Abstract: The techniques of this disclosure enable frequency-modulated continuous-wave radar-based detection of living objects. Instead of generating a chirp pattern with each chirp separated by an idle period, a radar generates a chirp pattern with multiple chirps separated by an idle period. From applying a Fourier transform to receiver signals for each frame, the radar determines an amplitude as a function of range for each frame. The radar computes the standard deviation between the amplitudes of two frames and then, for each additional frame, the radar incrementally updates the standard deviation to be inclusive of the amplitude contribution of the additional frame. That is, rather than recalculate the standard deviation for each new frame, the radar increments the standard deviation by a fraction of the amplitude for the new frame, which is proportionate to the total quantity of frames generated thus far.

Abstract: In an illustrative integrated circuit, a chirp generator provides a chirp signal having linearly-ramped chirp intervals, while a shift frequency generator provides a signal having a different shift frequency during each of multiple segments in each chirp interval. A modulator combines the signals to derive a segmented chirp signal having multiple linearly-ramped chirp segments in each chirp interval. The modulator may be a single sideband modulator to provide frequency up-shifted and frequency down-shifted chirp segments. The segmented chirp signal may be suppressed during resettling intervals of the original chirp signal.

Abstract: In an illustrative integrated circuit, a chirp generator provides a chirp signal having linearly-ramped chirp intervals, while a shift frequency generator provides a signal having a different shift frequency during each of multiple segments in each chirp interval. A modulator combines the signals to derive a segmented chirp signal having multiple linearly-ramped chirp segments in each chirp interval. The modulator may be a single sideband modulator to provide frequency up-shifted and frequency down-shifted chirp segments. The segmented chirp signal may be suppressed during resettling intervals of the original chirp signal.

Abstract: A method includes: receiving a reflected radar signal including a first radar chirp signal during a first chirp time period and a second radar chirp signal during a second chirp time period; downconverting the reflected radar signal to form a baseband signal; adding a DC offset to the baseband signal to form a DC offset baseband signal, adding the DC offset including adding a first DC offset to the baseband signal during the first chirp time period, and adding a second DC offset to the baseband signal during the second chirp time period, where the first DC offset is different from the second DC offset; and digitizing the DC offset baseband signal using an analog-to-digital converter to form a digitized baseband signal.

Abstract: A pseudo low intermediate frequency (IF) configuration is provided for a receiver having a zero IF radio architecture dedicated for radar detection, in order to reduce false radar detection. Energy from local oscillator leakage is shifted away from DC. After filtering out of the desired sub-channel, the local oscillator leakage energy is suppressed, reducing false radar detection.

Abstract: Disclosed examples include a radar system that operates in a first mode and a second mode. In the first mode, the system detects the presence of an object within a threshold range. In response to detection of the presence of the object, the system transitions to the second mode, and the system generates range data, velocity data, and angle data of the object in the second mode. When the object is no longer detected within the threshold range, the system transitions back to the first mode.

Abstract: Disclosed is a method and device for interconnection of printed circuit boards operating at millimeter wave frequency band. The device comprises a primary printed circuit board, a secondary printed circuit board, an interconnection module for coupling electromagnetic energy from the primary printed circuit board to the secondary printed circuit board. The primary printed circuit board further comprising a primary top dielectric layer, specific via arrangements, a radio frequency chip, a primary high frequency transmission line connected to the radio frequency chip at one end and other end to a first inset-fed patch. The secondary printed circuit board further comprising a secondary top dielectric layer, specific via arrangements, a printed array antenna, a secondary high frequency transmission line connected to printed array antenna at one end, and other end to a second inset-fed patch. The interconnection module further comprising a first cut-out section, a second cut-out section and a slot.

Abstract: A radar and method for making a radar undetectable, comprising comprises: on a transmit antenna consisting of N individual subarrays that are non-directional in at least one plane in transmission, each being linked to a waveform generator, generating, for each of the individual subarrays, a waveform so as to make each of the individual subarrays transmit continuous or quasi-continuous signals according to a temporal and periodic pattern by using transmission patterns made up of N different subarrays and which are deduced from one another by an individual delay, on the receive antenna comprising M individual subarrays adapted to pick up the reflected signals obtained from the transmission of the N individual subarrays of the transmit antenna, performing a compression of the received signal in space and in time of the received signals.

