Abstract: A phased array, phase-amplitude monopulse antenna arrangement for ground, shipboard or airborne radar systems. The phased array antenna is systematically warped and projects partially overlapping, separate beams from upper and lower regions of the array. A single set of phase-shifters is employed with a simplified feed structure to permit development of both azimuthal and elevation angle error signals in signal processing circuitry for target analysis.

Abstract: A process is proposed for determining the radio reception direction on the downlink at a radio base station location, comprising a plurality of radio coverage areas, in a mobile communications network, in which in each area on the downlink radio signals are radiated by means of a transmitting antenna for reception by at least one mobile communications terminal. For the determination of the radio reception direction, at least the reception levels of the radio signals radiated by a first and a second of the transmitting antennae are measured by the relevant mobile communications terminal. From the two measured reception levels, a ratio value is formed which is independent of the prevailing radio propagation conditions, and this ratio value is used to effect an estimation of azimuthal angles for the radio reception direction to be determined. The invention can thus be implemented in any individual radio base station location, it being unnecessary for there to be contact with a plurality of radio base stations.

Abstract: A monopulse radar system aims to correct an amplitude error and a phase error developed between receiving channels and improve the accuracy of a detected angle. To achieve the above aim, part of a transmit signal is supplied to respective channels on the receiving side through a signal transmission line for calibration. At this time, the gains of a variable phase shifter and a variable gain amplifier are adjusted so that an azimuth angle of a pseudo target, based on a signal for calibration, which is calculated by signal processing means, reaches a predetermined angle. Therefore, calibration work is simplified and an angular correction can be automated. Therefore, the present monopulse radar system is capable of coping even with variations in characteristic after product shipment due to environmental variations and time variations in parts characteristic.

Abstract: In regard to radar guidance of a launch container (15) for fragmentation projectiles (16) for defending against an attacking missile (12), from the object (11) to be protected, the present invention affords a radar guidance system which can be inexpensively set up from existing components and which, in the absence of interfaces between the object (11) and the launch container (15), operates in a trouble-free manner if, for space monitoring and target acquisition, provided on the substructure (14) of the launch container (15) which is fixed with respect to the object, there is a planar antenna (20) which transmits its target information to a target-tracking radar (19) which is integrated into the launch container (15), for directly guiding the launch container (15) on to the approach of the missile (12) to be defended against.

Abstract: The invention relates to a borehole radar tool comprising, in a housing (2) a transmitting antenna and a receiving antenna both of which comprise, near the housing wall (2), a dipole antenna (8) and a reflector (10) opposite thereto. Also provided are an algorithm, method and apparatus for determining electromagnetic contrast information of a site into which electromagnetic fields (27) are emitted. Signals (29) generated by induction are intercepted and, using a back-projection algorithm including a suitable weighting factor, are converted into contrast information. The algorithm and/or method can be recorded in a computer program or on a data carrier. Also disclosed is a method of determining said weighting factor. The invention further provides a method and apparatus for subsurface surveys in which electromagnetic pulse signals are emitted.

Abstract: An aircraft phased array antenna system has transmit and receive antenna structures externally mounted on the aircraft fuselage. Each antenna comprises a plurality of phased array elements and antenna power and support equipment. Aerodynamically shaping antenna structure to enclose an antenna element grid provides additional antenna structure volume, which is efficiently utilized by locating antenna support equipment within the antenna structure. To control signal attenuation a receive antenna internal converter converts receive frequency signals to L-band frequency signals for aircraft use, and a similar transmit antenna converter converts L-band frequency signals to transmit frequency signals, thus unconstraining antenna to internal aircraft equipment spacing. To reduce power loss and cabling weight, antenna operating power is first generated in the 28 to 270 volts DC range within the aircraft, and locally converted in each antenna to the 3 to 6 volt DC power to operate each antenna's phased array elements.

Abstract: The Ground Penetrating Radar (GPR) system introduced in this application provides data from an underground medium of the same caliber as that provided by conventional radars in air or space applications. This includes direction as well as distance to all targets, and some indication of target shape and orientation, within a conical volume of the underground having a solid angle of about 90 degrees and a radial depth of about 100 feet, under ideal conditions, as depicted in FIG. 9. The key to this capability is depicted in FIG. 3, and is a hemispheric dome (6) which is placed against the smoothed surface (1) of the underground medium (2), and which has a relative dielectric constant (ER) substantially equal to that of the underground medium (2).

