Harris Corporation

Eagle Technology, LLC

William C Adams, Jr

Francis Eugene Parsche

G Patrick Martin

Gary William Mason

Charles R Patisaul

Kathleen Marie Minear

Robert C Hildebrand

Michael P O'Reilly

Emil G Svatik

Darrell R Gimlin

Gerald S Duggan

Kenneth J Hendrickson

Lynda Margaret Ralston

John Roach

Allan V Dianic

Gary W Mason

An RF PNT system may include LORAN stations. Each LORAN station may include a LORAN antenna, and a LORAN transmitter coupled to the LORAN antenna and configured to transmit a series of LORAN PNT RF pulses having a time spacing between adjacent LORAN PNT RF pulses. One or more of the LORAN stations may include a message embedding generator coupled to the LORAN transmitter and configured to generate message RF bursts based upon an input message, and with each message RF burst being in the time spacing between respective adjacent LORAN PNT RF pulses.

RF PNT system with embedded messaging and related methods

A LORAN device may include a LORAN antenna, a LORAN receiver, an RF signal path extending between the LORAN antenna and the LORAN receiver and being subject to ambient RF interference, and an ambient RF interference canceller coupled in the RF signal path. The ambient RF interference canceller may include an ambient RF interference sensor configured to generate an estimated ambient RF interference signal based on the sensed ambient RF interference, and cancellation circuitry configured to cooperate with the ambient RF interference sensor to generate an ambient RF interference cancellation signal based upon the sensed ambient RF interference signal, and add the ambient RF interference cancellation signal to the RF signal path.

Loran device with interference cancellation and interference canceller device with related methods

A long range navigation system may include radio frequency (RF) transmitter stations at fixed geographical locations, each having an RF transmitter and an RF modulator coupled to the RF transmitter, and configured to generate a direct sequence spread spectrum (DSSS) RF signal being spectrally shaped so that 99% of power from the RF transmitter is within the frequency range of 90-110 KHz. Movable RF receiver units each include an RF receiver and a demodulator coupled to the RF receiver configured to demodulate the DSSS RF signal to determine a position of the movable RF receiver unit.

Long range navigation system having direct sequence spread spectrum (DSSS) RF signal

An enhanced LOng RAnge Navigation (eLORAN) system may include a plurality of eLORAN transmitter stations, and at least one eLORAN receiver device. The eLORAN receiver device may include an eLORAN receive antenna, an eLORAN receiver coupled to the eLORAN receive antenna, and a controller coupled to the eLORAN receiver. The controller may be configured to cooperate with the eLORAN transmitter stations to determine an eLORAN receiver position and receiver clock error corrected from additional secondary factor (ASF) data, the ASF data based upon different geographical positions and different times for each different geographical position.

Enhanced LORAN (eLORAN) system having corrected additional secondary factor (ASF) data

A space deployable antenna apparatus includes an inflatable antenna configurable between a deflated storage position and an inflated deployed position. The inflatable antenna includes collapsible tubular elements coupled together in fluid communication. The collapsible tubular elements in the deployed position include a longitudinally extending boom tubular element, at least one driven tubular conductive element transverse to the boom tubular element, at least one reflector tubular conductive element transverse to the boom tubular element, and at least one director tubular conductive element transverse to the boom tubular element. A foam dispenser is configured to inject a solidifiable foam into the inflatable antenna to configure to the inflated deployed position.

Space deployable inflatable antenna apparatus and associated methods

Systems () and methods () for method for providing a redundant or distinct transmission feature to a communication system (). The methods involve () detecting if there is a communication system fault. If a communication system fault is detected (:YES), then () a plurality of modified transmit signals are generated by combining a transmit signal with a plurality of complex weights (W, W, W). The modified transmit signals are then () transmitted from a plurality of antenna elements () of the communication system to an object of interest (). If a communication systems fault is detected (:NO), then () a plurality of redundant or distinct transmit signals are generated by combining the transmit signal with a plurality of first orthogonal or approximately orthogonal numerical sequences. The redundant or distinct transmit signals can then be () synchronously transmitted from the antenna elements.

