Optical detection device

• US 5,142,985 A
• Filed: 06/04/1990
• Issued: 09/01/1992
• Est. Priority Date: 06/04/1990
• Status: Expired due to Term

• Current Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Johnson, Robert H., Stearns, Edward J.
• Primary Examiner(s): Johnson, Stephen
• Application Number:
  US07/532,778
• Time in Patent Office: 820 Days
• Field of Search: 102/213, 102/201, 102/211, 356/4
• US Class Current: 102/213
• CPC Class Codes: F42C 13/023 using active distance measurement

Abstract

An advanced optical sensor for determining the stand-off distance from a trajecting container to a target utilizes various checks and filters to eliminate false detonations caused by glint and counter-measures. The sensor is comprised of a transmitter, a receiver, and a wave generator. The wave generator generates a unique wave form which is relayed to both the receiver and the transmitter. The light emitted from the transmitted follows a pattern defined by the wave generator. When light is received by the receiver, a synchronous detector coupled to the wave form generator determines if the return light has a pattern correlating with the unique wave form from the wave generator. If so, the associated electric signal in the receiver must pass a predetermined threshold for a predetermined period of time before the sensor will generate a detonate signal.

Claims

1. An optical sensor comprising:

transmitter means;

receiver means coupled to said transmitter means;

wave form generator means coupled to said transmitter means and said receiver means;

said wave form generator means for generating a unique wave form;

said transmitter means adapted to transmit a light beam according to a pattern including said unique wave form;

said receiver means for receiving said transmitted light beam;

said receiver means comparing an electrical signal that results from said received light beam with said unique wave form to differentiate said transmitted light beam from other received light;

detector means for detecting when the intensity of said transmitted light beam received by said receiver means equals or exceeds a predetermined threshold over a predetermined time;

said detector means generating a detect signal when said intensity equals or exceeds said predetermined threshold over said predetermined time;

said detector means including;

threshold means for detecting when said transmitted light beam is equal to or greater than said predetermined threshold;

pulse width means for determining when said predetermined threshold has been equalled or exceeded for said predetermined time;

said threshold means coupled to said receiver means to receive a signal resultant from said transmitted light beam;

said pulse width means coupled to said threshold means to receive another signal resultant from said transmitted light beam; and

said threshold means allowing only signals greater than said predetermined threshold to pass through to said pulse width means.

2. An optical sensor according to claim 1 wherein said receiver means comprises:

diode means for receiving said transmitted light and translating the associated light wave into an electric signal having a correlating wave form;

synchronous detector means for comparing said electric signal wave form with said unique wave form from said wave form generator means; and

said synchronous detector means coupled to said diode means to receive said electric signal.

3. An optical sensor according to claim 2 wherein said diode means is a photo-diode.

4. An optical sensor according to claim 1 wherein said transmitter means comprises:

light emitting means for transmitting said light beam according to said pattern;

modulator means coupled to said wave form generator means to receive said unique wave form, and coupled to said light emitting means; and

said modulator means for converting said unique wave form into said pattern for said light emitting means, said modulator means relaying said pattern to said light emitting means.

5. An optical sensor comprising:

transmitter means;

receiver means coupled to said transmitter means;

wave form generator means coupled to said transmitter means and said receiver means;

said wave form generator means for generating a unique wave form;

said trasmitter means adapted to transmit a light beam according to a pattern including said unique wave form;

said receiver means for receiving said transmitted light beam;

`said receiver means comparing an electrical signal that results from said received light beam with said unique wave form to differentiate said transmitted light beam from other received light;

detector means for detecting when the intensity of said transmitted light beam received by said receiver means equals or exceed a predetermined threshold over a predetermined time;

said detector means generating a detect signal when said intesity equal or exceeds said predetermined threshold over said predetermined time;

wherein said receiver means comprises;

diode means or receiving said transmitted light and translating the associated light wave into an electric signal having a correlating wave form;

synchronous detector means for comparing said electric signal wave form with said unique wave form from said wave form generator means; and

said synchronous detector means coupled to said diode means to receive said electric signal;

wherein said detector means comprises;

threshold means for detecting when an amplitude of said electric signal is equal to or greater than a reference value associated with said predetermined threshold;

pulse width means for determining when said reference value associated with said predetermined threshold has been equaled or exceeded for said predetermined time;

said threshold means coupled to said synchronous detector means to receive said electric signal;

said pulse width means coupled to said threshold means to receive said electric signal; and

said threshold means allowing only signals greater than said reference value associated with said predetermined threshold to pass through to said pulse width means.