Abstract: An active YIG oscillator driving device is comprised of: an YIG oscillator including a main coil, an FM coil, a frequency generator operating to generate an output frequency in response to a magnetic field generated from the FM coil; a phase locker setting the output frequency to a target frequency by controlling an amount of current provided into the FM coil and adjusting the output frequency; and a main coil controller regulating the amount of current provided into the main coil, if the output frequency varies out of a controllable range by the FM coil, and adjusting the output frequency. A time for setting the output frequency of the YIG oscillator is shortened to improve the stability of the output frequency thereof against environmental conditions.

Abstract: A phase component of a nonlinear frequency modulated (NLFM) chirp radar pulse can be produced by performing digital integration operations over a time interval defined by the pulse width. Each digital integration operation includes applying to a respectively corresponding input parameter value a respectively corresponding number of instances of digital integration.

Abstract: A radar device of FM pulse system, in which a pulsed radio wave with frequency modulated is transmitted or received, to calculate a distance to a target 203 and a relative velocity, comprising: range gate setting means 205 for determining a sampling timing every time a predetermined time period has passed from a transmission timing; sampling means 206 for making a sampling in a frequency up zone or frequency down zone in each range gate; and measurement time changing means 207 for setting a measurement data used as an input of Fourier transform based on sampling data obtained by the sampling means 206, and when letting a time period required to make a sampling of all measurement data a measurement time period, changing the measurement time period in each range gate. An optimum distance resolution and relative velocity resolution can be set based on the distance to a target.

Abstract: An ultra low power, long range, robust radar system, for applications such as ionospheric sounding. The HF transmit signal and the received (reflected) signal are both unswitched and high frequency and share a path to a common loop antenna. The transmit signal originates at a local oscillator (LO), and is sufficiently low power to not saturate the receive signal path. A balun divides the local oscillator signal between the transmit path forward to the antenna and a mixer path, and also divides the received signal between the mixer path and the LO path. A mixer converts the mixed LO and received signal to baseband.

Abstract: A radar system and method for determining the range and, optionally, the azimuth of a target, while maintaining a high transmitting duty factor is provided. A waveform generator is connected to an antenna aperture by a transmit-receive switch, and the waveform is transmitted for more than half of the period of time of the sum of the transmission period and the receiving period. For a frequency-modulated continuous-wave waveform (FMCW), the receiver may be turned on for short intervals at a rate which is at least the Nyquist rate for the signal received from at target. A monopulse or frequency-scanned antenna may be used to determine azimuth as well as range.

Abstract: A radar apparatus and method for determining the range to and velocity of at least one object comprising, transmitting a plurality of RF signals, each comprising a particular frequency and being transmitted during a particular unique finite period, the plurality of signals collectively comprising at least one first subset of signals having the same frequency and at least one second subset of signals having different frequencies, receiving the plurality of signals after reflection from an object, determining a phase difference between each of the signals and the corresponding reflected signal, each piece of phase difference information herein termed a sample, organizing the samples in two-dimensions wherein, in a first dimension, all samples have the same frequency and, in a second dimension, all consecutive samples are separated from each other by a fixed time interval; processing the samples in the first dimension to determine a phase rotation frequency corresponding to the samples in the first dimension, th

Abstract: The present invention relates to a UWB distance measurement system and method of driving the system. The system includes a reception antenna for receiving a signal, which is output from a transmission unit, is reflected from a target and is incident on the reception antenna, a UWB amplifier for amplifying the received signal and generating a first signal, a reference waveform generator for generating a reference waveform which is a reference for analysis of the first signal, a window function generator for generating at least one window function that is applied to the first signal, a correlator for correlating the first signal with the window function output from the window function generator, and generating a second signal which is a revised frequency response of the first signal, and a delay time detector for detecting a delay time component in the second signal.

