1 Hardware Setup-Offsets and Origins(硬件的OFFSET设置)
Weoften get questions from users who are configuring their hardware and aregetting lost in the maze of variables to consider in determining the origin,and changing offset signs. The key below is written to help guide you withthese questions. Here's how it works.
Choosethe first outline level that fits your setup. Now, under that heading, choosethe second level heading that describes your setup. Continue progressing downthrough the headings until a setup table follows your last choice.
Thesetup table tells you what to use for the origin, which Hardware program eachdevice should be entered in, and the signs used for the offset measurements.
Note:In all setups, except for the GPS, latency is usually zero. You may enter avalue initially from the GPS manual or start with it at zero, but you shouldrun a Patch Test and adjust this setting accordingly. Sonar systems usuallyautomatically compensate for latency. Latency is not an issue for MRUs andGyros.
I. Single Vessel
A. Gyro for heading
1. Single Beam
Consideration |
Solution |
Origin |
Transducer |
Hardware Setup Program(s) |
Hypack Hardware- All devices |
Offset Signs & Program(s) |
· Horizontal offsets are positive forward and starboard · Z offsets: o Transducer: 0--included in draft correction of device when calibrated o GPS: Positive upward |
2.Multibeam
Thereare two possible options for setting up multibeam systems. Solution A maintainsthe origin always at the vessel's pivot point. Solution B uses the transducerhead as the origin in Hypack® Hardware, while Hysweep® Hardware uses thevessel's pivot point. In this case, the helmsman display data is based on thetransducer, enabling more accurate positioning of the transducer over the surveyline.
Notealso, in most cases, the rotational offsets of the gyro and MRU are calibratedduring installation to the vessel. Any additional error will be compensated forby the Patch Test values that are then applied to the transducer.
Consideration |
Solution A |
Origin |
Vessel pivot point - ideal MRU position |
Hardware Setup Program(s) |
Hypack Hardware-GPS, Hysweep.dll (optional) Hysweep Hardware-MRU, Transducer, Gyro, Hypack.dll |
Offset Signs & program(s) |
· Horizontal offsets: positive forward and starboard of the origin. · Z offsets: o Transducer: 0--included in draft correction of device when calibrated. o GPS: Positive upward from the waterline in Hypack® Hardware; positive downward in Hysweep® Hardware. o MRU: For MRUs use zero.** · Yaw Offset: o Transducer (Determined in Patch Test.): positive for clockwise rotation from alignment with the keel. o Gyro*: Usually zero. May add correction for variation between magnetic N and true N. Add the variation to the mounting offset using positive values for clockwise rotation from alignment with the keel. o MRU*: positive for clockwise rotation from alignment with the keel. · Pitch offset (Determined in Patch Test.): Multibeam sensors not oriented directly below the vessel. Positive forward. · Roll offset (Determined in Patch Test.): Multibeam sensors and MRUs* not oriented directly below the vessel. The reference roll angle (in decimal degrees) is 0 for vertical mounting positive to the port side. |
Additional settings |
If MRU is not at the vessel pivot point, when you edit your data, check Correct for Induced Heave in the Advanced Read Parameters dialog. |
Consideration |
Solution B |
Origin |
Hypack Hardware: Transducer Hysweep Hardware: Vessel pivot point-ideal MRU position |
Hardware Setup Program(s) |
Hypack Hardware-GPS, Hysweep.dll (optional) Hysweep Hardware-Transducer, MRU, Gyro, Hypack.dll |
Offset Signs and program(s) |
· Horizontal offsets: positive forward and starboard of the origin. · Z offsets: o GPS: Positive upward from the waterline in Hypack® Hardware, positive downward in Hysweep® Hardware. o Transducer: 0--included in draft correction of device when calibrated. o MRUs use zero**. · Yaw Offsets: o Transducer (Determined in Patch Test.): positive for clockwise rotation from alignment with the keel. o Gyro*: Usually zero. May add correction for variation between magnetic N and true N. Add the variation to the mounting offset using positive values for clockwise rotation from alignment with the keel. o MRU*: positive for clockwise rotation from alignment with the keel. · Pitch offset: For multibeam sensors (determined in Patch Test.) and MRUs* not oriented directly below the vessel. Values are positive forward. · Roll offset: Multibeam sensors (determined in Patch Test) and MRUs* not oriented directly below the vessel. The reference roll angle (in decimal degrees) is 0 for vertical mounting. Values are positive to the port side. |
Additional settings |
If the MRU is not at the vessel pivot point, when you edit your data, check Correct for Induced Heave in the Advanced Read Parameters dialog of the editor. |
3. Multiple Transducer
a)System supported in Hypack Hardware.
