Abstract: A method for processing radar return data to determine a physical angle, in aircraft body coordinates to a target, is disclosed. The radar return data includes a phase difference between radar return data received at an ambiguous radar channel and a left radar channel, a phase difference between radar return data received at a right radar channel and an ambiguous radar channel, and a phase difference between radar return data received at a right radar channel and a left radar channel. The method includes adjusting a phase bias for the three phase differences, resolving phase ambiguities between the three phase differences to provide a signal, and filtering the signal to provide a physical angle to the target in aircraft body coordinates.

Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.

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.

Abstract: A method and bistatic synthetic aperture radar (SAR) imaging system generate an image of a target area without knowledge of the position or velocity of the illuminator. The system includes an illuminator to illuminate a target area with a null-monopulse radiation pattern interleaved with a sum radiation pattern. The illuminator adjusts the phase terms of the sum radiation pattern to maintain a static electromagnetic field pattern at the target area. A receiver receives the radiation patterns reflected from the target area and generates phase compensation terms by correlating a measured electromagnetic vector field with the known static electromagnetic vector field. The phase compensation terms are used to generate an image of the target area.

Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.

Abstract: A method, apparatus, and processing system for radar detection and tracking of a target using monopulse ratio processing comprising the following steps. First, receiving a signal comprised of a plurality of sum azimuth beams and difference azimuth beams. Then staggering the received signal. Next, filtering and localizing a clutter signal which is a portion of the received sum and azimuth beams. Then adaptively forming a sub-array sum azimuth beam and a sub-array difference azimuth beam from the filtered output to cancel the clutter. The adaptive beam forming including the determination of a sum and difference beam weight where the adaptive weight be equated to a product of the weight and the respective covariance matrices of the sum and difference beams, the product having no constraint points.

Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.

Abstract: A process and a device for electromagnetic guidance of a craft, applied in particular to the tracking of targets. Guidance is carried out with respect to the axis of the beam of a monopulse antenna, by coding in space of the beam. The coding is carried out by appropriate modulation of the signals radiated by a sum pattern and difference pattern. A receiver is disposed in the craft to make it possible to determine the position of the craft with respect to the antenna radiation patterns, and hence its position with respect to the axis of the antenna, the determination of this position being performed by demodulating the signals captured by the receiver. The process and device may be applied in particular in respect of the guidance of any number of missiles or intelligent munitions, for example in the tracking of targets.

Abstract: In a radar system, sampled aperture data are received from an antenna array. The sampled aperture data include data that do not correspond to echo returns from a beam transmitted by the antenna. A covariance matrix is generating using the sampled aperture data. An eigenvalue decomposition is performed on the covariance matrix. A direction of arrival is determined from which at least one jammer is transmitting a signal included in the sampled aperture data, based on the eigenvalue decomposition.

Abstract: A radar system including a blanker and a sidelobe canceler is described including an open loop nulling circuit for introducing one or more nulls in the main beam and a blanker beam. With this arrangement, the blanker can be operated even in the presence of strong sidelobe jamming without the conventional problems attributable to noise amplification. Also described is an antenna configuration for implementing the open loop nulling, including a pair of orthogonal linear arrays. One of the arrays is omnidirectional in azimuth and directional in elevation and the other array is omnidirectional in elevation and directional in azimuth in order to point the main and blanker beams in the direction of jammers. In one embodiment, the radar system further includes a spoofer and the crossed linear arrays process the spoofer signals on transmit and process blanker signals on receive.

Abstract: A radar system and technique provide the capability to detect a target of interest and maintain the detection in the presence of multiple mainlobe and sidelobe jamming interference. The system and technique utilize the versatility of digital beamforming to form sub-arrays for canceling jamming interference. Jamming is adaptively suppressed in the sub-arrays prior to using conventional deterministic methods to form the sum, &Sgr;, and difference, &Dgr;, beams for monopulse processing. The system and technique provide the ability to detect a target of interest, provide an undistorted monopulse ratio, m, and maintain target angle estimation, in the presence of multiple mainlobe and multiple sidelobe jammers. Further, this system and technique are not constrained by requiring a priori knowledge of the jamming interference.

