GPS-free navigation with JAM, another tool from Streamworks helping you through waters with intensive GPS-jamming like the Baltic Sea.

JAM utilizes data from the vessels log and compass in order to provide guidance along the planned route. By constantly comparing the ships estimated position to the GPS-signal, JAM gives warnings if suspicious behavior is registered.

Based on the estimated position JAM can transmit virtual GPS data to plotter devices so the ships position can be displayed on a nautical chart. JAM also contains a virtual map with the route where heading and position is plotted in relation to the route.

For using JAM on board you need :

• A laptop or a Raspberry Pi

• Your planned route as a GPX file
  

For feeding data to the system there are 3 options:

• Magnetic compass and Log data as wireless UDP NMEA0183 data stream.

• Manual trim of heading and speed along the trip

• Update JAM with ships log data so JAM can show your virtual position location at the virtual map, assuming you are following the planned route.

The JAM interface is organized in logical blocks according to the different tasks related to GPS-free navigation. Each block can be enlarged for clearer overview while sailing.

Deviation trim
– Values for Compass Magnetic Declination in the current area.
– The vessels magnetic deviation at current heading.
Automatically updated from the vessels deviation curve
(use Streamworks MagDev tool for creating the curve).
– Trim of deviation.
– Deviation from drift
– Deviation from current
– Total Deviation as a sum of the above parameters

Trim of STW (Speed Through Water) if against or with current.

Log/Settings
– Log with accumulated distance from STW and
from virtual speed (SOG).
– Settings of the way a trip should start
(from actual GPS position or from route’s first waypoint)
Selection of UDP ports for receiving and transmitting

Map
Virtual map of route with ships position and heading