JPH09274072A - Control device for vehicle-mounted satellite antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid tracking deviation by correcting the driving amount for driving an antenna based on the output of a gyroscope in the control of the satellite receiving antenna using the gyroscope. SOLUTION: A satellite receiving antenna 10 is mounted on a vehicle, and the satellite is tracked by rotating this antenna 10 by a stepping motor 16. The driving amount of the stepping motor 16 is determined by a control device 26 based on the output from a vibration gyroscope 18. The control signal is outputted to a stepping-motor driver 28. The control device 26 drives the antenna 10 at the same angular speed of the vehicle so as to face the reverse direction based on the output of the gyroscope. The amount of 1/2 of the difference from the driving amount at the previous time is added to the present driving amount and the correction is performed so as to eliminate the errors accompanied by the digitalization at an A/D board 22. Thus, the descretization errors are approximately eliminated, and the highly accurate tracking can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted satellite receiving antenna controller, and more particularly to tracking control of a vehicle-mounted satellite receiving antenna using a gyro sensor.

[0002]

2. Description of the Related Art Conventionally, it has been mounted on a moving body such as an automobile,
A device has been developed to constantly track the BS and receive radio waves in order to direct the onboard satellite receiving antenna to the direction of the broadcasting satellite (hereinafter referred to as BS). A gyro sensor that detects the turning state of a moving body such as a vehicle is used. A technique is generally used in which the vehicle-mounted satellite receiving antenna is rotationally driven based on the output from the gyro sensor.

For example, Japanese Patent Laid-Open No. 4-232483 discloses a configuration for driving a receiving antenna. In addition to the output from the gyro sensor, the antenna is swung right and left by a small angle to compare the signal strength between the current reception level and the previous reception level, and the step track that drives the reception antenna in the direction in which the signal level increases. A technique for performing control together has also been developed (Japanese Patent Laid-Open No. 4-33682).
No. 1).

[0004]

However, when the tracking operation is performed by rotationally driving the vehicle-mounted satellite receiving antenna based on the output (yaw rate) from the gyro sensor in this way, the output from the gyro sensor is output every predetermined time (for example, 5 msec), the driving amount of the stepping motor etc. is determined based on the detection value at the sampling timing, and the driving amount is kept constant until the next sampling timing, whereas the output from the gyro sensor is It changes continuously over time.
Therefore, an error occurs between the continuous value and the discrete value, and the drive amount to the stepping motor includes the error.

FIG. 4 schematically shows the drive amount (pulse rate) to the stepping motor for expressing this error with time. In FIG. 4, the horizontal axis is time,
The sampling timing is 5 msec. The vertical axis indicates the drive amount to the stepping motor (pulse count / se
c). While the gyro output changes continuously from one sampling timing to the next sampling timing, the drive amount for rotationally driving the stepping motor based on this gyro output is a constant value. An error as indicated by the shaded area in the figure occurs between the two, and this error becomes larger as the gyro output change increases. Therefore, this error may be integrated after a lapse of a predetermined time, and the direction of the directional beam of the antenna may be largely deviated from the direction of the satellite.

As a method of reducing this error, a method of narrowing the sampling interval and shortening the cycle for driving and controlling the motor can be considered. However, this method is a CP that enables high-speed calculation in order to calculate the drive amount of the motor in a short time.
Requires U. However, such a CPU inevitably consumes a large amount of current, and thus is not suitable for a vehicle-mounted device in which low current consumption is particularly important. From the viewpoint of current consumption, it is desirable that satellite tracking be performed accurately even if the sampling interval is set wide.

The present invention has been made in view of the above problems of the prior art, and its object is to perform a gyro output (that is, a turning amount of a vehicle) in tracking control for rotationally driving a satellite receiving antenna based on an output from a gyro sensor. ) And the drive amount for rotationally driving the vehicle-mounted satellite receiving antenna are suppressed, and a vehicle-mounted satellite receiving antenna control device capable of accurately tracking the satellite even when the vehicle turns at high speed is provided. Especially.

[0008]

In order to achieve the above object, a first invention is a control device for orienting a vehicle-mounted satellite receiving antenna in the direction of a satellite, which is a gyro sensor for detecting a turning amount of a vehicle. And a stepping motor that rotationally drives the vehicle-mounted satellite receiving antenna to change the directivity of the antenna in the azimuth direction, and a control that controls the driving amount of the step motor based on the turning amount detected by the gyro sensor. Means and correction means for correcting the drive amount based on the difference amount between the current turning amount detected by the gyro sensor and the previous turning amount.

In order to achieve the above object, in the second invention, in the first invention, the correction means sets the current turning amount to a half of the difference between the present turning amount and the previous turning amount. Characterized by adding to the quantity.

