Q: Is it possible to position Compatt 6s independently within the same array, and send each positioning out of Fusion to our navigation software?
A: If you add two Compatts to a vehicle, these will both be used to track the vehicle as long as they have appropriate references. If you wish to track the two independently (i.e.no knowledge of the fact they are mounted on the same structure and constrained by a known distance),we would suggest creating two vehicles (structures) and add a Compatt to each. Then you can track both simultaneously within the same array. Tracking two independent vehicles is mathematically different to tracking one with two Compatts mounted so you may see variation in the position differences.
Q: Please can you advise us how often the endcap sensors need to be calibrated to keep them in spec?
A: It’s vitally important that the performance of your endcap sensors is regularly checked. Check depth and sound velocity sensors annually whilst inclinometers and temperature sensors should be checked every two years. Our regional service centres are equipped to perform these specialist checks and re-calibrations, for a fast turnaround of your equipment.
Q: How can I get the best performance from my long layback tracking operations?
A: Here are some things to consider when planning a long layback towfish USBL tracking job. If extreme range is required, our LMF (Low Medium Frequency) HPT transceiver system reduces absorption and therefore may be better suited to the task. However performance will depend on the noise signature of your vessel so make sure you have a good understanding of this. Next, choose a transponder with a high acoustic output such as a directional 5,000 or 7,000 metre rated WMT. If space on your vehicle allows, use a Compatt 6 as it has twice the Tx power. In either case, always use WB2+ signals to get double the energy into the water. Angle your beacon to point towards your vessel and set it to Responder mode for the fastest possible position update rates. Tilting the transceiver can open the face to vessel noise and reduce effective range so if your vessel is noisy, inverted USBL (iUSBL) could be the answer. It’s important to discuss your exact requirements so get in touch with us by emailing: survey.support@sonardyne.com for free expert advice.
Q: Does Compatt 6 have modem capabilities?
A: Yes, all Compatt 6 transponders come with a robust, underwater telemetry capability built-in as standard. The transponder supports user transfer rates from 100 bps to 9,000 bps and is equipped with an internal 512 kB data buffer. Unlike many acoustic modems, it’s highly customisable and can support a number of different applications such as auto forwarding of ADCP data.
Q: When to use a float, when to use a stand?
A: First consider your error budget; how precise does your position information need to be for this job? For example, Metrology requires millimetric precision so rigid stands are your only option. But this requires planning in order to ensure stand heights are suitable to provide good line of sight between transponders, and will most likely require ROV resources to deploy and recover them. If however, you have more flexibility in your tracking solution, you may decide to go with the simpler float collar option. Deployed by freefall or ROV, tethered releasable weights keep the Compatt on the seabed as it floats upright. But be aware of currents; they’ll cause the Compatt to sway – the amount depends on the length of tether and design of float. In uneven topography, longer tethers may be needed to ensure line of sight. Our teardrop float is worth considering as it reduces drag, and minimises deflection. Our SSG team are here to help. Email them at: survey.support@sonardyne.com
Q: How do I correctly set a Compatt release mechanism?
A: If set incorrectly, your Compatt’s release mechanism can become damaged; it might fail to open or sinker weights may fail prematurely when lifted off the back deck. Use the following method to ensure the release is set correctly and safely.
There is a hole in the lever arm of the release and another in the side plate. Insert a 4mm Allen key into the lever arm hole. Make sure the supplied stainless steel shackle is situated and push the Allen key towards the body of the Compatt to move the lever arm into place. We only use the best quality shackles; cheaper alternatives are available, but using these can put your equipment at risk.
Keeping pressure on the Allen key, insert a screwdriver in the side plate hole, across the top of the lever arm and out of the other side plate. You can now relax and remove the Allen key as the screwdriver will keep the lever arm in place.
Using 6G Terminal Lite software or an iWand, ‘Arm’ and then ‘Close’ the release. The motorised cam will close, locking the lever arm in place.
Once this is complete, remove the screwdriver, attach the weights to the shackle and your release is set.
Q: How can I deploy my Compatt using iWand?
A: Place the iWand’s antenna against the Compatt’s transducer, then select ‘Get Configuration.’ After a quick ID and comms handshake, the unit’s settings are uploaded to the iWand’s memory. Move to the next Compatt and repeat the process. Now connect iWand to your PC using RS232, USB or Bluetooth. Open the 6G Configurator software and click ‘Refresh’ to see all the details for each of your recently added Compatts. Select each one in turn and make any configuration changes you need for your job including; addresses, power and gain levels. Once all changes are made, select Set Configuration and download the settings back to your Compatts. Now test the sensors and release before generating a report for each unit. Head to our YouTube channel to see iWand in action.