Abstract: A passive MMIC monopulse comparator includes a plurality of lumped element hybrids having pi and T filter structures. In one embodiment, a first hybrid receives first and second downcoverted signals and provides a first output signal to a third hybrid and second output signal to a fourth hybrid. A second hybrid receives third and fourth downconverted signals and provides respective third and fourth output signals to the third and fourth hybrids. The third hybrid provides sum and elevation channel signals and the fourth hybrid provides azimuth and G channel signals.

Abstract: A wireless tracking system consists of a wireless target including a wireless communication system for transmitting a data packet over a communication path, and a locating station for determining a position of the target. The data packet transmitted from the target includes an identification code uniquely associated with the target. The locating station includes a configurable directional antenna, a communication interval processing system, a direction processing system, and a position processing system. The communication interval processing system is in communication with the directional antenna and determines the transmission interval of the transmitted data packet over the communication path. The direction processing system determines the transmission angle of the communication path, and is in communication with the directional antenna for controlling the configuration of the directional antenna so as to facilitate the determination of the transmission angle.

Abstract: In a radio communication apparatus, delay profiles of a desired wave and delay waves thereof are estimated by plural delay profile estimation sections for each of received signals from directional antennas constituting an array antenna. Received signals from the antennas selected by a reception antenna selector on the basis of the delay profile are subjected to a temporal/spatial equalization processing by an adaptive signal processing section and a path diversity combining section, thereby obtaining a reception output. An arrival angle range of the desired wave is estimated by a DOA estimation section from the delay profile estimated by the delay profile estimation section. Based on the arrival angle range, the antenna for transmission is selected by a transmission antenna selection section, and transmission signals are sent out.

Abstract: A system for monitoring of the position of at least one portion of an object. The system includes a plurality of transmitters operative to transmit alternating magnetic fields within a three-dimensional space, and at least one positioning sensor arranged to be fixed to at least one corresponding portion of the object whose position it is sought to monitor. Each of the positioning sensors includes a magnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axes respectively, of the alternating magnetic fields.

Abstract: A monopulse source for a focal feed antenna including at least two waveguides machined in a metal flange supporting a microwave transmission and reception circuit of the antenna, and a dielectric substrate on the metal flange. Also included is a microwave short-circuit having an opening with a smaller dimension than a dimension of a respective waveguide. The microwave short-circuit is mounted on the dielectric substrate such that an axis of the microwave short-circuit coincides with an axis of the respective waveguide. Further, a transition positioned on the dielectric substrate and within the opening of the microwave short-circuit is configured to couple the respective waveguide.

Abstract: A monopulse antenna system comprising an inner antenna and an outer antenna disposed symmetrically about a central axis of symmetry. A central aperture is located at the axis of symmetry through which a weapon system may fire or an additional sensor may be located. The inner antenna is preferably annular in shape and produces a relatively broad antenna pattern. The outer antenna is also preferably annular and produces a beam pattern with many lobes. The received signals A and B, from each beam pattern, are combined in a hybrid to produce sum signals (A+B) and difference signals (A−B), which are then processed to produce a target off-axis radius relative to the antenna main beam axis, i.e., the axis of symmetry.

Abstract: A divergence measurement antenna for single-pulse radars comprises at least two radiant panels. With their beams having the same center of phase, they are oriented differently. A monotonic function of the angular divergence of a signal received by the antenna is obtained from the ratio of the power of the signal received by the first panel to its power received by the second panel. An even-parity function of the signal received is obtained by taking the sum of these two signals. Application to precise measurements of angular divergence.

Abstract: A compact RF monopulse receiver circuit having a relatively low noise figure which is particularly useful for operation in the millimeter wave frequency range is described. The compact monopulse receiver finds use in small projectile and small missile applications. Also, a combination of transmit signal protection circuitry and receiver circuit architecture allows the RF monopulse receiver circuit to operate in a missile or other projectile which utilizes high RF power transmit signals. The RF monopulse receiver circuit can directly provide a radiation pattern for target detection and tracking or alternatively, the RF monopulse receiver circuit can function as a monopulse feed circuit which can be used, for example, in a quasi-optically fed reflector antenna.

