JP2002214317A - Antenna control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna control device capable of performing a satellite tracking by step track method even in the fluctuation of receiving signal level by scintillation. SOLUTION: A receiving level detection part 2 detects the signal intensity received by an antenna 1, and an angle detector 3 detects the directing angle of the antenna 1. The receiving level integrating processing part 41 of an antenna control part 4 performs the integrating processing of receiving level, and a step track arithmetic processing part 42 performs an arithmetic operation including the approximating calculation of fluctuating quantity of receiving level from the receiving level. An angle data memory part 43 stores the information obtained from the angle detector 3, and a predicted position arithmetic processing part 44 calculates the predicted position of a satellite. A position comparative processing part 45 compares the information obtained from the angle detector 3 with the information obtained from the predicted position arithmetic processing part 44, and a drive instruction output part 46 outputs a drive instruction signal on the basis of the processing results of the step track arithmetic processing part 42 and the position comparative processing part 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna control apparatus, and more particularly to a tracking control method using a step track method for tracking an antenna with a satellite.

[0002]

2. Description of the Related Art Conventionally, as a tracking method for a geostationary satellite, the direction of an antenna is driven in small steps at small angles, and the reception signal levels of radio waves transmitted from the geostationary satellite before and after driving are compared. When increasing, step driving is performed in the same direction, and when decreasing, step driving is performed in the opposite direction. When the difference between the received signal levels before and after driving becomes smaller than a preset value, it is determined that the received signal level is the maximum value and the step is performed. The step track system in which driving is stopped is mainly used.

As a tracking method for a geostationary satellite, apart from the above-described step track method, since the movement of the satellite orbits a predetermined orbit at a predetermined cycle, arithmetic processing is performed based on past satellite track information. There are a tracking method for deriving a predicted position of a satellite and a program tracking method for deriving a predicted position by performing arithmetic processing using orbit calculation parameters of a geostationary satellite.

In the step track method, as shown in FIG. 6, the reception level is integrated at the start of the step track (step S21 in FIG. 6).
The antenna is driven by a one-step drive amount in an arbitrary direction (step S22 in FIG. 6). The reception level after driving is integrated (step S23 in FIG. 6), and the reception levels before and after driving are compared.

Based on the comparison result, it is determined whether or not the level difference before and after driving is equal to or less than a peak determination level value (step S24 in FIG. 6). Perform determination processing (FIG. 6
Step S30).

The antenna drive has two axes of azimuth (AZ) and elevation (EL), and the antenna is driven and directed in an arbitrary direction by changing the angle of these two axes. Therefore, it is necessary to switch the axes in order to determine the reception level. Here, if the switching of the drive axis has been performed more than the set number of times, the step track is ended, otherwise, the drive axis is changed (Step S31 in FIG. 6), and the process returns to Step S21.

If the level difference before and after the driving does not become equal to or less than the peak determination level value in step S24, the reception levels before and after the driving are compared (step S25 in FIG. 6). The reception level value is stored (step S26 in FIG. 6), and one step is performed in the same direction.
The antenna is driven (Step S27 in FIG. 6), and Step S27 is performed.
It returns to the process of 21.

If the reception level after driving is low, the reception level after driving is stored (step S28 in FIG. 6), and the antenna is driven one step in the reverse direction (step B in FIG. 6).
9), the process returns to step S21.

If the received signal level fluctuates due to scintillation, the amount of change in the received signal before and after driving includes the amount of fluctuation in the received signal level due to scintillation. The comparison will be incorrect and cause mistracking. Here, the scintillation is a change in a received signal from a compound target caused by a change in a viewing angle or the like.

Conventionally, as described in Japanese Patent Application Laid-Open No. Sho 62-55580, a fluctuation in the received signal level is measured when the antenna is stopped, and the antenna is tracked only when the fluctuation width is small. Alternatively, a tracking method that performs a calculation based on satellite trajectory information to derive a predicted position of a satellite when a scintillation occurs, or a program tracking method that performs a calculation process using a trajectory calculation parameter of a geostationary satellite to derive a predicted position, etc. The satellite tracking is performed by switching the system.

[0011]

In the above-mentioned conventional geostationary satellite tracking system, when the satellite tracking by the step track system is stopped while the received signal level fluctuates due to the scintillation, the geostationary satellite moves quickly. And so on escape during this time, so satellite tracking cannot be stopped for a long time.