Abstract: One embodiment relates to a transceiver. The transceiver includes first and second phase-locked loops. The first phase-locked loop is adapted to receive a reference signal and output a transmission signal based on the reference signal. The second phase-locked loop is adapted to receive the reference signal and output a local oscillator (LO) signal based on the reference signal. The frequency of the LO signal is shifted relative to the frequency of the transmission signal. Other methods and systems are also disclosed.

Abstract: A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.

Abstract: In a radar device including a transmitting unit for transmitting a transmission signal having plural modulation sections, a receiving unit for receiving a reflection signal obtained through reflection of the transmission signal from a target by an array antenna having plural channels, a mixing unit for mixing the transmission signal with reception signals of the plural channels to obtain beat signals of the plural channels, a frequency analyzing unit for frequency-analyzing the beat signals of the plural channels, and a direction calculating unit for calculating the direction to the target on the basis of frequency analysis results of the plural channels, the direction calculating unit adds correlation matrixes generated from peak frequency spectra of the plural modulation sections to obtain an summed correlation matrix, and calculating the direction to the target on the basis of the summed correlation matrix.

Abstract: Marine radar systems and methods for producing low power, high resolution range profile estimates. Non-linear Frequency Modulation (NLFM) pulse compression pulses are frequency stepped to form a low power, wide-bandwidth waveform. Periodically, calibration filters are determined and applied to return signals for correcting non-ideal effects in the radar transmitter and receiver.

Abstract: One aspect of this disclosure relates to a method for processing a received, modulated radar pulse to resolve a radar target from noise or other targets. According to an embodiment of the method, a radar return signal is received and samples of the radar return signal are obtained. A minimum mean-square error (MMSE) pulse compression filter is determined for each successive sample. The MMSE filter is separated into a number of components using contiguous blocking, where each component includes a piecewise MMSE pulse compression filter segment. An estimate of radar range profile is obtained from an initialization stage or a previous stage. The piecewise MMSE pulse compression filter segments are applied to improve accuracy of the estimate. The estimate is repeated for two or three stages to adaptively suppress range sidelobes to a level of a noise floor. Other aspects and embodiments are provided herein.

Abstract: Providing multi-spot inverse synthetic aperture radar (ISAR) imagery is disclosed. Embodiments of techniques in accordance with the present disclosure may advantageously improve multiple target discrimination, detection, identification, and tracking using ISAR imaging. In an embodiment, an inverse synthetic aperture radar (ISAR) method for producing multiple ISAR images from a single waveform includes transmitting a chirp signal into a dwell surveyed by the antenna beamwidth. Multiple dechirp reference signals may be generated to demodulate return signals from the dwell at multiple selected intervals within a pulse repetition interval (PRI) to create demodulated signals.

Abstract: A method and apparatus is operative for multiple target detection in a radar system which employs a radar waveform of two or more frequency diverse subpulses. The apparatus adds coherent processing of the subpulse echo signals to determine the presence of multiple scattering centers within the radar resolution cell. The subpulses are coherently combined and one can then estimate the number of scattering centers by forming a sample covariance matrix between the subpulse frequency channels and then performing an Eigenvalue decomposition. The resulting Eigenvalues represent the signal strengths of the scattering centers when the associated Eigenvectors correspond to the optimal subpulse weights associated with that signal. A single strong Eigenvalue indicates a single target while two or more strong Eigenvalues or those Eigenvalues larger than the noise related Eigenvalues or a threshold, indicates the presence of multiple targets.

Abstract: A radar system comprising a transmit antenna, a receive antenna and a mixer for combining a signal received by said receive antenna with a reference signal to produce an output signal. The transmit antenna includes an active antenna oscillator, the reference signal being derived from the active antenna oscillator. The active antenna oscillator is turned on and off by a pulse modulated biasing signal to produce a pulse modulated RF signal. The reference signal is delayed before being supplied to the mixer, the output of the mixer being used to determine when a detected object is a pre-determined distance from the system.