Abstract: Millimetric wave device, capable of operating as a signal transceiving antenna, with an optimum image definition even at extremely short distances (about 1 mm). Depending on the more or less concentration of the waves, the so realised radar antenna adopts, in its different configurations, a curved front optics, or an optics of hemispherical, aspherical, parabolic, concede, convex, biconcave, biconvex or stepped optics. The real focal length of the radar is shorter than that of the lens utilised in the antenna. The standard dimensions of the electronic transception and processing circuit part are very limited and contained.

Abstract: An apparatus according to various aspects of the present invention is configured to collect and/or emit electromagnetic waves, particularly microwaves. In one embodiment, a transducer system includes an integrated waveguide, transducer, and processing circuit. The processing circuit is disposed between two plates which also serve to define the waveguide. The transducer, such as an E-field probe, is disposed in the waveguide to collect or emit electromagnetic waves such as microwaves. The transducer is directly connected to the processing circuit within the integrated unit.

Abstract: This radar with a wide instantaneous angular field and a high instantaneous angular resolution, in particular for a missile homing head, includes essentially:a transmitting antenna with a relatively wide radiation pattern, transmitting a quasi-continuous wave;a receiving antenna including a plurality of radiating elements;means for formation of beams associated with said receiving antenna, to achieve a linear combination of the signals from the various radiating elements of said receiving antenna, in order to obtain a group of simultaneous reception beams allowing the instantaneous scanning of the airspace covered by said transmitting antenna.

Abstract: A planar array antenna comprises a plurality of antenna elements disposed in a predetermined matrix pattern. Feeders extend from a feed to the antenna elements. High-frequency switches cooperatively open or close the feeders connected to antenna elements of at least one row of the matrix pattern located at both a right-end and a left-end regions of an antenna surface. Switching signals are supplied to the high-frequency switches from switching terminals for alternately activating the associated antenna elements, thereby providing two time-divisional array antennas offset in position by a distance corresponding to the width of at least one row of the antenna elements controlled.

Abstract: The process and the corresponding phase or amplitude-single pulse radar device are used to locate a first and possibly a second target (TT1, TT2) detected by the radar beam from the direction x1, y1; x2, y2. The extended single-pulse aerial of the radar device has at least three partial aerials for a first measuring axis x (e.g. azimuth) which are arranged in such a way, have such directional characteristics and the signals of which are combined together and weighted in such a way that two mutually linearly independent, purely real or purely imaginary aerial functions which are independent of target displacements perpendicular to the first measuring axis are formed. The function course of these aerial functions F1(x) and F2(x) is measured for the individual case and the functional values dependent upon the target displacement x are stored in the storage unit (MEM). Measurements are found for the targets of the position x1 and x2 detected by the radar beam according to the aerial functions F1 and F2.

Abstract: A beam sharpened, low sidelobe antenna is obtained by segmenting the antenna to provide two sub-antennas, one of which is arranged as an interferometer. The output signals of the two antennas are added and subtracted to provide sum and difference signals. The sum and difference signals and the output signals are then utilized to provide the desired beam sharpened, low sidelobe antenna.

Abstract: This invention relates to a method and apparatus by which a coarse estimate of radar signal polarisation can be obtained. An array comprises at least three differently directed detectors. The polarisation is estimated by measuring an amplitude relationship, such as a ratio of amplitudes, for two adjacent detectors and for two non-adjacent detectors. This provides sufficient information to obtain a coarse estimate of the polarisation state, obtainable by using the value of the amplitude relationship for the two adjacent detectors together with a look-up table to estimate values of the amplitude relationship for the two non-adjacent detectors for different polarisation states, and then comparing the measured and estimated values for this amplitude relationship.

Abstract: A planar edge-slotted and end-fed traveling wave antenna is designed for monopulse operation, with an odd array of parallel elements interleaved with an even array of parallel elements. The even elements have an amplitude taper that is an arithmetic sum of Taylor and Bayliss amplitude tapers, while the odd elements have an amplitude taper that is an arithmetic difference of the Taylor and Bayliss tapers. Transmit energy is fed to both the odd and even elements, and the resulting radiation produces a pencil beam of a predetermined beamwidth for illumination of a distant target. The return excitation for the odd and even elements is combined to produce sum and difference monopulse patterns.

