US PATENT SUBCLASS 342 / 393
.~.~.~ Iso-frequency type


Current as of: June, 1999
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342 /   HD   COMMUNICATIONS: DIRECTIVE RADIO WAVE SYSTEMS AND DEVICES (E.G., RADAR, RADIO NAVIGATION)

350  DF  DIRECTIVE {10}
385  DF  .~ Beacon or receiver {2}
386  DF  .~.~ With transmisson of bearing or position determinative signals {6}
393.~.~.~ Iso-frequency type


DEFINITION

Classification: 342/393

Iso-frequency type:

(under subclass 386) Subject matter in which similar frequency modulated signals or pulses, simultaneously emitted by two or more remote radiating stations, are received and compared as to their instantaneous frequencies.

(1) Note. The difference in frequencies between the two received signals is a measure of the difference in the times required for the radiations to travel to the receiving station and so is a function of the difference in distance between each radiating station and the receiving station, thereby enabling the fixing of the position of the receiving station along a known hyperbola or hyperboloid which are the loci of all points in space having a constant difference in distances to the radiating stations.