Abstract: A navigation system particularly adapted for ships making a passing within a harbor or the like, utilizing signal inputs from on-board vessel position determining equipment such as Loran or Decca apparatus and an on-board object detecting equipment such as a radar or sonar apparatus. The system further includes an on-board vessel position computer which operates in a differential Loran mode in response to observed Loran time differences, stored data from an initial calibration, and Loran grid offset data from an on-shore monitor system to compute a highly accurate current or present position fix in longitude and latitude whereupon the computer causes a predetermined electronic chart to be displayed in color on the screen of a cathode ray tube, being generated from a plurality of electronic charts stored in the form of digital files in memory.

Abstract: 10. A transmitter for a secret communication system comprising a source of carrier frequency energy, a source of cyclically repetitive noise energy, means to synchronize the cyclical repetition rate of said noise energy with a sub-multiple of the frequency of said carrier frequency energy, means to reverse the phase of portions of said noise energy in accordance with a predetermined message code, means to modulate said carrier frequency energy with said encoded noise energy and means to transmit the suppressed carrier single sideband component of said carrier modulation.

Abstract: 10. A transmitter for a secret communication system comprising a source of carrier frequency energy, a source of cyclically repetitive noise energy, means to synchronize the cyclical repetition rate of said noise energy with a sub-multiple of the frequency of said carrier frequency energy, means to reverse the phase of portions of said noise energy in accordance with a predetermined message code, means to modulate said carrier frequency energy with said encoded noise energy and means to transmit the suppressed carrier single sideband component of said carrier modulation.