Abstract: Each pattern being associated with a reception channel, over a given time period, the unsolicited asynchronous replies, of long ADS-B squitters type, transmitted by targets present in the airborne environment of the radar, are detected, each of the squitters containing position information on the target which transmits it; for each detection, the long ADS-B squitter is decoded to check that the detected target is located in accordance with the position information contained in the squitter, the non-conforming detections being rejected; for each detection retained, the time of the detection, the value of the azimuth of the main beam of the antenna and the received power value on each of the reception channels is associated with the detection, the position information contained in the squitters giving the elevation segment wherein the detection is situated; the values obtained over the period being stored, the measured patterns being sampled, by elevation segment, from the stored values.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may measure a beam quality metric associated with a reference signal for each candidate beam of a plurality of candidate beams. The UE may determine a set of channel characteristics for each candidate beam of the plurality of candidate beams, where the set of channel characteristics indicates to the UE a level of channel equalization by the UE associated with processing signaling on each candidate beam of the plurality of candidate beams. In some cases, the set of channel characteristics may include a frequency selectiveness of a channel for each candidate beam of the plurality of candidate beams. The UE may select a candidate beam from the plurality of candidate beams based on the beam quality metric and the set of channel characteristics and communicate with a base station using the selected candidate beam.

Abstract: A method of correcting a target angle error of a radar sensor, the method may include recognizing a first target angle of a target through the radar sensor; recognizing a second target angle of the target through V2X communication and then calculating a target angle error between the first target angle and the second target angle; comparing the target angle error with a predetermined critical error; and correcting a phase curve of the radar sensor by applying the target angle error to the phase curve in accordance with the comparison result, and then giving a target warning using the corrected phase curve.

Abstract: A cellular radio architecture that includes a multiplexer coupled to an antenna structure and including multiple signal paths, where each signal path includes a bandpass filter that passes a different frequency band than the other bandpass filters and a circulator that provides signal isolation between the transmit signals and the receive signals. The architecture also includes a receiver module having a separate signal channel for each of the signal paths in the multiplexer, where each signal channel in the receiver module includes a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal. The delta-sigma modulator includes an LC filter having a plurality of LC resonator circuits, a plurality of transconductance amplifiers and a plurality of integrator circuits, where a combination of one resonator circuit, transconductance amplifier and integrator circuit represents a two-order stage of the LC filter.

Abstract: A radio communication method includes the steps of: storing a beam having a good characteristic and a beam having a bad characteristic on the basis of a result of beamforming setting; reserving a calibration period; changing a beam to the beam having the bad characteristic in the reserved calibration period; performing calibration in the reserved calibration period; and changing the beam having the bad characteristic to the beam having the good characteristic after the reserved calibration period has elapsed.

Abstract: A first microwave backhaul transceiver may comprise a reflector and a signal processing subassembly. The signal processing subassembly may comprise a plurality of antenna elements positioned at a focal plane of the reflector. The signal processing subassembly may process a plurality of microwave signals corresponding to the plurality of antenna elements using a corresponding plurality of phase coefficients and a corresponding plurality of amplitude coefficients. The signal processing subassembly may adjust a radiation pattern of the plurality of antenna elements during operation of the signal processing subassembly through adjustment of the phase coefficients and/or the amplitude coefficients.

Abstract: The invention relates to a driver assistance device (2) for a vehicle (1), which driver assistance device has a radar appliance (3, 4) for determining at least one measured variable (?1, ?2, R1, R2) referenced to an object (10) that is external to the vehicle, wherein the radar appliance (3, 4) comprises: at least a first and a second reception antenna (14, 15), each for receiving signals (SE1, SE2), a first down-converter (17), which is coupled to the first reception antenna (14) via a first reception path (16), and a second down-converter (23), which is coupled to the second reception antenna (15) via a second reception path (21), each for down-converting the received signals (SE1, SE2) into respective baseband signals (SB1, SB2), and a control device (5) for receiving the baseband signals (SB1, SB2) and for determining the at least one measured variable (?1, ?2, R1, R2) using the baseband signals (SB1, SB2), wherein the radar appliance (3, 4) has test means (32) for producing a local check signal (SP)

Abstract: An adaptive equalizer and an adaptive equalizing method are provided. The adaptive equalizer includes an adaptive equalizing unit, for adaptively equalizing an inputted signal to output the equalized signal; a coefficient updating unit, for updating a coefficient of a filter of the adaptive equalizing unit; a switching unit, connected between the coefficient updating unit and the adaptive equalizing unit and a monitoring device, for controlling on or off of the switching unit in accordance with the fact that a down sampling phase of the inputted signal or a down sampling phase of the equalized signal is within a predetermined range. When the switching unit is on, the coefficient updating unit is capable of updating the coefficient of the adaptive equalizing unit, and when the switching unit is off, the coefficient updating unit is incapable of updating the coefficient of the adaptive equalizing unit.