Abstract: Systems and methods relating to the use of one type of radar technology to accomplish the function of another type of radar technology. Secondary Surveillance Radar/Identification Friend or Foe (SSR/IFF) technology can be used as if it was Primary Surveillance Radar (PSR) to gain the advantages of both systems. Radar signals useful for SSR/IFF are used as PSR signals. Reflections of the SSR/IFF signal off of both airborne and ground based aircraft, and ground based vehicles and items are used to locate and identify these aircraft, vehicles and items. For SSR/IFF transponder equipped aircraft, the reflected SSR/IFF signals provide (prove dial) dual confirmation of the aircraft's presence while for non-transponder equipped aircraft, the reflected signals provide an indication of the aircraft's presence. The use of SSR/IFF signals reflected off of ground based vehicles and items provides an indication of ground based vehicles and items present around the installation receiving the reflected SSR/IFF signals.

Abstract: A microwave sensor adjusts its sensing range based on a range gate selected from multiple range gates. An active antenna module transmits a first FMCW signal toward a target based on the selected range gate and for receiving second FMCW signal reflected from the target. A modulating module is used for generating modulation signal. The bandwidth of the first FMCW signal depends on an amplitude of the modulation signal. A first demodulator is used for demodulating the first FMCW signal and the second FMCW signal to generate beat frequency. A second demodulator is used to demodulate the beat frequency signal to generate a Doppler signal. An indentifying circuit is used for generating a triggering signal based on a voltage difference between integral of the Doppler signal from an object within the rage gate and an integral of clutter.

Abstract: Provided is a device for detecting intruding objects that enables the detection of intruding objects without requiring antenna switching. Delay units (102) use different delay amounts to delay signals received at each of a plurality of antennas (110). A signal synthesis unit (103) synthesizes the delayed signals. A frequency conversion unit (106) converts the synthesized signal frequency to a baseband. A wave detection unit (107) detects the signal that has undergone frequency conversion. A radar profile generation unit (104) uses the detected signal to generate a profile formed from the distance from the antenna, and the signal strength at each distance from the antenna. A detection processing unit (105) detects a peak in the profile at which the signal strength exceeds a preset threshold value, and determines whether an intruding object is present in a detection region on the basis of the detected peak.

Abstract: Systems and methods for allowing dual-mode radar operation. An exemplary transmission system includes a hybrid coupler that receives a signal produced by a synthesizer and couples the received signal to two output ports. A pulse transmitter receives a pulse transmit-activate signal from a controller, receives an input signal from the hybrid coupler and, if the activate signal has been received, amplifies the received signal based on a predefined desired pulse output transmission setting. A frequency-modulation continuous-wave (FMCW) transmitter receives an FMCW transmit-activate signal from the controller, receives an input signal from the hybrid coupler and, if the activate signal has been received, amplifies the received input signal based on a predefined desired FMCW output transmission setting. An isolator protects the pulse transmitter during FMCW operation and also the FMCW transmitter from receiving power reflected off of pulse transmitter components.

Abstract: Distance between two radio frequency devices is estimated by receiving a plurality of spread spectrum chirp signals frequency offset from one another, and evaluating the received plurality of spread spectrum chirp signals for relative phase shifts between the plurality of spread spectrum chirp signals. A fine propagation time is derived using the phase shifts between the spread spectrum chirp signals. A frequency domain despreading window is shifted to reduce the influence of time-delayed near multipath signals in receiving the plurality of spread spectrum chirp signals.

Abstract: A radar system (100) is described including a transmitting assembly (10), a receiving assembly (20), a control unit (30) and a signal processing unit (40). The transmitting assembly (10) receives an input signal (31) and transmits an incident radar signal (2). The transmitting assembly (10) includes a Rotman lens (12) having a lens cavity (74), a plurality of beam ports (60), a plurality of array ports (62) and a patch antenna assembly (14). The lens cavity (74) has a lens gap (h) between 10 microns to 120 microns, and preferably 40 microns to 60 microns. The patch antenna assembly (14) includes a plurality of antenna arrays (130) operable to receive a plurality of time-delayed, in-phase signals from the Rotman lens (12) and to transmit the incident radar signal (2) towards a target (4). The receiving assembly (20) receives a reflected radar signal (6) and produces an output signal.

Abstract: Disclosed is a radar apparatus supporting short range and long range radar operations, wherein a plurality of short range transmitting chirp signals and a plurality of long range transmitting chirp signals are generated by a predetermined modulation scheme and is transmitted to an object through at least one transmitting array antenna and signals reflected from the object is received through at least one receiving array antenna, and the plurality of long range transmitting chirp signals have transmission power larger than that for the plurality of short range transmitting chirp signals.

