Abstract: Time is transferred from an ultra wideband (UWB) transmitter to UWB receiver by transmitting a signal structure having an associated timing reference point together with a time value for the timing reference point. The UWB receiver receives the timing signal structure by synchronizing a receiver time base to the signal structure, demodulating the time value information, and using the demodulated time value information to set a receiver clock value. Propagation delay information is used to adjust the receiver clock value by advancing the receiver clock value to account for the propagation delay. In one embodiment, propagation delay is determined from a known distance between the transmitter and receiver. In another embodiment, the transmitter and receiver are part of a two-way link wherein propagation delay is measured by round trip timing measurements.

Abstract: A method and apparatus for at least semi-autonomously controlling a vehicle so as to avoid collisions are provided. A sensor is utilized to scan an area proximate the vehicle for a potential object of collision. The apparatus calculates navigational states of the potential object of collision relative to the vehicle to determine that the vehicle is on a course to enter within a predetermined miss distance relative to the potential object of collision. The apparatus alters the course of the vehicle based on the calculated navigational states.

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: A radar system for motor vehicles, having a radar sensor and an evaluation device for measuring distances and relative velocities of objects in the surrounding field of the vehicle, and a collision detection device, which, on the basis of the measured distances and relative velocities, recognizes an imminent collision and delivers data on the expected time of collision and the impact velocity to a precrash system. The radar sensor is switchable by the collision detection device to a velocity measurement mode in which a more precise measurement of the relative velocity is made.

Abstract: In a sensor and a radar for measuring the distance and the moving speed of a target by radiating a radio frequency, particularly a millimeter wave, compatibility between cost reduction and high detection performance has been conventionally a significant problem. In the present invention, the frequency of a transmitted signal changes during a fixed time while performing digitally-frequency-modulation on frequency sweeping straight lines extending, with different slopes relative to the time axis, from plural slightly different initial values serving as starting points, the signal is transmitted after being modulated so as to periodically repeat the sweep time serving as a unit, signal components corresponding to the respective sweeping slopes are digitally sampled, in synchronization with the transmitted modulation signal, from a received signal which is reflected and returned from a target, and the received signal is analyzed.

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: A pulse radar apparatus, which includes transmitting means for transmitting a pulsed wave and receiving means for receiving a reflected wave of the transmitted wave transmitted by the transmitting means and calculates at least one of a relative distance and a relative speed with respect to an object based on a relationship between the wave transmitted by the transmitting means and the wave received by the receiving means, is provided with pulse width varying means for varying a pulse width of the wave transmitted by the transmitting means according to a position of a required detection range where calculation of the at least one of the relative distance and the relative speed with respect to the object is required.

Abstract: Systems and methods of improving sampling of WLAN packet information to improve estimates of Doppler frequency of a WLAN positioning device. A device estimates the position of itself. The device includes a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device, extraction logic for extracting information from said received WLAN signals to identify the WLAN APs, and logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device. The WLAN radio module includes logic for measuring multiple received signal strength indicator (RSSI) values for sufficiently long WLAN packets to increase the sampled rate of RSSI of WLAN packets from WLAN APs and to thereby improve an estimate of the Doppler frequency of said device.

Abstract: Marine radar apparatus propagates groups of three pulses A, B, C of the same amplitude but different widths, the shorter pulse enabling detection of close range targets and the longer pulses enabling detection of longer range targets. The pulses are encoded differently with the short pulse A being a continuous wave signal and the longer pulses being modulated with a frequency modulated chirp, one pulse C being chirp up and the other B being chirp down. The power of the radar need only be about 190 w.

Abstract: In an object recognition apparatus for a vehicle which uses intensities of reflected waves from reflecting objects to make a recognition on whether a reflecting object is a vehicle or a non-vehicle, a plurality of transmission waves are emitted to receive a plurality of reflected waves from the reflecting objects, and a decision is made as to whether or not the reflecting object producing the plurality of reflected waves is a unitary reflecting object. If the decision shows a unitary reflecting object, the highest intensity of intensities of the reflected waves from the unitary reflecting object is compared with a reference intensity to makes a decision on whether the reflecting object is a vehicle or a non-vehicle. This enables univocally making a decision for each unitary reflecting object as to whether the reflecting object is more likely to be a vehicle or to be a non-vehicle, thus improving the recognition accuracy.

