JP3510558B2 - Calibration method of installation position / posture of receiving antenna and jig used therefor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for calibrating the installation position / posture of a receiving antenna and a jig used for the method, and more particularly to a method for receiving an arrival angle of a radio wave emitted from a vehicle-mounted device. This is useful when calibrating the installation height and installation angle of the receiving antenna in a system for detecting the distance to a vehicle by receiving the signal with an antenna. [0002] E for the purpose of automatic toll collection on toll roads
TC (Electronic Toll Colle
ction) system is based on ITS (Intellige)
ntTransport Systems) has attracted attention as an application that can be realized at an early stage.
This ETC system enables tolls to be collected by wireless communication between a roadside wireless device installed at a tollgate and a wireless device mounted on a vehicle, so that the vehicle can collect tolls on a toll road. Non-stop cashless. In the automatic toll collection system as described above, wireless communication between a roadside wireless device (hereinafter referred to as a roadside device) installed at a tollgate and a wireless device mounted on a vehicle (hereinafter referred to as an onboard device). Currently, when collecting a fee, the radio wave emitted from the vehicle-mounted device is received by the receiving antenna of the roadside device, and the angle θ of the radio wave arriving from the vehicle-mounted device with respect to the reference plane is detected. Then, the distance to the vehicle that emitted the radio wave is detected by performing a predetermined arithmetic process based on the calculated value. Here, in detecting the angle θ of the arriving radio wave, the receiving antenna performs a predetermined calculation on the assumption that its height position and angle (depression angle) are installed as predetermined. [0004] As described above, the receiving antenna in the automatic toll collection system according to the prior art has a predetermined operation assuming that its height position and angle (depression angle) are installed as predetermined. Therefore, when the installation height and the angle include an error, the error becomes an error in locating the distance to the vehicle. Therefore, it is necessary to calibrate the installation height and angle of the receiving antenna after the installation. SUMMARY OF THE INVENTION In view of the above prior art, an object of the present invention is to provide a method of calibrating the installation position / posture of a reception antenna which can easily calibrate the installation state of the reception antenna, and a jig used for the method. I do. [0006] The structure of the present invention that achieves the above object has the following features. 1) A receiving antenna installed at a predetermined height and a predetermined depression angle receives a radio wave emitted from a vehicle-mounted device which is a radio device mounted on a vehicle, detects an arrival angle of the radio wave, and detects the arrival angle. A method for calibrating the installation position of a receiving antenna in a distance detection system that detects a distance from a receiving antenna to an on-vehicle device based on an angle, wherein the receiving antenna is disposed at different positions and at least a distance and a height between each other are known. From each of the five radios, radio waves are respectively emitted toward the receiving antenna, and by locating the position of each radio, an equation including at least five unknowns representing the position of each radio is obtained. Obtain at least the actual installation height and installation depression angle of the receiving antenna as a solution of the equation,
At least these heights and depression angles shall be calibrated as specified. According to the present invention, the expression representing the position of each wireless device includes at least the height of the receiving antenna and the depression angle of the receiving antenna as a function, and since the relational expression has an unknown number, at least the height of the receiving antenna And the depression angle can be obtained as a solution of the equation in this case. This solution becomes the actual installation height and installation depression angle of the receiving antenna. [0008] 2) In the method for calibrating the installation position / posture of the receiving antenna described in 1) above, the number of radios is 6 or more, including at least 5 unknowns, and one more than the number of unknowns. Or more equations are obtained, a plurality of sets of at least five equations are sequentially selected from among the six or more equations, and a plurality of sets of at least the installation height and the installation depression angle are obtained as solutions of the plurality of equations. Based on these average values, at least the height and depression angle of the receiving antenna are calibrated as specified. According to the present invention, since the average value of the solutions of a plurality of equations is taken,
A more accurate solution can be obtained. 3) A jig used in the method for calibrating the installation position / posture of the receiving antenna described in 1) or 2) above, wherein at least five radios are arranged in a horizontal plane at predetermined intervals. thing. According to the present invention, the invention described in the above 1) or 2) can be carried out. [0010] 4) A jig used in the method for calibrating the installation position / posture of the receiving antenna described in 1) or 2) above, wherein at least five radios are arranged at predetermined intervals in a vertical plane. That you did. According to the present invention, the invention described in the above 1) or 2) can be carried out. 5) A jig used in the method for calibrating the installation position / posture of the receiving antenna described in 1) or 2) above, wherein at least five radios are arranged at predetermined intervals in a horizontal plane and a vertical plane. It was arranged in. According to the present invention, the invention described in the above 1) or 2) can be carried out. Embodiments of the present invention will be described below in detail with reference to the drawings. First, a method of detecting the angle θ of an incoming radio wave by actual measurement will be described. As shown in FIG. 1, the angle detection system according to the present embodiment transmits a radio wave (indicated by a dotted line in the figure) emitted from an in-vehicle device 1a mounted on the vehicle 1 via an antenna 1b.