Abstract: This disclosure provides a range side lobe removal device, which includes a pulse compressor for acquiring a reception signal from a radar antenna and generating a pulse-compressed signal by performing a pulse compression of the reception signal, a pseudorange side lobe generator for generating a pseudo signal of range side lobes of the pulse-compressed signal based on the reception signal, and a signal remover for removing a component corresponding to the pseudo signal from the pulse-compressed signal.

Abstract: Presented is a method for determining speeds (vr14, vr16) and distances (r14, r16) of objects (14, 16) relative to a radar system (12) of a motor vehicle (10), wherein a coverage area (EB) of the radar system (12) is divided into at least two part-areas (TB1, TB2, TB3), the coverage area (EB) is examined for reflecting objects (14, 16) in successive measuring cycles (MZ1, MZ2; MZi, MZi+1), wherein radar signals received in a measuring cycle (MZ1, MZ2; MZi, MZi+1) are processed separated in accordance with part-areas (TB1, TB2, TB3) and processed signals are assembled to form a total result differentiated in accordance with spatial directions. The method is characterized in that from signals received in a first measuring cycle (MZ1; MZi), hypotheses for the distance (r14, r16) and speed (vr14, vr16) of reflecting objects (14, 16) are formed and the hypotheses are validated in dependence on signals received in at least one further measuring cycle (MZ2; MZi+2).

Abstract: A high speed high dynamic range and low power consumption analog correlator for use in a radar sensor. The analog correlator combines various pulse replication schemes with various parallel integrator architectures to improve the detection speed, dynamic range, and power consumption of conventional radar sensors. The analog correlator includes a replica generator, a multiplier, and an integrator module. The replica generator generates a template signal having a plurality of replicated pulse compression radar (PCR) pulses. The multiplier multiplies a received PCR signal with the plurality of replicated PCR pulses. The integrator module is coupled to the multiplier and configured to generate a plurality of analog correlation signals, each of which is based on the multiplying between the received PCR signal and one of the replicated PCR pulses.

Abstract: Apparatus and methods are described which are useful for determining a location characteristic between an RFID tag and an RFID tag reader or a second RFID tag. In various embodiments, signals backscattered from a singulated tag over a range of frequencies are evaluated for in-phase I and in-quadrature Q signal components. The I-Q data is processed to determine phase delay angles associated with each signal frequency. The phase delay data can be processed by a sum of squared errors method or Fourier transform method to determine a distance to the singulated tag. The methods can also be used to determine any of a location, a radial velocity, a directional velocity of the singulated tag, and proximity of the singulated tag to a second tag.

Abstract: An object ranging system operates by transmitting pulses derived from a frequency-swept signal and determining the beat frequency of a combination of the frequency-swept signal and its reflection from an object. A second (or higher) order harmonic is derived from the combination signal. Accordingly, determination of the beat frequency, and hence object range, is significantly enhanced. The frequency sweep is such that frequency changes occur at a substantially higher rate at the beginning of each the pulse repetition interval than at the end. Accordingly, because the frequency changes are concentrated in the period of pulse transmission, even reflections 'from a close object, where the time delay between the source signal and the reflection is very short, will cause a high beat frequency.

Abstract: Provided are transmitter topology, receiver topology and methods for generating and transmitting a radio signal at a transmitter and detecting and processing a radio signal at a receiver. The radio signals are transmitted across a wireless interface using Ultra Wideband (UWB) pulses. A transmitted reference approach is utilized. The radio signal include pairs of UWB pulses with each pair of pulses separated by a fixed time delay. The two pulses are then combined to provide for improved noise immunity.

Abstract: A single chip radio transceiver includes circuitry that enables detection of radar signals to enable the radio transceiver to halt communications in overlapping communication bands to avoid interference with the radar transmitting the radar pulses. The radio transceiver is operable to evaluate a number of most and second most common pulse interval values to determine whether a traditional radar signal is present. The radio transceiver also is operable to FM demodulate and incoming signal to determine whether a non-traditional radar signal such as a bin-5 radar signal is present. After FM demodulation, the signal is averaged wherein a substantially large value is produced for non-traditional radar signals and a value approximately equal to zero is produced for a communication signal that is not FM modulated with a continuously increasing frequency signal. Gain control is used to limit incoming signal magnitude to a specified range of magnitudes.

Abstract: A step frequency inverse synthetic aperture radar (ISAR) includes a transmitter configured to transmit a transmission pulse at a transmission frequency to a near earth object (NEO), the transmission frequency having a frequency range comprising a starting frequency, an ending frequency, and a step size; a receiver configured to receive a pulse response from the NEO, the pulse response corresponding to the transmission pulse; and a computer configured to determine a 3-dimensional image of the interior of the NEO from the pulse response.

