Direction finding cell phones
First Claim
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1. A direction finding system comprising:
- at least one first hand holdable unit comprising circuitry that transmits a radio beacon signal; and
at least one second hand holdable unit having a display screen and comprising direction finding (DF) circuitry that receives a radio beacon (RB) signal transmitted by a first unit of the at least one first unit and determines from the received radio beacon signal an azimuth angle for the location of the first unit;
wherein the controller generates a display on the display screen responsive to the azimuth angle that indicates a location of the first unit.
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Abstract
A direction finding system comprising: at least one first hand holdable unit comprising circuitry that transmits a radio beacon signal; and at least one second hand holdable unit having a display screen and comprising direction finding (DF) circuitry that receives a radio beacon (RB) signal transmitted by a first unit of the at least one first unit and determines from the received radio beacon signal an azimuth angle for the location of the first unit; wherein the controller generates a display on the display screen responsive to the azimuth angle that indicates a location of the first unit.
61 Citations
47 Claims
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1. A direction finding system comprising:
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at least one first hand holdable unit comprising circuitry that transmits a radio beacon signal; and
at least one second hand holdable unit having a display screen and comprising direction finding (DF) circuitry that receives a radio beacon (RB) signal transmitted by a first unit of the at least one first unit and determines from the received radio beacon signal an azimuth angle for the location of the first unit;
wherein the controller generates a display on the display screen responsive to the azimuth angle that indicates a location of the first unit. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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- 2. A direction finding system according to claim 2 wherein the direction finding circuitry comprises Watson-Watts direction finding circuitry.
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43. A communication system comprising:
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a plurality of cellular phones each of which comprises a display screen a GPS receiver that determines spatial coordinates for the phone'"'"'s position and a transceiver for transmitting non-telephony signals;
wherein the transceiver of a first phone of the plurality of phones is controllable to transmit an interrogation signal responsive to which the transceiver of a second phone of the plurality of phones that receives the interrogation signal transmits a signal comprising GPS coordinates of the second phone; and
if the first phone receives the signal transmitted by the second phone, it displays a position icon responsive to the GPS coordinates on the first phone'"'"'s screen that indicates a location of the second phone. - View Dependent Claims (44, 45, 46)
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Specification