Abstract: A system for locating earth cavities, or items in a building, or structural characteristics having a plurality of transmitters that generate at least a portion of a waveform. Each transmitter divides the waveform into sub-chirp intervals and transmits a known sub-chirp interval from a known location to contact an article of interest. The resulting sub-chirp intervals become a leakage signal that is then received and processed by a receiver. The receiver therein approximates a cavity size, article size, article composition, article location, earth cavity location, or other structural characteristic.

Abstract: Systems and methods for avoidance of partial pulse interference in radar. The systems and methods include a radar processor for generating control signals that direct the generation and transmission of two consecutive radar pulses using a waveform and pulse train generator and transmitter. The systems and methods also include receiving reflected echoes corresponding to the transmitted pulses using a receiver and processing the echoes using an analog to digital converter, filter, and digital signal processor to separate echoes from each pulse, process them, and combine the results to avoid partial pulse interference while maintaining pulse energy and an acceptable signal to noise ratio.

Abstract: A method for guiding the approach and landing of an aircraft is provided. The method involves receiving navigation information from the aircraft, receiving navigation information from an aircraft carrier, integrating the navigation information from the aircraft with the navigation information from the aircraft carrier to determine a relative velocity and a relative position between the aircraft and the aircraft carrier, and propagating the relative velocity and the relative position forward in time for navigation purposes.

Abstract: A system and method are provided to reduce an interfering signal in a radar return signal for a frequency modulated continuous wave (FMCW) radar. Once the interfering signal is detected, an extent of the interfering signal is determined and the interfering signal is removed from the radar return signal. This allows the radar to detect a target in the presence of the interfering signal. The system and method can benefit any FMCW radar that is within the range of an interfering radar source (e.g. another FMCW radar, a police radar gun, a pulse radar, etc.) operating in the same frequency band as the FMCW radar.

Abstract: A linear frequency-modulated pulse radar system is provided in which the echo signal is mixed with a de-ramp signal, in order to reduce the bandwidth. The transmission signal of the pulse radar and the de-ramp signal are generated with the same reference oscillator, whereby the transmission signal and the de-ramp signal are generated as the upper and lower side band of an upward mixing process.

Abstract: A method of minimizing detectability of an electronically communicated message is disclosed. A predetermined frequency modulation pattern about a nominal transmission frequency is defined. The predetermined frequency modulation pattern is suitable to vary the nominal transmission frequency during a dwell period. The dwell period is divided into a plurality of sub-dwell periods. Each sub-dwell period has a nominal sub-frequency assigned thereto according to the predetermined frequency modulation pattern. The plurality of sub-dwell periods and the respective assigned nominal sub-frequencies are randomly or pseudo-randomly ordered. The message is transmitted according to the random or pseudo-random ordering of the nominal sub-frequencies.

Abstract: A transmission signal generating unit has a window function calculator that generates a window function that makes all frequencies without a center frequency of an input signal and its adjacent frequencies zero and makes the signal to noise ratio of the center frequency maximum; and a transmission signal generator that generates a transmission signal whose amplitude is modulated in a shape of an envelope curve based on the window function generated by the window function calculator.

Abstract: A locator system includes two main components, namely, (1) a beacon tag that is readily attached to a person or article, and (2) a transportable finder or receiver/processor for sensing the relative position of the tag and indicating changes in that relative position to a user. The method for locating a person or article preferably uses an audible feedback signal to the user for informing the user, when moving, whether the relative position of the beacon tag is getting closer to the finder or farther from the finder. The locator system includes at least one beacon tag comprising a transmitter programmed to transmit a unique coded pulse signal. The beacon tag is housed in a lightweight portable envelope or container and includes a battery, an antenna, a large programmed gate array and a frequency reference (e.g., a crystal oscillator).

Abstract: A high-frequency oscillator that can tune oscillation characteristics is provided. A high-frequency oscillator includes a Gunn diode serving as a high-frequency oscillation element that generates high-frequency signals, a resonator connected to the Gunn diode, a varactor diode serving as a variable-capacitance element that is disposed on the resonator and changes a resonance frequency, and a bias supply circuit that is connected to the varactor diode and supplies a bias voltage applied in order to change a capacitance. The bias supply circuit includes a trimmable chip resistor serving as a pre-set variable resistor that regulates a bias voltage applied to the varactor diode. By regulating the resistance value of the trimmable chip resistor, it is possible to control the capacitance value of the varactor diode and tune oscillation characteristics to a desired state.

