Optimal flash characteristics for lighted buoys - an experimental evaluation
article
This paper presents an investigation into the light characteristics required to obtain an optimal flash pattern for battery-operated lighted buoys while at the same time achieving the best compromise between energy consumption and suitability as aid-to-navigation lights.
To meet this latter requirement, a light should have a certain flash duration ensuring an adequate operational range with low power consumption together with a duty cycle ensuring that the light is readily detectable and that the degree of group-flashing is such as to shorten the time required to take bearings.
The paper describes the experiments which w[h]ere carried out to select the most favourable values of these variables:
- A plot of average power consumption versus range, with duty cycle and flash length as parameters (Fig. 2), shows that the flash length should be at least 200-400 ms and the duty cycle 0.10-0.20.
- Fig. 4 shows that an adequate detectability will be obtained with the same duty cycle as mentioned above, i.e. 0.10-0.20.
- Fig. 5 shows that, with this optimal duty cycle, taking bearings will require about 10 s, the same time as for detecting the light.
The conclusion is that, with an optimal flash Itngth of 200-400 ms and a duty cycle of 0.10-0.20.
- the power consumption will be about 1 W,
- the expected visual range, 90% of the time along the Dutch coast, will be more than 4 km,
- the detectability and suitability for taking bearings will be about the same as with a steady light and group-flashing will hardly affect detectability.
To meet this latter requirement, a light should have a certain flash duration ensuring an adequate operational range with low power consumption together with a duty cycle ensuring that the light is readily detectable and that the degree of group-flashing is such as to shorten the time required to take bearings.
The paper describes the experiments which w[h]ere carried out to select the most favourable values of these variables:
- A plot of average power consumption versus range, with duty cycle and flash length as parameters (Fig. 2), shows that the flash length should be at least 200-400 ms and the duty cycle 0.10-0.20.
- Fig. 4 shows that an adequate detectability will be obtained with the same duty cycle as mentioned above, i.e. 0.10-0.20.
- Fig. 5 shows that, with this optimal duty cycle, taking bearings will require about 10 s, the same time as for detecting the light.
The conclusion is that, with an optimal flash Itngth of 200-400 ms and a duty cycle of 0.10-0.20.
- the power consumption will be about 1 W,
- the expected visual range, 90% of the time along the Dutch coast, will be more than 4 km,
- the detectability and suitability for taking bearings will be about the same as with a steady light and group-flashing will hardly affect detectability.
TNO Identifier
4646
Source
Bull de l'A.I.S.M., pp. 8-14.
Pages
8-14
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