Robert A Leverance

US Patent:

46399020, Jan 27, 1987

Filed:

Jun 24, 1985

Appl. No.:

6/748366

Inventors:

Robert A. Leverance - College Park MD
Socrates A. Longas - Glenndale MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G08B 1316

US Classification:

367 93

Abstract:

An intrusion detector is configured to transmit signal(s) of a very short ration and then process the returned signal(s) reflected from various surfaces and objects within the propagation path in a room to be secured. The return signal(s) is a succession of peaks whose return times represent the location of respective objects. As configured, the intrusion detector apparatus includes, inter alia, a microprocessor that stores processed facsimiles of the return signal(s) for an unoccupied room and continually makes comparisons with subsequent returned signal(s). When the returned signal(s) changes, as a result of an unauthorized entry into the room, for example, a visual and/or audible alarm indication is produced.

US Patent:

53493559, Sep 20, 1994

Filed:

Jan 21, 1993

Appl. No.:

8/016384

Inventors:

Socrates A. Longas - Glendale MD
Robert A. Leverance - College Park MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01S 1380

US Classification:

342 42

Abstract:

A microwave carrier signal emitted from a tracker unit is amplitude moduld periodically at different preset modulation frequencies during spaced intervals between established time slots. The carrier signal is detected by differently coded credential units within a reception zone whereby such signal is demodulated at the different modulating frequencies to produce reply signals at one of several different code frequencies during one of the time slots dependent on the credential unit coding. The reply signals are detected by the tracker unit during narrowed reception windows within the time slots. Such reply signals are decoded within separate frequency channels corresponding to the code frequencies thereof to extract signal data processed to indicate entry, departure and status of the credential units relative to the reception zone.