Code division multiple access based contingency transmission

Systems and methods for operating a communications system. The methods involve computing one or more complex weights to be applied to transmit signals and receive signals by beamformers. The complex weights are based at least on configuration data for the communications system. The methods also involve applying a first plurality of weight corrections to the complex weights based on phasing errors occurring in a communication path inclusive of a control system and antenna elements. The methods further involve applying a second plurality of weight corrections to the complex weights based on phase differences at the antenna elements relative to a reference location for the receive signals.

Compensation of beamforming errors in a communications system having widely spaced antenna elements

In a digital data recovery receiver, an optimal (in the Maximum likelihood sense) estimate of Es/No (dB) is obtained by the following mechanism. First, over a prescribed symbol span of N symbols, for each of 2.sup.B-1 -1 quantization bins, respectively associated with 2.sup.B-1 threshold levels used by a B-bit resolution analog-to-digital converter to digitize a received signal, the number of times that the received signal is quantized with respect to that level is counted. Each count total is divided by the number N of symbols in the span, to obtain plural ratios, respectively representative of probalities of symbol pseudo error rate over the symbol span. Using these ratios, respective Es/No (dB) values are derived from stored pseudo error relationships, each of which is associated with a respective one of the 2.sup.B-1 -1 quantization bins and defines the probability of symbol error rate in terms of Es/No (dB). Employing each derived Es/No (dB) value to a maximum likelihood estimate of Es/No (dB), a set of weights, respectively associated with respective Es/No (dB) values, is produced. Each weight is multiplied by its associated Es/No (dB) value and the products are summed, so as to obtain an output signal representative of an estimate of 10log.sub.10 of the ratio of received energy per symbol Es to noise power density spectra No. This output signal may then be used in a feedback loop to the transmitter site to control one or more characteristics of the transmitted signal, so as to attain a prescribed signal quality in the recovered signal.

Mechanism for estimating Es/No from pseudo error measurements

The possibility of overload (saturation-lockup) condition of an ALPC satellite communication network is avoided by a scheme that grants network entry (allocates TWT power) to each link one at a time. As each link is granted entry into the network, the corresponding TWT probability density function is computed and then integrated to obtain a TWT cumulative distribution function. The required rain margin M.sub.r for a specified availability is determined from the cumulative margin. The computed margin M.sub.r is set equal to the initial satellite TWT operating point change (multiplicative factor) MR.sub.1 due to rain fade, MF.sub.1 =M.sub.r to ensure that network stability considerations and rain fades equally constrain network performance. This result is then used to compute the value of the corresponding multiplicative factor MF.sub.2. These two factors, when expressed in decibels, may be added to the nominal (no rain) TWT operating point (also expressed in decibel notation) to predict the maximum TWT operating point value in response to rain stress at the specified system availability. This predicted maximum TWT operating point is then compared to the analytically determined value of the TWT stability point. If the TWT stability point is not exceeded for the current number of links then an additional link may be added, otherwise, the last link requesting entry into the network is denied access. After the maximum permissible number of terminals has been accommodated, the final actual values of TWT stability point, stability margin, and link availability are computed and the allocation process is terminated.

Optimal satellite TWT power allocation process for achieving requested

To measure the figure of merit (G/T) and beam radial pointing error of a satellite earth station multiple Y-factor measurement are taken using a 'drift cut' procedure and then these measurements are processed using a maximum likelihood estimate (MLE) algorithm. For carrying out the 'drift cut' measurement process, the earth terminal's antenna is positioned such that the antenna beam intersects the path of the apparent star motion with a predetermined declination offset and ahead of the current star position. As the star position approaches the stationary antenna beam position, power measurements uniformly spaced in time are recorded. These power measurement 'samples' are then divided by the 'cold sky' power measurement to obtain corresponding Y-factor measurements. To eliminate the problem of antenna pointing error and star ephemeris error, multiple drift cuts are carried out, each offset in declination by a different amount from the estimate star declination, to produce a matrix of Y-factor values. This matrix of drift cut Y-factors is then processed using a maximum likelihood estimate algorithm, to provide MLE measures of that earth terminal's figure of merit and beam radial pointing error.

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West Melbourne, FL, United States of America

William C Adams, Jr