When the prediction tracking method using the orbit calculation parameters can be performed, it can be dealt with by switching the tracking method. However, the satellite orbit is predicted based on the satellite orbit data obtained by the step track tracking. In the tracking method for calculating, if scintillation occurs chronically, satellite track data cannot be updated by step track tracking, so that the reliability of the prediction calculation result decreases and there is a possibility of mistracking. .

An object of the present invention is to solve the above-mentioned problems and to provide an antenna control device capable of performing satellite tracking by the step track method even when the received signal level fluctuates due to scintillation. It is in.

[0014]

An antenna control apparatus according to the present invention drives an antenna stepwise, compares the reception levels of the antenna before and after driving, and drives the antenna stepwise in a direction in which the reception level increases. An antenna control device including step track means for performing satellite acquisition by using a means for approximately calculating the amount of change in the reception level, and performing the satellite acquisition by the step track means based on the approximate calculation result. West

That is, the antenna control apparatus of the present invention
The received signal level difference at a fixed time is stored when the antenna is stopped before the antenna is driven by one step, and the received signal level difference is stored at a fixed time when the antenna is stopped after the completion of the one-step drive. Using the signal level difference, the received signal level fluctuation value due to scintillation is approximately predicted during one-step driving, and the received signal level fluctuation value due to scintillation approximately predicted from the amount of change in the received signal level before and after one-step driving. The amount of change in the reception level calculated after removal is used for peak determination and drive direction determination.

This makes it possible to prevent a peak determination error and drive in the reverse direction, and to perform satellite tracking by the step track method without mistracking even when scintillation occurs.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an antenna tracking control system according to one embodiment of the present invention. In FIG. 1, an antenna tracking control system according to an embodiment of the present invention detects an antenna 1 to be controlled, a reception level detection unit 2 for detecting a signal strength received by the antenna 1, and a directional angle of the antenna 1. Angle detector 3
An antenna control unit 4 for performing an antenna tracking process calculation;
It comprises a motor 5 for driving the antenna 1 and a drive power controller 6 for controlling the drive power of the motor 5.

The antenna control unit 4 includes a reception level integration processing unit 41 that performs integration processing of the reception level, a step track calculation processing unit 42 that performs calculation processing based on the reception level, and an angle for storing information obtained from the angle detector 3. Data storage unit 43
And a predicted position calculation processing unit 44 for calculating a predicted position of the satellite
And information obtained from the angle detector 3 and a predicted position calculation processing unit 4
A position comparison processing unit 45 for comparing information obtained from the step 4 with the step track calculation processing unit 42 and the position comparison processing unit 45.
And a drive command output unit 46 that outputs a drive command signal to the drive power control unit 6 based on the output of

FIGS. 2 and 3 are flowcharts showing the operation of the antenna tracking control system according to one embodiment of the present invention. The operation of the antenna tracking control system according to one embodiment of the present invention will be described with reference to FIGS.

First, at the start of the step track, the integrated value of the received signal level integrated for the time t is stored in L1 in order to absorb the fluctuation of the received signal having a fast cycle due to noise or the like (step S1 in FIG. 2).

In order to calculate the change in the received signal level due to the scintillation at the time T, the integrated value of the received signal level integrated once again for the time t after the time T is stored in L2 (step S2 in FIG. 2), and it is set in an arbitrary direction. The antenna 1 is driven by one step drive amount (step S3 in FIG. 2). After the one-step driving, the integrated value of the received signal level integrated for the time t is stored in L3 (step S4 in FIG. 2).

Here, in order to calculate the change in the received signal level due to the scintillation once again, the integrated value of the received signal level integrated for the time t is stored in L4 (step S5 in FIG. 2). From the received signal level integration values L1, L2, L3, and L4 stored so far, the received signal level fluctuation value Ls due to the scintillation during one-step driving is calculated as follows: Ls = ((L1-L2) / T + (L3-L4) / T) /
2 * Ts Ts: 1 step drive time It is obtained as an approximate value by the equation (step S in FIG. 2).
6).

The integral L2 of the received signal before one-step driving
And the received signal level difference L due to the scintillation during the one-step driving, and the received signal level difference L due to the scintillation during the one-step driving, L = L3- (L2-Ls) ) (Step S7 in FIG. 2).