The signals are received by the two receiving antennas 2 and 3 and subjected to predetermined processing to detect the angle θ of the incoming radio wave with respect to the reference plane. More specifically, the arriving radio waves received by the two receiving antennas 2 and 3 installed at a predetermined interval d are converted by the heterodyne converters 4 and 5 into the carrier frequency and the local oscillator 6. The difference from the frequency of the local oscillation signal to be output is obtained, converted into a low-frequency signal, and supplied to the phase difference meter 7. The phase difference meter 7 detects a phase difference Δφ between a radio wave received by the receiving antenna 2 and a radio wave received by the receiving antenna 3. The phase difference Δφ is the phase difference Δφ contained in the received radio wave due to the distance L _B up to the receiving antenna 3 is different from the distance L _A and the antenna 1b to the receiving antenna 2 from the antenna 1b, the distance ( L _A −
It reflects the L _B). That is, in FIG. 1, the distances L _A and L _B are drawn equally, but the distance from the center point of the antenna 1b to the center point of the receiving antenna 2 is actually the distance L _A , and from the center point of the antenna 1b. Since the distance to the center point of the receiving antenna 3 is the distance L _B , the distance L _A ,
Difference _{L B (L A -L B)} = Δφ · λ / 2π ( where, lambda is the wavelength of the incoming waves, theta is angle of arrival of radio waves) is represented by. Here, in the vicinity of the receiving antennas 2 and 3, the traveling directions of the incoming radio waves received by the receiving antennas 2 and 3 can be regarded as equivalently parallel. Therefore, Δφ = (2π / λ) · d · S
The relationship of INθ is established. As a result, the angle θ of the incoming radio wave
Is represented by the following equation (1). θ = SIN ⁻¹ (Δφ · λ / 2πd) (1) If the angle θ of the arriving radio wave is obtained by the above-described method, the position X of the orientation vehicle 1 can be calculated by the following equation (2). expressed. X = (h _ANT −h _OBE ) × TAN ⁻¹ (Ψ + θ) (2) where h _ANT is the antenna height, h _OBE is the vehicle-mounted device height, and Ψ
Is the antenna depression angle. On the other hand, the angle θ of the arriving radio wave can also be obtained by the following calculation. The road projection distances L _A ′ and L _B ′ of the vehicle 1 from the reception antennas 2 and 3 are expressed by the following equations (3) and (4). (Equation 1) If the road surface projection distances L _A ′ and L _B ′ are used, the distances L _A and L _B of the vehicle 1 from the reception antennas 2 and 3 are expressed by the following equations (5) and (6). (Equation 2) Here, the reception phase φ of the reception antennas 2 and 3
_A, is phi _B following equation (7), represented by (8). _{φ A = (L A / λ} ) · 2π ······ (7) φ B = where _{(L B / λ) · 2π} ······ (8), the reception phase phi _A, phi _B is a continuous phase, for receiving phase is 0~2π (rad), a modulo 2 [pi phi _a, and phi _B. That is, φ _A = MOD
[(L _A / λ) · 2π, 2π], φ _B = MOD [(L _B
/ Λ) · 2π, 2π]. Here, "MOD" is
This means taking the remainder of the division. That is, the formula C = MO
D (A, B) means that C is the remainder of A ÷ B. The aforementioned phi _A, reception phase on the basis of the phi _B difference Δφ
Can be expressed as in the following equation (9). Δφ = φ _A −φ _B (9) At this time, the following processing is performed to maintain continuity.
