Abstract: Methods, apparatuses, and systems for verifying alignment of a compact antenna test range (CATR) are presented. A radio frequency (RF) profile may be generated based on test signals received by a reference antenna at a plurality of orientations. Phase and amplitude data of the RF profile may be used to determine whether the CATR is aligned properly.

Abstract: A user station is provided for connecting to a bus line and a method for compensating for an interference due to a CAN bus system in a received signal. A signal of a CAN bus system is transmitted via the bus line in coexistence with a signal of a further bus system. The user station includes a receiving unit for receiving an overall signal and for compensating for an interference in the received overall signal which occurs due to a changing output impedance of a user station of the CAN bus system which is connected to the bus line.

Abstract: Multiple field units in a CDMA system are synchronized for communication with a base station using a shared forward and reverse link channel. Each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot from each field unit. Thereafter, a message is transmitted in a corresponding time slot to a particular field unit from the base station for adjusting its timing so that future messages transmitted from the field unit are received in the appropriate time slot at the base station.

Abstract: Provided is an apparatus and method for transmitting and receiving polarized signals. Wireless communication with multiple polarized signals may experience greater attenuation on one polarized signal than another polarized signal. The polarized signal that is more attenuated limits overall throughput for the wireless communication. According to an embodiment of the invention, signals undergo rotation processing with a transformation involving a rotation matrix prior to transmission. Each polarized signal that is transmitted is based on a different weighted combination of the signals. The rotation processing can be performed with an objective that signals recovered at a receiver have comparable signal quality, which can increase overall throughput. In some implementations, the rotation processing is performed based on feedback to dynamically adjust the rotation processing.

Abstract: A system and methods for aligning an elliptical beam of an antenna to a line-of-sight from the antenna to a remote receiver are disclosed. The methods offset the antenna from an initial pointing direction in an antenna pointing coordinate system. Coordinates of the pointing offsets are determined in the E-plane and H-plane of an antenna beam coordinate system. The method then converts the coordinates of the pointing offsets from the antenna beam coordinate system into coordinates of offset points each located in the antenna pointing coordinate system according to the polarization angle of the E-plane and the H-plane, and performs a tracking algorithm using relative signal strength measurement data at the initial pointing directions and at the coordinates of the offset points. The true location of the center/peak of the elliptical beam is calculated in azimuth/elevation planes of the antenna pointing coordinate system.

Abstract: A method and a system are disclosed which utilize the polarization properties of electromagnetic fields for a determination of the direction to the source of the electromagnetic radiation. The method and system primarily use a particular antenna device with is associated receiver means for obtaining a wave field measurement Assuming separate frequencies, the present method and system also make it possible to distinguish between several sources and register their separate polarizations simultaneously. At least three electric antennas, or three magnetic antennas, are used to measure the wave field. The registered field components need not be orthogonal to each other. The measured wave field is processed in accordance to predetermined formulae so that the propagation direction and other polarization characteristics, such as the spectral intensity I and the spectral degree of circular polarization rc, are derived. Furthermore the measurements need not be from more than one point in space.

Abstract: A communications system in which a communications channel is defined at least in part by an electromagnetic wave having a carrier frequency and an electric field vector, the extremity or terminus of which traces a non-linear periodic path at a rotation frequency less than the carrier frequency and greater than zero from the perspective of an observer looking into the axis of propagation of the wave. The transmitter of the communications system launches a wave having such characteristics and modulated with information in a suitable manner. The receiver of the communications system is sensitive to the periodic path and rotation frequency. The combination of the periodic path and the carrier frequency provides selectivity that can be used to define multiple communications channels.

Abstract: A polarization compensating device useful in correcting radome-induced polarization errors in a linearly polarized antenna in a missile is described.

Abstract: This invention consists of a method for measuring the direction and magnitude of the semi-major and semi-minor axes (13, 14) of the electric ellipse (5) of an incoming wave in a magnetized plasma from the in-phase and quadrature measurements (12) of the electric field that is measured on three orthogonal antennas (1, 2, 3), in order to measure the line-of-sight of the direction of wave propagation (15), and the wave propagation mode (16, 17), from the orientation and rotation sense of the measured wave electric ellipse. In addition, for a wave that consists of a linear combination of the ordinary and extraordinary modes in a magnetized plasma, these measurements can also be used to measure the line-of-sight of the direction of wave propagation (20), and the Faraday rotation angle (21), from the orientation of the semi-major axes of the electric ellipse (17, 18) that are measured at two or more adjacent frequencies.

Abstract: An apparatus and process for improving the performance of a cellular communication system using direct sequence spread spectrum techniques. The apparatus and process enable dynamic modification of communication system parameters including PN code length, chipping rate and modulation technique for transmission of a data packet. Modification is based on proximity of the transmitter and receiver, transmitter and receiver capabilities and other factors. The system evaluates tradeoffs between data transmission speed and communication range to improve system performance.

Abstract: An adaptive polarization cancellation arrangement which nulls out all types of concurrent interference signals received by a Global Positioning System (GPS) receiver from antenna mainlobe and sidelobe situated sources. The orthogonally polarized components of the composite received signal are separated by the receive antenna arrangement and adjusted in the polarization feed adapter network between the antenna and GPS receiver to optimally cancel components. The antenna and installation arrangement creates a polarization filter relative to interference sources which changes their apparent polarization orientation and supports adaptive discrimination based on dissimilar polarization characteristics relative to the desired signals. The orthogonal received signal components from the GPS satellite constellation and from interference sources are combined to adaptively create cross-polarization nulls that adequately attenuate interference sources while slightly modifying the GPS received signals.

Abstract: A wireless communication system combines time and space diversity to reduce fading and simplify receiver design. In particular, a data packet which carries digital telephone traffic, is transmitted at three different times from three different antennas. The mobile subscriber receiver thus receives the same data packet at three different times from three different antennas, and uses the best data packet or combination of the data packets to reduce the effects of fading. A transfer station receives a time division multiplex multiple access (TDMA) signal from a base station carrying telephone data packet traffic to form three data packet repeats at spatially diverse antennas locations. The transfer station further modulates a code division multiple access (CDMA) system using a TDMA signal which links the mobile subscriber receiver to the transfer station. Each data packet received at the transfer station is thus retransmitted at three different times to the mobile subscriber station on a CDMA link.

Abstract: An antenna system (20) in transponder article surveillance and identification system (10) employs a separate interrogating transmitting antenna (31) and interrogating receiving antenna (41) both of which are circularly polarized in opposite hand senses whereby very little of a transmitted electromagnetic interrogation signal is coupled to the interrogation receiving antenna (41) and reflections from nearby surfaces are transparent, significantly improving system performance. Interrogating transmitting antenna (31) and interrogating receiving antenna (41) are cavity-backed, crossed-dipole-fed antennas producing a substantially hemispherical radiation pattern. Transponder (11) is mounted together with a dipole antenna (50) on a tag (13) carried on each article to be identified.

Abstract: A reference signal used for orienting an object has a beam of electromagnetic radiation with a first signal component that is a rotating component and also a second signalcomponent which is periodically generated when the first signal component is in a predetermined direction. The beam may be a linearly polarized laser light beam with a rotating plane of polarization, an unpolarized laser light beam with a rotating and shaped image of predetermined configuration, or a linearly polarized microwave beam with a rotating plane of polarization. The second signal component may be generated as a component of the beam bearing the first signal component or separately generated and propagated. Provisions are made for receiving and comparing the direction indicated by the reference signal with the direction of the object to be oriented and the information derived from the comparison is analyzed and processed to provide an output signal that useful in orienting the object.