The objective of a Radar Image Prediction System is to provide a pilot or navigator with a predicted image of his enroute and target area radar display so that he can become familiar with significant terrain and cultural features as depicted by his sensor system, plan his course, and practice various approaches for achieving his mission. The requirements of a Radar Image Prediction System are:

a. Develop a near-real-time realistic display simulation from a data base that defines terrain and cultural features.

b. Provide a capability for quickly correlating the computed, or simulated, image with graphic (chart or photographic) data of the same area.

c. Provide an on-line capability to update or modify the computed image based on graphic source information.

d. Provide an interactive display capability so that changes in the data base can be immediately viewed by the operator.

The Radar Image Prediction System that meets the above requirements is illustrated in the block diagram of Figure 1(a). The digital data base defines terrain elevation and cultural features by lines that are reflectivity boundaries and elevation features (ridge and valley lines) and by target points. The image processor reads the digital data base and converts the elevation and reflectivity data to a real-time radar image that is displayed on a PPI. The Interactive Data Base Generator provides the capability to correlate the computed image with a map or photo image and to modify the data base.

A sketch of the basic laboratory Radar Prediction System is shown in Figure 1(b). A 16K core memory that stores the data base and the high-speed image processor that generates the radar PPI display are mounted in one six-foot equipment rack. The Interactive Data Base Generator includes the displays, the operator controls, and the logic required for generating or changing the data base. The computed image is displayed on the vertical CRT. The image of the map or photograph is displayed on the horizontal light table. The two images are combined by a 45-degree beam splitter.

Figure 2 is a photograph of the Interactive Data Base Generator Console. All console controls are in operator language and are automated so that anyone familiar with radar prediction techniques can generate or change a data base using graphic source data. Several data bases have been developed on this console. U. S. Geological Survey maps were used as the graphic source data. The average encoding rate was 300 words per hour. This rate can be easily doubled by more human factor optimized controls and by experienced operators.

The resulting PPI display is a real-time, full three-dimensional, realistic simulation of the radar display. A pilot or navigator can "fly" the image, plan an optimum route to a target area, and become familiar with the terrain and cultural features of the target area as they will be displayed by the on-board radar system.