Sandpiper House, Aviary Court, Wade Road, Basingstoke, Hampshire, RG24 8GX, UK
T
+44 (0) 1256 812 222
F
+44 (0) 1256 812 666
E
www.sematron.com
Making waves...
Operation Manual
Rev A. Feb 11.
Installation Instructions
RM120 Drive away Terminal
Page 15 of 19
The distribution of this document is controlled by Holkirk Communications Ltd. Print date 08/01/2011
2.2 Orientation
During this step 3 pieces of information are gathered.
1. The GPS is read to get the current location on earth.
2. The magnetometer is read to get a heading angle for the platform. This is the geographical
direction that the antenna is pointing at the unstow position.
3. Then the antenna is driven to an elevation angle above the geostationary arc to take a "noise floor"
measurement.
Once this drive has been completed the GPS and the magnetometer readings can be checked.
To see the gps data type the command "
gps
". Check that the last line indicates that the signal is valid.
To check the magnetometer heading information type "
platform
". The third number is the heading
angle in degrees.
This number could be as much as +/- 20 degrees from the correct reading without stopping the
system working. If the error is greater than 20 degrees then this can cause problems.
If required the correct heading can be provided.
Type the command "
platform 0 0 zz
" where zz is the correct heading in degrees.
2.3 Satellite Sweep
The start of the satellite sweep is shown in the diagnostic data.
During this stage the antenna elevation and pol angles are set to the correct angles for the reference
satellite and a range of azimuth movement is swept looking for an RF signal.
If during this phase a messge is seen reporting a “
horizon scan
” has been started then this indicates
that no RF signal above the noise floor was detected during the sweep. This is an indication that there
is a problem with the LNB of L-band cabling from the LNB to the Ipoint ACU.
2.4 Peak on reference satellite
No diagnostic data is provided for this stage but the "cross scan" movements of the antenna can be
seen.
2.5 Identify reference satellite
At the beginning of this step the diagnostic data reports "
Looking at ww
" where ww is the longitude of
the reference satellite.
At the end of this stage there is a line of information which starts "
CTRL
" first number indicates the
satellite longitude being checked. The last number is the number of DVB channels checked.
The second to last number is the number of channels successfully decoded. The success number
should be more than half of the number of channels checked.
If less than half of the channels checked failed to be identified then the system will start to check
channels from other satellites. Once it completes the list of satellites the system will report “
walking
the arc
”. This is an indication that it found an RF signal but was unable to identify it as any known
satellite. In some cases the system will find a satellite which is not the reference satellite, but is one
which it recognises when the channels are checked. If a satellite is recognised the system calculates
a more accurate reading for the platform heading. It indicates the correction of the heading, before
moving on to the next stage.
