L-3 Communications Corporation

Other

United States of America as Represented by the Secretary of the Air Force

L3 Technologies, Inc.

L-3 Communications Systems

Merle LeRoy Keller, Jr

Vaughn Lee Mower

Kent R Bruening

Steve J McEntire

Samuel Charles Kingston

Zachary C Bagley

Dale D Fonnesbeck

Michael Wilson

Steven T Barham

Raied N Mazahreh

Radivoje Zarubica

Alan E Lundquist

Randal R Sylvester

Ayyoob Dehgani Abbaszadeh

Roger T Baker

Scott M Lyon

LaMar K Timothy

Patricia F Batzer

Warren Paul Willes

Kenneth C Bark

Roy Fletcher Lunsford

Victor D Albertini

Albert Earl Hansen

Altaf Rahman

Steven J McEntire

A virtual boresight vector for an antenna array can be calculated. The virtual boresight vector defines the direction an antenna array is pointing and can be used to ensure that angle of arrival measurements are performed with high accuracy. The virtual boresighting process can include positioning a calibration node at two different locations in order to obtain different covariance matrices. With the covariance matrices and based on knowing the angle between the two locations, an angle of arrival node can perform a process to calculate a precise angle between the antenna array and the second location.

Calculating a virtual boresight vector of an antenna array

Processes for determining imperfection offsets between an antenna and the platform to which the antenna is coupled, where the imperfection offsets are unknown offsets due to imperfections such as manufacturing imperfections. The platform can include an orientation mechanism that provides the orientation of the platform, and the imperfection offsets can be between the antenna and the orientation mechanism. The processes can include determining two different relative pointing vectors that correspond to a detected peak strength of a test signal transmitted between one or more targets and the antenna. The processes can further include utilizing an optimization process to determine the heading, pitch, and roll of the imperfection offsets from the two different relative pointing vectors.

Aligning a radio frequency antenna bore sight

Systems and methods for improving the reliability of a hub-spoke communications system use a first antenna and a second antenna at the hub terminal. Spread spectrum transmission from the hub terminal uses the first antenna, and the second antenna is enabled when blockage between the first antenna and any one of the spoke terminals is present. The first antenna and the second antenna have substantially orthogonal polarizations. The spread spectrum transmissions from the first antenna and second antenna have different pseudonoise code timing so that the received transmissions are offset by at least one chip interval from each other.

Communications reliability in a hub-spoke communications system

Direct sequence spread spectrum communications can use composite codes and can operate at a plurality of different chipping rates. The composite codes can be formed using a plurality of component codes, wherein the component codes can be relatively prime and at least one of the nominal lengths of the component codes can include a plurality of prime number multiplicands. The chipping rate and code length can be reduced by dividing a master rate by one or more of the prime number multiplicands. Symbol timing and time division multiple access timing can be tied to epochs of the component codes.

Direct sequence spread spectrum system and method with plural chipping rates

A system and method for parallel Pseudo-random Noise (PN) code generation is disclosed. The method includes the operation of producing a PN code sequence having a predetermined length. The PN code can be divided into L segments. At least one of the L segments can have a length less than other segments. The L segments can be distributed into an array of L digital memories. Each of the digital memories can output every Lth chip of the PN code in parallel at a selected rate. An element of the PN code can be substituted from an element substitution cache into the output of the L digital memories to compensate for segment(s) having a shorter length.

System and method for memory-based parallel PN generation

A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.

Acquisition and tracking of burst code signals

A phase division multiple access (PDMA) system is provided. The PDMA system includes at least one receiver logic combiner adapted to generate a plurality of composite PN codes. Each of the plurality of composite PN codes are derived from a common composite PN code and are separated by a predetermined PN phase.

System and method for multi-phase composite PN code generation

A method and system for managing Priority Messages in a hybrid TDMA-Spread Spectrum (TDMA-SS) communication system is provided. The method and system include a HUB for generating a HUB TDMA epoch, wherein the HUB TDMA epoch includes at least one Priority Message (PM) slot. The PM slot includes a plurality of assignable PM sub-slots. The method and system also include at least one SPOKE, wherein the at least one SPOKE is adapted to transmit a Priority Message during its assigned PM sub-slot within the HUB TDMA epoch.

