Abstract: Apparatus and methods for monitoring interference in radio communication systems are provided. In certain embodiments, an interference monitor system for a ground terminal detects for interference based on a sum of the power levels of orthogonal polarizations of detected interference, thereby allowing the total and average peak interference power levels to be obtained independent of interference polarization. Further, the interference can be divided into frequency bins over the received signal bandwidth(s), thereby facilitating measurement of interference spectral characteristics. Multiple interference monitors can be included to detect interference over the full angular range over which potential interference has access as well as to determine an angular direction of the interference.

Abstract: Apparatus and methods for monitoring interference in radio communication systems are provided. In certain embodiments, an interference monitor system for a ground terminal detects for interference based on a sum of the power levels of orthogonal polarizations of detected interference, thereby allowing the total and average peak interference power levels to be obtained independent of interference polarization. Further, the interference can be divided into frequency bins over the received signal bandwidth(s), thereby facilitating measurement of interference spectral characteristics. Multiple interference monitors can be included to detect interference over the full angular range over which potential interference has access as well as to determine an angular direction of the interference.

Abstract: Satellite navigation receivers are provided herein. In certain embodiments, a satellite navigation receiver correlates a received RF navigational signal from a satellite with a replica code generated by the receiver. Additionally, errors due to multipath are mitigated by identifying the location of the peak values of the correlation function obtained when the replica code is aligned with the received RF navigational signal. Thus, the peak correlation value is detected by sweeping the user replica code in delay in place of a closed loop early/late discriminator. Moreover, multiple copies of the receiver generated replica codes with different time offsets can be used to perform the acquisition in parallel. This advantageously reduces the amount of acquisition time to align the replica code and provides averaging to improve the accuracy in detecting the delay location of the peak correlation value.

Abstract: Systems and methods are provided for repositioning a directional antenna that responds to a desired signal and directional interference. The antenna can generate a sum beam and first and second difference beams. Respective powers of the sum beam and the first and second difference beams can be determined. At least a portion of any of the directional interference can be excised from the sum beam and the first and second difference beams. Measures of the directional interference can be determined in the sum beam and the first and second difference beams. A first correlation between the sum beam and the first and second difference beams can be generated. Additional correlations between a signal identifier and the sum beam and first and second beams monitor the desired signal reception. The antenna can be repositioned away from the directional interference based on the powers, the measures, and the first correlation.

Abstract: A system is provided with circuits and methods for dynamically reducing interference to maintain linear system operation and mitigate interference degradation to desired signal components. The system can include a binning subcircuit system configured to divide the digitized input signal into a plurality of spectral bins each having a power level. A power analysis subcircuit can be coupled to the binning subcircuit and configured to compare a collective power level of spectral bins to a threshold level that would produce nonlinear system operation. Based upon the collective power level exceeding the threshold level, outputting a gain control signal to a variable gain amplifier so that the system remains linear. This dynamic gain control can be applied to systems that receive and/or transmit signals. Residual interference components that degrade signal components can be dynamically removed by excision and the distortion introduced by the excision process can be reduced with equalization circuitry.

Abstract: A system is provided with circuits and methods for dynamically reducing interference to maintain linear system operation and mitigate interference degradation to desired signal components. The system can include a binning subcircuit system configured to divide the digitized input signal into a plurality of spectral bins each having a power level. A power analysis subcircuit can be coupled to the binning subcircuit and configured to compare a collective power level of spectral bins to a threshold level that would produce nonlinear system operation. Based upon the collective power level exceeding the threshold level, outputting a gain control signal to a variable gain amplifier so that the system remains linear. This dynamic gain control can be applied to systems that receive and/or transmit signals. Residual interference components that degrade signal components can be dynamically removed by excision and the distortion introduced by the excision process can be reduced with equalization circuitry.

Abstract: Under one aspect, a system includes circuitry that digitizes and Fourier transforms first and second beams and outputs first and second sets of spectral bins. Each bin may include a portion of a group of signals or interference. The circuitry compares the collective power levels of each set of spectral bins to a predetermined threshold, and excises at least one bin of that set that contains the interference if the collective power level of that set exceeds the predetermined threshold. The circuitry determines an angular location of the interference based on excised bins, combines remaining bins with weights selected to form a null in a pattern of the first and second beams that is aligned with the interference's angular location, and inversely Fourier transforms the combined remaining bins and outputs the group of signals less any interference that was excised or excluded by the null.

Abstract: A dynamic equalization system and method for use with a receiver is provided. The receiver may include an antenna for receiving a signal having multipath signal components and a digitizer for obtaining and digitizing the received signal and multipath signal components. The digitized signal segment and multipath signal components may be discretized into signal segments of length n. Channel parameters of each of the discrete signal segments may be analyzed and locked to, and a time-domain representation of the analyzed channel parameters may be output. Each time-domain representation may be Fourier transformed into a frequency-domain representation, based upon which equalization parameters to equalize the multipath signal components for each of the analyzed channel parameters may be determined. The equalization parameters may be applied to corresponding signal segments of the digitized signal and multipath signal components so as to equalize the multipath signal components.

