-3- 
**•*» 
a recorded verticality of thirty arc seconds, the co 
ordinates of prominent features on the face of the earth 
can be established within a probable error of 15 feet. 
This mission substantially reduces the need for ground 
survey parties to provide ground control to support 
Aerial Mapping Photography. 
5. Terrain Profile Recording - This is the measuring of 
the terrain profile along the flight track of the aircraft 
The terrain data provides vertical control for the map 
ping photography. This function is normally accom 
plished in conjunction with electronically positioned 
Aerial Mapping Photography, Horizontal Control 
Photography and Precise Aerial Mapping Photography. 
6. Long Line Geodetic Azimuth Determination - In 
certain areas of the world, the positioning of a long 
narrow chain of islands is not well suited to trilatér 
ation surveying; that is, by measurement of distance 
alone. In such localities, the measurement of angular 
information in addition to distance is a necessity. 
In order to provide the capability of accomplishing the basic 
functions above, several new and advanced techniques and components 
had to be developed. Figure 1 illustrates the approximate layout of 
the overall Q-28 system. From the front of the aircraft rearward, 
the equipments and their specifications are discussed in detail. Some 
of the missions are reviewed as they affect the individual equipments. 
Figure 2 illustrates the navigator's station. This station con 
tains the standard aircraft instruments plus a special AN/USQ-28 
navigation control panel. This panel was designed to increase the 
power, speed and accuracy with which the navigator can perform his 
vital functions. The navigator can perform executive, decision 
making functions without the distraction of routine work. By utilizing 
the Q-28 control panel, he can: