JP3508531B2 - Direction detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth detecting device for detecting a specific direction such as a traveling direction of a moving body.

[0002]

2. Description of the Related Art FIG. 12 shows, for example, Japanese Patent Laid-Open No. 6-11815.
It is a block diagram of the conventional azimuth | direction detection apparatus shown by the 5th publication. In the figure, 1 is a broadcasting satellite on a geostationary orbit that transmits satellite broadcasting waves, 2 is a BS antenna that receives the electromagnetic waves from the broadcasting satellite 1, 3 is a motor that rotates the BS antenna 2,
Reference numeral 4 is a motor driver for driving the motor 3, 5 is a rotary encoder for detecting the rotation angle of the BS antenna 2, and 6 is an antenna rotation angle position detection unit for detecting the rotation angle position of the BS antenna 2 from the output of the rotary encoder 5. . 7
Is a BS tuner that receives the radio waves received by the BS antenna 2, and 8 is a satellite tracking control unit that monitors the strength of the radio waves received by the BS tuner 7 and controls the motor driver 4 so that the BS antenna 2 faces the broadcasting satellite 1. Is. Reference numeral 9 denotes a traveling azimuth calculation unit that calculates the traveling azimuth of the moving body, and 10 denotes an absolute azimuth storage unit that stores the azimuth when the broadcasting satellite is viewed from the moving body.

The satellite tracking control unit 8 rotates the BS antenna 2 so as to face the broadcast satellite 1, and the antenna rotation angle position θ when the BS antenna 2 faces the broadcast satellite 1 is detected by the antenna rotation angle position detection unit 6. To do. Heading calculation unit 9
Is the antenna rotation angle position θ detected by the antenna rotation angle position detection unit 6 and the absolute azimuth Θ when the broadcast satellite 1 is viewed from the moving body stored in the absolute azimuth storage unit 10, Calculate and obtain. For example, since the absolute azimuth of the broadcasting satellite 1 seen from all over Japan is in the range of 212 ° to 226 °, there is a method of setting the absolute azimuth Θ stored in the absolute azimuth storage unit 10 to 220 °, or the presence of a moving body. There is a method of storing the absolute azimuth of the broadcasting satellite 1 corresponding to the region and the latitude and longitude. For the position of the moving body, GPS (Global Positioning)
It is also possible to measure using System).

[0004]

In such a conventional azimuth detecting apparatus, the absolute azimuth Θ of the satellite viewed from the point where the moving body exists is stored in the apparatus in a data format and is referred to. The satellite to be tracked must be a geostationary satellite whose apparent position from the earth is stationary. When the azimuth detecting device is used only in Japan, the azimuth can be detected if there is an antenna and a receiver for receiving the data of the absolute azimuth Θ and the radio wave from the broadcasting satellite as described above. However, when using azimuth detectors in various countries around the world, the geostationary satellites that can be received differ from region to region,
Data for absolute azimuth Θ of geostationary satellites will be created for each region, and antennas and receivers specific to each satellite will be required, and the compatibility between devices will not be maintained, resulting in poor manufacturability and maintainability. There are challenges.

The present invention has been made in order to solve the above-mentioned problems, and it receives radio waves from GPS satellites instead of radio waves from geostationary satellites such as broadcasting satellites having a limited reception area. It is intended to obtain an azimuth detecting device capable of detecting azimuth and detecting an azimuth in a wide area.

[0006]

An azimuth detecting apparatus according to the invention of claim 1 receives a GPS signal to detect the position of a GPS satellite.
Position information calculating means for calculating information and position information of a moving body
And the position of the GPS satellite by this position information calculation means
Based on the information and the position information of the moving body,
Absolute azimuth for calculating the absolute azimuth of the above GPS satellite in
Angle calculation means and the azimuth direction of a part of the omnidirectional antenna
This antenna, which is shielded to partially reduce the gain, and this antenna
The tena receives the radio waves from the above GPS satellites and
Above the GPS satellite in the moving body due to wave strength
Relative azimuth detection to detect relative azimuth with respect to specific direction
Based on the output means, the relative azimuth and the absolute azimuth
Calculate the absolute azimuth angle of the specific direction in the moving body
Azimuth calculation means for
Part of the gain in the azimuth direction by shielding part of the directional antenna
And a shield plate that reduces the
Shielding plate drive that shields the directional antenna and releases it
Means, and the omnidirectional by the shielding plate driving means.
The shield of the aerial antenna is released and the GPS signal is received.
The position information of the GPS satellites and the position information of the moving body are calculated .

The azimuth detecting device according to the invention of claim 2 is a contractor.
In the azimuth detecting device according to the invention of claim 1, the antenna
Turns the shielding plate around the omnidirectional antenna.
It is provided with a shielding plate rotating means .

[0008]

[0009]

[0010]

[0011]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. The azimuth detecting apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a block diagram of an azimuth detecting apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 11 denotes a position information calculation unit that receives GPS signals and calculates position information of GPS satellites and position information of a moving body. Reference numeral 12 is an omnidirectional antenna for receiving GPS signals, and 13 is a GPS receiver. 1
Reference numeral 4 is an amplifier for amplifying the GPS signal, 15 is a local oscillator for generating a reference signal for modulating the GPS signal into a signal in the intermediate frequency band, and 16 is a down converter. Reference numeral 17 denotes a satellite selection unit that despreads and converts the GPS signal received according to the GPS satellite. The GPS receiver 13 calculates the position information of the moving body based on the GPS signals from three GPS satellites in the case of two-dimensional positioning and the GPS signals from four GPS satellites in the case of three-dimensional positioning. In order to receive these signals at the same time, the satellite selection unit 17 is composed of at least three satellite selection circuits. 18 sends a despreading code to the satellite selection unit 17, decodes the GPS satellite position information and time information from the GPS signal output by the satellite selection unit 17, and performs the above-described two-dimensional positioning or three-dimensional positioning of the moving body. It is a control decoding circuit that calculates position information.
Reference numeral 19 is an absolute azimuth angle calculation circuit for calculating the absolute azimuth of the GPS satellite as seen from the mobile body based on the position information of the GPS satellite and the position information of the mobile body from the control decoding circuit 18. 20 is a directional antenna for receiving radio waves from GPS satellites, 21
Rotates the directional antenna 20 in the azimuth direction with respect to the specific direction (for example, the traveling direction) specified in the moving body,
The antenna control circuit outputs the angle of the directional antenna 20. Reference numeral 22 is a switch for switching between the outputs of the omnidirectional antenna 12 and the directional antenna 20 and inputting them to the GPS receiver 13. Reference numeral 23 detects the relative azimuth angle between the specific direction and the GPS satellite based on the angle signal from the antenna control circuit 21 and the GPS signal from the directional antenna 21 that is despread and converted by the satellite selector 18 via the switch 22. It is a relative azimuth angle detector. Reference numeral 24 is a reception level detector that monitors the strength of the GPS signal from the directional antenna 21 that has been despread and converted by the satellite selector 17 via the switch 22.
An angle output circuit 5 holds and outputs an angle signal output from the antenna control circuit based on the output of the reception level detector 24. An azimuth calculation circuit 26 calculates the absolute azimuth angle of the specific direction from the relative azimuth angle detected by the relative azimuth angle detection unit 23 and the absolute azimuth angle calculated by the absolute azimuth angle calculation circuit 19.

21 (+3 spare) GPS units in orbit
Satellites are in orbit, and positioning can be performed by receiving GPS signals from GPS satellites all over the world. The omnidirectional antenna 12 receives GPS signals of GPS satellites which are visible from the mobile body, and the received GPS signals are input to the GPS receiver 13. In the GPS receiver 13, for example, when performing three-dimensional positioning, the four GPS units are used as described above.
A signal from the satellite is required, and the satellite selection unit 17 demodulates the received GPS signal based on the four despreading codes from the control decoding circuit 18, and the GPS signals from the four GPS satellites are received.
Receive signals without interference. Control decoding circuit 18
Detects the position information and time information of the GPS satellite from the received GPS signal, and calculates the position information of the moving body by two-dimensional positioning or three-dimensional positioning. The absolute azimuth angle calculation circuit 19 calculates the absolute azimuth angle of the GPS satellite viewed from the mobile body based on the position information of the GPS satellite and the position information of the mobile body decoded by the control decoding circuit 18. Figure 2 shows a moving body (point P) and a GPS satellite (point Q) in an orthogonal three-dimensional coordinate system centered on the earth (point O).
It shows the positional relationship of. GPS as seen from the mobile
The absolute azimuth angle Θ of the satellite is represented by an angle NPR shown in FIG. 3, where R is a point obtained by projecting the point Q on the NE plane (N is north, E is east) which is in contact with the earth surface at the point P.

