FINGERPRINT MODULATION FOR BEACON

Abstract

A beacon with a preferably anodized aluminum body, cylindrical in shape, and threaded employs a beacon modulation scheme for MWIR/LWIR beacons in which multiple frequencies of emission are overlaid, such as the addition of a high frequency pulse, several orders of magnitude faster than the low frequency blink, the high frequency modulation being beyond the capability of unaided human perception. This modulation would allow a high-speed detector and associated software to lock onto an asset in the presence of background radiation which would otherwise drown out the signal of interest.

Claims

1. A Mid-Wave and Long Wave Infrared beacon generating a fingerprint modulation that can be used to identify an asset while improving asset detection.

2. The beacon as claimed in claim 1, further comprising the beacon nesting of a high frequency pulse train in the modulation in a lower frequency blink.

3. The beacon as claimed in claim 2, wherein the high frequency pulse train is higher than human perception.

4. The beacon as claimed in claim 2, wherein the high frequency pulse train has a frequency of greater than 100 Hertz.

5. The beacon as claimed in claim 2, wherein the high frequency pulse train has a frequency of between 100 Hertz and 1 kiloHertz.

6. The beacon as claimed in claim 2, wherein the low frequency blink that is than a 100 Hertz.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings:

[0014] FIG. 1A is a side perspective views showing a beacon powered off and FIG. 1B is a side perspective view showing the beacon powered on;

[0015] FIGS. 2A and 2B are a side plan view and a side cross sectional view of the beacon; and

[0016] FIG. 3 is a plot of beacon emission as a function of time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The primary metric of any asset location technology is the distance, miles, between the beacon and detector at which the beacon’s signal can be clearly distinguished from background radiation (light noise). Multi-frequency (2+) modulated emission, such as nesting of a high frequency (kHz) pulse within a low frequency (Hz) blink, creates a known ‘fingerprint’ which when paired with a capable detector system would provide a pathway to filtering background radiation by employing lock-in detection, increasing signal (asset) to noise (background) ratio.

[0018] Within the wavelength range of Mid-Wave/Long Wave Infrared (MWIR/LWIR) imaging and sensing systems, it can be both a challenge to be “seen” and to “not be seen” with existing technology. The wavelength range of MWIR/LWIR is typically defined as 2.0 — 12.5 .Math.m, within this range many background sources exist which can ‘pollute’ the received signal reducing detection range. This fingerprint frequency modulation allow for both a user interpreting an image and a sensing system to identify its target more easily.

[0019] It is a common practice for locator beacons to blink, this is done because distinguishing any locator from background can be difficult based on environmental conditions.

[0020] The MWIR/LWIR beacon employs a beacon modulation scheme in which multiple frequencies of emission are overlaid, such as the addition of a high frequency pulse train, several orders of magnitude faster than the low frequency blink, the high frequency modulation being beyond the capability of unaided human perception.

[0021] Preferably the low frequency blink is less than 100 Hertz usually less than 10 Hertz.

[0022] The high frequency pulse train has a frequency of greater than 100 Hertz and can be higher than 1 kiloHertz.

[0023] This modulation enables the use of high-speed detector and associated software to lock onto an asset in the presence of background radiation which would otherwise drown out the signal of interest.

[0024] The approach also always the nesting of another pulse train, such as Morse code or other data encoding schemes including packet data, within higher frequency pulse(s) thus, allowing the MWIR/LWIR beacon to function as a communications emitter.

[0025] FIG. 3 is a plot of beacon emission as a function of time. It shows ‘fingerprint’ of a low frequency (Hz) blinks 310 with a nested kHz pulse train 312. The precise frequencies can be adjusted through circuitry design.

[0026] The implementation of this technology provides additional benefits related to power efficiency vs. detection range relative to continuous wave operation of conventional beacons.

[0027] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended xclaims.