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2.2 Scenarios and Results
We had several scenarios to evaluate AIS function and display with RADAR/ARPA data as follows.
(1) Scenario-1
This scenario is to evaluate in a case of moving parallel to on point standing abreast line laterally from Base station illustrated as Fig.2. Every ship navigates at approx. 5 knots.
Fig.2 Scenario 1
Investigation of scenario-1 was executed and we got the following results.
■It is good coincidence between AIS data and ARPA data before meeting point.
■ARPA data is comparatively stable in sailing, but in anchoring it is unstable such as swapping data between sailing ship close to own-ship.
■Because of changing data refresh rate by her speed, so AIS readout displays later than RADAR readout.
(2) Scenario-2
This scenario is to evaluate in a case of moving parallel to on point standing abreast line longitudinal from Base station illustrated as Fig.3. Every ship navigates at approx. 5 knots, and the distance between ships initial positions is approx. 360 meters.
Fig.3 Scenario-2
Investigation of scenario-2 was executed to clear the difference between scenario 1 and 2, and it was confirmed that there was no difference.
(3) Scenario-3
This scenario is to evaluate in a case of moving parallel and over-taking illustrated as Fig.4. Ship B and D start first at approx. 5 knots, and after 3 minuets Ship A and C start and over-take others at approx. 10 knots. The distance between ships initial positions are approx. 150 meters.
Fig.4 Scenario-3
Investigation of scenario-3 was executed and we got the following results.
■There is no swapping in sailing with the distance approx. 150 meters.
■It is difficult to identify the readout of ship's name in case of small range.
(4) Scenario-4
This scenario is to evaluate in a case of turning illustrated as Fig.5. Every ship navigates at approx. 5 knots and 10 knots.
Fig.5 Scenario-4
Investigation of scenario-4 was executed and we got the following results.
■In both case of speed 5 knots and 10 knots, AIS data ARPA data are stable in sailing, due to a small turning circle.
■ In stopping it is unstable such as swapping data between sailing ships close to own-ship.
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