System and method for ranging a target with a digital-pixel focal plane array
AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorsJeffrey L. Jew, Paul R. Moffitt, Leonard A. Pomeranz, Hermanus S. Pretorius
Life of this patent
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Abstract
An active receiver having a digital-pixel focal plane array (DFPA) ranges a target when observing return pulses from a pulsed laser beam synced with the receiver. The DFPA establishes a time when the pulsed laser beam contacts a target and the range can then be established because the speed at which the laser beam travels is known. Various basis functions may be implemented with the DFPA data to establish when the laser beam contacts the target. Some exemplary basis functions are binary basis functions, and other exemplary basis functions are Fourier basis functions.
Claims16
A system for ranging a target comprising:
- a pulsed laser configured to generate a pulsed laser beam;
- a digital-pixel focal plane array (DFPA) in operative communication with the pulsed laser for detecting pulses of the pulsed laser beam;
- at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by one or more processors, result in the following operations for ranging the target with the digital focal plane array determining the pulses from the pulsed laser, the operations configured to:
- (a) sync the pulsed laser beam with DFPA;
- (b) emit the pulsed laser beam from the pulsed laser towards the target at a location to which a range from the pulsed laser to the target is to be determined;
- (c) determine in the DFPA a time at which the pulsed laser beam returns from the target;
- (d) range the target relative to the pulsed laser based on the time at which the DFPA determined the pulsed laser beam returned from the target and the speed at which the pulsed laser beam traveled;
- (e) receive photocurrent in a bi-directional counter on the DFPA;
- (f) interpret in the counter whether the photocurrent is a positive pulse or a negative pulse, wherein if the photocurrent is a positive pulse, then the photocurrent occurred in a first window of time, and wherein if the photocurrent is a negative pulse, then the photocurrent occurred in a different second window of time;
- (g) determine, in the DFPA, a time when photocurrent switches from a positive pulse to a negative pulse, or vice versa;
- and
- (h) range the target based on the time when the DFPA determined the photocurrent switched and the pulsed laser beam speed.
A method comprising:
- syncing a pulsed laser beam with a digital-pixel focal plane array (DFPA);
- emitting the pulsed laser beam from a pulsed laser towards a target at a location to which a range from the pulsed laser to the target is to be determined;
- determining in the DFPA a time at which the pulsed laser beam returns from the target;
- ranging the target relative to the pulsed laser based at least in part on the time at which the DFPA determined the pulsed laser beam returned from the target and the speed at which the pulsed laser beam traveled;
- receiving photo current in a bi-directional counter on the DFPA;
- interpreting in the counter whether the photo current is a positive pulse or a negative pulse, wherein if the photo current is a positive pulse, then the photo current occurred in a first window of time, and wherein if the photo current is a negative pulse, then the photo current occurred in a different second window of time;
- determining, in the DFPA, a time when photo current switches from the positive pulse to the negative pulse, or vice versa;
- and
- ranging the target based on the time when the DFPA determined the photo current switched and the pulsed laser beam speed.
Dependencies are inferred from the claim text.