Abstract: A radar system and method for detecting targets using pulse-compressed signals is disclosed. In one application, the systems and methods can be used to detect one or more relatively small targets whose pulse-compressed signals are masked by the time-sidelobes of a larger target's return signal. The method includes an iterative, detect-and-subtract signal algorithm that processes the post-compressed signal to detect multiple targets. Specifically the processing algorithm operates on the post-compressed signal to identify a point spread function (PSF) that corresponds to the relatively large target. Once identified, the PSF corresponding to the largest target in the post-compressed signal is subtracted from the post-compressed signal to generate a residual signal. This residual signal, in turn, includes the PSFs for the other targets. This process of identifying and subtracting the PSF of the largest target in the residual signal is then repeated until all targets are detected.

Abstract: A transmitter emits into an intended search space a radar wave having a predetermined frequency pulse-modulated by a trigger pulse of a predetermined width. A receiver receives a reflected wave of the radar wave and outputs a receive signal. A local pulse generator outputs a local pulse signal having the predetermined frequency pulse-modulated by the trigger pulse delayed by the delay unit. A correlation value detector detects a strength correlation value between the receive signal and the local pulse signal. A delay time changing unit changes the delay time sequentially within a range of a predetermined period representing a generation period of the trigger pulse. A correlation value storage unit stores the strength correlation value detected for each delay time changed. A frequency distribution generator generates a frequency distribution of a stored correlation value against the delay time.

Abstract: A non-destructive detection method and system enables detecting a moisture patch located inside a building wall or the like. A transmitter generates a series of ultra-wideband pulses while an ultra-wideband antenna unit, preferably in the form of an antenna array including a plurality of switchable antenna pairs, directs the pulses toward the building structure so that the pulses are reflected therefrom, and receives the reflected pulses. A receiver processes the reflected pulses received by the antenna unit and produces a corresponding output. A controller controls the operation of the transmitter, receiver and antenna unit, and analyzes the output of the receiver for the presence of moisture inside of the building wall.

Abstract: A method and apparatus for generating short electronic pulses using a modified differential trigger that is partly an analogue sinusoidal voltage and partly a selectable, DC voltage. The differential trigger is applied to a differential base band pulse generator having a NAND gate and AND gate. The trigger is applied to both NAND inputs and to one AND input. The NAND output is applied the other AND input. Such a circuit is an OFF state for all input states. However, as the input switches state, the NAND gate delay causes the AND gate to be ON briefly, generating a short pulse. The timing of this pulse can be controlled by varying the constant DC voltage. By using fast switching SiGe CML gates, short pulses with a controllable time off-set can be generated that are suitable for use in automotive radar applications, using only sub-GHz clocks.

Abstract: A conventional waveform generation circuit was required to increase a number of bits or a sampling rate for a D/A converter to enhance a precision of waveform shaping, and had a problem that a cost was increased. Therefore, as a method for enhancing the precision of waveform shaping, a quantization error of an output waveform is made smaller by controlling an output time interval of an output value from a D/A converter so as to make a difference in an output voltage between target waveform and output waveform smaller. As a result, even if the D/A converter has a small number of bits, the waveform can be generated at high precision. Also, this waveform generation method may be applied to modulation control of a radar apparatus, as a result, constituting a small and inexpensive modulation circuit for an oscillator.

Abstract: A system and corresponding method for the concurrent operation of multiple radar systems on a common frequency and in the same geographical area includes a waveform generator that specifies certain operating parameters for the transmitted radar pulses. In a first instance, the carrier frequency can include an offset for each radar system. In a second instance, complementary codes can be used for the radar pulses such that each radar system operates with a unique code for substantially reducing the cross-talk between the radar systems. In another instance, both carrier frequency offset and complementary coded waveforms can be used to increase the number of radar systems that operate concurrently. Carrier frequency offset can also be used to combat range-wrap by using different carrier frequencies for adjacent radar pulses.

