6programming geostationary satellites, 7angle display of az/el position data, Programming geostationary satellites – Research Concepts RC2000C User Manual

Page 26: Angle display of az/el position data, 6 programming geostationary satellites, 7 angle display of az/el position data

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18

RC2000C Az/El Tracking Antenna Controller

Chapter 3

Installation/Setup

Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA

www.researchconcepts.com

3.6

Programming Geostationary Satellites

After the limits have been set and the slow speed code determined, geostationary satellites can be

programmed into the controller's memory. Inclined orbit satellites are programmed into memory after

the geostationary satellites are programmed (described in Chapter 4). The user should review this

section along with the following section before programming in any satellites. The following section

discusses the display of azimuth and elevation position data in an angle format, and explains the use of

the IBM PC programs found on the disk included with the controller. Displaying the azimuth and

elevation position in an angle format can be a great aid in locating satellites. Note that it is not

necessary to program any geostationary satellites into memory before initiating a track on an inclined

orbit satellite.

All satellites are programmed into memory via SETUP mode. In SETUP mode the user can jog the

antenna in azimuth and elevation to peak up on a satellite, specify the satellite name, and jog the

polarization to assign H and V polarization values (on those controllers which support polarization

control). This information is retained in the controller's non-volatile memory. The user can

automatically position the antenna on a satellite which has previously been programmed into memory

by invoking the AUTO mode, and using the SCROLL keys followed by the ENTER key to select the

satellite.

SETUP mode is straightforward. If the user wishes to assign a satellite name that is not in the list, the

USER entry in the satellite name list may be selected. The user is then prompted to enter an

alphanumeric string using the SCROLL UP, SCROLL DOWN, and ENTER keys.

After the satellite name has been selected the user is prompted to enter in the satellite's longitude

position. If the satellite name came from the controller's internal list, the user is presented with a

longitude value also from the controller's internal list. The range of longitude values accepted by the

controller ranges from 0 to 180 West and 0 to 180 East. Satellites located over North America have

West longitude values. Satellites located over Asia have East longitude values. Some Intelsat literature

gives satellite longitude values in a range of 0 to 359. In this scheme, values from 0 to 180 correspond

to East longitudes. Values from 180 to 359 correspond to West longitudes. To convert from the Intelsat

scheme to the scheme used by the controller, a simple example is presented. If the satellite longitude

is specified as 325 degrees in the Intelsat scheme, to convert to the value needed for entry into the

controller, calculate 360 - 325 (= 35). The value entered into the controller would then be 35.0 West.

It is recommended that the user first program in a pair of geostationary satellites, and then use the

AUTO mode to repeatedly position the antenna on one satellite and then the other. This will exercise

the controller, actuators, mount, and position sensors. If the antenna does not return to the peak for

each satellite make sure that the position sensors are properly wired. After the operation of the system

has been verified by testing with two geostationary satellites, the rest of the satellites may be

programmed in.

3.7

Angle Display of Az/El Position Data

The RC2000C antenna controller has the capability to display its azimuth and elevation position in an

angle format. This capability can facilitate the process of locating satellites during system setup. This

section describes the procedure for enabling, calibrating, and using the angle display feature. The

procedure outlined in this section makes use of the programs (designed to run on an IBM compatible

PC) found on the floppy disk in the back of this manual.

The controller can display azimuth and elevation position in a degrees format. When this feature is

enabled, the azimuth position is displayed as a true heading (in degrees - 0 to 360) and the elevation

position is displayed as an angle above the horizon (0 to 90 degrees). This feature is controlled by

parameters specified by the user via CONFIG mode. The scale3.exe program on the floppy disk can be

used to determine these parameters once a pair of geostationary satellites has been found.

Another program included on the floppy disk is antenna.exe. This is a general purpose program that

aids the user in locating any satellite. This program prompts the user to enter the antenna longitude

and latitude, the satellite longitude and the satellite inclination angle and calculates the magnetic

heading, true heading and elevation angle above the horizon needed to intercept the satellite. For

geostationary satellites, the satellite inclination angle is 0.

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