Abstract: The present invention is a method of finding range and velocity of a target in a radar system using a time scale factor. Specifically, sending at least one signal from at least one transmitter to a target. A return signal is then received from the target at each transmitter and the elapsed time is recorded. The range to the target and velocity of the target are calculated based on a time scale factor of the recorded elapsed times. These values are appropriately output to the user.

Abstract: An interferometric switched beam radar apparatus and method are disclosed. In one embodiment, a selected antenna of a planar array of beam forming antennas is activated with a substantially continuous frequency modulated transmit signal and a return signal is received from at least two return antennas that have a known offset distance relative to each other. Phase information is extracted from each return signal and used to present information regarding an operating environment to a user. Each beam forming antenna within the array may correspond to a particular viewing angle within the operating environment.

Abstract: A radar device can reliably, and rapidly detect dirt adhered to a radome surface without misdetection. The radar device includes a transmit/receive shared antenna (306) that transmits an electric wave to an object and receives a reflected wave that has been reflected from the object, a mixer (307) that mixes a transmission signal and a reception signal together to generate a beat signal, and a signal processing unit (312) that measures a distance to the object and a relative speed of the object on the basis of the beat signal. The transmit/receive shared antenna (306) modulates an unmodulated wave into a pulse and transmits the pulse modulated wave at a specific timing. In the case where the unmodulated pulse is transmitted, the beat signal that has been generated by the mixer (307) is converted into a digital voltage value by an A/D converter (310).

Abstract: A method for determining at least one of the distance to and the speed of an object is discussed. The method comprises determining an indication of whether the object is approaching or moving away and generating an interrogation signal comprising a sequence consisting of segments at constant frequency and segments of varying frequency, wherein if the determining step indicates the object is approaching then the varying frequency segments have decreasing frequency and if the determining step indicates that the object is moving away then the varying frequency segments have increasing frequency. The interrogation signal is transmitted and a version of the interrogation signal reflected from the object is detected. At least one of the distance to and speed of the object is then determined using a combination of the interrogation signal and the reflected version of the interrogation signal.

Abstract: A method for detecting an occurrence of interference between a return of a radar wave which has been transmitted by a radar and has an oscillating amplitude in time and a radio wave transmitted by some other radar, Includes steps of: detecting extremal points of an incident radio wave in which the radio wave transmitted by the other radar is superposed on the return of the radar wave, extracting, sequentially in time, an emerging pattern of the extremal points of the incident radio wave within each of periods of time to obtain a series of emerging patterns of the extremal points, detecting a period during which the emerging pattern of the extremal points is irregular among the series of the emerging patterns of the extremal points, and determining that the interference occurs during the detected period of time.

Abstract: In a method for estimating the width of radar objects in a position finding system for motor vehicles, which has at least two angle-resolving radar sensors, the reflection points positioned by several of the radar sensors, which are to be assigned to the same object on the basis of their distance data and relative velocity data, are combined into a group, lateral positions of the reflection points from this group are calculated, the difference of the lateral positions is calculated for various pairs of these refection points, and the maximum of these differences is sought out to determine an estimated value for a minimum width of the object.

Abstract: A method and device are provided for measuring distance and relative speed of a plurality of objects with the aid of an FMCW radar, transmitted signals being reflected by objects, and the reflected signals being received and mixed with the transmitted signals. A combination of distance and relative speed values is assigned to the mixer output frequencies of each frequency ramp for each object, and the distance and relative speed of a possible object are determined from points of intersection of a plurality of distance and relative speed combinations. The apparent (unreal) objects are eliminated by modifying the frequency slope of at least one frequency ramp according to the random principle in a subsequent measurement cycle.