Abstract: Embodiments of the invention provide systems and methods for systems and methods for adaptively canceling interfering signals generated by a transmission antenna. Under one aspect, a system includes: an auxiliary antenna co-located with the main antenna, the auxiliary antenna configured to transmit an auxiliary signal to the victim antenna; a sensing antenna located on a line-of-sight path between the transmission antenna and the victim antenna, the sensing antenna configured to receive a composite of the interference and the auxiliary signal, and to output a first signal based on the received composite; a controller comprising an input coupled to the sensing antenna and configured to receive the first signal, the controller being configured to adjust at least one of an amplitude, a phase, a polarization, and a frequency characteristic of the auxiliary signal based on the first signal so as to reduce the composite of the interference and the auxiliary signal received by the sensing antenna.

Abstract: Systems and methods for increasing communications bandwidth using non-orthogonal polarizations are provided herein. Under one aspect, a method of transmitting M independent signals, where M is at least 3, includes receiving the M signals from respective sources; at a transmitter polarization module, obtaining first and second linear combinations of the M signals; providing the first and second linear combinations to first and second input ports of a transmitter antenna; and transmitting with the transmitter antenna the first linear combination at a first polarization and the second linear combination at a second polarization orthogonal to the first polarization. The method may further include receiving at a receiver antenna the first linear combination at the first polarization, and the second linear combination at the second polarization; obtaining at receiver circuitry the M signals based on the received first and second linear combinations; and outputting the M signals on respective output ports.

Abstract: Systems and methods for increasing communications bandwidth using non-orthogonal polarizations are provided herein. Under one aspect, a method of transmitting M independent signals, where M is at least 3, includes receiving the M signals from respective sources; at a transmitter polarization module, obtaining first and second linear combinations of the M signals; providing the first and second linear combinations to first and second input ports of a transmitter antenna; and transmitting with the transmitter antenna the first linear combination at a first polarization and the second linear combination at a second polarization orthogonal to the first polarization. The method may further include receiving at a receiver antenna the first linear combination at the first polarization, and the second linear combination at the second polarization; obtaining at receiver circuitry the M signals based on the received first and second linear combinations; and outputting the M signals on respective output ports.

Abstract: Systems and methods for increasing communication throughput by superimposing multiple signal components in the same bandwidth are disclosed. Cochannel interference is reduced by using signal separation algorithms. The signal separation algorithms may use both a priori information about the superimposed signals and measured channel parameters. In addition, error correction encoding and interleaving may be used to reduce signal power and obviate the need for ideal signal separation.

Abstract: Systems and methods for increasing communications bandwidth using non-orthogonal polarizations are provided herein. Under one aspect, a method of transmitting M independent signals, where M is at least 3, includes receiving the M signals from respective sources; at a transmitter polarization module, obtaining first and second linear combinations of the M signals; providing the first and second linear combinations to first and second input ports of a transmitter antenna; and transmitting with the transmitter antenna the first linear combination at a first polarization and the second linear combination at a second polarization orthogonal to the first polarization. The method may further include receiving at a receiver antenna the first linear combination at the first polarization, and the second linear combination at the second polarization; obtaining at receiver circuitry the M signals based on the received first and second linear combinations; and outputting the M signals on respective output ports.

Abstract: Systems and methods for increasing communication throughput by superimposing multiple signal components in the same bandwidth are disclosed. Cochannel interference is reduced by using signal separation algorithms. The signal separation algorithms may use both a priori information about the superimposed signals and measured channel parameters. In addition, error correction encoding and interleaving may be used to reduce signal power and obviate the need for ideal signal separation.

Abstract: Embodiments of the invention provide systems and methods for systems and methods for adaptively canceling interfering signals generated by a transmission antenna. Under one aspect, a system includes: an auxiliary antenna co-located with the main antenna, the auxiliary antenna configured to transmit an auxiliary signal to the victim antenna; a sensing antenna located on a line-of-sight path between the transmission antenna and the victim antenna, the sensing antenna configured to receive a composite of the interference and the auxiliary signal, and to output a first signal based on the received composite; a controller comprising an input coupled to the sensing antenna and configured to receive the first signal, the controller being configured to adjust at least one of an amplitude, a phase, a polarization, and a frequency characteristic of the auxiliary signal based on the first signal so as to reduce the composite of the interference and the auxiliary signal received by the sensing antenna.

Abstract: An antenna method and system to implement a quasi-compact range technique/technology in which a reflector antenna is used to produce a test field within a test region at a quasi-compact range, which is within a near-field of the reflector antenna but further from the reflector antenna than a compact range of the reflector antenna.

Abstract: A method includes determining if a dynamics requirement for an antenna positioner is exceeded, and employing a combination of mechanical and electronic beam steering techniques to steer a single antenna beam if the dynamics requirement is exceeded.

Abstract: An antenna method includes using a reflector antenna to produce a test field within a test region at a quasi-compact range, which is within a near-field of the reflector antenna but further from an aperture plane of the reflector antenna than a compact range of the reflector antenna.

Abstract: An apparatus includes antenna elements configured to receive a signal including pseudo-random code, and electronics configured to use the pseudo-random code to determine time delays of signals incident upon the antenna elements and to compensate the signals to coherently combine the antenna elements.

Abstract: A method for main beam alignment verification includes providing data pertaining to one or more patterns associated with an antenna, measuring power levels of a signal acquired by the antenna, and comparing the measured power levels with the data to determine whether a direction of the signal is incident upon a main beam of the antenna.