© Valeport Limited 2003
MIDAS Surveyor Operating Manual
Page 23
0420805d.doc
4.2.8.7
Vertical Scale
The graphical trace on the display will automatically adjust its maximum and minimum values to keep track of the bottom.
The range of the scale must be set by the user as number of metres; available ranges are: 4, 5, 6, 10, 12, 15, 20, 30 or
60m. Use up or down to scroll through the options and Enter to confirm.
Note that when using a dual frequency system, the scale of each graph will be the same. The scales are labelled left
and right, and an additional scale will be displayed midway if the range alters during a trace
4.2.8.8
Horizontal Scale
The horizontal scale of the trace may also be adjusted. This is effectively done as “pings per pixel”, and may be set from
1 to 20 using the up, down and Enter keys. Note that when the trace reaches the end of the display, it begins again at
the left of the screen, with approximately 1cm being “carried over”.
4.2.8.9
Raw & Corrected
Depth data may either be displayed and logged as measured, or corrected for Tide and Heave data inputs. Use this
function to Toggle between logging and displaying of RAW or CORRECTED data. Up/down to toggle, Enter to confirm.
4.2.9
GPS SETUP
4.2.9.1
GPS Type
The MIDAS Surveyor is supplied as standard with an integral 12 channel GPS receiver, with SBAS differential correction.
Optionally, a 16 channel GPS receiver with SBAS and IALA Marine Beacon receiver may be fitted instead.
In order to accommodate customers who may wish to use an external differential input, the system has a certain amount of
intelligence in that if an external differential input is applied, it will recognise this and automatically use it in preference to the
internal SBAS correction. If an external GPS receiver is used, then the internal receiver must be manually disabled.
Use the up or down key to toggle through Internal A12, Internal DG16, or External GPS, and Enter to confirm.
Note that any external GPS input must include GGA & VTG data strings.
4.2.9.2
GPS Reset
Each time the MIDAS Surveyor is turned on, it will attempt to reacquire its satellite fixes. If this fails, the user may force a
reset using this function.
If satellite acquisition repeatedly fails, check antenna position and cable connections.
4.2.9.3
GPS RTCM baud
This feature changes the baud rate at which the internal receiver communicates with the system microprocessor. It
should not be changed.