Abstract: A two stage interference cancellation (IC) process includes a linear IC stage that suppresses co-channel interference (CCI) and adjacent channel interference (ACI). The linear IC stage disambiguates otherwise super-trellis data for non-linear cancellation. Soft linear IC processing is driven by a-posteriori probability (Apop) information. A second stage performs expectation maximization/Baum Welch (EM-BW) processing that reduces residual ISI left over from the first stage and also generates the Apop which drives the soft linear IC in an iterative manner.

Abstract: Provided is an apparatus for channel equalization in frequency domain, including: a channel estimation unit for estimating a channel on received signal from outside, a channel matched filter for changing channel characteristic of the channel estimated by the channel estimation unit and the received signal to channel characteristic to meet condition required for noncausal filtering, a noncausal filter for changing the channel characteristic changed by the channel matched filter from nonminimum phase channel to minimum phase channel, a reverse channel calculation unit for calculating a reverse of the channel changed by the noncausal filter in frequency domain, and a frequency domain equalization unit for performing channel equalization with respect to the channel changed by the noncausal filter in the frequency domain by using the reverse obtained by the reverse channel calculation unit as coefficients of the frequency domain equalization apparatus.

Abstract: In accordance with the teachings described herein, an extended equalizer circuit is provided for equalizing a digital communication signal transmitted over a transmission medium that causes a frequency-dependent attenuation of the digital communication signal. An equalizer may be used that includes a linear equalization circuit and a non-linear equalization circuit, the linear equalization circuit being configured to apply a linear filter to the digital communication signal to compensate for the frequency-dependent attenuation caused by a first portion of the transmission medium, and the non-linear equalization circuit being configured to apply one or more non-linear operations to the digital communication signal.

Abstract: A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface includes a line side interface, a board side interface, and a signal conditioning circuit. The signal conditioning circuit services each of an RX path and a TX path and includes a limiting amplifier and a clock and data recovery circuit. The signal conditioning circuit may also include an equalizer and/or an output pre-emphasis circuit. The limiting amplifier applies respective gains to the RX path and to the TX path that are based upon respective dynamic ranges of the incoming signals.

Abstract: A proposed spread spectrum signal receiver includes a radio front-end unit and a processing unit. The radio front-end unit, in turn, has an antenna, a digitizing circuit and a primary buffer unit. The antenna is adapted to receive radio signals (SHF) from a plurality of signal sources, and the digitizing circuit is adapted to downconvert and filter the received signals (SHF), and generate sample values (SBP-D) thereof. The primary buffer unit is adapted to temporarily store the sample values (SBP-D) from the digitizing circuit and allow the processing unit to read out a first set of stored sample values (SBP-D) contemporaneously with the storing of a second set of sample values (SBP-D) in the primary buffer unit. The processing unit is adapted to receive the sample values (SBP-D) from the primary buffer unit, and based thereon, produce position/time related data (DPT).

Abstract: A surface acoustic wave (SAW) expander based transmitter and correlator based receiver comprises SAW devices that perform expander or correlator functions based on the types of signals inputted to the SAW devices. The SAW devices incorporate chirp with adaptive interference and programmable coding capabilities. The SAW devices and method of operating the devices allow the implementation of very low power radios that overcome problems with temperature drift, lithography constraints and interference and jamming suffered by prior art implementations.

Abstract: Disclosed is a spread spectrum clock generator which includes: a first delay control type oscillator that variably controls an oscillation period at a control period interval according to a control signal; a control circuit; a maximum modulation value determination circuit that determines a maximum modulation value from a predetermined value, a frequency control signal, and a given modulation degree setting signal; a modulation signal generation circuit that receives the maximum modulation value from the maximum modulation value determination circuit and generates a modulation control signal within the maximum modulation value; and a second delay control type oscillator that receives a value obtained by adding the modulation control signal from the modulation signal generation circuit to the frequency control signal as a control signal and variably controls the oscillation period of an output clock signal at the control period interval according to the control signal.

