🛰️ How can I detect and delete implausible AIS positions from a vessel’s past track?

🧭 Why do implausible AIS positions occur?

AIS data is received from multiple sources and may occasionally contain errors due to:

• Signal collisions or interference
• Overlapping data from nearby vessels
• Delayed or incorrect transmissions

In rare cases, this results in:
➡️ Unrealistic jumps in position
➡️ Incorrect routes (e.g. vessel appears in a completely different region)
➡️ Artificially extended past tracks

🔍 How to identify implausible positions

Implausible positions are automatically detectable and typically appear as:

• Positions far away from the actual sailing route
• Sudden deviations
• Unusual spikes in speed or distance

⚙️ Step-by-step: Delete implausible positions

1️⃣ Open the past track

Go to: Data → Delete Positions 

2️⃣ Display the track

• Select a ship and the time frame
• Click on Update to open the vessel’s past track
• Review the positions visually on the map

3️⃣ Select implausible positions

Click:
👉 “Select implausible positions”

✔️ Fleettracker automatically highlights incorrect data points
✔️ Positions are visible both in the list and on the map as yellow position dots

4️⃣ Review selection

• Selected positions are clearly marked
• You can verify them before deletion

5️⃣ Delete positions

Click:
🗑️ “Delete selected positions”

➡️ Confirm the deletion
➡️ The past track is immediately corrected

💡 Tip

You can also manually select individual positions directly from:

• The position list
• The map view

⚠️ Important notes

• Deletion affects historical track data
• Changes cannot always be undone
• The feature is designed to handle rare but impactful data errors

🚀 Result

After cleanup, you get:

• ✔️ Accurate vessel tracks
• ✔️ Reliable distance calculations
• ✔️ Improved data quality for reporting and performance modules