Navigational aid device

Claim 1

A navigational aid device which comprises: a radar station having a narrow beam antenna scanning an area traveled by at least one craft; means for broadcasting over said area a signal carrying an instantaneous indication of the azimuthal orientation of the antenna, and a representation of the radar pulse and target echo timing; on board said craft, means for receiving said signal; a digital storage means; means for sequentially addressing said storage means; means for randomly addressing said storage means in function of the sine and cosine components of said indication wherein the combined instantaneous values of sine and cosine components define the address locations in the storage means; first means, responsive to said pulse and target echo timing, for writing information into said storage means in a location defined by the said instantaneous values at the time corresponding to the detection of said target echo by the radar station; means for extracting said information from said storage means by equal increments of said means for sequentially addressing; video means for displaying said information; and means for synchronizing the raster scan sequence of said video means with said means for sequentially addressing.

Claim 10

A method for displaying the radar generated image of an area on a raster-sweep type monitor, in function of the azimuthal orientation of the radar antenna and the timing of the radar pulse and target echo, which comprises: (a) converting the azimuthal orientation of the antenna to the sine and cosine component signals; (b) generating two ramp signals by repetitively charging a capacitive circuit with each of said component signals after each radar pulse; (c) continuously converting said ramp signals into digital values; (d) randomly and continuously addressing a storage memory in function of the product of said digital values; (e) writing an information into said randomly addressed memory in a location defined by said digital values at the time corresponding to the detection of said target echo by the radar station; (f) sequentially and repetitively addressing said storage memory up to a maximum address corresponding to the maximum value of said product; (g) generating synchro and blanking pulses in coordination with the sequential addressing of said storage means; (h) combining said synchro and blanking pulses with the information read out of said sequentially addressed memory; and (i) applying said combined synchro and blanking pulses and information to a raster-sweep type CRT monitor; said method further comprising: performing steps (a) and (b) at a first location; transmitting said ramp signal and said target echo to a second location; and performing step (c) through (i) at said second location.

Claim 11

A method for displaying the radar generated image of an area on a raster-sweep type monitor, in function of the azimuthal orientation of the radar antenna and the timing of the radar pulse and target echo, which comprises: (a) converting the azimuthal orientation of the antenna to the sine and cosine component signals; (b) generating two ramp signals by repetitively charging a capacitive circuit with each of said component signals after each radar pulse; (c) continuously converting said ramp signals into digital values; (d) randomly and continuously addressing a storage memory in function of the product of said digital values; (e) writing an information into said randomly addressed memory in a location defined by said digital values at the time corresponding to the detection of said target echo by the radar station; (f) sequentially and repetitively addressing said storage memory up to a maximum address corresponding to the maximum value of said product; (g) generating synchro and blanking pulses in coordination with the sequential addressing of said storage means; (h) combining said synchro and blanking pulses with the information read out of said sequentially addressed memory; and (i) applying said combined synchro and blanking pulses and information to a raster-sweep type CRT monitor; said method further comprising: performing steps (a) and (b) at a first location; transmitting said ramp signal and said target echo to a second location; and performing step (c) through (i) at said second location.