In FIG. 3, the direction PS is a specific direction specified in the moving body, such as the traveling direction of the moving body. The directional antenna 20 rotates in the azimuth direction with respect to the direction PS, and the antenna control circuit 21 outputs the rotation angle for the specific direction to the angle output circuit 25. A GPS signal from a GPS satellite received by the directional antenna 20 is input to the GPS receiver 13 via the switch 22, despread-converted by the satellite selector 17 and input to the reception level detector 24. As described above, when performing, for example, three-dimensional positioning, in order to receive GPS signals from four GPS satellites without interference, the GPS signals from each GPS satellite are spread-modulated below the noise level. There is. Therefore, in order to monitor the strength and weakness of the GPS signal, it is preferable to use a signal obtained by despreading the GPS signal. The reception level detector 24, as shown in FIG.
Detects the level of the GPS signal that changes with the rotation of 0,
Output to the angle output circuit. As shown in FIG. 4, the angle output circuit 25 uses the directional antenna 2 having a peak reception level.
The rotation angle θ _{R of} 0 is held and output to the azimuth calculation circuit 26. As shown in FIG. 3, the azimuth calculation circuit 26 detects the absolute azimuth angle Θ of the GPS satellite viewed from the mobile body calculated by the absolute azimuth calculation circuit 19 and the specific direction of the mobile body detected by the angle output circuit 25. Relative azimuth θ _R
And the absolute azimuth angle α (= Θ-θ _R ) of the moving body in a specific direction
To calculate. If the directional antenna 20 has a wide radiation pattern in the elevation direction and a narrow radiation pattern in the azimuth direction, the directional antenna 20 moves on the circular orbit while changing the elevation angle without driving the antenna in the elevation direction. GP
GPS signals from S satellites can be received.

Embodiment 2. In the first embodiment, the absolute azimuth angle calculation circuit 19 calculates the absolute azimuth angle for one GPS satellite, and the relative azimuth angle detector 23 in the relative azimuth angle detection unit 23 calculates the absolute azimuth angle based on the strength of the GPS signal received by the directional antenna 20. The relative azimuth angle of the mobile unit with respect to the specific direction was detected, and the absolute azimuth angle of the mobile unit in the specific direction was calculated by the azimuth calculation circuit 26. The absolute azimuth angles of a plurality of GPS satellites were calculated as shown in FIG. Alternatively, the directional antenna 20 may be used to calculate and receive GPS signals from these GPS satellites to detect the relative azimuth angle of each GPS satellite with respect to the specific direction of the moving body. In FIG. 5, R1, R2, and R3 are points obtained by projecting, for example, three positions out of four GPS satellites received in three-dimensional positioning on the NE plane, and the angle Θ
_R1 , Θ _R2 , and Θ _R3 are absolute azimuth angles of each GPS satellite calculated by the absolute azimuth angle calculation circuit 19. The GPS signal received by rotating the directional antenna 20 is received by the satellite selector 17
Reception level detector 24 that is despread and converted by the satellite selection circuit of
Is monitored as shown in FIG. In FIG. 6, θ
_R1 + ε _R1 , θ _R2 + ε _R2 , and θ _R3 + ε _R3 are rotation angles of the directional antenna 20 at which the level of the GPS signal from each GPS satellite reaches a peak. Depending on the accuracy and resolution of the reception level detector, It is assumed that there are errors in _R1 , ε _R2 , and ε _R3 . From FIG. 5, the errors ε _R1 , ε _R2 , ε _R3 are

[0016]

[Equation 1]

[0017]

[Equation 2]

[0018]

[Equation 3]

And the azimuth calculation circuit 26 uses the errors ε _R1 , ε
The absolute azimuth angle α in the specific direction of the moving body that minimizes the sum of squares of _R2 and ε _R3 is calculated by the following formula.