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 circuit (100) for performing base 10 logarithmic calculations of a binary signal in a digital system that optimizes accuracy of the calculation. The circuit comprises a priority encoder (108) for determining a most significant bit position of the binary number, with the most significant bit representing a base 2 logarithmic integer component of the input binary signal. A decimal selector (120) selects a predetermined number of bits to follow the base 2 logarithmic integer component determined by the priority encoder, with the predetermined number of bits representing a base 2 logarithmic fractional component following the integer component of the input binary signal. An adder (116) combines the integer component with the fractional component to thereby output a base 2 logarithmic value of the input binary signal. A multiplier (132) divides the base 2 logarithmic value of the input binary signal by a base 2 logarithmic value of 10 to thereby output a base 10 logarithmic value of the input binary signal.

Abstract: A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle &agr;. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle &agr; is obtained for each cutting plane.

Abstract: An antenna array system with dynamic signal routing to a set of receivers. A monopulse electronically scanned antenna (ESA) has a plurality of antenna elements divided into subarrays. ESA beam steering phase shifters are associated with the respective subarrays of antenna elements, such that the output signals from the respective antenna elements associated with the respective quadrants are phase shifted and summed to provide respective subarray signals. A monopulse network responsive to the subarray signals provides monopulse outputs to a set of receivers. A beam steering controller provides phase shift commands to the ESA phase shifters to set the phase shift associated with the respective phase shifters of the subarrays. The controller commands the ESA phase shifters to modulate the phase shift of selected quadrants.

Abstract: A method and system for identifying the locations of plural targets lying within a main beam of a monopulse antenna including four ports for generating sum, elevation difference, azimuth difference and double difference signals. The method comprises the steps of forming a monopulse ratio matrix from the sum, elevation difference, azimuth difference and double difference signals; and determining eigenvalues of the monopulse ratio matrix. These eigenvalues are then used to determine the angular locations of the plural targets. Preferably, the eigenvalues are determined by performing an eigenvalue decomposition of the monopulse ratio matrix to generate eigenvalues, and the angles of the targets may be determined from the eigenvalues by the use of a look-up table.

Abstract: A method and apparatus are provided for determining whether a signal received the main channel (2) of an antenna (1) was incident on the antenna (1) in a direction corresponding to a high gain main lobe. A sidelobe suppression signal is generated from signals received from a other channels at least some of which are derived from elements where output generates the main channel, the signal being categorized as originating from a direction corresponding to the high gain main lobe of the main channel by comparing the value of the signal received on the main channel with that of sidelobe suppression signal.

Abstract: A radar system includes a null processor coupled to transmit receive modules. The null processor inserts nulls in the sum pattern at locations for suppressing a jamming source. The null processor determines the difference pattern based upon the product: sum*sin(x), where sum is the sum pattern and x is the azimuth angle.

Abstract: A method and system for identifying the locations of plural targets lying within the main beam of a monopulse antenna including four ports for generating sum, elevation difference, azimuth difference, and double difference signals. The method comprises the steps of processing the sum, elevation difference, azimuth difference, and double difference signals in accordance with a series of linear equations to obtain a set of intermediate values; and processing the set of intermediate values in accordance with a set of algebraic equations to obtain signals representing an angular direction of each of the plural targets. Preferably, the method further includes the step of processing the sum, elevation difference, azimuth difference and double difference signals and the signals representing the angular directions of the targets according to a further set of algebraic equations to obtain signals representing the amplitude of the beam reflected from each of the targets.

Abstract: A radar apparatus is provided which is capable of discriminating between azimuth angles of two or more targets moving side by side close to each other. The radar apparatus provides antenna beams which partially overlap with each other to define a plurality of monopulse areas and processes input signals produced in each of the monopulse areas to obtain angular direction data. The radar apparatus determines a time-sequential variation in angular direction data in each of the monopulse areas and determines the angular direction data whose variation is within a preselected allowable range as being effective in determining the angular direction of each target correctly.

Abstract: A technique is described which makes novel use of monopulse data to augment the normal CFAR detection processing by incorporating monopulse data in a computationally simple way into the detection decision process such that off-axis signals which are of sufficient strength to pass a CFAR detection threshold are effectively rejected by a second detection threshold. The signal compared to the second detection threshold is formed from all of the monopulse channels. Detection processing is thus a two step process, incorporating not only the information contained in the magnitude of the Sum channel, but information contained in all of the monopulse channels.

