JPH07270514A - Satellite automatic tracking method - Google Patents

Abstract

PURPOSE:To continue an accurate tracking drive by predicting the direction of a satellite based on stored data and driving an antenna in that direction when rain is falling or a beacon signal transmission/reception system fails temporarily. CONSTITUTION:An antenna control drive panel 8 periodically drives an antenna 1 according to the output from a timer 4. The drive panel 8 examines the presence or absence of rain-fall by the alarm information from a beacon reception device 3 and a rain-fall detector 6 when the time for driving the antenna comes, and drives the antenna 1 in the direction where the beacon signal reception intensity of the device 3 is maximized by a step track system when neither alarm nor rain-fall exists and then stops the antenna 1. Also, when the rain-fall is detected by a detector 6, a prediction drive is performed if a elapsed time from a satellite trace correction is longer than a prediction drive startable time as in beacon failure. On the other hand, when the prediction drive startable time is shorter, a step track drive is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite automatic tracking method for always accurately pointing an antenna in the direction of a satellite in satellite communications requiring accuracy in the direction of the antenna.

[0002]

2. Description of the Related Art Conventionally, a beacon signal from a satellite is constantly received, and the direction in which the reception intensity of the beacon signal is maximized is the direction of the satellite, and the antenna is driven by step-track driving in that direction for tracking.

[0003]

The above-mentioned prior art uses the step track method as a satellite tracking method.
There is a problem that the beacon signal reception level fluctuates greatly during rainfall, and as a result, the position at which the beacon reception signal becomes maximum is incorrect and tracking cannot be performed accurately. Further, since the tracking method depends on the beacon signal, there is a problem in that tracking is impossible when a failure occurs in the beacon signal transmission system on the satellite side or the beacon signal reception system on the earth station side.

An object of the present invention is to provide a method capable of continuing highly accurate tracking drive even when it is raining and when a beacon signal transmitting / receiving system generally fails.

[0005]

Means and Actions for Solving the Problem In a normal time, a beacon signal is received and the satellite tracking drive is performed by a step track method, and during that time, data of time and antenna angle are stored. When it is raining or when a beacon signal transmission / reception system temporarily fails, the satellite direction is predicted based on the stored data and the antenna is driven in that direction.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a block diagram showing an embodiment of the satellite tracking method according to the present invention. In FIG. 2, 1 is an antenna for receiving a target satellite radio wave, 2 is an angle detector for detecting and outputting direction angle data of the antenna, and 3 is a beacon capable of measuring the intensity of a beacon reception signal input from the antenna 1. Receiving device 4, timer for outputting date and time and periodic time, 5 rewritable storage device, 6 rainfall detector capable of detecting rainfall, 7 storage device 5 for input date and time and antenna angle information Output terminal device, 8 is 2
7 is an antenna control drive panel for inputting information output from the devices to control and drive the antenna 1.