Abstract: A pulse compression processor 20 compressing a modulated pulse signal correlately received by a receiver, includes a coefficient calculator 30 calculating a set of filtering coefficients for converting sampled output signal values outside a vicinity of main-lobe of a compressed pulse signal into zero as well as for minimizing S/N loss in a peak value of the main-lobe, and a pulse compression filter 40 compressing the modulated pulse signal based on the set of the filtering coefficients calculated by the coefficient calculator.

Abstract: A radar apparatus comprises: a transmitter unit having a high-frequency oscillating unit whose oscillation frequency is variable, and a pulse amplitude modulating unit for amplitude-modulating a pulse of a transmission high-frequency signal output from the high-frequency oscillating unit with a first control pulse signal; a receiver unit having a gating unit for controlling ON/OFF of an input of a received high-frequency signal with a second control pulse signal; and a controlling and signal processing unit for controlling the transmitter unit and the receiver unit, and for switching a first operation mode for making the apparatus function as an FM-CW radar, and a second operation mode for making the apparatus function as a pulse radar.

Abstract: A bistatic radar has a radar transmitter at a first location on a moving platform having a motion and a radar receiver at a second location, remote from the first location. The transmitter illuminates a target along an indirect path with an encoded radar signal. The target reflects the encoded radar signal to the radar receiver. The transmitter concurrently provides the encoded radar signal to the radar receiver along a direct path. The encoded radar signal is radiated at a start time from a central reference point, and contains the first location, the pulse start time, the central reference point and the motion of the moving platform. Bit synchronization codes are also included. The radar receiver receives the encoded radar signal from the radar transmitter along the direct path during a first time interval, and the same encoded radar signal reflected from the target along the indirect path during a second time interval.

Abstract: A radar device includes a code generator, a transmission section, a reception section, a delay section, a despreading process section, a correlation value detection section, a target detection section, an estimation section, an acquisition section, and a correction section. The estimation section estimates a reception intensity of a reflection wave from a target located at a first distance on a basis of a detected correlation value. The acquisition section acquires a cross-correlation value between the first distance and a second distance, on a basis of the estimated reception intensity of the reflection wave from the target located at the first distance, a delayed despreading code used to detect a correlation value for the first distance and a delayed despreading code used to detect a correlation value for the second distance. The correction section corrects the correlation value for the second distance on a basis of the cross-correlation value.

Abstract: A unique hardware architecture that combines short pulse, stepped frequency and centerline processing. The inventive architecture implements a radar system having a transmitter for transmitting short pulses, each pulse being stepped in frequency and a receiver receiving the pulses and providing an output signal in response thereto. In the illustrative embodiment, the transmitter includes a frequency source, an RF switch coupled to the source and a controller for controlling the RF switch. The receiver includes a signal processor implemented with a center line roughing filter. The signal processor has multiple channels each of which has a range gate and a digital filter. The digital filter includes a Fast Fourier Transform adapted to output a range Doppler matrix.

Abstract: In a radio wave radar system using a two-frequency CW modulation method, it is possible to detect a distance between a host vehicle and a forward vehicle and to realize a stable ACC following travel, even in a condition in which the relative speed is 0. By combining the two-frequency CW modulation method with the frequency pulse CW modulation method, that is, by using combination with the two-frequency CW method when the relative speed occurs and the frequency pulse CW method when the relative speed is close to 0, even if the relative speed is 0, the IF signal obtained from the reflected wave from the forward vehicle can be generated to detect the existence of the ACC target vehicle, so that it is possible to realize a stable ACC following travel.

Abstract: A method for active ranging, such as radar, which sequentially transmits pulses of mutually different waveforms. Receive processing is performed concurrently for all the transmitted waveforms during each interpulse interval, to thereby provide range ambiguity resolution together with continuous return signal integration.