Abstract: An apparatus and method for protecting against incoming projectiles comprising transmitting two radar waveforms, the first waveform comprising a pulsed continuous wave waveform, and the second waveform comprising a pulsed linear chirp waveform over a bandwidth, and based on returned radar data, causing deployment of a defense mechanism to intercept a detected incoming projectile.

Abstract: A radar having a high time and high spatial resolution and being capable of performing volume scanning with an inexpensive and simple structure, while enabling reduction is size and weight. A radar (50) is provided with an antenna unit (51) including a radio wave lens antenna device, which has a spherical transmission radio wave lens (2), a spherical reception radio wave lens (3), a primary radiator (4) arranged at a focal point of the radio wave lens (2), and a primary radiator (5) arranged at a focal point of the radio wave lens (3). The primary radiators (4, 5) pivot in an elevation direction about an axis connecting center points of the radio wave lenses (2, 3) and pivot in an azimuthal direction about an axis orthogonal to the axis connecting the center points of the radio wave lenses (2, 3).

Abstract: A system and method for concurrently operating a plurality of agile beam radar modes by pulse-to-pulse interleaving groups of the radar modes. Radar modes are grouped, each radar mode being allocated a certain amount of time for operation and a suitable pulse repetition frequency to improve or optimize the duty cycle of the antenna while concurrently operating the plurality of modes. Priorities may be assigned to groups or to individual radar modes within each group. In some embodiments, TDM communications are further interleaved within the radar modes to enhance the operation of the radar antenna.

Abstract: Narrow virtual transmit pulses are synthesized by differencing long-duration, staggered pulse repetition interval (PRI) transmit pulses. PRI is staggered at an intermediate frequency IF. Echoes from virtual pulses form IF-modulated interference patterns with a reference wave. Samples of interference patterns are IF-filtered to produce high spatial resolution holographic data. PRI stagger can be very small, e.g., 1-ns, to produce a 1-ns virtual pulse from very long, staggered transmit pulses. Occupied Bandwidth (OBW) can be less than 10 MHz due to long RF pulses needed for holography, while spatial resolution can be very high, corresponding to ultra-wideband (UWB) operation, due to short virtual pulses. X-Y antenna scanning can produce range-gated surface holograms from quadrature data. Multiple range gates can produce stacked-in-range holograms. Motion and vibration can be detected by changes in interference patterns within a range-gated zone.

Abstract: A signal transmission and reception device is disclosed that can be made compact and has wide-band band-pass characteristics. The signal transmission and reception device includes a first filtering unit that is composed of a distributed constant circuit and is capable of eliminating a first frequency component or a second frequency component. The second frequency is higher than the first frequency, and a second filtering unit that attenuates components of frequencies lower than the first frequency or components of frequencies higher than the second frequency.

Abstract: A level measuring instrument has a variable transmitting power for measuring a filling level in a tank. The level measuring instrument includes a generator unit generating one of a first oscillator signal and a second oscillator signal. The generator unit generates a transmit signal from one of the first oscillator signal and the second oscillator signal. The level measuring instrument includes further a controller controlling the generator unit. The generator unit generates one of first and second transmitting powers for the transmit signal.

Abstract: A monolithic substrate contains an integrated circuit comprising an amplifier having input and output, a mixer and a hybrid coupler for coupling the amplifier to the mixer. Metallic pads on the substrate are connected to each of two ports of the coupler and separate metallic pads are also connected to each of the input and output of the amplifier. The metallic pads allow the amplifier and mixer to be separately tested by a probe and the input or the output of the amplifier to be selectively connected to the mixer to enable the circuit to operate either as a receiver or transmitter. Alternatively, connections between the mixer and both input and output of the amplifier may be preformed and one of the connections subsequently severed depending on whether the circuit is to operate in receive or transmit mode.

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: An electronic circuit comprises a randomizing bit generator configured to generate a randomizing bit sequence based on a sequence selection input signal. The randomizing bit generator includes a counter operable to provide an individual starting count for the randomizing bit sequence and a parity generator responsive to an output of the counter. The circuit further comprises a pseudo-random number generator responsive to the randomizing bit generator. The pseudo-random number generator is operable to provide at least one pulsed signal based at least in part on the random bit sequence. The electronic circuit is operable to substantially eliminate interference in a series of pulsed signal transmissions comprising the at least one pulsed signal from each of two or more navigation devices, where each of the pulsed signals from each of the navigation devices is separated by an automatically adjustable time interval.