That is, when Δφ <−π, Δφ = (φ _A −φ _B ) +
2 [pi, when [Delta] [phi> [pi, and _{Δφ = (φ A -φ B)} -2π. Using the phase difference Δφ obtained in this way, the angle θ of the arriving radio wave can be expressed in the same manner as in the above equation (1). Therefore, the angle θ of the arriving radio wave can be obtained by using the above equations (3) to (9), and the distance X can be obtained by the above equation (2) using this angle θ. This means that the distance X is a function of the antenna depression angle Ψ, the antenna height h _ANT , the traveling direction distance x, and the road width direction distance y. An equation including the antenna depression angle Ψ, the antenna height h _ANT , the traveling direction distance x, and the road width direction distance y as functions can be made corresponding to the number of on-vehicle devices. That is,
The in-vehicle device emits radio waves from a plurality of different positions and measures the position of each in-vehicle device to measure the antenna depression angle Ψ, antenna height h _ANT , travel direction distance x and road width direction distance according to the position of each in-vehicle device. An expression including y is obtained. Therefore, if an appropriate number of equations can be created with the antenna depression angle Ψ and the antenna height h _ANT as unknowns, the antenna depression angle Ψ and the antenna height h _ANT in an actually installed state should be obtained as a solution to the equations. Can be. FIG. 3 is an explanatory view conceptually showing a jig for obtaining the above equation. The jig is placed on a road surface on which the receiving antennas 2 and 3 to be calibrated are installed, and is measured at a predetermined height (this is h _OBE in the above equation (2)). 5 wireless devices 1
1, 12, 13, 14, and 15 are arranged at predetermined intervals in a horizontal plane to be portable, and are arranged in an arbitrary state with respect to the receiving antennas 2 and 3. That is, the distance and height between the radios 11 to 15 are known,
Although it can be considered that no error is included, the entire jig is shifted with respect to the position where the in-vehicle device should be installed (the position indicated by a circle in the figure). In such a jig, the position (x, y) of the wireless device 11 whose origin is immediately below the receiving antennas 2 and 3 is a position that changes depending on how the jig is placed. On the basis of the position (x, y) of the wireless device 11, the positions of the wireless devices 12 to 15 can be expressed by the following equation (10). X coordinate of the wireless device 12 = x + α · COSγ y coordinate of the wireless device 12 = y + α · SINγ x coordinate of the wireless device 13 = x + 2α · COSγ y coordinate of the wireless device 13 = y + 2α · SINγ (10) x coordinate = x + α · COSγ−β · SINγ y coordinate of the wireless device 14 = y + α · SINγ + β · COSγ x coordinate of the wireless device 15 = x + α · COSγ + β · SINγ y coordinate of the wireless device 15 = y + α · SINγ−β · COSγ Using the relationship of equation (10), the positions of the radios 12 to 15 can be represented using the position of the radio 11. Here, the angle γ is an angle that changes depending on how the jig is placed on the road surface, and therefore needs to be an unknown number. Therefore, together with the antenna depression angle Ψ and the antenna height h _ANT that need to be obtained when calibrating the installation state of the receiving antennas 2 and 3, the reference wireless device 11 changes depending on how the jig is placed on the road surface. Position (x, y)
And five angles including the angle γ and unknowns, and forming five equations using these as functions, the antenna depression angle Ψ and the antenna height h in the actually installed state as solutions of the equations.
You can ask for _ANT . In this case, the equations are as follows.
Location X of each radio 11 to 15 by actual measurement using
Can be made using That is, radio waves are emitted from the wireless devices 11 to 15 toward the receiving antennas 2 and 3,
Based on the angle θ of the arriving radio wave obtained by the above equation (1), each of the orientation positions X of each of the wireless devices 11 to 15 based on the above equation (2).
