Dead Reckoning

Dead Reckoning User Guide

Deep Trekker is advancing the ability of ROV operators to track positioning with the latest underwater navigation capabilities. This position-tracking capability is called Dead Reckoning.

Dead Reckoning is the process of calculating the current position of a moving object using previously determined positions. This type of tracking can be accomplished using purely on-vehicle sensors without the need for a USBL setup, creating navigation opportunities in environments where USBL is less effective.

Map Modes

Once you have booted up your ROV, the BRIDGE controller will automatically enter into Global Map mode. You can swap to Local Maps on the Map Settings page.

Global Map

Global Map uses real-world map data and tracks position through latitude and longitude. This mode allows you to use different map styles such as street view or satellite view.

Local Map

Local Map uses a grid overlay with no map tiles and tracks through distance in meters from a starting point (0,0). This map can be useful when operating in indoor environments especially when the dimensions of the asset being inspected are known

Requirements for Dead Reckoning 

Equipment

• BRIDGE Controller

  • Version 8.0 or higher

• REVOLUTION (6.9 or above) ROV, PIVOT (3.0 or above) ROV

  • Disclaimer: Dead Reckoning is inadvisable with a grabber claw on the PIVOT. See the Pivot Dead Reckoning SOP for details

• SensorPod+

• DVL

Key Features of Dead Reckoning

ROV Trail

In BRIDGE Controller version 8.0, the ROV’s previous positions will be displayed on the map through a ghost trail. This will be drawn as long as there is an ROV position being provided. The trail can also be cleared at any point by pressing FN + Pitch Lock or by pressing “Clear ROV trail” on the settings page, which can be accessed by pressing FN + Menu.

Uncertainty Bubble

When using Dead Reckoning, the uncertainty of the ROV’s position will grow. You should be able to get 30 minutes of operation before reaching an uncertainty of 10 meters. This uncertainty is represented by the uncertainty bubble around your ROV on the map. If the position uncertainty grows too high, it is recommended to re-initialize your ROV’s position.

Gyro Only Mode

The sensorpod+ can be put into gyro only mode where the system will ignore magnetic heading data in favor of gyroscope input only for rotational movement. This function can be useful when operating in inconsistent ferrous environments or for sections of missions where the magnetic environment changes throughout. 

A good example of where this function can be used is in ship hull inspections. In standard mode, the magnetometer may be affected by the large ferrous objects within the ship such as an engine block. In this scenario, gyro only mode could be turned on as you approach the engine ina horizontal sweep and then turned back off once past it.

This function can be turned on either through the heading menu or with a programed button.

It is important to note that the dead recking feature will have ~10 degrees of angular drift per hour while in gyro only mode, which can equate to significant positional changes over distance, and should only be used when absolutely necessary.

when activated, Gyro only mode will be displayed with a small strikethrough above the compass.

Settings to Consider Before Starting

If you are using Global Maps, there are a few settings you should consider before beginning your mission.

If you would like to have your Topside location appear on the map, you can enter your coordinates in the Location menu. This will enable the “Snap to Topside” option in Dead Reckoning. There are 2 recommended options.

• Device Type

• ROV GPS

  • Utilizes the ROV GPS mounted on your ROV for real-time topside location. Ideal for applications requiring mobility.

  • Simply slide the ROV GPS on the quick mont base, lock it in place using the spring plungers, inset the GPS harness connector, and fully thread the connector collar into the mount.

• • If the GPS does not auto-connect, navigate to the Location menu and configure the ROV GPS with the ROV port

• • Static

    • Used a fixed, predefined location set manually by the user.

Maps

• Map Centering

  • Operator

    • The map is centered around the operator's current position.

• ROV

  • The map is centered around the ROV's current position.

• Both

  • The map dynamically centers between the operator and the ROV. this provides a balanced view, allowing the user to monitor both positions simultaneously.

Orientation

• North Up

  • The map is oriented with North always at the top. Ideal for users familiar with standard navigation maps and for maintaining a fixed directional reference.

• Controller Up

  • Aligns the map with the operator's perspective, making it easier to relate the map to the operator's actual view.

• ROV Up

  • The map is oriented with the ROV’s current heading at the top. Allows the user to see the map from the ROV’s perspective.

• Map Zoom

  • Adjust the scale of the map.

  • This can be hot-keyed onto your controller via Input Mapping to avoid constantly pausing your missions to open the Maps menu.

• Map View

  • Adjust the map view on your screen between Minimized, Pop-Up, or Fullscreen.

  • This can be hot-keyed onto your controller via Input Mapping to avoid constantly pausing your missions to open the Maps menu.

• Map Type

  • Choose between Street view or Satellite view

    • You will require a Wifi connection to load either view.

    • If you don’t have Wifi access on-site you can pre-download the maps.

Global Maps

To track your ROV position you will need to give the vehicle an initial position to track from. This

can be set manually through the hand controller or if using a USBL it will do this for you automatically. In either scenario, the ROV position can be manually initialized simply by pressing FN + Camera Home when the mini or full-screen map is open. You are also able to enter your topside location in the Location menu and snap your ROV to your topside position. 

There are a few ways to move the ROV’s marker:

• Input the latitude and longitude of your ROV by pressing FN + Camera Home. 

• Drag and drop by moving the left joystick and pressing Enter

• Snap to Topside location by pressing Camera Home if you have entered your Topside location

Once your initial position has been set, you are able to adjust your topside location or ROV location.

Local Maps

Once you have first booted up your ROV & BRIDGE controller, Global Map should automatically open. You are able to switch to Local Map in the Maps Settings menu. 

Local Maps can be useful when operating in indoor environments, especially when the dimensions of the asset being inspected are known. On startup, the ROV position will be set automatically to 0,0 meters. Afterwards, manual initialization is required.

Location from dead reckoning will be saved in the data log folder for your mission, see the page on Data logging for more information