Abstract: A system and method in which the position update rate is adaptively modified, based on previous position measurements. By adjusting the update rate based on velocity predictions from two or more position fixes, a lower update rate may be used without exceeding the maximum error. Lowering the update rate reduces power consumption in the UE, providing longer battery operation. The updating method may comprise periodically repeating the velocity prediction and periodically adjusting the update rate responsive thereto. The update rate may be adjusted using additional information such as an acceleration prediction, a minimum update rate, or a preferred error. In some embodiments a model for user movement may be used to provide more accurate predictions, for example, stationary, walking, jogging, city driving, and freeway driving. The updating method may comprise receiving user input regarding the maximum position error.

Abstract: In a method for checking the plausibility of objects in driver assistance systems for motor vehicles is described, two measured variables are derived from position data from two object position-finding systems of the vehicle that operate independently of one another, for an object located by the two position-finding systems, one variable for each position-finding system, these variables representing one and the same physical parameter, and the two measured variables are then checked for consistency, which is characterized by the fact that the parameter is the time to collision of the vehicle with the object, which is calculated in advance.

Abstract: A detecting and ranging apparatus and a program product obtain a correct relative velocity vector by a simple calculation based on a relative distance etc. obtained by a plurality of detectors such as a radar etc. by including: two relative distance measurement units receiving a reflected wave of a transmitted electromagnetic wave by an object to be detected, and thereby measuring a relative distance to the object to be detected, arranged at with each other different position; and an actual velocity vector calculation unit calculating an actual velocity vector of the object to be detected moving with an angle made in a direction from either relative distance measurement unit to the object to be detected based on the relative distances measured by the relative distance measurement units.

Abstract: In a radar system, harmonic excitation of an antenna is carried out in different frequency ranges. The antenna characteristic which varies as a function thereof is used to analyze different solid angle ranges around an object.

Abstract: An image pickup device for detecting a moving speed of a shot object and a method thereof are described. First, a coordinate of the image pickup device and a coordinate of the shot object are obtained at a first time point. Next, a coordinate of the image pickup device and a coordinate of the shot object are obtained at a second time point. Then, a moving distance of the shot object is calculated according to the coordinates of the shot object at the first and second time points. A moving speed of the shot object is calculated according to a time difference and the moving distance. Afterward, the obtained moving speed is displayed on the image pickup device, such that the user knows about the moving speed of the shot object.

Abstract: By pulsing transmission radio waves of continuous wave radar, clutter components included in a reception signal are suppressed. In a radar system that emits into space pulsed transmission radio waves being generated based on a frequency-modulated reference continuous waveform, acquires a reception signal by receiving the pulsed transmission radio waves reflected from an external object, and computes distance thereto and velocity thereof from the frequency of a beat signal obtained by mixing the acquired reception signal with the reference continuous waveform, the radar system includes a frequency-band selector 19 for classifying, on the basis of a spectral spread corresponding to the pulse width of the pulsed transmission radio waves, frequency components of the beat signal, and a distance/velocity calculator 20 for computing, on the basis of the classified results from the frequency-band selector 19, relative distance to and velocity of a moving object, or relative distance to a stationary object.

Abstract: A method and a radar sensor for transmitting frequency-modulated transmitted signals and receiving partial waves reflected by objects in the sensor detection range. A frequency shift of the received signal relative to the transmitted signal is determined for each object reflecting in each frequency ramp, it being possible to determine the relative speeds and the distances of the detected objects from the combination of frequency shifts of a plurality of ramps. The objects detected in preceding measurement cycles are stored in a memory, their relative speed and their distance being computed in advance for a future measurement cycle. The expected frequency shifts are determined and the frequency shifts of a plurality of ramps are combined in order to determine the relative speeds and the distances for objects that have not yet been stored in the memory.

Abstract: In order to prevent delays in output of detection results, even when a plurality of frequency modulation methods with different frequency change rates are used, an FM-CW radar device employing frequency modulation with two different frequency change rates, has distance/velocity detection unit for detecting the relative distance or relative velocity of a target object based on beat signals of transmission signals with the same frequency change rate and for detecting the relative distance or relative velocity using beat signals when the frequency change rates are different, and distance/velocity confirmation unit for adding evaluation values for relative distances or relative velocities detected in the detection processing, and for confirming the relative distance or relative velocity based on the evaluation value which has reached a criterion value. As a result, more data can be obtained in one detection cycle, and the same advantageous results as when executing a plurality of detection cycles can be obtained.