_1, X _2, X ₃ , X ₄ , and X ₅ are functions of the antenna depression angle Ψ, the antenna height h _ANT , the position (x, y) of the wireless device 11, and the angle γ. In this case, five equations are generated for five unknowns. By solving these equations, the antenna depression angle Ψ and the antenna height h _ANT can be obtained. Therefore, the jig is appropriately placed on the road surface on which the receiving antennas 2 and 3 are installed, and radio waves are emitted from each of the radios 11 to 15 toward the receiving antennas 2 and 3, and the radio waves are emitted as described above. Of each radio 11
Or it is possible to obtain the position X ₁ to X ₅ of 15, further making the equation using the position information, the antenna depression Ψ and antenna height of the reception antenna 2 in the actual installation state by solving this h _ANT can be determined. Therefore, after that, by calibrating the set value indicating the mounting state of the receiving antennas 2 and 3 based on the antenna depression angle Ψ and the antenna height h _ANT , the receiving antennas 2 and 3 are maintained in a predetermined installation state. The system can be operated. The solution of the above equation can also be obtained by the following method. That is, similarly to the above-described method, the jig is placed on the road surface, and the positions of the wireless devices 11 to 15 are located. After that, by the processing of the computer, the set values, that is, the antenna depression angle Ψ, the antenna height h _ANT , the x, y coordinates and the angle γ of the wireless device 11 are swept as parameters, and these values are swept so as to match the measured values. Find the optimal setting value. The system is operated using the set values thus obtained. In the above embodiment, the five radios 1
In the case of making five equations using 1 to 15,
This number is not limited to this. The number is not particularly limited as long as the number is 5 or more. This is because there are at least five unknowns. If the number of unknowns can be reduced to six by setting the number of radios to six, the reception antennas 2 and 3
Can be obtained in the horizontal plane, and thereby, the set angles of the receiving antennas 2 and 3 in the horizontal plane can be calibrated so as to be the predetermined angles. Further, one more radio than the unknown number (in the above embodiment, there are five unknowns, and in this case, six), is disposed in the jig, and If the position is also determined, it is possible to obtain one more equation than the number of unknowns. As a result, from among these equations (six in the above-described embodiment), a plurality of sets of equations having one set of equations of the number of unknowns (five in the above-described embodiment) are sequentially selected. As a solution to the equation, a plurality of sets of antenna depression angles と し て and antenna heights h _ANT can be obtained. Therefore, in this case, it is possible to calibrate the antenna depression Ψ and antenna height h _ANT receive antennas based on the average value of the plurality of sets of antennas depression Ψ and antenna height h _ANT to a predetermined manner. Further, in the above jig, the radios 11 to 15 are arranged in a horizontal plane of the same height, but the present invention is not limited to this. As long as the distance to the reference wireless device (for example, the wireless device 11) is known and can be handled as including no error, the reference wireless device may be disposed in the same vertical plane, or may be distributed in the horizontal plane and the vertical plane. May be arranged. As described in detail with the above embodiments, the invention described in [Claim 1] is a receiving antenna installed at a predetermined height and a predetermined depression angle, which is mounted on a vehicle. A radio wave emitted from a vehicle-mounted device, which is a wireless device, is received, the arrival angle of the radio wave is detected, and the distance from the reception antenna to the vehicle-mounted device is detected based on the arrival angle. A calibration method, comprising: arranging radio waves from at least five radios whose distances and heights are known to each other toward the receiving antenna, and arranging the radios at different positions, and locating the radios. To obtain an equation containing at least five unknowns representing the position of each radio, the solution of which is at least the actual height and location of the receiving antenna. Since the depression angle is obtained and at least the height and the depression angle are calibrated as predetermined, the expression representing the position of each wireless device includes the height of the reception antenna and the depression angle of the reception antenna as a function, and Since there are as many relational expressions as unknowns, at least the height of the receiving antenna and the depression angle of the receiving antenna can be obtained as a solution of the equation in this case. This solution becomes the actual installation height and installation depression angle of the receiving antenna. Therefore, according to the present invention, it is possible to calibrate at least the installation height and the installation depression angle of the reception antenna based on the actual installation height and the installation depression angle of the reception antenna, and to accurately determine the distance using the reception antenna. Can be done. According to a second aspect of the present invention, in the method for calibrating the installation position / posture of the receiving antenna according to the first aspect, the number of radios is six or more, and at least five unknowns are included. In addition, six or more equations that are one more than the number of unknowns are obtained, and a plurality of sets of at least five equations are sequentially selected from among the six or more