Abstract: Channel quality can be detected accurately in a wireless transmission system such as an HSDPA method. In the case of estimating a channel quality of a signal transmitted by a Code Division Multiple Access method and of estimating the channel quality in a system having a synchronization channel not orthogonal to a channel receiving data, a noise component of a desired channel is estimated; degree of a noise component caused by the synchronization channel is estimated with respect to the estimated noise; and a channel quality of a receiving channel is detected based on the estimated degree of the noise component.

Abstract: A frequency hopping communications system is disclosed. A server is adapted to have one or more radio head interface modules and a call processing software module. The call processing software module performs modulation and demodulation of voice and data streams using one or more air interface standards. A radio head unit is coupled to the radio head interface module over one or more transport mediums and communicates with one or more subscriber units using the one or more air interface standards. The one or more radio head interface modules, are adapted to receive frequency channel hopping information, including a channel and a time to hop trigger, from the call processing software module for one or more of a plurality of communication channels.

Abstract: A code division multiple access (CDMA) communication system using spread spectrum signaling over a communication bandwidth uses two different signal spectra generated using two different respective spreading code formats, such as NRZ code formatting and staggered Manchester code formatting, for respectively providing nonsplit spectra having a center peak and split spectra having a center null. The spectra are combined during transmission as a CDMA communication signal having a composite spectrum. The use of different code formats produces the composite spectrum of respective center peak and center null spectra that enables increased channel capacity.

Abstract: An apparatus and method for channel estimation and CP reconstruction in an OFDM-STBC mobile communication system are provided. An ISI canceller cancels ISI signal components from first and second received symbol sequences. A cyclicity restorer cancels ICI signal components from the ISI-cancelled first received symbol sequence and the ISI-cancelled second received symbol sequence. A recoverer acquires the recovered sequence estimates of the ICI-cancelled first received symbol sequence and the ICI-cancelled second received symbol sequence by decoding. The ICI cancellation of the ISI-cancelled first and second received symbol sequences and the ISI cancellation of the second received symbol sequence are iterated a predetermined number of times.

Abstract: The invention provides an adaptive frequency hopping spread-spectrum (FHSS) transmission system and method, which efficiently utilizes available transmission bandwidth, whilst providing robustness to jamming techniques in wireless communication systems. The proposed technique operates by transmitting a wide-band signal over multiple, single-carrier, parallel transmission subbands, which may occupy non-contiguous frequency regions. The proposed scheme exhibits significant gain in error rate performance, as compared to a data rate equivalent single-subband system in the presence of signal jamming and/or interference without a reduction in the transmission data rate nor an increase in transmitter power. In addition, the proposed system and method are adaptive and enable more efficient use of the available bandwidth for communicating, thus increasing the overall bandwidth utilization of the system.

Abstract: A method and a standard radio wave receiver for receiving a plurality of standard radio waves respectively having signal configurations in accordance with respective specifications which define carrier channels and formats and for decoding time code signals carried by the standard radio waves. The method extracts at least part of a bit waveform common to the specifications as a extracted signal from a waveform of each of the time code signals given by each of the carrier channels, synchronizes bits to each of the time code signals in accordance with the extracted signal, determines an evaluation index indicating good or bad of a reception condition for each of the carrier channels from the bit waveform, and selects a single channel from the carrier channels in accordance with the evaluation index.

Abstract: An ultra wideband (UWB) receiver system operable to process a high order Gaussian pulse includes an integrator group, a correlator circuit and a comparator circuit. The integrator group includes an input coupled to receive the high order Gaussian pulse and an output coupled to the correlator circuit, the integrator group having two or more successively coupled integration stages, each integration stage operable to integrate, over a predefined time period, the signal received thereby, the integrator group operable to output, in response, a lower order Gaussian pulse. The correlator circuit is coupled to receive the lower order Gaussian pulse, and is operable to output a correlated output signal corresponding to the correlation between the lower order Gaussian pulse and a predefined reference signal.

