5
| TECHNICAL DESCRIPTION | |
| the high accuracy of the model the tracking is within 0.05dB of | |
| peak signal tracking. |
|
| In Tracking Mode the INTRAC continuously updates the model | |
| by making small perturbations of the antenna and incorporating | |
| the resultant data into the model. During periods when the | |
| satellite’s orbit is changing because of station keeping | |
| manoeuvres the INTRAC may increase the frequency of the | |
| perturbations. |
|
| If the beacon receiver stops providing a useful signal* the | |
| INTRAC will enter “Predicting” sub mode. In this mode the | |
| INTRAC will continue to point the antenna according to the | |
| model but will not update the model. Once “Tracking Mode” | |
| has been achieved “predicting” can continue for 72hrs. If the | |
| beacon receiver returns to providing a useful signal* within this | |
| period the INTRAC returns to updating the model. If, after | |
| 72hrs, the beacon is still not producing a useful signal* the | |
| model is deemed to have expired. If this occurs the INTRAC | |
| can fall back on the “Reserve Model” which is a Program Track | |
| using either | |
| page 48) |
|
* useful signal | A useful signal is defined as one that varies sensibly during | |
| antenna movements, is neither over or under range and the | |
| beacon receiver is in lock. |
|
Manual | Manual Mode allows the operator to drive the antenna using | |
| the Manual Control keys on the INTRAC front panel. It is | |
| normally only used for small movements of the antenna such | |
| as peaking when the position of the satellite is known with | |
| close accuracy. |
|
| For larger antenna movements one of the Goto modes is faster | |
| and where the satellite’s position is only roughly known search | |
| is employed to peak the antenna. |
|
| There are two Manual Modes. Manual (P) Mode is manual | |
| control from the front panel. Manual (A) Mode is manual | |
| control from the Remote Terminal. (see section 9). The | |
| antenna can be driven through North (Azimuth 0°), in the | |
| Northern Hemisphere, or South (Az 180°), in the Southern | |
| Hemisphere, only in Manual (P) Mode. |
|
Goto | There are three Goto sub modes. Goto Position and Goto | |
| Satellite provide a convenient method of driving the antenna to | |
| a specific position. Search mode is the automatic scanning of | |
| an area of sky for a satellite. |
|
Goto Position | In this mode the operator enters the | |
| frequency of the required satellite and presses the enter key. | |
| The entered | |
© 2011 Advantech Wireless | Page 57 |