Aerial Photography For Wireless Internet Applications

by

Kelby Harrell

ES 555 Small Format Aerial Photography, Emporia State University

Wireless Internet Access

Wireless internet access is a relatively new method of delivering high speed internet access to internet customers without the need for land based infrastructure. This enables a network of multiple computers with high speed access to each computer. This internet service sends packets of data at high speed through the air between two points. Wireless internet service operates in the public 2.4 GHz frequency range, which is generally classified as being for industrial, scientific and medical uses. A licence is not needed to use equipment in the 2.4 GHz band if one adheres to certain power level restrictions. Speed depends on distance from the transmitter and network activity. Transfer rates are from 10 to 20 times faster than a modem connection. If a customer's computer is on, the connection is running.

Coverage Area And Signal Acquisition

In addition to speed, coverage area depends on line of sight (LOS) from a broadcasting platform (towers or buildings) to the network location. LOS refers to obstacles or lack thereof which includes trees as well as architectural structures. Often the only way to determine feasibility is to utilize aerial photographs taken from the location of the broadcast antenna viewing toward a receiving antenna which attaches to the side of the house or roof. The receiving antenna is wired to a radio which connects to the customer's computer.

Photo Data

Photo data is used to determine which buildings are visible and which buildings are shadowed from view. Shadowed regions are regarded as inappropriate locations for receiver locations unless relay antennas are place in such a way that the signal can be present in the these locations.

Aerial Photos For Wichita, Kansas

As an example, a wireless system was installed in the downtown area of Wichita, Kansas. The purpose of the system was to connect the city building to the county jail. Such a system was intended to aid in quick communication and information sharing between the two locations. The installation was conducted by Stutler Technologies located in Emporia, Kansas. The following images show the roof of the city building. Note the facade which surrounds the roof of the building.

In this situation, the antenna location would be selected within view of the receiver. In the following photo the location of the receiver site is as shown.

In addition to a receiver mounted on the roof of the city building, police and other emergency vehicles must be able to acquire a signal from that structure as well. It can be seen in the following photo that there are portions that are not visible from this location. The image was acquired from the city building.

The large structure in the foreground of this view presents obstacles that limit LOS receiver locations. Relay antennas must be placed accordingly.

Conclusion

Wireless technology transmits data via wireless radio frequencies from a tall structure in the community. A small antenna attached to a wireless radio at the customer's home or office. This technology provides internet access that can be up to 20 times faster than conventional dial-up services. The service requires line of site to the transmitting tower. Radio line of sight can be determined by viewing the coverage area from the proposed antenna mounting point and looking for the destination point. Aerial photography can be utilized to determine if the destination point is obstructed by trees or buildings. If there is an obstruction, the photographs can be useful in determining alternate transmitter sites as well as relay transmitter sites that would bypass structures that block line of site.

Acknowledgements

All photos and information about wireless communications courtesy of: Stutler Technologies LLC, Emporia, Kansas

This web page was created to fulfill the requirements for Small Format Aerial Photography Class at Emporia State University.