Marine NavigationAustralia · 2026

Foundations

How position, charts, orientation and onboard data actually work — the physics and limits behind every screen on the boat.

5 guides33 min of reading
A cruising yacht receiving satellite positioning, sweeping radar toward a distant vessel transmitting AIS, radiating VHF to the horizon and sounding the seabed with sonar. 14222631 GNSS · RADAR · AIS · SONAR
One hull, four independent sensors. Each answers a different question, and each is blind to something another one sees.
A cruising yacht receiving satellite positioning, sweeping radar toward a distant vessel transmitting AIS, radiating VHF to the horizon and sounding the seabed with sonar. 14222631 GNSS · RADAR · AIS · SONAR

navigation systems

Marine navigation systems: the complete overview

The system-level guide: eight questions every navigation system has to answer, why sensors matter more than screens, and how to design a boat where technologies cover one another's blind spots.

Foundations5 min read

Read the guide Three navigation satellites transmitting to a vessel on a curved horizon, with the heading arrow pointing 040 degrees and the course over ground arrow pointing 057 degrees, showing the effect of current. HDG 040° COG 057° GPS · GALILEO · BEIDOU

GNSS

Marine GPS and GNSS explained

What a GNSS receiver actually knows, why display precision is not accuracy, how course over ground differs from heading, and how to build position redundancy that survives a network failure.

Foundations8 min read

Read the guide An electronic chart extract showing shallow water shaded blue grading to white in deeper water, depth contours, printed soundings, a drying reef, an isolated danger symbol and a Zone of Confidence category diamond. 3₂5₈11141721263329 B AusENC · ZOC

charts

Australian marine charts, AusENC, ZOC and S-100

Why a beautifully rendered electronic chart can still be built on an old survey — and how to read Zone of Confidence, manage chart datum and plan around survey quality in Australian waters.

Foundations7 min read

Read the guide An attitude and heading reference sensor at the centre of a diagram, with magnetic interference reaching it from a speaker, an alternator, a battery and high-current cabling. AHRS speakeralternator batterycabling true

heading

Heading sensors and satellite compasses

Heading is infrastructure. A single bad sensor location degrades the autopilot, radar overlay, MARPA, true wind and laylines at once — here is how to get it right.

Foundations7 min read

Read the guide A tide curve rising and falling above the chart datum line, with a vessel at mid-tide and the remaining clearance between keel and seabed dimensioned. CHART DATUM (LAT) under-keel margin HEIGHT OF TIDE

tides

Tides, currents and chart datum

Available water depth is charted depth plus tide, minus draft, minus margin — and every one of those terms carries uncertainty. Here is how to compute it honestly.

Foundations6 min read

Read the guide

Other topics

The library is organised so each shelf answers a different kind of question.

Equipment & SensorsBuying GuidesBy Vessel TypeSeamanship & SafetyProjects & InstallationReference