Abstract: A method is presented for packet detection and symbol boundary location using a two-step sign correlation procedure. When the correlation crosses a threshold, a packet detection signal is generated to initiate processing of downstream blocks, and a symbol boundary location signal is generated for use in aligning data during processing.

Abstract: The invention relates to a spread-signal multiplexing circuit for frequency-multiplexing a plurality of spread signals that were generated in parallel according to the SSMA scheme. An object of the invention is to adapt to various degrees of multiplicity and to keep the SN ratio and the power efficiency high. To this end, a spread-signal multiplexing circuit of the invention comprises an amplitude monitoring part for multiplexing a plurality of spread signals and determining amplitude of a resulting signal in time-series order; a delaying part for delaying the spread signals in parallel by a time that is equal to a propagation delay time of the amplitude monitoring part; and a multiplexing part for generating a multiplexed signal by multiplexing the delayed spread signals while weighting the delayed spread signals in parallel using weights that are smaller as an average value of the determined amplitude is larger.

Abstract: In the method of processing signals, multi-path signals are received, channel estimates for the received multi-path signals are determined, and a combining operation is applied to the multi-path signals, the combining operation being a function of a correlation matrix of the received multi-path signals, a correlation matrix of estimates for channels of the received multi-path signals, a cross-correlation matrix of the channels and channel estimates for the received multi-path signals, and the channel estimates.

Abstract: A method of generating a composite signal includes the steps of: (a) generating a plurality of sub-carriers, each sub-carrier having a different frequency position in a frequency spectrum; (b) generating a plurality of codes; and (c) forming a plurality of code combinations from the plurality of codes generated in step (b). The method also includes the steps of (d) first modulating each sub-carrier using a respective one of the code combinations formed in step (c) to form a plurality of modulated sub-carriers; and (e) second modulating in-phase and quadrature components of a base carrier using the plurality of modulated sub-carriers to form the composite signal having multiple carriers. The composite signal is a constant envelope signal, and a single sideband signal.

Abstract: The number of times for averaging operation for averaging a correlation value of a received signal and a reference signal is properly controlled. When the correlation value is not averaged, since a lower limit value TH_A of a correlation level of a distribution of timings of which a path exists is larger than an upper limit value TH_B of a correlation level of a distribution of timings of which a path does not exist, the correlation value of a path is hidden by noise. Since the averaging operation is repeated until the relation of TH_A>TH_B is satisfied, the averaging operation is stopped when the relation is satisfied. The TH_A and TH_B are decided in accordance with RSCP and ISCP of a pilot channel and RSSI of a received base band signal.

Abstract: A method of Partial Parallel Interference Cancellation (PPIC) is provided for recursively eliminating the Multiple Access Interference from a received signal. Such method is to use a recursion way to eliminate all the Multiple Access Interference (MAI) one by one from the received signal. Moreover, the present invention is to take the output of the pre-stage as the input of the present stage with the recursion method so that we can use only one operating circuit to obtain the function the MAI eliminating.

Abstract: A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface includes a line side interface, a board side interface, and a signal conditioning circuit. The signal conditioning circuit services each of an RX path and a TX path and includes a limiting amplifier and a clock and data recovery circuit. The signal conditioning circuit may also include an equalizer and/or an output pre-emphasis circuit. The clock and data recovery circuit has an adjustable Phase Locked Loop (PLL) bandwidth that is set to correspond to a jitter bandwidth of a serviced high-speed bit stream.

Abstract: A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface includes a line side interface, a board side interface, and a signal conditioning circuit. The signal conditioning circuit services each of an RX path and a TX path and includes a limiting amplifier and a clock and data recovery circuit. The signal conditioning circuit may also include an equalizer and/or an output pre-emphasis circuit. The limiting amplifier applies respective gains to the RX path and to the TX path that are based upon respective dynamic ranges of the incoming signals.

Abstract: An antenna calibration system consists mainly of a signal source, an antenna, a first radio frequency mixer, a first local oscillator, an power detecting device, a personal computer, and a servo amplifier. The signal source emits a signal, and the antenna receives the signal. The signal and the first local oscillator, which emits a signal, are emitted into the first radio frequency mixer. Then the first radio frequency mixer emits a signal into the energy detecting device which calculates the signal power, and transmits the power into the personal computer. The personal computer calculates the powers, and then transmits an angle control signal into the servo amplifier. The servo amplifier amplifies the signal, and then drives the antenna pedestal to turn until the antenna is aimed at the signal source. This can calibrate exactly the antenna's azimuth and elevation offset angle.

