculation means.

Specifically, first, an appropriate value is determined as H using the elevation angle θ from the relationship shown in FIG. 5A, and R is calculated from the following equation (1). As H, for example, the distance from the ground to the bottom of the aircraft may be used. In the figure,
The z-axis is vertical.

R = H / tan θ (1) Next, from the relationship shown in FIG.
The x and y coordinate components X and Y of the satellite are represented by (2) and (3) below.
It is calculated from the formula.

X = R sin α = (H / tan θ) · sin α (2) Y = R cos α = (H / tan θ) · cos α (3) In step 2, each satellite is determined based on the reception level of the radio wave from each satellite. , A weighting coefficient Lsv is calculated.

In step 3, the elevation angle θ of each GPS satellite from which radio waves are received is compared with a preset elevation angle θf (for example, θf = 20 °) in order to minimize the influence of surrounding buildings on the radio wave reception level. Then, a GPS satellite satisfying θ ≧ θf is selected as a direction detection target satellite.

In step 4, for each of the GPS satellites selected in step 3, their coordinate components X and Y are multiplied by the respective weighting coefficients Lsv calculated in step 2 to obtain coordinates for each GPS satellite in consideration of the reception level. Positions, in other words, coordinate positions Xsv, Ysv (Xsv = Lsv.X, Ysv =
Lsv · Y) is calculated. This coordinate position indicates the distance relationship between the aircraft and each satellite. Here steps 2 and 4
Corresponds to coordinate position conversion means.

In step 5, the Xsv and Ysv of each satellite calculated in step 4 are summed with the total value X
s = ΣXsv, Ys = ΣYsv are calculated. This Xs,
Ys represents the center of gravity of each coordinate position calculated in step 4, and indicates the aircraft position estimated from the reception levels and positional relationships of the selected GPS satellites. Step 5 corresponds to the center-of-gravity calculating means.
4 and 5 constitute the position estimating means.

In step 6, every time information is received from a GPS satellite, that is, 10 times of Xs and Ys calculated every second.
Xsf = ｆXsi, Ysf = ΣYsi (i
= 1 to 10). Xsf and Ysf are 10
This is the total value of the ten pieces of data up to two seconds before, and when the latest data Xs and Ys are obtained, the earliest data X ten seconds ago is obtained.
The data is sequentially updated by replacing s and Ys with the latest data Xs and Ys.

In step 7, Xsf and Ysf at the time when it is determined that there is an aircraft in the aircraft detection operation shown in the flowchart of FIG. 6 are set to Xd and Yd. Here, the aircraft detection flow of FIG. 6 will be described.

In step 11, based on the elevation angle information of each GPS satellite obtained in the movement direction detection flow, the sanitary having an elevation angle equal to or greater than a predetermined elevation angle is selected as the aircraft detection target hygiene. Specifically, for example, a satellite having an elevation angle of 40 ° or more is set as a detection target satellite.

In step 12, the reception level of the selected target sanitation is measured. In step 13, step 1
The presence or absence of an aircraft is determined based on the reception level of each satellite measured in step 2, and steps 11 to 11 are performed until the determination becomes YES.
The process of step 13 is repeated each time new information is received.

As the determination method, for example, the reception level of the selected target satellite is compared with a preset threshold value, and if the reception level is below the threshold value, it is set to “1”; If the number of satellites indicating "1" is more than half, it is determined that an aircraft is present.

As another determination method, an average may be calculated by summing the reception levels of the target satellites, and if the average value is equal to or less than the set threshold, it may be determined that an aircraft is present. If at least one of the receiving levels of the target satellite falls below the set threshold, it may be determined that an aircraft is present. Furthermore,
The presence or absence of an aircraft may be determined by combining these determination methods.

Steps 11 to 13 correspond to the function as the object detecting means. In step 8, the coordinate origin (GPS receiver 6) is determined from the coordinate positions Xd and Yd in step 7 when it is determined in step 13 in FIG.
(Equivalent to the installation position of the aircraft) is defined as the traveling direction of the aircraft. Here, steps 6, 7, and 8 constitute a direction determining unit including a moving data storage unit and a direction calculating unit.

When the direction of the aircraft is determined in step 8, the direction is indicated by an arrow on the display device 10 of FIG. For example, if the movement of the aircraft from the taxiway 2 to the runway 1 is detected at the position of A1, as shown in FIG.
The first runway approach arrow (left side in the figure) is lit, for example, for 5 seconds and then for 5 seconds. At the same time, a sound such as “runway approach at alpha 1” is generated.

According to the direction detecting device having such a configuration, the direction of movement of the aircraft can be detected by one GPS receiver 6 without the need for a transmitting device, and a direction detecting device that is less expensive than the conventional one can be provided. In addition, since the GPS receiver 6 is buried, it does not become a protrusion on the ground and does not hinder the travel of the aircraft. Furthermore,
There is an advantage that equipment for detecting aircraft by the GPS system can be used. Excellent reliability with almost no influence of weather such as rain and snow. Then, by displaying the detected direction as in the present embodiment, it is possible to confirm the aircraft entering the runway and the aircraft exiting from the runway when visibility is poor. As a result, it is possible to support the traffic control operation of the traffic controller, which is effective in preventing a mistaken accident.