Thereafter, similarly to the conventional step track method, it is determined whether or not the level difference L before and after driving is equal to or smaller than a peak judgment level value (step S8 in FIG. 2). If the level difference L is equal to or smaller than the peak judgment level value. For example, a process of determining the number of times the drive shaft is switched is performed (step S9 in FIG. 2). If the switching of the drive axis has been performed more than the set number of times, the step track is ended, otherwise, the drive axis is changed (step S in FIG. 2).
10), and return to the process of step S1.

If the level difference before and after driving does not become equal to or less than the peak judgment level value in step S8, unlike the conventional step track method, the reception levels before and after driving are compared (step S11 in FIG. 3). If it is larger, the last received level integration value L4 is stored in L1 (see FIG. 3).
Step S12), the integrated value of the received signal level integrated for the time t after the time T is stored in L2 (step S13 in FIG. 3),
The antenna 1 is driven in the same direction for one step (step S14 in FIG. 3), and the process returns to step S4.

If the reception level is lower after driving, the last reception level integration value L4 is stored in L1 (step S15 in FIG. 3), and the reception signal level integration value integrated for t time after T time is stored in L2. (Step S16 in FIG. 3), the antenna 1 is driven one step in the reverse direction (Step S1 in FIG. 3).
7), the process returns to step S4.

The relationship between the change in the received signal level in step track tracking by the above-described operation and the level difference L between the received signals before and after driving (step S11 in FIG. 3) will be described below with reference to FIGS. .

In FIG. 4, the received signal level before and after the one-step driving is reduced (L2> L3). According to the calculation in the above operation, the received signal level difference L by the one-step driving is L> 0, and It is determined that the antenna 1 has been driven in the direction of the geostationary satellite.

In FIG. 5, the received signal level difference L is L <L.
0, and it is determined that the antenna 1 has been driven in the direction opposite to the direction of the geostationary satellite. By the above operation, when the received signal level fluctuates due to the scintillation, the stationary satellite tracking is performed by the step track method.

As described above, the received signal level due to the scintillation during one-step driving is approximately predicted, and the change in the received signal level due to the step driving is calculated.
Even when the received signal level fluctuates due to scintillation, the satellite tracking by the step track method can be performed.

Since the received signal level due to the scintillation during one-step driving is approximately predicted and the change in the received signal level due to the step driving is calculated, the satellite orbit is calculated based on the satellite position data acquired by the step track tracking. In the tracking method for predictive calculation, satellite position data can be updated by step track tracking even when received signal level fluctuation due to scintillation occurs.

When a received signal level fluctuation due to scintillation occurs in a tracking method for predicting and calculating a satellite orbit based on satellite position data obtained by step track tracking, a step track tracking method according to one embodiment of the present invention. By acquiring the satellite position data by using, it is possible to prevent the accuracy of the prediction calculation of the satellite orbit from lowering.

[0033]

As described above, according to the present invention, the satellite is captured by step-driving the antenna, comparing the reception levels of the antenna before and after the driving, and step-driving the antenna in the direction of increasing the reception level. In the antenna control apparatus including the step track means for performing the calculation, the fluctuation amount of the reception level is approximately calculated, and the satellite tracking by the step track means is performed based on the approximate calculation result, so that the fluctuation of the reception signal level due to the scintillation occurs. In this case, there is an effect that satellite tracking can be performed by the step track method.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an antenna tracking control system according to one embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the antenna tracking control system according to one embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the antenna tracking control system according to one embodiment of the present invention.

FIG. 4 is a diagram showing a change in a received signal level in one embodiment of the present invention.

FIG. 5 is a diagram showing a change in a received signal level in one embodiment of the present invention.

FIG. 6 is a flowchart showing a conventional step track operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Reception level detection part 3 Angle detector 4 Antenna control part 5 Motor 6 Drive power control part. 41 reception level integration processing unit 42 step track calculation processing unit 43 angle data storage unit 44 predicted position calculation processing unit 45 position comparison processing unit 46 drive command output unit

Claims (2)

[Claims] 1. An antenna control system comprising: a step track unit for performing step driving of an antenna, comparing reception levels of the antenna before and after driving the antenna, and step-driving the antenna in a direction in which the reception level increases to perform satellite acquisition. An antenna control device, comprising: means for approximately calculating the amount of change in the reception level, wherein the step tracking means performs the satellite acquisition based on the result of the approximate calculation. 2. The apparatus according to claim 1, further comprising a prediction tracking unit for performing a calculation process using the satellite orbit data obtained by said step track unit to predict the position of said satellite, and said step track unit based on said approximate calculation result. 2. The antenna control device according to claim 1, wherein orbit data is acquired.