As described above, in the present invention, the driving amount for driving the step motor is corrected based on the difference between the previously detected turning amount and the present turning amount.
As a correction method, 1/2 of the difference value between the current turning amount and the previous turning amount may be added to the current driving amount. As shown in FIG. 4 described above, the error between the gyro output and the drive amount of the step motor (that is, the turning amount of the receiving antenna) is indicated by the shaded area. This error amount is the current turning amount and the previous turning amount. Is approximately equal to 1/2 of the difference value of, and by adding this correction amount to the current step motor drive amount, it becomes possible to easily and surely suppress the error.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an on-vehicle satellite receiving antenna and a tracking device according to this embodiment. The satellite receiving antenna (BS antenna) 10 is connected to a BS tuner 14 inside the vehicle through a converter 12, and the satellite broadcast received by the antenna 10 is demodulated by the BS tuner 14 and is not shown as a video output in a CR (not shown).
It is output to T etc. The antenna 10 is provided with a stepping motor 16 that changes the direction of directivity by rotationally driving the antenna, and the drive amount of the stepping motor 16 is determined by a control signal from the vehicle interior unit. Any antenna may be used as long as it has a certain directivity. For example, a plane beam tilt antenna as shown in FIG. 5 is preferable. The plane beam tilt antenna is a plane antenna in which the beam of the antenna is tilted by a certain angle from the vertical direction by adjusting the phase of each element of the antenna. The directivity of this antenna is fixed in the direction shown in the figure, but since the altitude of BS (broadcast satellite) or CS (communication satellite) is constant, the plane antenna shown in the figure is used as the stepping motor 1.
By rotating in the azimuth direction by 6, it is possible to direct the beam of the antenna toward the BS or CS even if the vehicle moves. Such a planar antenna is
Since it can be formed thin, it can be provided on the roof of a vehicle. Of course, it is also suitable to incorporate a planar antenna in the sunroof. The vehicle interior unit includes, in addition to the BS tuner 14 described above, a vibration gyro 18 for detecting the yaw rate of the vehicle, a motor control board 20, and A.
A connection unit 24 including the / D board 22,
It is composed of a controller 26 and a stepping motor driver 28 that drives the stepping motor 16. The received signal C / NOUT from the BS tuner 14 and the output from the vibrating gyro 18 are supplied to the A / D board 22 in the connection unit 24, converted into digital signals, and then supplied to the control device 26. The control device 26 determines the rotation amount of the antenna 10 based on the gyro output and the received signal, and instructs the motor control board 20 in the connection unit 24.

Specifically, this control is performed as follows. That is, after the initial search operation is completed, the antenna 10 is driven at a yaw rate that is the same as the yaw rate detected by the vibration gyro 18 and has a sign opposite to the yaw rate. This control is performed at every predetermined sampling timing (for example, 5 msec). Then, when it is detected that the C / NOUT from the BS tuner 14 is lowered and becomes equal to or less than the predetermined threshold value 1 during the control, the control device 26 performs the gyro tracking and at every predetermined time ( For example, the antenna 10 is swung by a predetermined angle for 100 msec), and the previous reception level and the current reception level are compared. If the reception level increases, the antenna 10 is driven again in the same direction, and conversely the reception level decreases. If so, the system shifts to a hybrid system in which so-called step track tracking is also used in which the antenna is driven so that the reception level always increases by rotating in the opposite direction. Then, when the reception level again becomes equal to or higher than the predetermined threshold value 2 due to the hybrid tracking, the vibration gyro 1
The antenna 10 is driven based on only the output from 8. Here, threshold value 1 <threshold value 2, so that the tracking characteristic has hysteresis when the reception level is between threshold value 1 and threshold value 2. The reason why the hysteresis characteristic is provided is that when the reception level increases due to the hybrid tracking and the threshold value 1 is reached, the gyro tracking is immediately started. This is because there is a high possibility that the threshold value becomes 1 or less again and the control becomes unstable. In this way, not only the gyro output but also the step track control for controlling the reception level to the increasing side together with the gyro output when the reception level becomes equal to or less than the predetermined threshold value 1 and the tracking error easily occurs. By doing
Satellite tracking can be performed with high accuracy.

However, as described above, an error occurs between the actual output value of the gyro that continuously changes and the stepwise changing drive amount of the motor that is determined by the control device 26 based on this gyro output. . Therefore, the control device 26 suppresses this error simply and accurately as described below to control the tracking of the antenna 10 with higher accuracy than ever before.