Abstract: A radar apparatus includes: a modulation signal generating circuit that generates a modulation signal; a carrier wave generating circuit that generates a carrier wave; a modulation circuit that outputs a high frequency signal generated by modulating the carrier wave using the modulation signal that has been inputted; a modulation signal extracting circuit that extracts the modulation signal from the high frequency signal that has been inputted; and a detection signal generating circuit that generates a detection signal, which can be used to measure a distance to a measured object, based on the modulation signal extracted by the modulation signal extracting circuit from a component, out of the high frequency signal that has been transmitted via a transmission antenna, the component having been reflected by the measured object and received by a reception antenna.

Abstract: A method for randomly phase modulating a radar altimeter is described. The method includes momentarily applying a signal from a random noise source to an amplifier, applying an output of the amplifier to a voltage controlled oscillator (VCO), applying an output of the VCO to a transmitter and mixer of the radar altimeter to modulate transmissions of the radar altimeter and to demodulate reflected radar transmissions received by the radar altimeter and holding the output of the amplifier constant from before a radar altimeter transmission until after reception of the reflected radar signals from that transmission by the radar altimeter. The method further includes repeating the applying steps and the holding step.

Abstract: An apparatus for preparing a RF radar transmit waveform and for decoding RF return waveforms comprising: a RF-lightwave encoder and a decoding preprocessor to phase-encode the RF radar transmit waveform and partially decode the return signal, the encoder including switched optical delay lines for producing desired RF phase shifts, and the decoding preprocessor including a tapped optical delay line and optical delay lines that counteract the delays imposed by the delay lines of the encoder, wherein the RF-lightwave encoder and the decoders allow shorter compressed pulses and larger pulse-compression ratios to be achieved than can be obtained using conventional electronic approaches. Wideband transmit waveforms can be generated due to the use of the switched optical delay lines and, unlike prior art approaches, is not restricted to single-frequency waveforms. The taps can be weighted to accomplish objectives such as reduction of side lobes in the compressed pulse.

Abstract: The synthesizer and method provide a relatively wideband swept frequency signal and include generating a first swept frequency signal with a first generator, and successively switching between different frequency signals with a second generator. Such switching creates undesired phase discontinuities in the output swept frequency signal. The first swept frequency signal is combined with the successively switched different frequency signals to produce the relatively wideband swept frequency signal, and the second generator is calibrated to reduce the undesired phase discontinuities during switching based upon the output swept frequency signal.

Abstract: A millimeter wave pulsed radar system includes a radar synthesizer having a voltage controlled oscillator/phase locked loop (VCO/PLL) circuit, direct digital synthesizer (DDS) circuit and quadrature modulator circuit that are operative to generate an intermediate frequency local oscillator signal (IF/LO signal). A radar transceiver is operative with the radar synthesizer for receiving the IF/LO signal. A transmitter section has a frequency multiplier that multiplies the IF/LO signal up to a millimeter wave (MMW) radar signal and a receiver section and includes a direct conversion mixer that receives a MMW radar signal and the IF/LO signal to produce I/Q baseband signals that are later digitized and processed.

Abstract: Methods and apparatus are provided for radar systems using multiple pulses that are shorter than the expected range delay extent of the target to be imaged. In one implementation, a method for performing radar includes the steps of: transmitting a plurality of pulses, each pulse having a different center frequency and a time duration shorter than an expected range delay extent of a target, wherein a total bandwidth is defined by a bandwidth occupied by the plurality of pulses; receiving reflections of the plurality of pulses; and performing pulse compression on the received pulse reflections to generate a detection signal having a radar resolution approximately equivalent to the transmission and reception of a single pulse having the total bandwidth. In preferred form, the pulses comprise ultrawideband (UWB) pulses each occupying a sub-band of the overall system bandwidth.