Abstract: A balanced receive antenna circuit configuration determines an accurate position of a transponder within the antenna field pattern of the reader antenna. The balanced receive antenna configuration consists of two antennas physically rotated 90 degrees relative to one another, disposed concentrically on top of one another. Furthermore, each receive antenna consists of two coils located a predetermined distance apart. The optimum distance separating the coils is determined by trading off zero position detection with the transponder detection range. A third receive reference antenna is concentrically disposed, sharing the same horizontal plane with the balanced antenna coilsets. The transmitter antenna is disposed separately from the receive antennas. In operation, initially the transmitter antenna sends a power burst signal for a predetermined duration to charge up the transponder to the maximum charge possible.

Abstract: A radar apparatus provided with a Cassegrain antenna to be mounted on the barrel of a gun. The Cassegrain antenna is of the polarization twist type with a flat adjustable mirror being used to generate a lead angle. In addition, gun-induced vibrations transmitted to the Cassegrain antenna are compensated by adjusting the flat mirror so that the radar beam generated by the Cassegrain antenna is not susceptible to these vibrations.

Abstract: A dual channel monopulse transceiver is described for use at millimeter wavelengths and for the detection of targets for vehicle collision avoidance. A microstrip antenna is located on one side of a plate and a transceiver microstrip circuit coupled to the antenna is located on the other side of the plate. The transceiver includes a reflective balanced mixer, an isolated balanced mixer and a hybrid circuit for connecting the mixers to antenna feed points. Sum and difference signal generating circuits are employed to provide single and split antenna beams for the detection of targets.

Abstract: The invention includes an arrangement of actual sensors in an antenna array with a computation of higher-order statistics to provide virtual second order statistics corresponding to virtual elements in the array; employment of the actual and virtual elements of the array for covariance based direction finding; and, with the addition of a separate sensor spaced from the main array, suppression of non-Gaussian measurement noise. This is accomplished employing cross-correlation of the virtual sensors or alternately calibrating the existing actual array employing cross-correlation of the array and it's virtual sensors.

Abstract: A dually polarized monopulse feed system for processing radar signal information from a target so the target may be identified and tracked includes a symmetrical multimode input waveguide, a coupler for separating polarized modes of signal waves to identify and track the target, waveguides for rejecting and terminating selected polarized modes of signal waves, and a backshort for reflecting selected polarized modes of signal waves.

Abstract: A monopulse tracking apparatus comprises first to fourth electromagnetic horns disposed symmetrically to each other in an azimuthal direction and elevation direction in a 2.times.2 matrix state, a first hybrid circuit for creating the sum signal and difference signal of the first and second electromagnetic horns, a second hybrid circuit for creating the sum signal and difference signal of the third and fourth electromagnetic horns, a third hybrid circuit supplied with the respective sum signals of the first and second hybrid circuits and for outputting the sum signal and difference signal thereof, a fourth hybrid circuit supplied with the respective difference signals of the first and second hybrid circuits and outputting the sum signal and difference signal thereof, and a fifth hybrid circuit for creating the sum signal and difference signal of the first and fourth electromagnetic horns or the second and third electromagnetic horns.

Abstract: An antenna beamformer is provided for coupling to a circular antenna aperture comprising a plurality of vertical beamformers and four horizontal beamformers coupled to the vertical beamformers so that each horizontal beamformer has the capability to form a different predetermined electromagnetic field radiation pattern.

Abstract: A method and apparatus to determine angles .theta..sub.1 and .theta..sub.2 between paths of two sets of reflected radar waves and a radar boresight utilizes the electrical angles .beta..sub.1 or .beta..sub.2 and two successive radar target observations. One set of radar waves may travel a path from a target and the second set may travel a multipath from the same target. Alternatively, the two sets of radar waves may follow direct paths from two targets. For coherent radar hardware, signals from two halves of an array are processed through a linear coherent receiver, analog-to-digital converter and processing unit with associated memory. The memory contains a database and program which calculates the electrical angles .beta..sub.1 and .beta..sub.2 and angles .theta..sub.1, and .theta..sub.2. For non-coherent radar hardware, mixers, a phase detector and two magnitude detectors are substituted for the linear coherent receiver.

