Laser perimeter awareness system

Abstract

A method of laser scanning a perimeter zone of a target site for the detection of potential threats comprises: scanning a pulsed laser beam across the perimeter zone; receiving echoes from the pulsed laser beam during the perimeter zone scan; deriving range data corresponding to the received echoes; determining position data of the received echoes in the perimeter zone; forming a scene image of a scan of the perimeter zone based on the range and position data of the received echoes thereof; repeating the steps of scanning, receiving, deriving, determining and forming for a plurality of perimeter zone scans to form scene images of each scan of the plurality; and comparing scene images of the plurality to detect a potential threat in the perimeter zone. In addition, a method of authenticating a potential threat detected in a perimeter zone of a target site comprises: detecting the potential threat and upon detection, interrogating the potential threat for a response by a wireless transmission; declaring the potential threat unauthorized if no response is transmitted wirelessly within a predetermined time interval from the interrogation; receiving the response, if transmitted, and determining if the response comprises a proper access code; and declaring the potential threat unauthorized if the received response is determined not to comprise the proper access code.

Description

CROSS REFERENCE TO RELATED PATENT APPLICATIONS [0001] U.S. patent application Ser. No. 10 / 109,372, filed Mar. 28, 2002, and entitled “Distributed Laser Obstacle Awareness System”; [0002] U.S. patent application Ser. No. 10 / 251,422, filed Sep. 20, 2002, and entitled “Railway Obstacle Detection System and Method”; [0003] U.S. patent application Ser. No. 10 / 347,908, filed Jan. 21, 2003, and entitled “System For Profiling Objects On Terrain Forward and Below An Aircraft Utilizing A Cross-Track Laser Altimeter”; [0004] All of the above referenced patent applications are assigned to the same assignee as the instant application. [0005] This application is a divisional application of U.S. patent application Ser. No. 10 / 440,918, filed May 19, 2003.BACKGROUND OF THE INVENTION [0006] The present invention is related to perimeter security and search and rescue systems, in general, and more particularly, to a system for and method of laser scanning a perimeter zone around a target site to render...

AI Technical Summary

Problems solved by technology

Current perimeter security systems and processes have been demonstrated to be insufficient for these emerging threats.

For example, video cameras, night vision systems, radar, and conventional security patrols have proven ineffective at preventing recent terrorist attacks.

In addition, use of conventional radar systems for threat monitoring may result in confusion due to multi-path returns over water and will suffer from radar “clutter” at close in ranges (blind radar zones).

Additionally, changes in sea states can degrade the detection performance of the radar system even further.

Further, radar systems also suffer from broad main beam lobes, on the order of 1-10 degrees.

Once the body temperature of the terrorist approaches that of the surrounding water, the ability to detect the body with passive infrared sensors quickly diminishes, i.e. the thermal gradients necessary for an infrared body signature are lost.

Thus, under these circumstances, conventional passive infrared imaging systems may miss detecting the terrorist's body in the water.

In this case, use of thermal imaging for recovery is voided.

Images