Abstract: A radar seeker employing a 4-element antenna and amplitude or phase comparison target location. The azimuth (C and D) and elevation (A and B) elements share two channels alternately by means of cycling switches (S1, S2). Sum (31) and difference (29) signals are derived from the two channels and then the difference channel is re-distributed (S4) to dedicated azimuth and elevation channels. The shared channels (G, H) are interchanged cyclically (S3) so that mismatches between them are cancelled out.

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: Where two or more antenna beams may receive signals from the same cellular communication system user, post-reception beam channel gain variations may obscure choice of the channel providing the strongest user signal. Thermal atmospheric noise, assumed to equally enter each beam, is utilized as a standard signal level in order to calibrate the relative gain factor for each channel. Thermal noise level is measured by use of a single common receiver (32) sequentially coupled to each channel (22-25) to listen for lowest signal levels during inactive intervals, over periods of time which may extend for hours. Lowest signal levels provide thresholds for each channel from which gain correction factors are developed. When a user signal is received in two channels, the gain correction factors are employed to select the channel providing the best signal, on a substantially real time basis. A long-term lowest signal level monitoring algorithm is described.

Abstract: A method of correcting phase and amplitude imbalances of I and Q components using digital correction coefficients. The amplitude Gc and phase coefficient Pc obtained solely in the time domain from a pilot signal. The I and Q components of the pilot signal are sampled over at least one integer cycle after which the number of samples taken during an integer number of cycles is determined for the samples of the component with the steepest slope. The sums of self and cross products are used to calculate the coefficients.

Abstract: A digitally formed monopulse radar employing dynamic real-time calibration uring operation. The invention has a transmitter section, timing circuit, RF section, IF section, in-phase and quadrature section and a digital signal processor. A portion of the transmit signal is diverted from the transmitter section for preparation of calibration factors during the calibration period between receive signals. The calibration factors prepared by the digital signal processor are applied by the processor to antenna received signals during the receive mode and to produce the corrected sum and delta pitch, and delta yaw signals and the tracking errors .epsilon..sub.y and .epsilon..sub.p.

Abstract: A method and apparatus that uses iteration to achieve a better prediction of the values of the commands needed to balance the gains of .SIGMA.+.DELTA. and .SIGMA.-.DELTA. channels of a radar guidance system, when an imbalance occurs due to a change caused by the AGC circuitry. An improved method of measuring channel-to-channel gain imbalance versus AGC measurements is provided, which produces modified input values that are used as commands that correct the mismatch during missile flight so that residual error is minimized and more accurate guidance is achieved. The present method is implemented by measuring the gain imbalance at predetermined AGC points during system calibration, and iterating these measurements to produce a relatively small channel-to-channel gain imbalance at the .DELTA.AGC amplifiers. The measured imbalance is then converted to .DELTA.AGC commands and applied to the .DELTA.AGC amplifiers. The resulting gain imbalance is measured and this value is added to the originally measured value.

Abstract: A phase dependent radar guidance system, the receiver (18) of which separates returns into a channel (22) where returns are summed (S) and a further channel (24) where the returns are differenced (jD). The S and jD signals are combined (26) and formed into two further channels as S+jD and s-jD, both of which are passed through AGC controlled amplifiers (28, 30) into a phase angle detector (32) which provides the target (14) angle .beta. to boresight (20). A test signal is applied to the receiver (18) with jD=O, the output value of the phase angle detector (32) for various values of AGC attenuation are stored by a digital processor (34), and the processor (34) modifies measured target phase value with the stored values to correct for AGC amplifier-induced errors.

Abstract: A compensated amplitude comparison monopulse receiver (10) having an angular measurement capability substantially unaffected by mismatches in channel transient response and target range tracking inaccuracy is disclosed herein. The inventive monopulse receiver (10) includes a first receiver channel (24) for impressing a first output voltage S1 on a first output port (28) thereof in response to excitation by a sum signal. A second receiver channel (26) impresses a second output voltage S2 on a second output port (30) thereof in response to excitation by the sum and a difference signal. In a calibration mode, a calibration source (22) provides a series of calibration pulses to the first and second channels (24, 26) which induces first and second calibration voltages to appear on the first and second output ports (28, 30) thereof. Sampling gates (32, 34) sample the first and second calibration voltages subsequent to application of each calibration pulse to the first and second receiver channels (24, 26).