Abstract: A planar array of linearly polarized antenna elements, each element tilted so that its polarization orientation is disposed at an angle with respect to the array vertical axis so that array polarization loss is minimized as a function of roll about an array normal. Half of the elements are tilted uniformly at a positive angle with respect to the array vertical axis and the remaining elements are tilted at a negative angle with respect to the array vertical axis. The invention substantially reduces the unwanted variation in received RF energy magnitude as a function of array roll angle caused by polarization loss, for both vertical and horizontal components. The vertically polarized signal component magnitude remains nearly constant with respect to array roll angle values of 50.degree.-60.degree. and more. If the element tilt angle magnitude is between 0.degree.-45.degree.

Abstract: An antenna distribution network for an antenna array which provides independent sum and difference aperture excitations and enables a reduction in the difference channel radiation sidelobe levels. The circuit operates to smooth out the step discontinuity in the complex signal excitation of the radiating aperture in the difference mode by reducing considerably the amplitude of at least two corresponding elements located on opposite sides of the array center. A circuit of four four-port hybrid devices is employed, and introduces no effect when in the sum mode.

Abstract: A pulse radar for operation at 94 GHz and higher frequencies is shown to include an antenna, a diplexer and first detector that are each optically fed so that radio frequency signals may be, when transmitting, passed through the diplexer to the antenna and, when receiving, from the antenna through the diplexer to the first detector.

Abstract: A transmit/receive system for electromagnetic radiation, particularly radar, employs an array of active transmit/receive (T/R) modules. Only a portion of the modules are actuated to transmit or receive signals at any given time. Input transmit power is supplied to all modules, but only the selected portion of modules actually amplify their inputs. The power loss is thus kept small because the amplified signal power far outweighs the lost input power. This approach makes possible a monopulse signal routing scheme that minimizes the number of switches used and their accompanying reliability problems. Transmit and receive signals are routed through sum-and-difference circuits and respective sectors of the T/R modules such that during RECEIVE no switches are necessary to acquire a monopulse sum (.SIGMA.) signal, and only a single switch is required to acquire a monopulse difference (.DELTA.) signal. Similarly, no switching of module inputs is required during TRANSMIT.

Abstract: A pulse radar for operation at 94 GHz and higher frequencies is shown to include an antenna, a diplexer and first detector that are each optically fed so that radio frequency signals may be, when transmitting, passed through the diplexer to the antenna and, when receiving, from the antenna through the diplexer to the first detector.

Abstract: A mode coupler for monopulse applications in an antenna feed system which is used for obtaining angle deviations in azimuth and elevation, and which has a main wave guide in which a plurality of electromagnetic wave modes can be propagated. The mode coupler also has a plurality of mode-selective in/out coupling ports which are all formed as simple standard wave guides mounted on the main wave guide, and in which only the H.sub.10 mode is propagatable. A separator plate is disposed in the main wave guide to convert the (H.sub.11 +E.sub.11) mode into two phase-opposed wave guide waves and, via a coupling loop, to couple them into a second wave guide mounted laterally on the main wave guide. The front edge of the separator plate forms a reflector for the H.sub.01 mode, and the reflected HO.sub.1 wave is coupled out of the main wave guide by a pair of wave guides mounted symmetrically on the main wave guide and connected via an H-plane junction to a common output wave guide.

Abstract: A monopulse antenna feed system utilizing multiple modes within the feed. A TEM mode and two TE.degree..sub.11 modes that are orthogonal and in phase quadrature are utilized in the antenna feed system to provide tracking information and data communication from a far-field source of circularly polarized radiation. The output from a port that is responsive to the TEM mode is compared with the output from a port that is responsive to the TE.degree..sub.11 modes to obtain tracking information and the output from the latter port also provides a channel for communication of data. The phase of the TEM mode relative to the phase of the TE.degree..sub.11 modes is indicative of the angular rotational position of a far-field source relative to the axis of the feed system and the relative amplitude of the TEM mode is indicative of the angular displacement of the far-field source away from the axis of the feed system.

Abstract: An architecture for a monopulse, active aperture array is provided which functions as a high precision error compensation system correcting both the Sum and the Difference beams simultaneously. The architecture incorporates; a radiating antenna, a transmit-receiver, a -3.01 dB Wilkinson divider operable to split the signal received from the transmit-receiver, a Sum plus Difference network, a Sum minus Difference network both of which accept the split signal from the -3.01 dB Wilkinson divider and simultaneously error compensate the beams, and a four port magic tee operable to output the error compensated signals from the Sum plus Difference network and the Sum minus Difference network.

