A self-contained perspective radar system is modified and improved by providing an additional display on the radar screen in accordance with known information such as the range and bearing of the aircraft at a given fix point during an approach and landing operation. The additional display may take the form of a vertical vector generated on the display screen the upper terminal point of which indicates the location of the threshold of the airport runway and the overall length of which decreases with decreasing range as the aircraft approaches the runway. The horizontal position of this vector will also indicate any deviation in heading. In a more advanced embodiment, the additional display may actually constitute a generated runway outline for comparison with the actual runway detected by the perspective radar. In it's most sophisticated form, in addition to other features, an actual image containing all known information of the physical characteristics of an airport complex is stored rather than displayed in a condition such that it may be compared with the perspective radar display by a suitable comparing means which provides output signals such as error signals to advise the pilot of a mismatching of the actual perspective radar picture with the stored image. The same output signals may be used to automatically control an auto-pilot so that approach and landing of the aircraft can be effected completely automatically without the necessity of any pilot intervention and by a system which is wholly self-contained within the aircraft.
This application is a continuation-in-part of my copending patent application Ser. No. 847,121 filed Aug. 4, 1969 and entitled AIRCRAFT CONTAINED PERSPECTIVE RADAR/DISPLAY AND GUIDANCE FOR APPROACH AND LANDING, now U.S. Pat. No. 3,778,821 issued Dec. 11, 1973.
Signals from a source of flight path data, normally a memory device which stores forward-looking radar data, for example, are sampled in "reverse-time". That is, the data points along the flight path are taken in reverse order relative to the direction of flight. By simple circuits, the signals from the flight path data source are modified to conform with the basic criteria of the desired flight and with other desired parameters such as vertical acceleration and velocity limits so that a reverse-time flight simulation is made. The special "inside-out" form of indicia is a pair of bands which are fence-like in appearance and form the vertical sides of a tunnel-like outline, along the vertical center of which is the desired flight path. By generating these bands on a cathode ray oscilloscope with vertical displacements in accordance with the desired flight path and relative vertical widths in perspective with the range, the curved center line is easily followed.
A method of identifying a runway is disclosed. A first scan of an area of ground known to include a runway is performed. The first scan is accomplished using a weather radar system at a predetermined position. A first image is obtained from the first scan. The first image is stored in a memory. A second scan of an area of ground proposed to include the runway is performed. The second scan is accomplished using a weather radar system at what is believed to be the predetermined position. A second image is obtained from the second scan. The first image is retrieved from the memory. It is determined whether features in the first image correlate to features in the second image. A runway confirmation signal is sent to a pilot of the aircraft when there is a substantial certainty of correlation between the first and second images.
Alignment apparatus is disclosed for use in a radar display system in which targets are displayed on a raster scanned cathode ray tube and a computer causes target identities to be displayed adjacent to each target. To align the display system the computer generates a first signal which is applied to the system in the same manner as are radar video signals, and generate a second signal which is applied to the system in the same manner as are target identity signals. The two signals cause two dot test patterns to be displayed on the tube and interactive display techniques including a positional entry device such as a light pen are used to cause the two test patterns to be superposed. In response to superposition of each dots of the test patterns, the computer generates and stores correction signals which are thereafter used to modify the target identity signals to assure that target identities are displayed in proper registration with the targets.
A non-linear range scale for a radar system is implemented whereby the full range capability of the system is shown with emphasis on close-in targets. The arrangement is adaptable to a variety of non-linear functions having the advantage of selection by the user to provide good close-in visibility and visibility of distant conditions simultaneously.
A signal light comprising an elongate translucent tubular member formed of a light plastic material having a light source disposed therein for emitting illumination therefrom and providing guidance and orientation to aircraft and the like. A battery and a light bulb comprising a light source are housed entirely within the tubular member. A flush mounted switch is recessed entirely within a predetermined end of the tubular member to control an electrical connection between the battery and the light source. The signal light has a smooth continuous outer surface to provide structural rigidity and enable its use for visual signalling during both daytime and nighttime.