Abstract: A method for determining a variable associated with an object, the object having a plurality of points suitable for reflecting measuring signals, a probability of reflections occurring at these points is taken into account for evaluating at least one measuring signal.

Abstract: A radar sensor is described that includes a radar transmitter, a radar receiver configured to receive reflected returns of signals output by the radar transmitter, and a signal processing unit configured to process signals received by the radar receiver. The signal processing unit includes a comparator, a first filter comprising an output coupled to a reference input of the comparator, and a second filter comprising an output coupled to a signal input of the comparator. The first and second filters are configured to receive a common input related to the reflected returns. The first filter is configured to have a time constant such that a rise time of the first filter output is faster than a rise time of the second filter output.

Abstract: According to a conventional method of correlating beat frequencies in a radar device, a detecting state of a target differs at the time of up-chirping and at that of down-chirping, so that, when the number of peaks of beat frequencies does not match with each other, there occurs a situation in which the beat frequencies cannot be accurately correlated.

Abstract: A method for detecting and documenting red-light violations and/or speeding violations in which a radar beam is directed across all lanes of a roadway of interest and in which the speed and the position of a vehicle which passes through the radar beam are determined from the radar signals so as to be able to predict the probability of a red-light violation from the speed and the determined distance of the measured vehicle from a stop line and to trigger the recording of images of the violating vehicle at predetermined distances from the stop line.

Abstract: The proper timing or alignment for coherent or noncoherent integration of radar pulses returned from a potentially moving target is determined by determining the entropy associated with sets of range samples based on a plurality of different velocity hypotheses. That set associated with the minimum entropy is deemed to be the correct velocity hypothesis, and integration is then performed using the velocity hypothesis so determined.

Abstract: A method for processing received radar returns of a radiated wide-band arbitrary waveform in a wide-band radar processing system using spectral processing. The received wide-band radar returns are undersampled by using a first sampling rate to obtain an undersampled digital wide-band radar waveform. Spectral processing is performed on the power spectrum of the undersampled digital wide-band radar waveform in order to obtain a discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. Ripple frequencies indicating radar targets are located in the discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. A radar receiver, a digital wide-band radar processing system and a computer program product.

Abstract: In one embodiment, the disclosure relates to a method for estimating and predicting a target emitter's kinematics, the method including the steps of: (a) passively sampling, at a first sampling rate, an emitter signal to obtain at least one passively measured signal attribute for estimating the target kinematics; (b) inputting the passively measured signal attribute to an estimator at a first sampling rate; (c) determining a radar duty cycle for active radar measurements as a multiple of the first sampling rate, the multiple defining a duration between radar transmissions; (d) directing a radar system to make active target measurements at the determined duty cycle; (e) inputting to the estimator the active target measurements at the determined duty cycle, while continuously inputting the passively measured signal attributes.

Abstract: A target tracking method uses sensor(s) producing target signals subject to positional and/or angular bias, which are updated with sensor bias estimates to produce updated target-representative signals. Time propagation produces time-updated target states and sensor positional and angular biases. The Jacobian of the state dynamics of a target model produces the state transition matrix for extended Kalman filtering. Target state vector and bias covariances of the sensor are time propagated. The Kalman measurement residual is computed to produce state corrections, which are added to the time updated filter states to thereby produce (i) target state updates and (ii) sensor positional and angular bias updates.

Abstract: Radial gap measurement on turbines by a microwave measuring method and an evaluation of a Doppler effect which varies according to the size of the radial gap is described. At least one radar sensor embodied as a transmission and reception unit is provided in the wall of a turbine housing which is radially oriented towards the centre of the turbine. The relative speed of an outer end of a turbine blade, dependent on the size of the radial gap, is evaluated many times in relation to the radar sensor during the passage of the blade end past the same, and the course of the relative speed over time on the zero crossing constitutes a measure for the radial gap on the basis of the relation between the absolute value of the relative speed and the incline thereof in the zero crossing.