Abstract: The invention described herein relates generally to the field of signal processing for signal reception and parameter estimation. The invention has many applications such as frequency estimation and filtering, and array data processing, etc. For convenience, only applications of this invention to sensor array processing are described herein. The array processing problem addressed is that of signal parameter and waveform estimation utilizing data collected by an array of sensors. Unique to this invention is that the sensor array geometry and individual sensor characteristics need not be known. Also, the invention provides substantial advantages in computations and storage over prior methods. However, the sensors must occur in pairs such that the paired elements are identical except for a displacement which is the same for all pairs. These element pairs define two subarrays which are identical except for a fixed known displacement.

Abstract: A monopulse antenna feed system utilizing multiple modes within the feed. In one embodiment a TEM mode and one or two TE.phi..sub.11 modes are utilized in the antenna feed system to provide a data and a reference signal responsive to the one or two TE .sub.11 modes and to provide an error indicating signal responsive to the TEM mode that provides monopulse tracking operation. The relative phase of the TEM mode and the one or two TE .sub.11 modes is indicative of the off-axis orientation of a far-field source relative to the axis of the antenna system. The relative amplitude of the TEM mode is indicative of the angular departure the source from the axis.

Abstract: Two distinctly polarized monopulse signals are orthogonally superimposed using antennas spaced in pairs which are transversely aligned. Signals from the pairs are separately summed and differentiated. Signals from both pairs are summed in one system. A transmitter supplies pulses directly to one pair and through a 90.degree. phase shifter to the other pair.

Abstract: A compact, dual series waveguide feed network is disclosed which has application to monopulse radar antennas and is usable in applications requiring compact and light weight feed networks. The network in accordance with the invention uses phase shifters at the phase reversal points of the secondary (42) feed lines to establish a 180.degree. relative phase difference with the corresponding phase reversal point of the primary feed line. No phase shifters are used in the crossguide feed lines (44). Because of the invention's phase shifter arrangement, crossguide lines (44) may be located directly opposite each other instead of being staggered as in prior techniques; hence the size of the network is reduced and resolution is increased. Also, the primary and secondary feed lines may be located closer together because there are no phase shifters with associated matching and transition devices located in the crossguide feed lines.

Abstract: An omni-directional scanning group antenna with electronically phase-control beam for precise target locating or target tracking comprising a plurality of line fed individual radiators (1) distributed within the volume of an imaginary three-dimensional body (2) such as a sphere which is divided into eight separate sub-volumes V1 through V8 forming octants wherein the signals SV1 through SV8 of the octants ae combined with a circuit (4) comprising eleven sum-difference elements so as to form one sum signal, one elevation difference signal and two azimuth difference signals. The invention is suitable for application in three-dimensional phase-array antennas for all-around scanning with precise target locating and target tracking.

Abstract: A monopulse comparator is formed by milling grooves in opposed surfaces of aluminum circular blocks. The milled grooves define a number of waveguides, ports and hybrid junctions. A, B, C and D ports are coupled by respective waveguides to respective side branches in first and second hybrid rings. The series branches of these hybrid rings are coupled by respective waveguides to parallel and series branches respectively of a third ring hybrid ring. One side branch of this hybrid ring is coupled to an azimuth differential port by one of the waveguides. The other side branch is coupled to a termination by a waveguide. The parallel branches of the first and second hybrid rings are coupled by respective waveguides to respective side branches of a fourth hybrid ring. The parallel branch of this hybrid ring is coupled by a waveguide to the elevation differential port. The series branch of this hybrid ring is coupled by a waveguide to the sum port.

Abstract: A cylindrical cavity-backed multipole antenna system for high frequency applications is disclosed. The antenna system comprises a plurality N of planar radiation elements disposed on a dielectric disc mounted on the top surface of a conductive cylindrical cavity and equally spaced about its axis. A network circuit is adapted to introduce, for the system sum signal, progressive phase shifts of 360.degree./N to signals associated with adjacent elements and, for the difference signal, progressive phase shifts of 720.degree./N. The antenna system may be used to both transmit and receive electromagnetic radiation. The antenna sum and difference patterns are substantially symmetric in space about the antenna boresight.