FIG. 2 shows a flow chart of the error suppressing process performed by the control device 26. First, the digitized gyro output is read from the A / D board 22 in the connection unit 24 (S101). This reading is performed every predetermined timing (5 msec). Next, the read gyro output is converted into the angular velocity of the vehicle (S102). Since the gyro output generally includes an offset error, this offset error is first corrected (S103). There are several possible methods for this offset error, but in consideration of variations among products and variations in temperature conditions, the antenna 10 is rotated in either direction when shifting to hybrid tracking that also uses step track tracking. It is desirable to determine whether or not the reception level increases and adjust the offset amount appropriately based on the direction to focus. That is, if the reception level increases when the antenna 10 is rotated clockwise, this means that the antenna 10 is rotated counterclockwise too much, and the rotation of the antenna 10 during gyro tracking. Is in the opposite direction to the gyro output, so the gyro output has output a larger amount of clockwise turning than the original amount of turning of the vehicle. Therefore, since the vibrating gyro 18 includes an offset error in the clockwise direction, it may be corrected so as to eliminate the error in this direction. However, since the offset error amount is unknown, such error correction may be repeatedly performed in predetermined steps to finally eliminate all offset errors.

After the offset error correction is completed, the controller 26 calculates the motor pulse rate PPS required to rotate the antenna 10 in the opposite direction at the same angular velocity based on the offset error corrected gyro output (S10).
4). Since there is an error between the pulse rate PPS and the actual gyro output (actual angular velocity of the vehicle) as indicated by the shaded area in FIG.
If the antenna 10 is rotationally driven by S, the satellite cannot be accurately tracked. Therefore, the control device 26 first calculates the difference ΔPPS between the current pulse rate PPS and the pulse rate PPS at the previous sampling timing in order to eliminate the error shown by the hatched portion in FIG.
One half thereof is added to the current pulse rate PPS calculated in S104. That is, for PPS calculated based on the gyro output,

## EQU1 ## The current pulse rate PPS is corrected by PPS1 = PPS + 1 / 2ΔPPS to calculate a new pulse rate PPS1 (S105). ½ · ΔPPS in the above equation substantially corresponds to the shaded portion in FIG. 4, and by adding this amount to the current pulse rate PPS, the error shown by the shaded portion in FIG. 4 can be almost eliminated. .

After the drive amount PPS1 to be supplied to the stepping motor 16 is calculated in this way, the current pulse rate PPS is substituted for the immediately preceding pulse rate PPSlast for the next difference amount calculation (S106), and then S1.
Stepping motor 16 with PPS1 calculated in 05
Is driven to rotate the antenna 10 (S107).

FIG. 3 shows a comparison between the pulse rate and the actual gyro output when the stepping motor 16 is driven and the antenna 10 is rotated by correcting the pulse rate in this way. By adding 1/2 of the difference between the current pulse rate and the previous pulse rate to the current pulse rate for correction, the pulse rate supplied to the stepping motor 16 becomes a close approximation of the actual gyro output, Therefore, it is understood that the antenna 10 can be tracked with higher accuracy than ever before.

In this embodiment, the gyro output correction in the hybrid system using both the gyro control and the step track control has been described, but it goes without saying that the same can be applied to the system using only the gyro control. Nor.

[0020]

As described above, according to the present invention,
When tracking the satellite receiving antenna based on the output of the gyro sensor, it is possible to easily and reliably suppress the error from the actual vehicle turning amount based on the difference from the previous drive amount, so that tracking error does not occur. The tracking operation can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment of the present invention.

FIG. 2 is a processing flowchart of a correction operation in the same embodiment.

FIG. 3 is a graph showing a relationship between a gyro output and a pulse rate in the same embodiment.

FIG. 4 is a graph showing a relationship between a gyro output and a pulse rate in the related art.

FIG. 5 is a diagram showing functions and pointing directions of a planar antenna.

[Explanation of symbols]

10 satellite receiving antenna (BS antenna), 12 converter, 14 BS tuner, 16 stepping motor, 18 vibration gyro, 24 connection unit, 26
Controller, 28 stepper motor driver.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeki Aoshima 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. Toyota Central Research Institute, Inc.

Claims (2)

[Claims] 1. A control device for orienting a vehicle-mounted satellite receiving antenna in the direction of a satellite, comprising: a gyro sensor for detecting a turning amount of a vehicle; and a direction of the antenna by rotating and driving the vehicle-mounted satellite receiving antenna. A stepping motor that changes in the azimuth direction, a control unit that controls the drive amount of the step motor based on the turning amount detected by the gyro sensor, the current turning amount detected by the gyro sensor, and the previous turning A correction unit that corrects the drive amount based on a difference amount from the amount, and a control device for a vehicle-mounted satellite receiving antenna. 2. The control device for a vehicle-mounted satellite receiving antenna according to claim 1, wherein the correction means sets the difference between the present turning amount and the previous turning amount to 1
A controller for a vehicle-mounted satellite receiving antenna, characterized in that the amount of / 2 is added to the current turning amount.