System and method for priority communication management in a hybrid TDMA-SS system

A system for verifying composite pseudo-noise (PN) encoded signals. The system provides at least three PN component codes, wherein the at least three PN component codes are relatively prime. The system partially correlates a received PN composite encoded signal with a first minor epoch derived from the at least three PN component codes. The system searches for phase alignment of the received PN composite encoded signal with a second minor epoch derived from the at least three PN component codes. The system correlates the received PN composite encoded signal with a receiver PN composite code phase when the first minor epoch and the searched second minor epoch are separated by a predetermined phase.

System and method for detecting PN code phase

A system for TDMA-SS signal prioritization and collision mitigation is provided. The system includes a Hub transceiver having plurality of parallel PN correlation branches, wherein each of the plurality of parallel PN correlation branches is prioritized with respect to each of the other plurality of parallel PN correlation branches. The system also includes a first Spoke transmitter adapted to transmit a first prioritized PN encoded signal corresponding to a first one of the first plurality of prioritized parallel PN correlation branches. In addition, a second Spoke transmitter is adapted to transmit a second prioritized PN encoded signal corresponding to a second one of the first plurality of prioritized parallel PN correlation branches.

System and method for PN encoded signal prioritization and collision mitigation

A system for fast data encryption/decryption is provided. The system includes a transmitter system having a transmitter direct digital synthesizer (DDS). The DDS includes at least three transmitter pseudo-noise (PN) component code generators PN, PN, PN, where each transmitter PN component code generator is adapted to generate relatively prime transmitter PN component codes when compared with each of the other transmitter PN component code generators. The transmitter also includes a first processor coupled to the transmitter DDS, where the first processor is adapted to determine a time slot number (TSN) relative to at least two of the relatively prime transmitter PN component codes. Also included in the transmitter is an encryptor for encrypting clear data in accordance with the TSN. The system includes a receiver system having a second processor adapted to determine the TSN; and a decryptor coupled to the second processor. The decryptor is adapted to decrypting the encrypted clear data in accordance with the TSN.

System and method for fast data encryption/decryption using time slot numbering

A method and system for determining Psuedo-Noise (PN) composite phase is provided. The method includes providing at least three relatively prime PN component codes and partially correlating a received PN composite encoded signal with one of the PN component codes. The method also includes partially correlating the received PN composite encoded signal with a second one of the PN component codes while maintaining phase alignment of the first partially phase aligned PN code through the use of normalized autonomous phase numbers (NAPNs). The received PN composite encoded signal is then phase aligned with a receiver PN composite code phase in steps of epoch lengths of the partially phase aligned PN component codes.

Linear search system and method for determining Psuedo-Noise (PN) composite phase

This invention generates pseudo-noise (PN) codes that map a transmitted data rate into the PN code structure. This invention further then acquires the PN code to automatically discover the transmitted data rate. This invention is operable with communication systems that utilize GPS time synchronization of the transmitted and received PN codes, as well as with communication systems where GPS time synchronization is not available. A method and a system are disclosed to transmit a modulated signal from a transmitter to a receiver, where the modulated signal has a data rate. The method includes selecting, to represent the data rate, at least one PN component code from a set of PN component codes. The PN component code is a constituent code of a composite PN code comprised of a plurality of PN component codes. The selected PN component code is one that phase aligns with a PN composite encoded signal. The method further includes modulating the signal to be transmitted using the PN composite code that includes the selected PN component code, receiving the modulated signal, demodulating the received signal using a demodulation process and discovering the data rate during the demodulation process. The demodulation process includes generating instances of a plurality of PN component codes, and correlating the received modulated signal either sequentially or in parallel with the instances of the PN component codes.

System and method for fast data rate discovery from PN codes

A system for generating (PN) spread signals is provided. The system includes a first clock synchronized with a second clock and at least three first pseudo-noise (PN) component code generators coupled to the first clock. A logic combiner is coupled to the PN component code generators and is adapted to generate a composite PN code. Both clocks are coupled to respective N-bit and M-bit counters.

System and method for generating and acquiring pseudo-noise (PN) spread signals

A method and system for synchronizing the PN phase of a pseudo-noise (PN) coded signal with a phase of a master PN decade-code is provided. The method includes the steps of associating the master PN decade-code initialization twith a first time zone reference date and time and determining an elapsed time t. The next steps equate the elapsed time tto a corresponding phase of the master PN code and synchronize the phase of the PN coded signal with the corresponding phase of the master PN decade-code.

Growing community of inventors

Salt Lake City, UT, United States of America

Merle LeRoy Keller, Jr