Laser pulse receiver for detecting and recording weak laser pulses in variable background radiation
First Claim
Patent Images
1. A laser pulse receiver system for detecting and recording very weak laser pulses in the presence of variable background radiation, said system comprised of:
- a plurality of optical bandpass filters wherein each of said plurality of optical bandpass filters passes only one wavelength of signal pulses of one each of a plurality of selected valid laser sources and blocks all other wavelengths of said selected valid laser sources;
an optics and a detector, said detector positioned on a detector bias line wherein said optics focuses incoming radiation from said plurality of optical bandpass filters including said variable background radiation onto said detector wherein said detector produces an output varying electrical current in response to said incoming radiation;
a microprocessor;
a plurality of electrical signal paths and inhibit signal electrical lines for receiving said detector output varying electrical current, wherein each of said plurality of electrical signal paths isolates and passes only one of said selected valid laser source wavelength signal pulses included in said detector output varying electrical current therethrough and wherein said plurality of inhibit signal electrical lines identifies invalid variable background radiation source, wherein separate outputs from each of said plurality of electrical signal paths, and said inhibit signal electrical lines constitute a multibit data word which is passed to said microprocessor for selectively storing and retrieving by said microprocessor to determine the presence of specific valid laser pulses.
3 Assignments
0 Petitions
Accused Products
Abstract
A radiation detection system for use in the visible and near infrared reg which is capable of detecting and recording extremely weak laser pulses in the few nanoseconds range. The system receiver can be directed towards strong radiation sources, such as the sun, without changing the receiver or recording unwanted information. The detection system discriminates between various selected laser sources wavelengths and is comprised of optics, detector, electronic hardware, microcomputer, and signature analysis algorithm.
14 Citations
9 Claims
-
1. A laser pulse receiver system for detecting and recording very weak laser pulses in the presence of variable background radiation, said system comprised of:
-
a plurality of optical bandpass filters wherein each of said plurality of optical bandpass filters passes only one wavelength of signal pulses of one each of a plurality of selected valid laser sources and blocks all other wavelengths of said selected valid laser sources; an optics and a detector, said detector positioned on a detector bias line wherein said optics focuses incoming radiation from said plurality of optical bandpass filters including said variable background radiation onto said detector wherein said detector produces an output varying electrical current in response to said incoming radiation; a microprocessor; a plurality of electrical signal paths and inhibit signal electrical lines for receiving said detector output varying electrical current, wherein each of said plurality of electrical signal paths isolates and passes only one of said selected valid laser source wavelength signal pulses included in said detector output varying electrical current therethrough and wherein said plurality of inhibit signal electrical lines identifies invalid variable background radiation source, wherein separate outputs from each of said plurality of electrical signal paths, and said inhibit signal electrical lines constitute a multibit data word which is passed to said microprocessor for selectively storing and retrieving by said microprocessor to determine the presence of specific valid laser pulses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A laser pulse receiver system for detecting and recording very weak laser pulses and discriminating the laser pulses from radiation from extraneous high radiation sources under varying background noise conditions;
- said system comprised of;
a plurality of optical bandpass filters wherein each of said plurality of optical bandpass filters passes only one wavelength of signal pulses of one each of a plurality of selected valid laser sources and blocks all other wavelengths of said selected laser sources; an optics and a detector wherein said optics focuses incoming radiation passing through from said plurality of optical bandpass filters including radiation from said extraneous high radiation sources onto said detector and detector produces a varying electrical current signal at its output according to the incoming radiation pattern thereon; a microprocessor; a laser signature recognition means comprised of a plurality of electrical signal paths positioned between said detector and said microprocessor for producing a plurality of bits to a multibit data word of said microprocessor with each of said plurality of electrical signal paths sensing only radiation at the wavelength of a selected laser source, each of said plurality of electrical signal paths comprised of a detector overcurrent protection means, a preamplifier having an input connected to receive the detector current fluctuations as an input thereto for converting said detector output varying electrical current to a varying amplitude voltage and amplifying said voltage, a postamplifier which further amplifies said variable amplitude voltage and an automatic gain control circuit connected from an output of said postamplifier back to an input of said postamplifier wherein said automatic gain control circuit operates on said variable amplitude voltage at the postamplifier input to maintain a constant postamplifier output voltage prior to receiving valid laser source pulses on said electrical signal path, a comparator having an input connected to the postamplifier output wherein said comparator has a reference voltage therein which causes said comparator to be stable until a short valid laser pulse arrives at said input from said postamplifier output, and a latching circuit means connected between an output from said comparator and an input to said microprocessor wherein said valid laser pulse at said comparator input causes said comparator to become conductive and trigger a pulse clock in said latching circuit means causing said latching circuit means to set to insure that said microprocesses recognizes said specific valid laser pulse; an automatic radiation overload sensing circuit comprised of three inhibit signal electrical lines between a detector bias line and said microprocessor wherein said three inhibit signal electrical lines provide control signals to 3 bits of said multibit data word, first of said inhibit signal electrical lines provides sensing of the detector direct current, second of said inhibit signal electrical lines provides a control signal to said microprocessor generated by small but rapid increases in the detector current level when the detector is moved from low to high background level of radiation, and third of said inhibit signal electrical lines provides a control signal to said microprocessor generated by small but rapid decreases in the detector current level when the detector is moved form a high to a low background level of radiation; and a signature recognition means of identifying and recording valid laser signals in said plurality of electrical signal paths by separating valid signals from invalid signals wherein invalid signals are comprised of a control signal from one of said three inhibit signal electrical lines or improper combination of broadband laser signals caused by extremely fast response time of the detector when the detector is passed through a high radiation source in which none of said three inhibit signal electrical lines provide a control signal to said microprocessor.
- said system comprised of;
Specification