equations, and a plurality of sets are set as solutions of the plurality of equations. At least the installation height and the installation depression angle are obtained, and at least the receiving antenna height and the depression angle are calibrated as specified based on the average values thereof, so that more accurate calculation is performed based on the average value of the solutions of the plural sets of equations. Solution can be obtained. As a result, according to the present invention, the actual installation height and installation depression angle of the receiving antenna can be obtained more accurately than in the case of the invention described in [Claim 1], and the receiving antenna is used accordingly. This distance can be detected with higher accuracy also in the distance orientation. According to a third aspect of the present invention, there is provided a jig for use in the method for calibrating the installation position / posture of the receiving antenna according to the first or second aspect, wherein at least five jigs are provided. Since the wireless devices are arranged at predetermined intervals in a horizontal plane, the invention described in [Claim 1] or [Claim 2] can be satisfactorily implemented. As a result, the installation state such as the installation height and the depression angle of the receiving antenna can be easily calibrated. According to a fourth aspect of the present invention, there is provided a jig for use in the method for calibrating the installation position / posture of a receiving antenna according to the first or second aspect, wherein at least five jigs are provided. Since the wireless devices described above are arranged at predetermined intervals in a vertical plane, the invention described in [Claim 1] or [Claim 2] can be satisfactorily implemented. As a result, the installation state such as the installation height and the depression angle of the receiving antenna can be easily calibrated. According to a fifth aspect of the present invention, there is provided a jig used in the method for calibrating the installation position / posture of a receiving antenna according to the first or second aspect, wherein at least five jigs are used. Since the wireless devices are arranged at predetermined intervals in the horizontal plane and the vertical plane, the invention described in [Claim 1] or [Claim 2] can be satisfactorily implemented. As a result, the installation state such as the installation height and the depression angle of the receiving antenna can be easily calibrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram for detecting an angle θ of an incoming radio wave by actual measurement. FIG. 2 is an explanatory diagram conceptually showing the relationship between a receiving antenna and a vehicle that performs position location. FIG. 3 is an explanatory diagram conceptually showing an embodiment of the present invention. [Description of Signs] 1 Vehicle 1a In-vehicle unit 2, 3 Receiving antenna 7 Phase difference meter 11 to 15 Radio unit (in-vehicle unit) X Orientation position θ Angle of arriving radio wave 俯 Antenna depression angle h _ANT antenna height x _Traveling distance y Road Width distance

Continuation of the front page (56) References JP-A-9-319901 (JP, A) JP-A-11-120396 (JP, A) JP-A-11-339079 (JP, A) JP-A-2000-48227 (JP, A A) JP-A-11-203426 (JP, A) Patent 3303676 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 3/00-3/74 G01S 11/00 G07B 15 / 00

Claims (1)

(57) [Claims] [Claim 1] A receiving antenna installed at a predetermined height and a predetermined depression angle receives a radio wave emitted from a vehicle-mounted device which is a radio device mounted on a vehicle, and receives the radio wave. This is a method for calibrating the installation position of a receiving antenna in a distance detection system that detects the angle of arrival of the receiving antenna and detects the distance from the receiving antenna to the vehicle-mounted device based on the angle of arrival. From at least five radios whose distances and heights are known, radio waves are respectively emitted toward the receiving antennas, and by locating the radios, at least five radios representing the positions of the radios are obtained. Is obtained, and at least the actual installation height and installation depression angle of the receiving antenna are obtained as a solution to this equation, and at least these heights and depression angles are calibrated as specified. A method for calibrating the installation position / posture of a receiving antenna, characterized in that: 2. The method of claim 1, wherein the number of radios is six or more, the radio includes at least five unknowns, and one is less than the number of unknowns. A large number of six or more equations are obtained, a plurality of sets of at least five equations are sequentially selected from among the six or more equations, and a plurality of sets of at least the installation height and the installation depression angle are determined as solutions of the plurality of equations. Wherein the height and the depression angle of at least the receiving antenna are calibrated in a predetermined manner based on these average values. 3. A jig used in the method for calibrating the installation position / posture of a receiving antenna according to [1] or [2], wherein at least five radios are arranged at predetermined intervals on a horizontal plane. A jig characterized by being arranged inside. 4. A jig for use in the method for calibrating an installation position / posture of a receiving antenna according to claim 1 or 2, wherein at least five radios are vertically arranged at a predetermined interval. A jig arranged in a plane. 5. A jig for use in the method for calibrating the installation position / posture of a receiving antenna according to claim 1 or claim 2, wherein at least five radios are arranged at predetermined intervals on a horizontal plane. A jig disposed inside and in a vertical plane.