Consideration |
Solution |
Origin |
Vessel pivot point-ideal MRU position |
Hardware Setup Program(s) |
Hypack Hardware-all devices |
Offset Signs & program(s) |
· Multitransducer offsets are entered in the Transducer Offsets Program. · Horizontal offsets: positive forward and starboard of the origin. · Z offsets: o GPS & Transducer: positive upward from the waterline. o MRU: Use zero.** · Yaw Offset o Gyro*: Usually zero. May add correction for variation between magnetic N and true N. Add the variation to the mounting offset using positive values for clockwise rotation from alignment with the keel. |
b)System supported in Hysweep Hardware
Consideration |
Solution |
Origin |
Vessel pivot point-ideal MRU position |
Hardware Setup Program(s) |
Hypack® Hardware: GPS, Hysweep.dll (optional) Hysweep® Hardware: Transducers, Gyro, MRU, Hypack.dll |
Offset Signs & program(s) |
Hypack® Hardware: · Horizontal offsets: positive forward and starboard of the origin. · Z offsets: o GPS: positive upward from the waterline. Hysweep® Hardware:· · Horizontal offsets: positive forward and starboard of the origin. · Z offsets: o GPS in Hypack.dll is positive downward. o Transducer: positive downward from the waterline. o MRU: Use zero.** · Yaw Offset: o Gyro*: Usually zero. May add correction for variation between magnetic N and true N. Add the variation to the mounting offset using positive values for clockwise rotation from alignment with the keel. |
4. Single Beam and Multibeam
Consideration |
Solution |
Origin |
Hypack® Hardware: Transducer most important over survey line. Hysweep® Hardware: vessel pivot point |
Hardware Setup Program(s) |
Hypack® Hardware: GPS, Single beam Transducer, Hysweep.dll (required--passes heading to Hypack® Survey) Hysweep® Hardware: Multibeam Transducer, MRU, Gyro, Hypack.dll (passes position to Hysweep® Survey) |
Offset Signs and program(s) |
Hypack® Hardware: · Horizontal offsets: positive forward and starboard of the origin. · Z offsets: Positive upward from the waterline. Hysweep® Hardware: · Horizontal offsets: positive forward and starboard of the origin. · Z-offsets: o GPS in Hypack.dll is positive downward. o Transducer: 0--included in draft correction of device when calibrated. o MRU: Use zero.** · Yaw Offsets: o Transducer (determined in Patch Test) & MRU*: positive for clockwise rotation from alignment with the keel. o Gyro*: Usually zero. May add correction for variation between magnetic N and true N. Add the variation to the mounting offset using positive values for clockwise rotation from alignment with the keel. · Pitch offset: Multibeam sensors (Determined in Patch Test) and MRUs* not oriented directly below the vessel. Positive forward. · Roll offset: Multibeam sensors (determined in Patch Test) and MRUs* not oriented directly below the vessel. The reference roll angle (in decimal degrees) is 0 for vertical mounting-use values positive to the port side. |
Additional settings |
If MRU is not at the vessel pivot point, when you edit your data, check Correct for Induced Heave in the Advanced Read Parameters dialog. |
5. 2 Single Beam Systems
Consideration |
Solution |
Origin |
The transducer that is most important to keep over your survey line. |
Hardware Setup Program(s) |
Hypack Hardware- All devices |
Offset Signs & program(s) |
· Horizontal offsets are positive forward and starboard · Z offsets: o Transducer: 0--included in draft correction of device when calibrated o GPS: Positive upward |
B. GPS for heading (1or 2)
Ifyou are using 2 GPS and OTFGYRO.dll, the forward GPS is the origin and is theonly one where latency offsets should be applied.
