Designated area instrument landing system

Claim 1

IN AN AIRCRAFT NAVIGATIONAL SYSTEM TO PERMIT INSTRUMENT LANDING TO TOUCHDOWN AT A DESIRED SPOT ON A LANDING SITE, WHEREIN A BEACON LOCATED AT THE DESIRED LANDING SITE TRANSMITS A LOCATING SIGNAL, THE AIRCRAFT BORNE APPARATUS COMPRISING: (A) A RADAR TRANSCEIVER RESPONSIVE TO SAID LOCATING SIGNAL TRANSMITTED BY SAID BEACON TO PROVIDE A SLANT DISTANCE TO BEACON SIGNAL, AN ANTENNA AZIMUTH SIGNAL, AND AN ANTENNA DEPRESSION ANGLE SIGNAL, (B) FIRST MEANS RESPONSIVE TO SAID SLANT DISTANCE TO BEACON SIGNAL AND TO SAID ANTENNA DEPRESSION ANGLE SIGNAL TO PROVIDE A HEIGHT TO BEACON SIGNAL AND A HORIZONTAL DISTANCE TO BEACON SIGNAL, (C) GLIDE SLOPT SELECTOR MEANS TO PROVIDE A DESIRED GLIDE SLOPT ANGLE SIGNAL, (D) SECOND MEANS FOR COMPARING SAID HORIZONTAL DISTANCE TO BEACON AND HEIGHT TO BEACON SIGNALS WITH SAID DESIRED GLIDE SLOPE ANGLE SIGNAL TO PROVIDE A VERTICAL FLIGHT PATH POSITION ERROR SIGNAL, (E) THIRD MEANS RESPONSIVE TO SAID HORIZONTAL DISTANCE TO BEACON SIGNAL AND TO SAID ANTENNA AZIMUTH SIGNAL TO PROVIDE LONGITUDINAL AND LATERAL DISTANCE TO BEACON SIGNALS IN AIRCRAFT COORDINATES, (F) COMPASS MEANS TO PROVIDE A HEADING INFORMATION SIGNAL, (G) FOURTH MEANS RESPONSIVE TO SAID HEADING INFORMATION SIGNAL AND TO SAID LONGITUDINAL AND LATERAL DISTANCE TO BEACON SIGNALS IN AIRCRAFT COORDINATES TO PROVIDE LONGITUDINAL AND LATERAL DISTANCE TO BEACON SIGNALS IN EARTH COORDINATES, (H) COURSE SELECTOR MEANS TO PROVIDE A DESIRED COURSE TO THE BEACON SIGNAL, (I) FIFTH MEANS FOR COMPARING SAID DESIRED COURSE TO BEACON SIGNAL WITH SAID LATERAL AND LONGITUDINAL DISTANCE TO BEACON SIGNALS IN EARTH COORDINATES TO PROVIDE A LATERAL FLIGHT PATH POSITION ERROR SIGNAL, (J) SIXTH MEANS FOR COMPARING SAID DESIRED COURSE TO BEACON SIGNAL WITH SAID HEADING INFORMATION SIGNAL TO PROVIDE A SELECTED HEADING REFERENCE ERROR SIGNAL (K) SEVENTH MEANS RESPONSIVE TO SAID LATERAL AND LONGITUDINAL DISTANCE TO BEACON SIGNALS IN EARTH COORDINATES AND TO CHANGES IN SAID HEADING INFORMATION SIGNAL TO PROVIDE LATERAL AND LONGITUDIANL GROUND SPEED SIGNALS IN AIRCRAFT COORDINATES, (1) AIR SPEED SENSOR MEANS TO PROVIDE A MEASURED AIR SPEED SIGNAL, (M) AIR SPEED SELECTOR MEANS TO PROVIDE A DESIRED AIR SPEED SIGNAL, (N) EIGTH MEANS FOR COMPARING SAID DESIRED AIR SPEED SIGNAL WITH SAID HORIZONTAL DISTANCE TO BEACON SIGNAL TO INITIATE PROGRAMMED AIR SPEED DECELERATION AT A PREDETERMINED RELATIONSHIP BETWEEN SAID COMPARED SIGNALS, (O) NINTH MEANS FOR COMPARING SAID MEASURED AIR SPEED SIGNAL WITH SAID LONGITUDIANL GROUND SPEED SIGNAL IN AIRCRAFT COORDINATES TO INITIATE PROGRAMMED GROUND SPEED DECELERATION AT A PREDETERMINED RELATIONSHIP BETWEEN MEASURED AIR SPEED AND LONGITUDINAL GROUND SPEED,