Abstract: A method is provided of optimizing, within an area which itself contains a number of part areas, the coverage of a sensor which has an angle-dependent range in a least one plane, and which sensor is in addition arranged on a mobile platform. The method includes determining at least two movement directions for the sensor platform, determining a center of movement for the two movement directions, and also determining periods of time during which the sensor platform is to move in each of the two movement directions. The center of movement of the platform is preferably located within the search area.

Abstract: A radar apparatus comprising: a receiving antenna having an array antenna in which a plurality of antenna elements are arrayed in a horizontal direction; and a signal processing section for carrying out recognition of a target existing in a predetermined horizontal bearing range from receive signals received by the receiving antenna, by electrically carrying out horizontal scanning of an antenna pattern of the receiving antenna, wherein at least one of the antenna elements is placed with a shift in a vertical direction, and wherein the signal processing section detects an altitudinal bearing of the target by a monopulse method by use of a receive signal from the antenna element with the shift in the vertical direction.

Abstract: Apparatus for determining positional information for an object transmits a probe signal towards the object. The probe signal as returned by the object is received at a plurality of spaced apart locations. The relative timing of the returned probe signals as received at the plurality of locations is detected, whereby positional information for the object can be determined. A number of realizations of the invention are disclosed.

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 dual beam monopulse antenna system includes a flat plate antenna (10). The antenna (10) comprises a plurality of slotted waveguides (20) which transmit radiation through slots (28). The antenna is divided into quadrants (12, 14, 16, 18) for monopulse operation. Each of the quadrants is provided with primary and secondary feed lines which are connected through directional couplers (42-136) to connecting lines (146-192) to the slotted waveguides (20). The primary feed lines (26, 28, 30, 32) are connected to a primary monopulse comparator network and the secondary feed lines (34, 36, 38, 40) are connected to a secondary monopulse comparator network. The summation terminals of the monopulse comparator networks are connected to a switch network (322). The azimuth differential terminals of the monopulse comparator networks are connected to a switch network (332). The elevation differential terminals of the monopulse comparator networks are connected to a switch network (342).

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 sensor performs input pulse deinterleaving based on an angle of arrival (AOA) of each sensed pulse. An AOA determination unit determines an AOA for each received pulse. The pulses are then sorted based on AOA into a number of AOA bins. The data within each bin is then analyzed to determine whether it corresponds to an emitter of interest. Bin data corresponding to emitters of interest are then transmitted to a remote processing facility for additional processing.

Abstract: A processing method or algorithm is for use with a monopulse radar system that provides accurate position information in a cross-range direction for ground moving targets detected using the monopulse radar system. The method corrects the phase of each detected moving target on an individual basis, and thus more accurately compensates for the phase error introduced into each target in a random fashion as a result of noise. The direction of angle correction is determined from clutter data. A gain correction factor includes a term for antenna effects to provide for a more accurate gain correction factor calculation.

Abstract: A method of operating a radar to track echo signals from a target in the presence of a barrage jammer is shown to comprise the steps of actively determining the apparent direction of the combination of echo signals from a target and jamming signals, passively determining the actual direction and average power of a barrage jammer, calculating, from the foregoing, the actual direction of the target and instituting range and angle tracking of the target when the target is clear of the jamming signals.

Abstract: The process is used for suppressing the effect of signals that are received or sent via side lobes of an antenna (PA; HA) of an amplitude or phase monopulse radar device, in which for the purpose of position measurement of a first and, if need be, a second target (T1, T2) detected by the radar beam, three illumination functions Je(Lx), Jk(Lx) and Js(Lx) for the antenna (PA; HA) are provided for each measurement axis, as well as antenna functions Fe(X), Fk(X), and Fs(X) resulting from them. The first, second, and third illumination functions Je(Lx); Jk(Lx), and Js(Lx) are selected in this connection so that a quotient function Qe(X)=Fe(X)/Fs(X) or Qk(X)=Fk(X)/Fs(X), which is linearly or quadratically dependent on the target direction, is produced by normalizing the first and the second antenna functions Fe(X); Fk(X) with the third antenna function Fs(X). The power of this quotient is compared with at least one threshold value th.sub.e or th.sub.

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: A monopulse system generates sum (.SIGMA.), elevation difference (.DELTA..sub.EL), azimuth difference (.DELTA..sub.AZ), and double difference (.DELTA..sub..DELTA.) signals, and generates a covariance matrix. The covariance matrix is decomposed to produce at least the principal eigenvector. The location or angular direction within the main beam of a single target is determined from the real component of the quotient of elements of the principal eigenvector, by the use of a look-up table. In another embodiment of the invention, the eigenvalues are generated from the covariance matrix, and the number of significant eigenvalues determines the number of targets within the main beam. If a single target is found, its location is found as described above. If two targets are found in the main beam, the locations of the two targets are determined by a closed-form solution of quadratic equations.

