Perspective object indicator

Claim 1

A DISPLAY SYSTEM INCLUDING A TWO DIMENSIONAL INFORMATION DISPLAY SURFACE ON WHICH THE THREE DIMENSIONAL POSITION OF AN OBJECT IN SPACE IS CONTINUOUSLY DISPLAYED WITH RESPECT TO A KNOWN POSITION, SAID SYSTEM COMPRISING: A GRID SUPERIMPOSED ON THE DISPLAY SURFACE CONSISTING OF A SERIES OF EQUIDISTANT VERTICAL LINES WHICH REPRESENT A FIXED AMOUNT OF BEARING WITH RESPECT TO EACH OTHER, INTERSECTED BY A SERIES OF EQUIDISTANT HORIZONTAL LINES WHICH REPRESENT A FIXED AMOUNT OF ALTITUDE WITH RESPECT TO EACH OTHER; MEANS FOR REPRESENTING THE OBJECT ON THE DISPLAY SURFACE BY AN INDICATION COMPRISING A HORIZONTAL LINE AND A VERTICAL LINE HAVING AT LEAST ONE POINT IN COMMON WITH SAID HORIZONTAL LINE; MEANS FOR REPRESENTING THE KNOWN POSITION ON THE DISPLAY SURFACE BY AN INDICATION; MEANS FOR POSITIONING THE KNOWN POSITION INDICATION ON THE DISPLAY SURFACE AT THE INTERSECTION OF ANY OF SAID SUPERIMPOSED HORIZONTAL AND VERTICAL LINES; MEANS FOR CONTROLLING THE DISTANCE OF SAID VERTICAL LINE OF THE OBJECT INDICATION ON THE DISPLAY SURFACE FROM THE VERTICAL REFERENCE LINE THAT INTERSECTS THE KNOWN POSITION INDICATION AS A FUNCTION OF THE BEARING OF THE OBJECT WITH RESPECT TO THE KNOWN POSITION, SO THAT THE DISTANCE FROM SAID VERTICAL REFERENCE LINE IS PROPORTIONAL TO THE BEARING OF THE OBJECT WITH RESPECT TO THE KNOWN POSITION; MEANS FOR CONTROLLING THE DISTANCE OF SAID HORIZONTAL LINE OF THE OBJECT INDICATION ON THE DISPLAY SURFACE FROM THE HORIZONTAL REFERENCE LINE THAT INTERSECTS THE KNOWN POSITION INDICATION AS A FUNCTION OF THE ALTITUDE OF THE OBJECT WITH RESPECT TO THE KNOWN POSITION SO THAT THE DISTANCE FROM SAID HORIZONTAL REFERENCE LINE IS PROPORTIONAL TO THE ALTITUDE OF THE OBJECT WITH RESPECT TO THE KNOWN POSITION; AND MEANS FOR CONTROLLING THE LENGTH OF SAID HORIZONTAL AND VERTICAL LINES THAT COMPRISE THE OBJECT INDICATION AS A FUNCTION OF THE RANGE OF THE OBJECT WITH RESPECT TO THE KNOWN POSITION SO THAT THE LENGTH OF SAID LINES IS INVERSELY PROPORTIONAL TO SAID RANGE.