Individual beacon identification system

• US 5,299,227 A
• Filed: 04/13/1993
• Issued: 03/29/1994
• Est. Priority Date: 04/13/1993
• Status: Expired due to Term

• Current Assignee: Zimmerman Associates, Inc.
• Original Assignee: American Electronics, Inc. (Ducommun Incorporated)
• Inventors: Rose, David
• Primary Examiner(s): Cain, David C.
• Application Number:
  US08/045,186
• Time in Patent Office: 350 Days
• Field of Search: 375/1, 342/45, 380/23, 343/6.5 R, 340/825.54, 340/825.34, 340/825.44
• US Class Current: 342/45
• CPC Class Codes: G01S 17/74 Systems using reradiation of electromagnetic waves other than radio waves, e.g. IFF, i.e. identification of friend or foe
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements
• CPC Class Codes: H04B 10/118 specially adapted for satellite communication
• CPC Class Codes: H04K 1/02 by adding a second signal to make the desired signal unintelligible

Abstract

A compact beacon-detector type IFF system to be carried by individual soldiers. The system consists of a beacon and a special purpose detector. The beacon is a small, light-weight, battery powered device that is worn on the soldier'"'"'s web gear. The detector consists of a small flashlight-like device that can be hand held or mounted on a weapon, similar to a rifle scope. The beacon'"'"'s signal is not visible to those using existing night vision equipment nor is it otherwise exploitable by a potential adversary. The system achieves its covertness through the selection of the optical wavelength used by the beacon. Further signature reduction is achieved through the use of a Low Probability of Intercept ("LPI") spread spectrum waveform as the beacon output. This waveform utilizes a spreading code to encode the beacon output signal. Even if an enemy has a sensor capable of detecting the proper optical wavelength, it would not be able to detect or emulate the beacon'"'"'s signal without prior knowledge of the specific spreading code used. The detector of the present invention is designed to despread the beacon output waveform, allowing the signal to be detected. This spread/despread code can be changed as frequently as required, so that capture of the beacon or detector would not be a serious risk to compromising the system.

Claims

1. An individual beacon identification system comprising:

a) light emitting means for providing a continuous transmission of a pulse coded optical radiation output signal utilizing a spread spectrum output signal modulated by a spreading code; and

b) a special purpose detector, placed in a location that is remote from the light emitting means, the detector being adapted for detecting the output signal from the light emitting means and is further adapted to despread the pulse coded optical radiation output signal to allow detection of the pulse coded optical radiation output signal.

2. The individual beacon identification system of claim 1, wherein the light emitting means is smaller than about 35 cubic inches and weighs less than about 3 ounces.

3. The individual beacon identification system of claim 1, wherein the light emitting means includes means for attaching the beacon to a user.

4. The individual beacon identification system of claim 1, wherein the light emitting means further provides a continuously transmitted pulse coded output signal that can be detected by the special purpose detector at a range of up to about 400 meters.

5. The individual beacon identification system of claim 1, wherein the light emitting means further provides a continuously transmitted pulse coded output signal that can be detected by the special purpose detector at a range of at least 400 meters.

6. The individual beacon identification system of claim 1, wherein the light emitting means output signal is detectable by the special purpose detector from any angle.

7. The individual beacon identification system of claim 1, wherein the spreading code is changeable by the user.

8. The individual beacon identification system of claim 7, wherein the light emitting means further comprises a DIP switch and the spreading code is changeable by manipulating the DIP switch.

9. The individual beacon identification system of claim 7, wherein the light emitting means further comprises a memory means and the spreading code is changeable by replacing the memory means.

10. The individual beacon identification system of claim 7, wherein the light emitting means further comprises a memory means and the spreading code is changeable by reprogramming the memory means.

11. The individual beacon identification system of claim 1, wherein the continuously transmitted pulse coded output signal has a wavelength of 1.5 micrometers for allowing detection of the continuously transmitted pulse coded output signal only by the special purpose detector.

12. The individual beacon identification system of claim 1, wherein the light emitting means is attached to shipping containers for identification by a person using the detector.

13. The individual beacon identification system of claim 1, wherein the light emitting means is attached to cargo for identification by a person using the detector.

14. The individual beacon identification system of claim 1, wherein the light emitting means is attached to inventory for identification of particular items by a person using the detector.

15. The individual beacon identification system of claim 1, wherein the light emitting means comprises a laser diode.

16. The individual beacon identification system of claim 1, wherein the special purpose detector further comprises an output means for indicating to a user of the special purpose detector that the continuously transmitted pulse coded output signal provided by the light emitting means has been detected.

17. The individual beacon identification system of claim 16 wherein the output means of the special purpose detector indicates the relative strength of the continuously transmitted pulse coded output signal provided by the light emitting means.

18. The individual beacon identification system of claim 16, wherein the output means of the special purpose detector is selected from the group of output means consisting of tone generators, light emitting diodes, and tactile vibrators.

19. An individual beacon identification system comprising:

a) a light emitting means for providing a continuously transmitted pulse code modulated optical wavelength output signal; and

b) a special purpose detector, placed in a location that is remote from the light emitting means, that is adapted for detecting the output signal from the light emitting means;

c) the light emitting means including means for attaching the beacon to a user;

d) the light emitting means further providing an output signal that can be detected by the special purpose detector at a range of at least 400 meters;

e) the light emitting means output signal detectable by the special purpose detector from any angle;

f) the light emitting means utilizing a spread spectrum output signal modulated by a spreading code;

g) the spreading code being changeable by the user; and

h) the special purpose detector further comprises an output means for indicating to a user of the special purpose detector that the continuously transmitted pulse coded output signal provided by the light emitting means has been detected.

20. The individual beacon identification system of claim 19, wherein the light emitting means is smaller than about 35 cubic inches and weighs less than about 3 ounces.

21. The individual beacon identification system of claim 19, wherein the light emitting means further comprises a DIP switch and the spreading code is changeable by manipulating the DIP switch.

22. The individual beacon identification system of claim 19, wherein the light emitting means further comprises a memory means and the spreading code is changeable by replacing the memory means.

23. The individual beacon identification system of claim 19, wherein the light emitting means further comprises a memory means and the spreading code is changeable by reprogramming the memory means.

24. The individual beacon identification system of claim 19, wherein the continuously transmitted pulse coded output signal has a wavelength of 1.5 micrometers for allowing detection of the continuously transmitted pulse coded output signal only by the special purpose detector.

25. The individual beacon identification system of claim 19, wherein the light emitting means comprises a laser diode.

26. The individual beacon identification system of claim 19, wherein the output means of the special purpose detector indicates the relative strength of the continuously transmitted pulse coded output signal provided by the light emitting means.

27. The individual beacon identification system of claim 19, wherein the output means of the special purpose detector is selected from the group of output means consisting of tone generators, light emitting diodes, and tactile vibrators.

28. The individual beacon identification system of claim 19, wherein the light emitting means is attached to shipping containers for identification by a person using the detector.

29. The individual beacon identification system of claim 19, wherein the light emitting means is attached to cargo for identification by a person using the detector.

30. The individual beacon identification system of claim 19, wherein the light emitting means is attached to inventory for identification of particular items by a person using the detector.