Abstract: A system and method for estimating azimuth angle, elevation angle and signal detection and which includes an antenna system having a plurality of elements, each element receiving a different concurrent portion of an incoming analog signal having a real and an imaginary portion. A converter is provided for each antenna element for converting each analog signal to digital form. A processor is provide for multiplying the sum of the real parts of the signals from a first group of the elements with the conjugate of the sum of the remainder of the elements to provided an estimated azimuth, elevation of signal detection measurement. In the case of a four element antenna, AzEst=Angle((A+B)*(C+D)Conjugate))=(x.sub.A +iy.sub.A +x.sub.B +iy.sub.B)*(x.sub.C -iy.sub.C +x.sub.D -iy.sub.D), ElEst=Angle((A+D)*(B+C)Conjugate))=(x.sub.A +iy.sub.A +x.sub.D +iy.sub.D)*(x.sub.B -iy.sub.B +x.sub.C -iy.sub.C) and Magnitude ((A+B*(C+D)Conjugate)) or Magnitude ((A+D*(B+C)Conjugate)).

Abstract: A target tracking radar system for a guided missile wherein sum and difference signals from a reception antenna are multiplexed at a variable rate into a single channel receiver, the multiplexing rate depending on an alternating reference signal. The output of the receiver is applied to a phase sensitive detector operating in synchronism with the alternating reference signal and whose output is utilised to guide the missile towards the target. The detector output is also integrated and applied to circuit means which produces the reference signal, thereby forming a closed loop. The integrated detector output is also applied to a servo motor which drives the antenna to track the target.

Abstract: When an IFF system interrogates a target aircraft and receives IFF reply signals, monopulse processing of the reply signals can provide more accurate determination of target azimuth. However, when reply signals have amplitudes close to noise or jamming levels, azimuth processing by non-monopulse techniques such as beamsplitting or center of gravity analysis can provide better accuracy than monopulse azimuth processing. Methods are described to enable adaptive selection of the type of azimuth processing to be employed. Such selection is based on active comparison of received signal magnitudes against monopulse sum and difference signal threshold values and a noise threshold value. Monopulse azimuth processing can thus be used at all times, except when non-monopulse azimuth processing is chosen by such adaptive selection.

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: An inertial navigation system (INS) and a monopulse radar system are mounted on a body. The inertial navigation system outputs at least a velocity of the body. Either a synthetic aperture radar (SAR) map or doppler beam sharpening (DBS) map is created using the outputs of the monopulse radar system. The monopulse radar system outputs at least a summation output, an azimuth difference and an elevation difference associated with an object detected in either the SAR or DBS map. The position processor of the system and method of the present invention, however, only inputs the summation output and one of the azimuth difference and election difference. The position processor determines the other of the azimuth difference and the elevation difference by converting the velocity output by the INS into a doppler angle .theta. (the angle between the velocity, a vector, and a line connecting the object and the body) and determining either the azimuth difference or the elevation difference from the doppler angle .theta..

Abstract: A method and apparatus for improving resolution of targets in a monopulse radar beam.

Abstract: A method for calibrating the radar system includes the steps of: replacing stored statistically generated "average" error correction coefficients with error correction coefficients personal to a missile under test. More particularly, stored in the missile's memory are: (a) first personalized error correction coefficients generated in response to test signals produced internal to the missile and injected into a monopulse arithmetic unit for the missile's receiver/processor; and (b) a second set of personalized error coefficients generated in response to test signals external to the missile and injected through the missile's antenna to the receiver/processor. The missile includes a radio frequency (R.F.) energy test signal generator for performing a test during the missile's flight to determine "in-flight" personalized error correction coefficients. The test is performed in-flight by injecting the R.F.

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 four-port transmission line device that processes two incoming RF signals of arbitrary phase and amplitude to output two corresponding RF signals of equal phase and amplitude. Two sets each of two quarter-wave transmission line segments are connected in series between corresponding input and output ports. A short circuit interconnect shorts together the junctions of the two series connected line segments. A resistive element is connected across the two input ports, and another resistive element is connected across the two output ports. The short circuit interconnection forces the combination of the two input signals into one resultant signal at the short circuited junction. Out-of-phase components of the resultant signal are absorbed in the resistor across the input ports. The remaining in-phase components are divided into two outputs signals of equal phase and amplitude.

