L-3 Communications Corporation

Loral Corporation

Robert A Wright

Thomas R Giallorenzi

Samuel Charles Kingston

Johnny M Harris

John W Zscheile, Jr

Larry S Thomson

Alan E Lundquist

Sam Kingston

Theodore J Wolcott

Decreased capability for detection of communications signals by an adversary is provided by applying frequency hopping, frequency chirping, and direct sequence spreading to the signals. The frequency hopping and frequency chirping can be driven by pseudo random functions. The direct sequence spreading can use a pseudo random chip sequence.

Radio communications system and method having decreased capability for detection by an adversary

A system and method is disclosed for protecting a receiver configured to receive a plurality of contemporaneous spread spectrum signal bursts from a denial of service attack. The method includes the operation of detecting a burst transmission that includes a random burst number. The burst transmission can be analyzed to determine a denial of service statistic based on the random burst number. The burst transmission is processed when the denial of service statistic is within a predetermined threshold.

System and method for protecting against denial of service attacks

A system for despreading a spread spectrum signal includes at least one receiver for capturing a plurality of snapshots of the signal and a processing device for constructing a confidence vector from at least two of the plurality of snapshots. The processing device is operable to generate a first estimated spreading sequence of the signal, and to correlate the first estimated spreading sequence and the confidence vector to generate a second spreading sequence for despreading the signal.

Method for determining the spreading sequence of a spread spectrum signal

Apparatus and a method for increasing the speed of acquisition of PN coded signals includes a novel PN code clock extraction circuit which is coupled in parallel to a code tracking loop and acquisition loop of a PN receiver of the type having a replica PN code generator which is slip controlled to synchronize with the received PN coded signals. The novel PN code clock extraction circuit detects the clock transition of the received PN coded signals and synchronized the replica PN code generator clock transition signals so that there is no misalignment during acquisition. A switch control in the acquisition loop circuit senses the synchronization of the replica PN code generator transition and the received PN code transition and disconnects the PN code clock extraction circuit after synchronization of clock transition and before acquisition of the PN code so that the acquisition loop detects the PN code synchronization with a full strength signal.

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Sandy, UT, United States of America

Robert A Wright