Next, FIG. 1 is a flow chart showing an embodiment of the satellite tracking method according to the present invention. The operation of satellite tracking will be described according to this flow. The antenna control drive board periodically drives the antenna by the output from the timer 4. When it is time to drive the antenna, the antenna control drive board 8 first checks the presence / absence of rainfall by the alarm information of the beacon receiving device 3 and the rainfall detector 6. When there is no alarm and no rain, the antenna 1 is driven in the direction in which the beacon signal reception intensity of the beacon receiver 3 is maximized by the step track method, and the antenna is stopped.
In addition, the date and time output by the timer 4 and the antenna angle information output by the angle detector 2 at this time are stored in the storage device 5. Then, the antenna is kept in the stopped state until the next time to drive the antenna output from the timer 4. When the alarm of the beacon reception system failure is detected, the elapsed time from the failure occurrence and the elapsed time from the satellite orbit correction are checked. The elapsed time from the occurrence of the failure is calculated from the difference between the time stored in the storage device 5 at the time of the failure and the current date and time output by the timer 4. The elapsed time from the satellite orbit correction is calculated from the difference between the date and time when the satellite corrects the orbit stored in the storage device 5 and the current date and time output by the timer 4. The satellite orbit correction date and time due to maintenance or the like is input from the terminal device 7 in advance and stored in the storage device 5. If the failure occurrence elapsed time exceeds the predetermined predictable drive continuation time, or if the elapsed time from the satellite orbit correction is less than the predetermined predictable drive startable time, the antenna is stored in the storage device 5. Stop toward the center of the orbit memorized in. After that, it remains in the stopped state until the beacon reception system failure alarm is cleared. Here, the predictable drive continuation time is compared with the case where the tracking error accumulated by continuing the predictive drive has the antenna directed toward the center of the orbit.
Set so that the time becomes smaller. Further, the predictable drive startable time is set such that a sufficient time has elapsed after the start of data collection and the tracking error becomes smaller than that when the antenna is directed toward the center of the orbit.
When the failure occurrence elapsed time is shorter than the predicted drive elapsed time and the elapsed time from the orbit correction is longer than the predicted drive startable time, satellite direction predictive drive is performed. In this driving, the time information stored in the storage device 5 and the antenna direction angle information corresponding to the time are fetched into the antenna control panel 8, the predicted direction of the satellite is calculated, and the output of the angle detector 2 is calculated in the calculated direction. It is used to drive the antenna. After driving the antenna in the predicted direction, the antenna control drive board stores the angle data and the time data in the storage device 5 and stops the antenna. If the beacon transmission / reception system is normal, but if rainfall is detected by the rainfall detector 6, predictive drive is performed if the elapsed time from satellite orbit correction is longer than the predictive drive startable time, as in the previous beacon failure. To do. However, when it is shorter than the predictable drive start time, the step track drive is performed. After driving, the time data and the angle data are stored in the storage device. As a satellite direction prediction method, if we focus on the fact that the orbit of a satellite consists of periodic movements and deviations in one direction, and its cycle is known to be one day, I can think.

When the satellite position at time t is P (t) and the satellite position at the same time on the previous day is P (t-24), the difference ΔX
(t) is

[0010]

## EQU1 ## ΔX (t) = P (t) -P (t-24). When the predicted position at time a is P ′ (a), first, the average value of the difference [Equation 1] from the same time on the previous day is calculated up to the immediately preceding time (a-1). Let the average value for n hours be E [ΔX] (a)

[0011]

[Equation 2] Becomes For the predicted position at time a, the value of E [ΔX] (a) obtained by [Equation 2] is used to determine the predicted position at the same time (a-2
Correct the satellite position P (a-24) in 4) to stop. The above concept is shown in FIG.

[0012]

## EQU00003 ## P '(a) = P (a-24) + E [.DELTA.X] (a) For the time t after the time a, the correction value E [.DELTA.X] (a) at the predicted start time a is also used and t > [A] E [ΔX]
As (t) ≈E [ΔX] (a), the prediction direction P ′ at time t
(T) = P (t−24) + E [ΔX] (a).

In the present embodiment, the timing for performing the tracking drive is activated by the time output from the timer 4. However, the input value from the beacon transmission / reception device 3 does not change cyclically by the timer, but changes by a certain value or more. It's okay if you do. In addition, instead of the presence / absence of rainfall, the rainfall intensity or the measured value of the rainfall intensity change may be used for the judgment at the time of rainfall.
Further, instead of the rainfall detector, the fluctuation range of the reception level of the beacon receiving device may be measured and the value thereof may be used as the judgment standard.
In addition, the predictive drive at the time of a beacon system failure can also be used in the case of another tracking method that depends on a beacon signal, for example, a monopulse method.

[0014]

According to the present invention, it is possible to significantly improve the tracking accuracy when it is raining or when there is a failure in the satellite beacon transmission / reception system.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of a satellite tracking method according to the present invention.

FIG. 2 is a block diagram showing an embodiment of the same.

FIG. 3 is a diagram showing a predicted position at time a.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Angle detector, 3 ... Beacon receiving device, 4 ... Timer, 5 ... Storage device, 6 ... Rainfall detector, 7 ... Monitoring control terminal device, 8 ... Antenna control drive device.

Claims (1)

[Claims] 1. An antenna for receiving a beacon signal of a target satellite, an angle detector for outputting a direction angle of the antenna, a receiving device capable of measuring the received signal strength of the beacon signal, a timer for outputting time, a rainfall for detecting rainfall. It is equipped with a detector, a storage device that stores time and angle data, and an antenna control drive device that controls and drives the antenna based on the output information of the above components. A satellite automatic tracking method, characterized in that the antenna is driven toward the antenna, and the antenna is driven using a tracking method using a beacon signal other than the above.