Abstract: A positioning system including a sensor, a drive sequencer and an actuator. The sensor senses the actuator position and provides position signals to drive the sequencer which responsively computes and drives the actuator in open loop moves containing dwell intervals of position. The actuator positions a mirror or other load means to reflect an optical beam as desired. Either preprogrammed or non-repeating sequences of actuator stopping positions can be synchronized with a laser. During dwell times, mirror position accuracy better than 10 microradians is suitable for tuning CO2 pulse burst or CW lasers.

Abstract: A stepped-frequency chirped waveform improves SAR groundmapping for the following reasons. Range resolution in SAR image is inversely proportional to the transmitted signal bandwidth in nominal SAR systems. Since there is a limit in the transmitted bandwidth that can be supported by the radar hardware, there is a limit in range resolution that can be achieved by processing SAR data in conventional manner. However, if the frequency band of the transmitted signal is skipped within a group of sub-pulses and received signal is properly combined, the composite signal has effectively increased bandwidth and hence improvement in range resolution can be achieved. The proposed new and practical approach can effectively extend the limit in range resolution beyond the level that is set by the radar hardware units when conventional method is used.

Abstract: A pulse radar system has a high-frequency source, which supplies a continuous high-frequency signal and is connected on the one side to a transmission-side pulse modulator and on the other side to at least one mixer in at least one receive path. A pulse modulator is connected upstream of the mixer with regard to its connection to a receiving antenna. The mixer evaluates a radar pulse reflected by an object together with the signal of the high-frequency source. This system does not require a ZO switch and is insensitive to interference.

Abstract: A sensor front end for an electronic radar sensor is disclosed that provides for a lower parts count while providing technical functionality by using multifunction parts, i.e., parts that are used both in transmitting and receiving. The sensor front end includes a continuous wave signal source that functions as a signal source when the front end is transmitting a signal and as a local oscillator when the front end is receiving a signal. The sensor front end also includes a tri-mode mixer that functions as a phase-modulator and transmit switch when the front end is transmitting a signal and as a mixer/down-converter when the front end is receiving a signal. The sensor front end further includes a common aperture antenna that acts as both a transmitting antenna for transmitting a sensor signal and for receiving a reflected signal from a object.

Abstract: To provide a radar system mounted on a vehicle that reliably detects the reception of the interference wave with high-performance and inexpensively. There is provided a radar system mounted on a vehicle for detecting a target object, including a transmitter for transmitting an electromagnetic wave, a receiver for receiving the electromagnetic wave reflected by the target object, a signal processor for measuring a distance between a vehicle of his/her own and the target object and a relative velocity on the basis of the transmitting electromagnetic wave and the receiving electromagnetic wave, and an interference detector for suspending a transmit operation of the transmitter under a control of the signal processor to detect an interference signal from another external device.

Abstract: A chirp-based method and apparatus measures phase variation through a reference frequency transport cable for a phased array antenna. A chirp is injected into the a signal transport path from a remote transmit/receive portion of the antenna, so that the chirp is conveyed over the signal path, reflected from an upstream bandpass filter at a local transmit/receive portion of the antenna, and returned to a remote transmit portion of the antenna. Energy in the returned chirp is extracted by a downstream bandpass filter and correlated in a delay lock loop with energy in an auxiliary chirp signal, that is delayed relative to the injected chirp. The delay of the auxiliary chirp is adjusted to maximize the correlation output and provide an indication of the delay through the signal path.

Abstract: A chirp-based arrangement derives a measure of phase variation through a reference frequency transport cable of a phased array antenna architecture, such as a spaceborne synthetic aperture radar system. A direct digital synthesized chirp signal is injected in an upstream direction into the transport cable from a downstream end thereof, so that the chirp signal is transmitted in an upstream direction, reflected from an upstream bandpass filter, and returned in a downstream direction. At each of a plurality of nodes that are distributed along the transport cable, the two chirp signals are extracted and frequency domain-processed to derive said measure of transport delay through the cable between the source of the reference frequency signal and each of the nodes.