MOUNTING SUBSONUS
Subsonus comprises a hydrophone under the boat that measure the positions of one or more Tags attached to divers, ROVs, fishing gear or similar. Data from Subsonus are shown on Olex.
Maximum range is 1000 meters. Suboptimal conditions, which reduces the range, may include, air bubbles, turbulence, echo surfaces, intermediate objects in the water column and variations in oceanographic conditions such as salinity or temperature. Nominal accuracy is 1.5 meter per 100 metres of distance. The Tags can withstand a depth of 2000 metres. The interval between updates varies from less than once per second, to several seconds.
Even though one may interact with Subsonus via a web browser, this is not necessary when used with Olex. All configuration and debugging is done through Olex.
INSTALLING THE HYDROPHONE
The hydrophone is mounted submerged, with "Forward" pointing forward. Acoustic direction is from the metallic underside and out through the blue plastic covered elements. Nominal mounting orientation is with the acoustics pointing straight down, or tilted towards where the Tags are expected to be. After installation, the hydrophone is not to be moved again, lest one redoes its calibrations.
Subsonus is vulnerable to multipath. Try to avoid nearby reflective surfaces. The manufacturer recommends a depth of atleast 1 meter, and a distance of atleast 1 meter from the hull.
Subsobnus measure its own roll and pitch, so a mounting pole doesn't have to be perfectly rigid. It does not take well to vibration, though. Heading is fed from Olex. After installation, orientation must be zeroed and heading adjusted.
The cable must be connected before the hydrophone is submerged. Use Molykote or similar for protection. The connection is through a PoE injector and then on to Olex or its local area network.
READYING THE TAGS
The Tags comes already configured, with unique Tag ID. A Tag is in either of three states: Shipping, Performance, or Endurance. It is woken from Shipping by placing it on a Qi charger in its charging orientation, with the display pointing straight up. From then onwards it is nominally in Performance. After a week or two (shorter if used) it depletes its battery. Charge it by placing it on the Qi charger again. A full charge takes 6 to 8 hours.
The Tags are fastened by common cable ties. Tensile strength: 50 lbs, width 7 to 9 mm, length > 250mm. Don't over-tighten! Nominal orientation is vertical, with the blue transducer pointing straight up or towards Subsonus. The Tags emit pitch, roll and heading, with the latter pointing straight out of the display. While the device is robust its plastic cage is not. Don't let the Tag be the outermost or highest point. Lean it against a sturdy and slightly higher post.
SETTINGS ON OLEX
Olex must have a software nokkel called UP. It must run Olex version 14.5 or higher. If Subsonus is running version 3.0 or higher, Olex must run version 15.1 or higher.
There must be a network NMEA link from Olex to Subsonus. On Olex, create this on Show Dataflow->Network. IP address is 192.168.65.102, TCP port is 16720. Actually, the data is not NMEA but ANPP, a proprietary binary protocol from Advanced Navigation.
STARTUP
After hardware installation, the following steps must be completed:
* Zeroing of orientation
* Adjustment of heading
* Activating of Tags
Zeroing of orientation is performed by going to the Subsonus window and pressing Config->Zero orientation while the boat lies stationary. Afterwards, confirm that pitch and roll is reported as centered around 0.
Adjustment of heading is done by entering the More window for the network link labelled Subsonus on the Dataflow window, and adjusting the heading rotation. The window show the heading the Subsonus is assuming, based on heading given by Olex and the configured rotation. The headings are not necessarily entirely identical, as Subsonus filters variations.
Tag activation is done on Subsonus->0 tags->Add tag. Specify the ID number of the tag, shown as Address on the lower left on the Tag display. It is a number from 1000 to 65535, preprogrammed by Olex AS.
The Tags must also be discovered by Subsonus. This process may take several minutes. The acoustic conditions must be good, the Tags not too close to boat or bottom. Thereafter, Subsonus remembers the configuration even if powered down.
NOISE FILTERING
Quality of acoustics is shown as a correlation ratio for the transmissions, displayed thus: <97>. The number varies from 0 to 100. Lower ratio means weaker positioning. Olex ignores positions with ratio below a certain threshold, usually 86 but adjustable on Subsonus->Config->Minimum correlation ratio.
If one is bothered by much transmission noise, one may consider reducing the correlation threshold so that more Tag positions slip through the filter, although at the cost of more erratic positioning.
SOURCES FOR NOISE
These are the usual suspects. The acoustic pathway between Subsonus and Tag must be free from physical obstructions, and must not pass through turbid or bobble-filled waters. Avoid wakes from bow and propellers. Try to mount Subsonus as deep as possible.
Signal frequency is centered around 30 kHz. Avoid other sonars near this frequency. Likewise, avoid strong noise sources such as propellers.
OPTIONAL CONFIGURATION OF TAG
Tags can be set to Endurance, get a different ID, get a local name, or others by programming from an Android app named "Subsonus Tag manager". Communication is via Bluetooth. The manual for Tag and app is available at www.advancednavigation.com.
OPTIONAL CONFIGURATION OF SUBSONUS
Subsonus comes ready configured from Olex AS. We recommend that users DO NOT upgrade its firmware, as the manufacturer might have introduced changes which break Olex compatibility. Upgrading its firmware may render it unoperational.
Still, if Subsonus for some reason has been wiped or reconfigured it can be set up via a web browser. Its manual from www.advancednavigation.com should be consulted in that case. The main aspects are:
* Originally, Subsonus is without an IP address, and is accessed via Zeroconf. Address is "http://an-subsonus-1.local/". Make sure to use a DHCP-equipped router. Give Subsonus a static IP address of 192.168.65.102 and netmask 255.255.255.0. From then on, the router can be removed and the network cable from the PoE injector inserted directly into Olex. Subsonus can reached at IP address 192.168.65.102.
* Data is sent to Olex by going to Configuration->Data Streams. For TCP server 16720, press "Select Action", and select "Edit stream". On the new subwindow "Edit Stream", set Data Sources to "All devices". Leave with "Submit". Thereafter, by using "Add messages", configure the following:
ANPP 020, 10 Hz
ANPP 024
ANPP 025
ANPP 028, 10 Hz
ANPP 029
ANPP 100
* Data is received from Olex by going to Configuration->Devices->Create new Device, and adding "GNSS Compass - Generic NMEA", IP address 192.168.65.15, port 16700. One must pass through various subwindows. Don't forget to activate "Enable aiding".
* Firmware versions must be coordinated between Subsonus and Tags. If Subsonus run a lower version than 3.0, all its Tags must run a version lower than 2.0. Conversely, if Subsonus is at 3.0 or higher, all Tags must be at 2.0 or higher.