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: In an apparatus for detecting a distance and improving the SN ratio of received signals, an angular frequency (?1) of sinusoidal wave signals generated by a sinusoidal wave generator is brought into synchronism with an angular frequency (?) of burst pulse signals, and signals received by a transmitter/receiver microphone are orthogonally demodulated by using sinusoidal wave signals of the synchronized angular frequency. A microcomputer adds up the vectors of the demodulated signals for only a period of time equal to a section of transmitting the transmission waves from the transmitter/receiver microphone. A distance to a body is detected by using the received signals of which the vectors are added up.

Abstract: A level measuring instrument has a variable transmitting power for measuring a filling level in a tank. The level measuring instrument includes a generator unit selectively generating different transmitting powers. The generator unit is controlled so that the transmitting power is respectively adapted to the corresponding environmental conditions. For this purpose, the generator unit has for instance two different oscillators, which are driven selectively.

Abstract: A Quadrature Error Corrected Digital Waveform Synthesizer (QECDWS) employs frequency dependent phase error corrections to, in effect, pre-distort the phase characteristic of the chirp to compensate for the frequency dependent phase nonlinearity of the RF and microwave subsystem. In addition, the QECDWS can employ frequency dependent correction vectors to the quadrature amplitude and phase of the synthesized output. The quadrature corrections cancel the radars' quadrature upconverter (mixer) errors to null the unwanted spectral image. A result is the direct generation of an RF waveform, which has a theoretical chirp bandwidth equal to the QECDWS clock frequency (1 to 1.2 GHz) with the high Spurious Free Dynamic Range (SFDR) necessary for high dynamic range radar systems such as SAR. To correct for the problematic upconverter local oscillator (LO) leakage, precision DC offsets can be applied over the chirped pulse using a pseudo-random noise dither.

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: The present invention is a method and apparatus for providing a pseudo random sequence for a spread spectrum system that prevents interception and provides real estate and power consumption efficiency. A pseudo random sequence may be created in real-time by associating a pseudo random sequence of a channel location of the carrier frequency at an instant in time. For example, the entire band of the spread spectrum system may be scanned to detect a channel with a low received signal strength. The location of the channel, or the actual frequency of the channel, could be associated with a particular pseudo random sequence to create a hop set for frequency hopping. Additionally, the location of a characteristic of the spread spectrum system, such as a noise characteristic, could be utilized to determine a content of a pseudo random sequence.

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 distance can be measured with high resolution. A frequency controller (7) controls a voltage control oscillator (2) so as to change a signal source frequency f in a range containing two center frequencies f1 and f2 and transmits it as a traveling wave from an antenna (4) to a target (5). A reflected wave reflected by the target (5) and the traveling wave interfere each other and form a standing wave. A power detector (6) detects power corresponding to the amplitude of the standing wave and performs Fourier transform based on the two center frequencies f1 and f2 in Fourier transform means (11, 12), respectively, thereby calculating radar image functions P1(x), P2(x). The distance d to the target (5) satisfies the conditions that the phase difference of the two radar image functions zero-crosses and the amplitude of the radar image functions becomes maximum. The zero cross point of the phase difference is a zero cross point of a linear function and can be identified with high resolution.

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: A radar has a transmission section, a reception section that receives a reflected wave of the transmission wave, a transmission switch section, a delay section that delays a predetermined timing, a reception switching section, a difference processing section, and a calculation section. The transmission section switches between a first frequency and a second frequency to transmit a transmission wave having one of the frequencies. The transmission switch section switches between turning-on and turning-off of an operation of the transmission section at the predetermined timing. The reception switching section switches between turning-on and turning-off of an operation of the reception section according to the timing delayed. The difference processing section outputs a difference between the transmission wave and the reflected wave. The calculation section calculates a distance on a basis of a delay amount, when a detection waveform has a difference frequency between the first frequency and the second frequency.

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: An arrangement comprising a master unit and one or more slave units, where the master sends out bursts, at specified intervals, in a frequency hopping manner, with each burst being at a different frequency. The slave responds with acknowledgements, and the signal strengths of the acknowledgments are used to select one or more of the acknowledgments as the signals used for distance, or range, estimation. Advantageously, the durations of the intervals are fairly long during normal operation, and short at times when certain conditions occur, such as loss of communication or when accurate range estimation is required. Also, the slave is adapted to sleep while it is not expecting a burst transmission from the master, thereby saving power. The frequency hopping sequencing is preferably pseudo random, with a different sequencing of the same set of frequencies at different modes of operation.

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.