| 摘要 |
1,109,403. Radio navigation. DECCA Ltd. 1 Nov., 1966 [1 Aug., 1965], No. 55998/67. Divided out of 1,190,402. Heading H4D. [Also in Division G1] Navigational apparatus for a mobile craft comprises a receiver for a radio position fixing system of the kind in which equipment on the craft determines its range and bearing from a selected ground station, a computer to which the range and bearing information is fed, data storage means, storing information representative of the positions of a plurality of radio stations of the position fixing system, a selector switch arranged to feed information about the position of the selected ground station to the computer, the computer providing input signals to a chart recorder for continuously marking the position of the craft on a chart in accordance with the inputs received from the radio receiver and the data storage means the computer being operative to determine the distance between the position of the craft, as determined by the receiver using one ground station and the next selected ground station so that when the distance to the station being used exceeds that to the next selected station the receiver may be returned, manually or automatically, to the next station. The receiver may be automatically tuned to the most appropriate, usually the nearest, ground station. In this case the position of the craft determined by a VOR/DME system is compared in a selector with the positions of the various stations stored in the data storage means to select the appropriate ground station. The output from the selector drives the selector switch to the setting corresponding to the selected station, the receiver then being automatically tuned to this station and the chart recorder will indicate the craft position using information from the selected station. If two receivers are provided one may be tuned to the nearest ground station for position fixing and the other tuned to the next station to be used. In this ease the computer may switch over automatically when the range to the next station becomes less than that from the station in use. Whilst changeover from one ground station to another is taking place the computer may feed the chart recorder with signals representing the last received heading and speed values so that correction of the indicated craft position on the chart after such period of changeover will be minimized. |
