Dead Reckoning Improvements in TZ Professional v5.4 for GPS Spoofing and GNSS Disruption

GPS spoofing, GNSS interference, and other positioning anomalies mean the on-screen position can’t always be trusted. TZ Professional v5.4 strengthens Dead Reckoning—an independent, motion-based backup—to help mariners keep navigating and spot suspicious GPS behavior sooner.

What’s improved in v5.4

Easier to access and manage: Dead Reckoning settings are now grouped in a dedicated Options section, making core controls quicker to find.

  • Enabling Dead Reckoning
  • Displaying the Ghost Ship
  • Monitoring GPS deviation

Ghost Ship (spoofing detection)

  • Ghost Ship runs a Dead Reckoning track alongside GNSS, using heading and Speed Through Water (instead of GPS) as an independent reference.
  • Use it to compare the GPS position to a motion-based estimate.
  • If the separation grows beyond your threshold, an alarm can warn that the displayed GNSS position may be unreliable.

Radar-assisted position verification

  • Works with Furuno radar so you can cross-check position using radar overlay and known references (e.g., coastline, buoys).
  • In Dead Reckoning mode, you can manually shift the vessel position to match the radar picture; the corrected point becomes the new reference for ongoing estimates.

More accurate position estimation

Dead Reckoning can now incorporate transverse water speed from sensors such as the Furuno DS 60 or Airmar DX900+ in addition to Speed Through Water, improving estimates when the vessel is pushed sideways by wind, sea state, or current.

More flexibility when data is incomplete

In degraded conditions v5.4 extends Dead Reckoning so it can keep running with whatever data is available.

  • Automatic mode when heading and speed are available
  • Manual entry when either heading or speed is missing
  • Expanded manual mode for very limited data
  • Estimated position input through LOP tool

This ensures that users can maintain navigation continuity even in degraded conditions, instead of losing the benefit of Dead Reckoning when it is needed most.

Why this matters

With these updates, Dead Reckoning helps users:

  • Maintain an estimated position without relying on GPS
  • Detect GPS spoofing and suspicious GNSS behavior
  • Compare GNSS data with an independent motion-based reference
  • Continue navigating when onboard data is incomplete
  • Verify and correct position using radar

Conclusion

GPS spoofing and GNSS disruption while rare are becoming increasingly more common. Safe operations require tools that verify and cross-check position—not just display it.

Dead Reckoning in TZ Professional v5.4 is built to maintain navigation continuity and help confirm whether GNSS data is trustworthy.

Discover The Bahamas with New BathyVision Data on TZ MAPS

From the Abacos to Eleuthera, Exuma Sound, Bimini, Harbour Island, Spanish Wells, Great Harbour Cay, and Crooked Island, the latest BathyVision detail on TZ MAPS brings a clearer view of the shallow-water around some of the most important boating routes in The Bahamas.

In The Bahamas, chart detail matters most where navigation becomes highly visual: reef-lined cuts, narrow harbor entries, bank-to-sound transitions, and close-to-shore island approaches. That is exactly where this new BathyVision data stands out.

For captains, cruisers, and boaters exploring the islands, BathyVision adds a more readable picture of the underwater landscape in places where detail matters most. Across The Bahamas, it helps bring greater visual clarity to the areas that define everyday navigation: shallow banks, coral heads, harbor entrances, narrow passes, and the approaches to anchorages and islands.

One of the clearest examples is found in the Abacos, one of the most important boating regions in The Bahamas. With busy routes, shifting shallows, and reef-lined passages, this area demands close attention on the water. New BathyVision detail gives a sharper view of key routes and approaches around Man-O-War Cay, Whale Cay, Tilloo Cut, North Bar Channel, and Little Harbour Channel, making some of the country’s most traveled cruising grounds easier to read at a glance.

“Big improvement on reef location and details” – Captain Jeff Gauthier on improved North Man-O-War Data

“It looks very good with your level of detail.” – Captain Jody on improved Devils Backbone data

This same advantage continues across other popular locations around The Bahamas. Around Eleuthera, Harbour Island, and Spanish Wells, navigation often depends on interpreting shallow-water detail through narrow, high-attention routes. In places like Devil’s Backbone and the approaches between Spanish Wells and Harbour Island, a clearer visual representation of bottom structure and surrounding terrain adds valuable context when planning and navigating these well-known passages.

Further south and east, BathyVision also brings stronger visual detail to the Exuma Sound cuts, where boaters regularly move on and off the bank, and to the entrance of Crooked Island North Harbour, where winding approaches and prominent coral heads make local detail especially important. In western arrival points such as Bimini, and key cruising gateways like Great Harbour Cay, this added clarity strengthens the overall navigation picture in areas that are central to many Bahamas itineraries.

What makes BathyVision especially valuable in The Bahamas is the way it helps transform complex underwater terrain into something more immediate and easier to interpret. Instead of seeing only isolated soundings and basic contour information, boaters can view the seabed with a more natural visual presentation that makes bottom shape, depth transitions, and shallow structure easier to understand in context.

That added visual detail supports better route awareness throughout the voyage, whether approaching an island, entering a harbor, following a pass, or reviewing a route between cays. It gives mariners a clearer sense of the water around them and helps make chart reading more intuitive in one of the most visually navigated cruising destinations in the world.

With new BathyVision data now available for The Bahamas on TZ MAPS, TIMEZERO delivers an even more refined way to explore and navigate these iconic waters. From the Abacos to Eleuthera, Exuma Sound, Bimini, Harbour Island, Spanish Wells, Great Harbour Cay, and Crooked Island, BathyVision enhances the view where it matters most, bringing more confidence, more clarity, and a better understanding of the shallow-water world beneath the boat.

The History of MaxSea Infographics 1984-2012

Many of you might have some questions regarding our company’s past and present. Well, this infographics is intended to help you understand our history through some key dates and facts.

The History of MaxSea1984-2012 - marine navigation software leader

Key Dates 

1984 – Brice Pryszo, naval architect and passionate about informatics, invents a revolutionary algorithm for automated sea routing

1985 – Creation of Informatique et Mer company and its first software for Mac, called MacSea

End of 80’s – After a huge success in the french market, MaxSea starts developping its distribution network. Iceland becomes its first distributor, followed by other scandinavian countries

1994 – Foundation of the electronic cartography company MapMedia

1999 –

  • Switch from Mac to PC
  • Company and software change their name to MaxSea
  • Launch of 3D PBG  module

1990-2000 – MaxSea’s distribution network covers Northern Europe

2000 – Setting-up of a US subsidiary company: MaxSea Inc.

2001 – SigNet Group was created to group together all companies: MaxSea International, MaxSea Naval and MapMedia

2000-2005 – Further expansion of MaxSea’s distribution to Southern Europe and Latin America

2004 – Technical and financial alliance with FURUNO, marine electronics leader

2007 – Foundation of MaxSea Naval, the Spanish subsidiary

2008 – Launch of TimeZero technology and first sailing software powered by it: MaxSea TimeZero Navigator and Explorer

2009 –

  • Purchase of Nobeltec, main rival and US leader
  • Launch of MaxSea Webstore

2010 – Launch of MaxSea TimeZero professional range: ECS and Plot

2011 – Launch of Nobeltec software powered by TimeZero technology

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This is the first of a series, we will hopefully enhance the aesthetics of the next one!

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