Abstract: The disclosure describes a system for ordering and pairing feature boundary intersections on a sweepline of a simulated digital radar visual display screen in order to arrange a variable length list of data in accordance with a desired order. This ordering and pairing system resolves the correct range order of the intersection pairs for any closed feature shape regardless of boundary convexity, range inaccuracy or possible shape anomalies. The system includes an input data control means (11) having one input connection and a plurality of output connections (14, 16, 18) to store the input data temporarily. There is described two sorting pipelines (12, 13) connected to two of the output connections to receive certain described "key" data in order to sort the data in each respective pipeline in accordance with a desired correct relationship of ranges. A temporary storage means (19) is connected to receive the "non-key" data.

Abstract: A training cockpit on a hydraulic motion system is responsive to the cockpit controls to simulate an aircraft in flight. A simulated radar display of the aircraft vicinity is provided from a data base memory of the topographic and cultural data of the gaming area.As the antenna scans, particular blocks of data are transferred from the district memory to smaller sector core memories at high speed access and transfer rates. The sector memory provides a line of data for each sweep of the simulated radar. Reflectance and elevational data is retrieved from the sector memories and processed, one sweep at a time, through digital radar equation computation equipment which calculates the brightness of each spot in the simulated radar display. This digital brightness data is processed through an earth curvature subsystem which modifies the brightness in accordance with the horizon effect. The modified brightness is applied to a digital to analog converter and then to the radar display.

Abstract: Input data from an XY encoder stage is continuously monitored and compared to an internally generated count as the stage is adjusted in position. The internal count is generated a single count at a time by transitions in the X-Y input data on the basis that each transition is a one-step change in encoder position. A series of one-step transitions causes both the input data and the internal count to change together, or track. If a single transition is greater than a single encoder step, the input data advances ahead of the internal count and tracking is lost, causing a comparison error. The error halts the monitoring process, activates an alarm, and holds the current input data and internal count for visual comparison in a numerical display. The operator can then remonitor the faulty portion of the stage encoder to determine the nature of the error.