Abstract: A method and correction circuit is described incorporating a monopulse receiver, injecting a first signal of known amplitude and arbitrary phase and a second signal of the same amplitude shifted 90.degree. and measuring the output voltages of the channel and using the measurements to generate four coefficients which may be mathematically applied to the ouptut signals of the channel to provide a corrected output. The invention overcomes the problem of compensating for phase and gain drift in the in-phase and quadrature paths of the sum and difference channels of a monopulse receiver.

Abstract: Radar systems that operate in accordance with the crossfeed method require an exact balancing of the individual Doppler frequency evaluation channels in the receiver. According to the invention, a special method is used first to make the amplitude levels in the individual channels equal to one another and then to determine and balance the phase differences between the channels. A radar system using this method is also described.

Abstract: A multichannel processor for signals modulated onto a common IF frequency includes first and second analog-to-digital converters (ADC) for first and second channels, respectively. Each ADC receives a 4XIF frequency clock for producing digital samples, which are applied to a pair of gates for alternately coupling the digital signal to two signal paths. Each signal path alternately negates and does not negate the signals passing therethrough, thereby generating baseband I and Q signals for that channel. Since each channel has a separate ADC, there may be amplitude and temporal error between the channels. One of the channels is selected as a reference, and uses a pair of interpolators to produce samples representing the I and Q signal values at a common time between clock pulses. The other channels include controllable interpolators which are adjusted so that their I, Q common times correspond to that of the reference channel.

Abstract: A static-split tracking radar system with substantially improved performance. The system includes parallel signal processing channels for processing sum and difference signals from a target-seeking aerial array, to produce target tracking signals. Novel means are provided for trimming relative phase and gain of these channels to achieve substantially perfect matching, which gives a receiver stability sufficient for homing head use in a guided missile system. The system also includes a receiver for acquiring a reference frequency signal, the receiver having novel bandwidth adaptation and doppler tracking facilities. Other novel features provide improved clutter rejection and jamming immunity.

Abstract: A monopulse radar equipment is developed which comprises first and second radiators arranged in symmetrical positions with respect to the boresight axis to radiate radar pulses in a predetermined cycle and thus to produce first and second directional radiation patterns, a beam forming network for synthesizing in an in-phase and opposite-phase relation the first and second directional radiation patterns of the first and second radiations into sum and different patterns, and a multichannel receiver for forming from the sum and difference patterns an off-boresight signal representing a deviation of a target object from the boresight direction and a sidelobe suppressed signal resulting from suppressing a sidelobe response of the sum pattern. The first and second directional couplers are interposed on the sum and difference pattern signal transmission channels between the beam forming network and the multichannel receiver.

Abstract: The radar comprises in known manner a transmitter (1), a transmitting antenna (E.sub.1), two receiving antennas (R.sub.1,R.sub.2), mixers (6,7) and means for processing the subtractive beat signals supplied by the mixers for effecting detection of the bearing of a target (10) and of the range and/or the relative velocity of the target. According to the invention, a target simulator is provided to correct the phase errors of electrical and mechanical origins. The simulator comprises a transmission circuit including a modulator (11) and a simulated target echo transmission antenna (E.sub.2) which transmits towards the receiving antenna. The radar also includes means for processing a beat signal derived from the simulated echo and for effecting detection of the simulated target bearing and means for correcting phase errors.

Abstract: An improved monopulse radar system wherein target return signals received by a plurality of antenna elements are corrected with correction signals derived within the system in response to pilot pulses. The improvement comprises a plurality of receiver channels, each receiver channel being coupled to a single one of the plurality of antenna elements. The improvement also comprises means for generating a first set of quadrature components of video signals developed in the plurality of receiver channels in response to the pilot pulses received by the plurality of antenna elements, and for generating a second set of quadrature components of video signals developed in the plurality of receiver channels in response to return signals from the target received by the plurality of antenna elements. Digital signals representative of the first and second sets of quadrature components of video signals are generated.