Session Setup - Fixing

Fixing can be used for generating fixes for seismic surveys, annotations on echo sounders etc. It is also possible to receive external fixes.
Fixes are stored in the database with the exact time of fix.
Before fixing can be used, a number of parameters need to be set.

Eventing
Event Mode	Manual - No further parameters are needed. When online use either the manual fix button or the F9 keystroke. Time - A fix will be generated each time the entered time interval (in seconds) has elapsed. Trigger - Select from the list of available ports the COM port to which the external fix trigger is attached. A new fix will be generated every time the external fix is triggered from the COM port. Distance Sailed - A fix will be generated each time the steered node has moved the entered Interval (in whichever direction, in survey units). Distance Along - A fix will be generated at the entered Interval (in survey units) along the selected survey line. This will be done in both directions. Distance Seismic - A fix will be generated at the entered Interval (in survey units) along the selected survey line. Each fix number is attached to a certain distance along the selected survey line. Distance Preload - A fix signal for a peripheral device will be generated at the entered Preload Time interval (in seconds). This requires the definition of a Fix Output System in Database Setup. Generation takes place at each occasion the steered node approaches the nominal fix position derived from the entered fix Interval (based upon inline distance along the sailing line, in survey units). The fix is then taken when the closure (issued by the peripheral device) is received at the selected COM port, which leads to data storage, etc. No closure: no fix.
Fixnumber Increment	Default is 1. Adjust if necessary.
First Fixnumber	Default is 100. Adjust if necessary.
Event Interval	Enter the seconds or survey units between fixes. Only available when Event Mode was set to 'Time'.
Serial Port	Select the port to which the Trigger is connected. Only available when Event Mode was set to 'Trigger'.
Last Fixnumber	Check here which number was last created. Not available for first three Event Modes.
Preload Time	Only available when Event Mode was set to 'Distance Preload'. Option to fire the fix a set time prior to the planned fix time of the external device. This is to take into account the time required to prepare the external device for firing.
Trigger Timeout	Only available when Event Mode was set to 'Distance Preload'. The external device will send a trigger back after the device has been fired. A timeout can be set for the time QINSy will wait to receive this trigger. The next fix can only be fired when the trigger of the previous fix has been recevied or when it passed the trigger timeout.
Options
Beep on fix event	If this box is checked, you will hear a beep on the computer speaker at each fix, no matter how the fix is generated.
Generate fixes only when recording	Enable this option when you only want to create fixes when recording.
When recording starts, begin with the first fix number	Enable this option when you want the fix number to be reset to the first fix number when recording is started. This way you can begin multiple recording sessions with the same fix number. This option is not available if "Generate always unique fix numbers" is enabled.
Generate always unique fix numbers	Enable this option when you want the last fix number to be remembered, even when you close the Controller. You can set the first fix number at the beginning of the survey, and then maintain a unique fix numbering throughout the project. This option can be used in conjunction with the "Generate fixes only when recording" option, incrementing the fix number whenever you are recording.
Reset unique fix number to first fix at the next event	This option is only available when the "Generate always unique fix numbers" option is enabled. The fix number is reset to the value you enter as "First Fixnumber" in the Eventing section of the dialog. This option normally only happens once per project as it is used to create unique fix numbers for the whole project.

Activate Fixing

Please realize that Fixing will be active as soon as you press OK (hence the value in the Controller will update).
If you have selected Time, Distance Sailed or Distance Along as the fixing mode, then fixing will begin immediately (assuming you are moving).
If you selected Manual then manual fixes (F9 hotkey) can be taken.
Distance Preload and Distance Seismic are dependent upon the steered node being between the start and end of line co-ordinates.

Difference between Distance Seismic and Distance Along

When using Distance Seismic each fix number is positioned relative to the start of the line in such a way that fix numbers will always be at the same position along the line.
The first fix generated will therefore be different from the specified first fix number (unless you start fixing very close to the SOL).
When using Distance Along, however, the first fix number you ask for is the first fix you get - regardless of position relative to the SOL.

For both applies that the fixes are always in the same place along the line.

When using Distance Seismic, the direction of the fix numbering is determined by the planned line direction only, rather than the line bearing during acquisition.
Distance Seismic can work in both directions if used with a negative fix increment.

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