Remote Cloud-Height and Visibility Sensing for Weather and Aviation

This organization is seeking a method to determine the cloud ceiling height up to at least 3000 feet (ideally up to 20,000 ft), cloud coverage, and visibility up to at least 5 miles using a small, low-power automatic sensor. This device would operate periodically to provide cloud and visibility measurements for these assessments. The device must provide these measurements in day and night conditions. These devices need to be small to allow easy placement at remote sites, not necessarily near cities or existing airports, and to operate autonomously. Novel methods and techniques to provide the cloud ceiling height, coverage, and visibility are also sought.

Surprisingly, in an age of Doppler radar, lasers, and satellite images of your house freely available over the Internet, there exists no small, easy, and automated ground-based method of determining cloud and visibility conditions. This is especially true for more remote areas along air routes or at destinations not served by established airports. Remote runways sometimes have weather sensors, but they require power and other infrastructure. This user would like a solution that makes both unnecessary.

Ideally, the end result will be a five-pound, brick-sized item that can easily be transported to a remote location or airstrip, or that can be deployed along air routes not otherwise served by weather offices or weather observers.

Cloud ceiling, visibility, and flight (Visual Flight Rules, Instrument Flight Rules, and sub-categories) fall into several well-defined categories that the required technology must be able to identify and discriminate between at its location (see NOAA’s classifications of ceiling and visibility categories.)

The current state of the art in establishing ceiling and visibility from the ground — especially in more remote areas with no infrastructure — involves launching helium balloons and estimating their altitudes when they disappear into clouds. Sometimes these balloons include altitude–encoding altimeters and strobe lights for nighttime operation.

NOAA (National Oceanic and Atmospheric Administration) uses a device called the Automated Surface Observing System (ASOS). The device is very large and heavy, requires a power supply, and is difficult to transport. It also requires personnel on the ground to operate it.

Pilot reports from aircraft ascending or descending through overcast can estimate ceiling altitude; tower personnel can estimate ground visibility. However, ascending and descending flights are not always available at specific altitudes and specific locations. By definition, remote areas and airstrips almost universally have no control tower.

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