[0020]

[Equation 4]

Here, C1, C2 and C3 are given by the following equations.

[0022]

[Equation 5]

[0023]

[Equation 6]

[0024]

[Equation 7]

When α is 360 deg or more, α
The value obtained by subtracting 360 deg from is to be set as α again.
If the number of GPS satellites used for azimuth detection increases as described above, the accuracy of azimuth detection improves.

Embodiment 3. In the first embodiment, the directional antenna 20 is rotated to detect the rotation angle of the directional antenna 20 at which the reception level reaches the peak as shown in FIG. An antenna in which a part of the antenna is shielded in the azimuth direction by a shield plate may be used. In FIG. 7, 27 is an omnidirectional antenna, and 28 is a shielding plate. Since the omnidirectional antenna 27 is partially shielded in the azimuth direction by the shield plate 28, when the antenna is rotated in the azimuth direction, the GPS signal from the GPS satellite is generated by the shield plate 28 as shown in FIG. The reception level drops when in the direction of GPS satellites. The angle output circuit 25 detects the rotation angle θ _R of the moving body from the specific direction at which the reception level becomes the minimum, and outputs it to the azimuth calculation circuit 26. The azimuth calculation circuit 26 calculates the absolute azimuth angle α (= θ−θ _R ) of the moving body in a specific direction as in the first embodiment.

Fourth Embodiment In the first embodiment, the omnidirectional antenna 12, the directional antenna 20, and the switch 22 that switches the outputs of these antennas constitute the front stage of the GPS receiver 13. However, the omnidirectional antenna as shown in FIG. It is also possible to use an antenna in which a part of the azimuth angle direction is shielded by a shield plate and the shield plate can be rotated about the elevation axis. In FIG. 9, reference numeral 29 is a rotary base having a hinge capable of rotating the shield plate 28 around the elevation axis and rotating about the azimuth axis. With respect to the rotation of the turntable 29 about the azimuth axis, the omnidirectional antenna 27 is attached to the shield plate 28 and the turntable 29.
The omnidirectional antenna 27 may be fixed, and only the shield plate 28 and the turntable 29 may be rotated together. However, the latter has a smaller inertia in the movable part, and the omnidirectional antenna is therefore possible. It is easy to fix the RF cable from 27. The shield plate 28 is rotated around the elevation axis in the hinge using a motor or the like. FIG. 10 is a block diagram of an azimuth detecting apparatus according to Embodiment 4 of the present invention. Figure 1
At 0, 30 is a shield plate drive circuit for generating a drive signal for rotating the shield plate 28 around the elevation axis, and 31
Is a shield plate rotation circuit that generates a signal for rotating the shield plate 28 and the turntable 29 about the azimuth axis.

After the shield plate 28 is rotated in the direction in which the elevation angle becomes smaller as shown in FIG. 9 to release the shield of the omnidirectional antenna 27, GPS signals are received and the GPS receiver 13 receives the G signal.
The position information of the PS satellite and the position information of the moving body are calculated. After the shield plate 28 is rotated in the direction of increasing the elevation angle shown in FIG. 9 to shield a part of the azimuth angle of the omnidirectional antenna 27, the shield plate 28 and the turntable 29 are rotated, as shown in FIG. When the shield plate 27 is in the direction of the GPS satellite, the reception level is lowered, and the relative azimuth angle θ of the GPS satellite with respect to the specific direction of the moving body is detected.

Embodiment 5. In the fourth embodiment, the shield plate 28 is rotated around the elevation axis to rotate the omnidirectional antenna 27.
However, the shielding plate 28 may be rotated around the horizontal axis of the turntable 29 as shown in FIG. When the shield plate 28 is rotated in the direction of decreasing the elevation angle shown in FIG. 9, the tip end of the shield plate 28 moves in the direction away from the azimuth axis, so that the space occupied by the device becomes large.
When the shield plate 28 is rotated around the horizontal axis as shown in FIG. 9, the tip portion of the shield plate 28 moves closer to the azimuth axis than in the case of FIG. 9, so the space occupied by the device becomes smaller.