By using the coordinates calculated in step 1 of FIG. 4, a GPS satellite Sv capable of receiving radio waves as shown in FIG.
The positions of 1 to Sv8 (eight in this embodiment) are G
It can be displayed in a circle display system centering on the PS receiver. 0 ° to 90 ° in the drawing indicate the elevation angle, and the position at the central elevation angle of 90 ° is the installation position of the GPS receiver.

Using such a display, the moving direction of the aircraft can be determined. That is, each of the displayed satellites Sv1 to Sv8
Is displayed darker as the reception level decreases, for example. Referring to FIG. 7, the aircraft 20 is west (W)
Is moving east (E) in the direction of the arrow. In this case, first, the reception level of the satellite Sv3 decreases and darkens. After that, Sv1 → Sv2 → Sv6 → Sv5 →
The reception level decreases in the order of Sv7, and the display becomes dark in this order. In this way, the moving direction of the aircraft can be determined by visually observing the display state of each of these satellites. Also, if the direction to be determined is simple in only one direction, such as approaching to the runway and exiting from the runway, then it is possible to determine which side of the satellite has become darker first by centering on the origin. Can be determined.

In this embodiment, an example in which the present invention is applied to the direction detection of an aircraft has been described. However, it is needless to say that the present invention is not limited to the aircraft and any moving object such as an automobile or a train can be applied to the direction detection. No.

[0042]

As described above, according to the first to fourth aspects of the present invention, the direction of an object can be detected using a single GPS receiver without the need for a transmission device. It is cheaper than the device. In addition, there is no protrusion on the ground, and there is no influence on the traffic of the object. Furthermore, there are many advantages such as excellent reliability with little influence of weather such as rain and snow.

According to the fifth aspect of the invention, in addition to the effects of the first to fourth aspects, the influence of the surrounding buildings can be reduced. According to the invention of claim 6, it is possible to visually confirm the moving direction of the detected object.

According to the seventh aspect of the present invention, it is effective as an air traffic control support system at an airport.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment in which the present invention is applied to aircraft direction detection.

FIG. 2 is a diagram showing an installation example of a GPS receiver according to the embodiment;

FIG. 3 is a diagram showing an example of the display device of the embodiment.

FIG. 4 is a flowchart of a direction detecting operation according to the embodiment;

FIG. 5 is an explanatory diagram of a calculation operation of a coordinate position of a satellite.

FIG. 6 is a flowchart of an aircraft detection operation according to the embodiment.

FIG. 7 is a diagram showing an example in which the positions of satellites are displayed in a circle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Runway 2 Taxiway 6 GPS receiver 7,8 Radio 9 Computer 10 Display 20 Aircraft

Claims (7)

[Claims] 1. One receiving means provided in a traveling area of an object and capable of receiving a radio wave transmitted from a GPS satellite, and receiving each of radio waves transmitted from a plurality of the GPS satellites received by the receiving means. The decreasing tendency of the level and the plurality of G
A direction determining means for determining a moving direction of the object based on the position information of the PS satellite; 2. The method according to claim 1, wherein the direction determining means determines an object position with respect to an installation position of the receiving means based on each of information on an elevation angle, an azimuth angle, and a reception level of the plurality of GPS satellites obtained at predetermined time intervals. Position estimating means for estimating the position of the receiving means based on the tendency of movement of the object position for each fixed time estimated by the position estimating means. Item 1. A moving direction detecting device for an object according to Item 1. 3. The position estimating means, based on elevation information and azimuth information of each of the plurality of GPS satellites, determines the position of each GPS satellite in an xy plane coordinate system whose origin is the installation position of the receiving means. Satellite position calculating means for calculating a coordinate position; x, y of each GPS satellite calculated by the satellite position calculating means
A weighting process is performed on the coordinate components based on the respective reception levels, and the coordinate position of each GPS satellite is determined by each GPS satellite.
Coordinate position conversion means for converting to a coordinate position representing the positional relationship between the satellite and the object, and a center of gravity calculation means for calculating the center of gravity of each coordinate position obtained by the coordinate position conversion means, the calculated center of gravity position The direction determining means updates the center-of-gravity position data calculated by the center-of-gravity calculating means at regular intervals with the latest data. A movement data storage means for storing a predetermined number of pieces of the center-of-gravity position movement data, and a coordinate position calculated by adding the x and y coordinate components of the predetermined number of pieces of the center-of-gravity position data stored in the movement data storage means The moving direction detecting device for an object according to claim 2, further comprising: a direction calculating unit that sets a direction from the object to the origin as a moving direction of the object. 4. An object detecting means for detecting the presence or absence of an object based on a result of comparison between a reception level of the radio wave in the receiving means and a preset threshold value, wherein the direction calculating means detects the presence of the object from the object detecting means. 4. The object movement direction detecting device according to claim 3, wherein a direction from the calculated coordinate position at the time when the presence detection signal is input to the origin is set as the object movement direction. 5. The apparatus according to claim 1, wherein said direction judging means comprises a GP having a predetermined elevation angle or more.
The apparatus according to any one of claims 1 to 4, wherein the direction is determined using a radio wave from the S satellite. 6. A display device for displaying a moving direction of an object based on a determination result of said direction determining device.
The moving direction detecting device for an object according to any one of the above. 7. The apparatus according to claim 1, wherein said object is an aircraft, and said receiving means is installed near an end of a taxiway on a runway side to determine whether said aircraft enters or exits a runway. An apparatus for detecting a moving direction of an object according to any one of the above.