ANTENNA CONTROL UNIT

 Antenna Control unit(ACU) is used to control the movement of the antenna. ACU have different parts:The Antenna Control Unit (ACU) is ideally suitable for Geo-stationary and V-SAT terminals where auto step tracking is considered as the prime mode of operation. The ACU is a micro controller based unit and provides operations of the antenna in different modes and also updates the information about received signal strength and and antenna angle position in both Azimuth and Elevation axes on the LCD display provided on the unit front panel.

The ACU is configurable for the required STEP TRACK TIME INTERVAL and STEP SIZE. This feature makes the unit usable for different size of antenna operating in different frequency band of reception.The  best-fit parameters suitable to the system are to be choose in kept in memory for regular operation.The step track algorithm is  so designed that the system searches for the point in both the axes where the peak signal strength is available.The step track works on the principle periodic jogging of the antenna CW/CCW in Azimuth axis and UP/DOWN in Elevation axis for repositioning to the point of the maximum signal reception level.The algorithm features height rate data acquisition and mathematical data processing for correct definition of maximum signal. 

Different parts of Antenna Control Unit are:

1.ACU Main Board

2.24V module

3.Relay Interface Card

4.Relays

5.Power Supply(230V AC i/p 180V DC o/p) 

6.LPT-25(Low power transform)

Main Board is the main part of ACU.This main board consists of a microcontroller and perform all the logical operations.All the input commands like encoder,E-compass and GPS will be analyzed in this board.Control of motors will be operated through relays.Depending on the requirement of the control system respective programs are dumped into microcontroller.
24V module is converts AC into DC, Input 230V AC and output is 24 V DC/1A.This is used to active the relay interface card.
The relay interface card construct with relays for motors movement generate.The commands which are given by main board will be converted into higher voltage through transistor relay combination.Feed motor movement is also controlled in this relay board.Relays are used to execute the commands given by relay interface card to active azimuth and elevation motors.   

Features of antenna control unit:

•Micro Controller based with Menu driven software.

•Positioning the antenna to desired satellite.

•Operates in two speeds SLEW(Continuous & Constant)  and STEP(in steps but not continuous and useful for precise alignment of antenna).

•Feed rotation facilitate the change of polarization.

•Display that in t AGC level w.r.t the received signal strength.

•Allows user to set the Step Size & Time Interval required for Step Tracking.

•Antenna Auto Tracking in selected time intervals.

•Emergency Stop to halt the antenna system opertions.

•RS 232 Interface which enables remote monitoring & control.

•Built in GPS.

•Provision for integration of Electronic Compass.

ANTENNA CONTROL UNIT CONFIGURATION:

It is mandatory that in the Antenna Control Unit the following are set to be before the system in attempted for use

Encoder offset correction

• Antenna position for Deploy & Sleep

• Limits(Software) for AZ & EL

  Additionally the following are also to be set before the unit is attempted for normal operations

• Step Size

• Tracking Time Interval

• Satellite ID

 USE GPS IN ACU(GLOBAL POSITION SYSTEM): 

The Antenna Control Unit is integrated with an built-in GPS and Patch Antenna Positioned on the top of the vehicle.Upon selection of GPS in the configuration mode, the GPS provides latitude and longitude of the place on the ACU front panel along with Time.

While in Auto operations, ACU enables the user to select SAT_ID and goes necessary internal calculations after talking the required input information from GPS and Electronic Compass and then positions the Antenna to required Satellite.