1. Single Beam
Consideration |
Solution |
Origin |
GPS |
Hardware Setup Program(s) |
Hypack Hardware- All devices |
Offset Signs & program(s) |
· Horizontal offsets are positive forward and starboard · Z offsets: o Transducer: 0--included in draft correction of device when calibrated o GPS: Positive upward |
2. Multibeam -- not recommended
3. Multi-transducer
Theorigin is at the GPS. All else is the same as multitransducer systems with aGyro.
4. Single beam and Multibeam-not recommended
5. 2 Single beam
Theorigin is at the GPS. All else is the same as multitransducer systems with aGyro.
II. Multiple Vessels
A. Towfish
TowfishOffsets and Measurements
Offsetsfor any devices on the vessel are measured from the vessel origin.
Thecablecnt.dll and towcable.dll in Hypack® Hardware uses the towfish depth,Z?offset and corrected cable length to calculate the horizontal distance from theA?frame connection point to the towfish. That distance is added to the Y?offsetto calculate the layback.
Offsetson the Towfish are from the connection point of the cable to the towfish. Thehopper arms on a dredge are also configured with reversed horizontal offsetsand from the connection point of the arm.
2 关于TOWFISH的注意问题
Note: When configuring offsets for the cablecnt.dllor towcable.dll, and the Towfish or other Mobiles in the Hypack®Hardware program, regardless of what type of mobile you have, port and starboard offsets specified in the Offsetsdialog must have their signs reversed from the way you normally express offsets for other devices.
Measurements |
Normal Device Offsets |
Mobile Offsets |
Port and Aft |
Negative |
Positive |
Starboard and Forward |
Positive |
Negative |
如果坚持使用Startboard and Forward为positive,请不要设置OFFSETS,而用Driver Setup设置。
Theexample below illustrates a towfish setup
Towfish with Simple Layback |
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Devices |
Dialogs |
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Driver Setup |
Offsets |
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GPS |
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Starboard -5 Forward -5 Height antenna height (not shown) |
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Cablecnt.dll or Towcable.dll |
Y Offset -20 Z Offset=height above water (not shown) |
Starboard -5 Forward 0 Height 0 |
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Towfish Device |
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Starboard 0 Forward -10 |
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Cable out is controlled in the Survey program. |
Note: In this example, it is also correct to use thefollowing settings for the Cablecnt.dll or Towcable.dll.
Devices |
Driver Setup |
Offsets |
Cablecnt.dll or Towcable.dll |
Y Offset 0 Z Offset = height above water (not shown) |
Starboard -5 Forward 20 Height 0 |
TheTrack point systems calculate the towfish position. No towfish offsets or cableout distances are required.
Track Point Systems |
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Devices |
Dialogs Offsets |
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GPS |
Starboard -5 Forward -5 Height antenna height (not shown) |
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Track point |
Starboard -10 Forward 20 Height 0 |
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Dredge Systems |
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Devices |
Dialogs Offsets |
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Hopper Arm #1 |
Starboard 12 Forward -10 |
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Hopper Arm #2 |
Starboard -4 Forward 10 |
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B. Independent Multiple Vessels
Acentral vessel can track multiple vessels via radio modems. Set up the deviceson each vessel individually. The NMEA.dll can be setup to output GGA, VTG andDBT messages via the radio modem to the data collection vessel. You can alsouse the Shared Memory NMEAOUTPUT program to send the desired data to thecollection vessel. If you will be tracking more than one vessel in this manner,the radio modems must be of different frequencies so that the collectingcomputer can differentiate between devices.
Thedata collection vessel will have a NMEA.dll configured for each incomingmessage to receive the data and record data from each sensor separately. Thesurvey screen on the collection vessel can display all of the vessels fromwhich it is receiving data.