1Q Where is the best place to locate the counter for maximum accuracy?
1A The best location for the counter is on the ground at the approximate lift off point of most takeoffs and 75 to 150 feet from the runway centerline. The location is somewhat flexible, however. The most important aspect of choosing a proper location is to find a spot that maximizes the sound of the takeoff as compared to other normal activity such as warm up and taxiing. Usually this is accomplished by placing the counter on the runway side that is away from a taxi or tie down area. We are always available to help determine the best location for a specific airport layout. | TOP
2Q How is ADS protected from the weather?
2A The 4 inch diameter ADS core electronics package is housed in a removable outer weather shield tube. By installing the counter level with the ground on a well drained surface, rain and snow drain away from the sealed enclosure. As long as the system does not become submerged in standing water it will continue operating and collecting data. | TOP
3Q Can ADS be connected to video or still cameras?
3A The counter can be modified to trigger or otherwise control additional recording devices such as a video camera. The output channels are already a part of the system hardware and can be activated with a software revision. Video recording is not a standard feature because most users' needs are met with the basic acoustic count data and adding video does add cost. If you foresee the need for video in your application WST would be happy to outline a set of specifications with you and provide a quote. | TOP
4Q How long will the battery last?
4A The solar power option ships with a 17 ampere hour sealed lead acid battery. Without any solar recharging the battery alone will power the ADS system for approximately 4 weeks under normal operating conditions. With solar power recharging the system will run continuously until the battery reaches its normal life span on the order of 4-5 years. The internal ADS microprocessor also has a small battery for memory retention and this should last a minimum of ten years before needing replacement. | TOP
5A Yes, it is possible to miss a takeoff if, for example, there are two aircraft that take off nearly simultaneously or if the aircraft is exceptionally quiet. That is why the accuracy is stated as +/- 10% of the true count. Higher accuracies could be obtained but at a substantially higher cost. The 90% accuracy level was chosen as the operational target because it provides a robust system at a reasonable cost. The system is designed so that the analysis algorithm is set at a point where missed takeoffs (false negatives) are approximately offset by false positives (typically low and loud flyovers). In rare cases severe winds can also generate false positives, but that type of event is usually easily detected and can be removed from any final count. On balance the recorded count will be within 10% of the actual number of take offs. | TOP
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