Location & Positioning Devices

Sensorpods

The Deep Trekker™ sensorpods add significant intelligence to the Deep Trekker™ vehicles. Included in this system are the following sensors:

• Depth Sensor

• Compass

• Pitch Sensor

• Roll Sensor

• Camera Angle Sensor

• Turns Counter

• Water Temperature

Using the readings from the depth sensor and the compass, the ROV can hold a depth and heading. These additional features are called auto-depth, and auto-heading.

Heading lock

The auto-heading function is activated by pressing the auto-heading button on the controller. As soon as this is pressed, the ROV will set the current heading to the target heading and attempt to hold it until the auto-heading button is pressed again. When active, the heading on the GUI will be highlighted blue, with the target heading shown in parentheses () below the actual heading.

 This is a more aggressive iteration of the autonomous yaw control in which the ROV will not just fight rotational velocity but will return to the target heading displayed on the GUI. The ROV can still yaw using the left joystick, however steering gain is reduced significantly. This allows the pilot to travel in a straight line. When the auto-heading is active, it adjusts the power of each thruster accordingly. If the thrusters are not being activated by the operator, the auto-heading will activate them accordingly in order to maintain the desired heading. To adjust the target heading with auto-heading activated, move the front left joystick right/left to yaw the ROV. The target heading will change to reflect the new target. 

Note: missions near large ferrous structures or any other sources of magnetic interference will cause the compass to drift and the ROV’s direction of movement will also drift when in heading lock mode.

Depth Lock

The auto-depth function is activated by pressing the auto-depth button on the controller. When activated, the depth indicator on the GUI will be highlighted blue.

When the auto-depth button is pressed, the depth measurement on the GUI will be highlighted in blue and the ROV will actively maintain its current depth within 2-3 centimeters, until it is disabled. Vertical motion control will remain the same. To adjust the target depth, move the depth joystick up/down. From the pilot’s perspective the ROV behaves normally from control inputs but stays at whatever depth you leave it.  It is recommended to have this setting active all the time.

Altitude Lock

If the ROV has a DVL installed, when the FN + DEPTH LOCK buttons are pressed the altitude measurement on the GUI will be highlighted in blue and the ROV will actively maintain its current altitude until it is disabled. Vertical motion control will remain the same. To adjust the target altitude, move the depth joystick up/down.  This is useful when performing a search pattern or collecting visual data of the seafloor minimizing control inputs and allowing the pilot to focus on the visual or sonar data.

Turns Counter

The turns counter records the number of turns an operator has made during the dive. It is a good idea to keep this number as close to 0 as possible and return it to 0 before reeling in the tether to avoid twists and loops in the tether. If the ROV is powered OFF and ON again, the turns counter will reset to 0.

Camera Head Stabilization

When auto-stabilize is active, the camera head will remain at its current angle, regardless of any change in position from the ROV. This allows the camera to remain focused on a specific object even if the ROV is ascending, descending, or moving forwards or backwards. 

Yaw Stabilization

The sensor pod will constantly take measurements of rotational velocity using its 3-axis gyroscope and magnetometer. The ROV will autonomously thrust to maintain the target velocity. This causes the ROV to hold its yaw position, and to smooth out control inputs.  Most significantly, the ROV will automatically counter momentum from turns.  The ROV will stop rotating the moment your thumb leaves the joystick, so movements feel snappy and the ROV is easy to control.

Auto-Stabilization Off

If operating in an environment with lots of loose sediment the ROV’s auto-stabilization can cause the thrusters to automatically enable and kick up said sediment. To combat this auto-stabilization can be turned off which will disable the yaw, heading and roll stabilization along with the station holding fed from the Sensor Pod and optional DVL. This will also disable intelligent modes like auto-depth and auto-heading until auto-stabilization is turned back on.

To turn auto-stabilization off, navigate to MENU → SETTINGS → ROV then turn the Auto-Stabilization toggle to ‘Off’. Alternatively, you can toggle it through a program button by navigating to the MENU → SETTINGS → CONTROLLER → INPUT MAPPING → PROGRAM BUTTONS and assigning it to a program button.

Limitations:

Magnetically dynamic or compromised areas may have adverse affects on any sensopod functions that rely on magnetic/compass readings. See specs below for more limitations.

DVL

A Doppler Velocity Log (DVL) is a device which uses acoustic waves to relate the altitude and velocity of the ROV with respect to the bottom of the body of water being operated in. Integrating a DVL with a ROV can give an enhanced level of control and stability while operating the ROV. The PIVOT can also use the DVL for station holding in current and altitude holding depth and position in the water. Deep Trekker™ supports two different types of DVL systems: the Waterlinked A-series DVL and the Teledyne Pathfinder DVL. Both DVL systems will come attached to the ROV with no setup required. 

To verify that the DVL is on and working, locate the DVL near the rear of the vehicle and turn the ROV on by using the controller. Once the ROV has been turned on, a flashing green light should appear near the front of the DVL. This flashing light indicates that the DVL is powered on and it is working properly. 

You can also verify that the DVL is working properly on the controller GUI by locating the DVL status at the top of the screen. A green dot indicates that the DVL is working properly and is able to measure altitude. If the altitude of the ROV is in range of what the DVL can measure, that altitude will be read out under “ALT” at the top of the screen. If the altitude of the ROV is out of the range of what the DVL can measure, a “-” will appear under “ALT” on the screen.

Limitations:

The DVL uses acoustic waves to measure the velocity and altitude of the ROV with respect to the bottom of the body of water. The bottom of the body of water must be within the altitude limits given in the specs below to give any accurate readings. Objects at the bottom of the body of water, moving objects below the vehicle or acoustic interference from other sources may skew the DVL’s acoustic wave and cause error in the ROVs position. If the seafloor’s angle is greater than 30 degrees the DVL may also start to lose connection. 

USBLs

USBLs are able to approximate the geographical coordinates of the ROV by using acoustic signals to determine the angle and distance between the ROV beacon and the topside beacon. The topside beacon then compares these measurements to a known topside GPS coordinate.

Limitations:

USBLs are subject to some environmental, movement and operational limitations. Measurements taken outside of these specs can lead to errant, messy or entirely incorrect data.

Please see the setup guide for your USBL detailing the limitations of each system.

Blueprint Subsea SeaTrac USBL

See this page for details on using your SeaTrac USBL system

The standard Deep Trekker™ setup for these beacons is an X010 on the ROV and an X150 As the topside beacon