[0030]

According to the invention described in claim 1, non-directional
Partial azimuth shielding of the antenna
GPS for specific direction of moving body by reduced antenna
The GPS signal for detecting the relative azimuth of the satellite is detected and
The position information of GPS satellites and the position of the
Since the GPS signal for calculating the location information is received,
You can have one antenna.

According to the invention of claim 2, the omnidirectional antenna
Is fixed and the shield is rotated, so
Sha can be made smaller.

[0032]

[0033]

[0034]

[0035]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an azimuth detecting device according to a first embodiment of the present invention.

FIG. 2 is a moving body and a GP according to the first embodiment of the present invention.
The schematic diagram which shows the positional relationship of S satellite.

FIG. 3 is a schematic diagram showing a relationship between a specific direction of a mobile body and an absolute azimuth direction of a GPS satellite according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing an output of the reception level detector when the directional antenna according to the first embodiment of the present invention is rotated.

FIG. 5 is a schematic diagram showing a relationship between a specific direction of a mobile unit and an absolute azimuth direction of three GPS satellites according to the second embodiment of the present invention.

FIG. 6 is a characteristic diagram showing an output of a reception level detector when the directional antenna according to the second embodiment of the present invention is rotated to receive GPS signals of three GPS satellites.

FIG. 7 is a perspective view showing the configuration of an antenna in which a part of the omnidirectional antenna according to the third embodiment of the present invention is shielded in the azimuth direction.

FIG. 8 is a characteristic diagram showing an output of a reception level detector when an antenna in which a part of the omnidirectional antenna according to the third embodiment of the present invention is shielded in the azimuth direction is rotated.

FIG. 9 is a configuration diagram of an antenna that shields and unshields a part of the omnidirectional antenna in the azimuth direction according to the fourth embodiment of the present invention.

FIG. 10 is a configuration diagram of an azimuth detecting device according to a fourth embodiment of the present invention.

FIG. 11 is a configuration diagram of a part of the omnidirectional antenna according to the fifth embodiment of the present invention that shields in the azimuth direction and rotates the shield plate around the horizontal axis to release the shield.

FIG. 12 is a configuration diagram of a conventional azimuth detecting device.

[Explanation of symbols]

11 Position calculator 12 Omnidirectional antenna 13 GPS receiver 19 Absolute azimuth calculation circuit 20 Directional antenna 22 Switch 23 Relative azimuth angle detector 26 Direction calculation circuit 27 Omnidirectional antenna 28 Shield 30 Shield drive circuit 31 Shield plate rotation circuit

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-93364 (JP, A) JP-A-59-90112 (JP, A) JP-A-5-75338 (JP, A) JP-A-4- 125417 (JP, A) JP-A-6-118155 (JP, A) JP-A-4-161876 (JP, A) JP-A-4-161877 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/00-5/14 H01Q 3/00-3/46 H01Q 21/00-25/04

Claims (2)

(57) [Claims] 1. Position of a GPS satellite by receiving a GPS signal
Position information calculating means for calculating information and position information of a moving body
And the position of the GPS satellite by this position information calculation means
Based on the information and the position information of the moving body,
Absolute azimuth for calculating the absolute azimuth of the above GPS satellite in
Angle calculation means and the azimuth direction of a part of the omnidirectional antenna
This antenna, which is shielded to partially reduce the gain, and this antenna
The tena receives the radio waves from the above GPS satellites and
Above the GPS satellite in the moving body due to wave strength
Relative azimuth detection to detect relative azimuth with respect to specific direction
Based on the output means, the relative azimuth and the absolute azimuth
Calculate the absolute azimuth angle of the specific direction in the moving body
Azimuth calculation means for
Part of the gain in the azimuth direction by shielding part of the directional antenna
And a shield plate that reduces the
Shielding plate drive that shields the directional antenna and releases it
Means, and the omnidirectional by the shielding plate driving means.
The shield of the aerial antenna is released and the GPS signal is received.
Calculates GPS satellite position information and mobile unit position information
An azimuth detecting device characterized by the above. 2. The antenna comprises the finger-less shield plate and the finger-free cover plate.
Shielding plate rotating means for rotating around the directional antenna
The azimuth detecting device according to claim 1, wherein