Abstract: A secondary radar uses monopulse reception techniques to improve the estimate of the aircraft position and to improve the reliability of the reply decoding process. Digital signal processing techniques are utilized to replace the analog circuit used in the prior implementations. The secondary radar implements monopulse processing using a half angle phase method wherein the sum and difference signals are encoded in a complete phasor. The detection of the signal and extraction of the azimuth angle data is implemented using a digital receiver concept. The complex phasor is sampled at an intermediate frequency, down converted to baseband and detected. The azimuth angle is computed using arithmetic methods implemented by digital signal processing circuitry.

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: Monopulse radar operation is improved by nulling a single mainlobe jammer and multiple sidelobe jammers while maintaining the angle measurement accuracy of the monopulse ratio. A sidelobe jammer cancelling adaptive array is cascaded with a mainlobe jammer canceller, imposing a mainlobe maintenance technique or constrained adaptation during the sidelobe jammer cancellation process so that results of the sidelobe jammer cancellation process do not distort the subsequent mainlobe jammer cancellation process. The sidelobe jammers and the mainlobe jammer are thus cancelled sequentially in separate processes.

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: A multi-mode seeker which comprises a stationary antenna and electronic circuitry responsive to signals received by the antenna to cause the antenna to scan a field of view determined by the signals received by the antenna. The seeker has a nose region positioned at the forward portion thereof and an adjunct sensor disposed in the nose region ahead of the antenna. The electronic circuitry includes circuitry for performing a Sum/Delta monopulse processing technique on the signals received by the antenna the Sum/Delta monopulse processing including calculating each of a standard Sum signal, Delta-Azimuth signal and Delta-Elevation signal. The seeker has a boresight axis, the center of the field of view being off boresight, in general. The seeker has a field of regard, the field of regard having plural sectors, each of the sectors having separate predefined compensation.

Abstract: A system and method that provides for all-weather precision guidance of conventional air-to-surface weapons. The system and method employs a coherent monopulse radar disposed on a launch platform and a noncoherent passive (receive only) radar disposed on the weapon. The synthetic aperture radar generates a synthetic aperture radar monopulse map of an area around the target. The radar is used designate the location of the target, and transmit a sequence of alternating sum and simultaneous azimuth and elevation difference patterns centered on the target. The weapon includes a guidance system and seeker that is responsive to guidance commands transmitted by the synthetic aperture radar. The guidance system and seeker receives reflections of the alternating sum and combined azimuth and elevation difference pattern from the target, and the sum pulse is used by the weapon to acquire and track the azimuth and elevation difference pattern null on the target to fly an optimum trajectory to the target.

Abstract: An antenna system comprising two similar radiation antenna elements with a single monopulse feed system is scanned while transmitting in-phase radio waves from the two elements. Reflected radio waves are received by the two elements and fed to a hybrid circuit which in turn produces a sum signal .SIGMA. and a difference signal .DELTA.. After detection is performed by a detector, a signal processing unit subtracts the difference signal .DELTA. from the sum signal .SIGMA.. In this processing step, the output signal produced by the above subtraction process is actually output only if the receiving pattern waveform associated with the sum signal .SIGMA. has an upwardly convex form, that is, its double differential coefficient is negative and further if the receiving pattern waveform associated with the difference signal .DELTA. has a downwardly convex form, that is, its double differential coefficient is positive, whereby an antenna pattern with beam compression is provided.

Abstract: A radar target discrimination method (50) prevents sidelobe monopulse tracking. The beamwidth difference between the main beam monopulse and sidelobe monopulse is utilized to distinguish the main beam monopulse tracks from sidelobe monopulse tracks. After the first monopulse beam (52, 54), the monopulse beam is moved (58) to two additional beam pointing angles such that the target will stay on the same side of the true main beam monopulse slope but will fall on the opposite side of the sidelobe monopulse slope. The sign and magnitude of the difference/sum (.DELTA./.EPSILON.) measurements (60, 62, 64) can be used to distinguish a valid main beam track from a false sidelobe track. False tracks are detected if the signs of the difference/sum measurements are not identical, or if the magnitudes of the measurements do not monotonically increase or decrease.