Dead Reckoning

In case of GNSS (GPS) failure, TimeZero can use Heading (magnetic or gyro-compass sensor) and Speed Through Water (doppler sensor recommended) to estimate position using Heading as COG and Speed Through Water as SOG.

First, activate the "Allow Dead Reckoning" setting from the Initial Setup Options. Then you need to make sure to configure a heading (that does not rely on GNSS data) and speed through water sensor.

Note: If you are using a Satellite Compass that provides GPS, it is OK to use its heading data and configure it as a master as long as you have a backup heading sensor (magnetic compass for example) configured on a separate NMEA0183 port.

If the GPS signal is lost (resulting in a loss of position, COG and SOG data) and if TimeZero detects valid heading and speed through water data, TimeZero will automatically enable the Dead Reckoning mode after triggering a "Position Lost" alarm. When the Dead Reckoning mode is enabled, a notification will be displayed in the status bar, the boat icon will start to flash slowly and the position, COG and SOG NavData value (if configured) will be displayed in yellow to indicate the data is estimated:

TimeZero uses STW as SOG and HDG as COG to estimate new positions. If there are currents or winds, this estimated position can become false over time (because drift effect cannot be taken into account). If you have a way to manually estimate your position and have an up to date Lat/Lon, you can re-initialize and validate a new position manually by right clicking on the boat icon and selecting "Move Own Ship by Lat/Lon". This will open a window allowing you to enter a new position manually.

Alternatively, if you are connected to a compatible Furuno Radar (providing a radar picture through Ethernet), the radar overlay can be used to adjust the position by simply dragging the boat icon until the radar overlay matches the coastline or any other specific target (AIS or Buoy):

After adjusting the position thanks to the radar overlay, TZ will then continue to estimate the new refined position automatically (until further adjustments are needed because of currents or wind).

As soon as a valid position is received again by TimeZero, the Dead Reckoning mode will be disabled automatically.