PERSONAL LOCATOR

• US 3,806,936 A
• Filed: 08/14/1972
• Issued: 04/23/1974
• Est. Priority Date: 08/14/1972
• Status: Expired due to Term

• Current Assignee: Charles A. Koster
• Original Assignee: Charles A. Koster
• Inventors: Koster, Charles A.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Buczinski, S. C.
• Application Number:
  US05/280,503
• Time in Patent Office: 617 Days
• Field of Search: 343/113PT,119,718 325/16,111,118,361
• US Class Current: 342/419
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information

Abstract

A tone modulated transmitter and a pair of radio receiver circuits provide a personal locator which can transmit emergency distress signals and can receive signals which are used to indicate the direction from which the signals are being received. The locator is small enough to be carried in a pocket or connected to the pants belt of a user.

Claims

1. A personal locator comprising:

a tone modulated radio transmitter;

first and second radio receiver circuits, each having an input lead and an output lead;

first and second directional antennas, said first directional antenna being coupled to said input lead of said first receiver circuit, and said second directional antenna being coupled to said input lead of said second receiver circuit;

an indicating device, said device being connected between said output leads of said first and said second receiver circuits, said device indicating the difference in signal between the output leads of said first and said second receiver circuits;

a source of electrical potential; and

means for selectively connecting said source to said transmitter and to said receiver circuit.

2. A personal locator as defined in claim 1 including:

an audio amplifier; and

a loudspeaker, said audio amplifier being connected between said output lead of said first receiver circuit and said speaker.

3. A personal locator as defined in claim 1 including:

means for generating a rapidly changing audio frequency, said means for generating being coupled to said transmitter to provide a distinctive emergency signal from said transmitter.

4. A personal locator as defined in claim 1 including:

means for shielding said first and said second directional antennas to eliminate error indication in the direction of a radio frequency signal being received.

5. A personal locator as defined in claim 4 including:

means for orienting said first and said second directional antennas to aid said means for shielding in eliminating error indication in the direction of a radio frequency signal being received.

6. A personal locator comprising:

a tone modulated radio transmitter;

first and second radio receiver circuits each having an R.F. stage, a mixer, an IF amplifier and an audio detector;

first and second directional antennas, said first directional antenna being coupled to said R. F. stage of said first receiver circuit, said second directional antenna being coupled to said R. F. stage of said second receiver circuit;

an indicating device, said device being coNnected between said audio detectors of said first and said second receiver circuits;

a battery; and

means for selectively connecting said battery to said transmitter and to said receiver circuits.

7. A personal locator as defined in claim 6 wherein said tone modulated transmitter includes:

a crystal controller oscillator;

an RF amplifier, said crystal controlled oscillator being coupled to said RF amplifier;

a unijunction transistor oscillator circuit;

a free running multivibrator, said oscillator circuit being coupled to said multivibrator, said oscillator circuit providing a signal to said multivibrator to cause the frequency of said multivibrator to change over an audio frequency range at a predetermined rate, said multivibrator being coupled to said RF amplifier to cause the amplitude of an RF signal of said RF amplifier to change at the audio frequency rate; and

a transmitting antenna, said transmitting antenna being coupled to said RF amplifier.

8. A personal locator as defined in claim 7 including:

means for shielding said first and said second directional antennas to eliminate error indication in the direction of a radio frequency signal being received.

9. A personal locator as defined in claim 7 including:

means for orienting said first and said second directional antennas to aid said means for shielding in eliminating a 180* error indication in the direction of a radio frequency signal being received.

10. A personal locator as defined in claim 7 including:

an audio amplifier; and

a loudspeaker, said audio amplifier being connected between said output lead of said first receiver circuit and said speaker.