Adjustable near infrared rangefinder illuminator

• US 5,336,899 A
• Filed: 11/24/1992
• Issued: 08/09/1994
• Est. Priority Date: 11/24/1992
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Nettleton, John E., Barr, Dallas N., Redman, Brian C.
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US07/980,088
• Time in Patent Office: 623 Days
• Field of Search: 250/561, 250/221, 250/214 VT, 250/330, 250/333, 356/359, 356/238, 356/4, 356/5, 313/388
• US Class Current: 250/559.29
• CPC Class Codes: F41G 3/06 with rangefinder rangefinders per se G01C
• CPC Class Codes: G01S 17/18 wherein range gates are used

Abstract

A near infrared illuminator for enhancing viewing of a target viewed with infrared viewing device when the target falls within a predetermined range. A pulse generator generates a laser pulse in the near infrared with a pulse clock for control of laser brightness and a pulse frequency adjust for control of laser blink rate. The pulse is transmitted along an optical path at a specific brightness and blink rate to a target. A detector within the optical path detects a reflected infrared signal from the target and converts the signal to an electrical signal which is processed by a processor to obtain target range information. A trigger logic controls the pulse clock rate means whereby when the target range falls within a predetermined range the laser pulse rate is increased such that increased illumination of the target is viewable with an infrared viewing device.

Claims

1. A near infrared illuminator for enhancing viewing of a target viewed with an infrared viewing device when the target falls within a predetermined range, the illuminator including:

pulse generator means for generating a laser pulse in the near infrared;

pulse clock rate means for control of laser brightness;

pulse frequency means for control of laser blink rate;

pulse transmitting means for transmitting along an optical path a near infrared laser pulse at a specific brightness and blink rate to a target;

detector means within the optical path for detecting a reflected infrared signal from the target and converting the signal to an electrical signal;

processing means for processing the electrical signal to obtain target range information;

logic means for control of the pulse clock rate means whereby when the target range falls within a predetermined range the laser pulse rate is increased such that increased illumination of the target is viewable with an infrared viewing device.

2. The illuminator of claim 1 wherein the illuminator further includes:

adjusting means for adjusting the illumination field of view seen through the infrared viewing device.

3. A technique for enhancing viewing of a target viewed with an infrared viewing device when the target fails within a predetermined range, the technique including the steps of:

generating a laser pulse in the near infrared at a specified clock rate and frequency which determines respective laser brightness and blink rate;

transmitting along an optical path the near infrared laser pulse to a target;

detecting within the optical path a reflected infrared signal from the target and converting the signal to an electrical signal;

processing the electrical signal to obtain target range information;

determining if the target range falls within a predetermined range such that if the target range falls within the predetermined range the pulse clock rate is increased and the increased illumination of the target is viewable with an infrared viewing device.

4. The technique of claim 3 wherein the technique further includes the additional step of adjusting the field of view of the increased illumination.