Abstract: A radar device is mounted on a vehicle, for detecting an object, and includes: a transmitting unit for transmitting an electromagnetic wave as a transmitter signal; a receiving unit for receiving a reflected signal that is reflected from the object as a receiver signal; a signal processing unit for measuring a distance and a relative velocity between the vehicle and the object on the basis of a beat signal that is obtained by the transmitter signal and the receiver signal; and an interference detecting unit for detecting the interference signal from another radar device or a communication device on the basis of a signal intensity of the frequency range that is not used for measuring the distance to the object and the relative velocity of the object.

Abstract: A dual mode motion sensor for detecting both motion of a moving target and a range of the moving target. The dual mode motion sensor normally operates in a pulse transmission mode. If motion is detected, the sensor automatically switches to a frequency modulated continuous wave transmission mode. This will allow the sensor to determine the range of the moving target. The sensor includes a microcontroller that compares the determined range of the moving target with a predetermined maximum detection range. If the determined range is outside or exceeds the predetermined maximum detection range the sensor will ignore the motion. If the determined range is within the predetermined maximum detection range, an alarm will be generated.

Abstract: A method for determining or compensating for the positional errors of a sensor tracking a target comprises the steps of operating the sensor to generate sensed information relating to the target and adding any sensor positional bias update information to produce updated sensed information. The target state is propagated to produce time updated state estimates. The Jacobian of the state dynamics and the state transition matrix for the extended Kalman filter algorithm are computed. The covariance of a state vector is time propagated using the state transition matrix.

Abstract: The present invention relates to a method and device for determining a relative velocity between a host (100) and a target (102). The present invention relates in particular to a method of the type that can be used in motor vehicle radar systems and specifically in radar systems of the type that detect obstacles in a blind spot of a motor vehicle. In the method according to the invention the following steps are carried out: substantially simultaneously determining a value for a radial velocity and a bearing with regard to a predefined spatial direction for a large number of measurement points (106) on the target (102); calculating a large number of quotients from the radial velocity and the cosine of the associated bearing, a quotient being calculated for each of the measurement points (106); determining an estimated relative velocity between the host (100) and the target (102) by forming an average of the large number of quotients.

Abstract: This radar device includes: a transmitter to transmit a transmitting signal whose frequency is periodically increased/decreased at a predetermined rate of change; a mixer to generate a beat signal by multiplying a received signal being transmitted by the transmitter and reflected back from an object to be detected and the transmitting signal; a frequency detector to detect a frequency of the beat signal; and a controller to control the rate of change of the frequency of the transmitting signal so that the frequency of the beat signal detected by the frequency detector becomes equal to or larger than a cut-off frequency of a flicker noise caused by the mixer.

Abstract: An embodiment of the invention includes a step of transmitting an OFDM waveform including several frequency carrier signals transmitted simultaneously, the frequency carrier signals being coded in order to improve the Doppler response. An embodiment of the invention includes a step of receiving the echoed waveform from the target. The initial phase of each frequency carrier signal is recovered from the echoed waveform. The recovered initial phase of each frequency carrier signal is cyclically shifted in order to compensate for the Doppler effect and subsequently decoded. A compressed pulse is synthesized from the decoded initial phases.

Abstract: A system and method for classifying a target vehicle using a sensor system, including a plurality of target vehicle sensors. The sensor system acquiring target vehicle data points that define at least an upper and lower portion of the target vehicle. The sensor system reconstructing a target vehicle shape using the target vehicle data points to provide a first and second target vehicle classification value. The sensor system determining an overall target vehicle classification based in part upon the first and second target vehicle classification values.

Abstract: A vehicular lamp includes a lamp chamber formed by a lamp body opening forward and a transparent front cover attached to a forward opening portion thereof; a lamp unit disposed within the lamp chamber; a millimeter wave radar for sending a millimeter wave to reflect off of an object in order to detect a distance and a relative speed of the object; and a millimeter wave direction-changing mechanism for sending forward the millimeter wave sent by the millimeter wave radar from a back surface side of the lamp unit, without reflecting the millimeter wave on a rearward side of the lamp unit.

Abstract: A method and device are provided for measuring distance and relative speed of a plurality of objects with the aid of an FMCW radar, transmitted signals being reflected by objects, and the reflected signals being received and mixed with the transmitted signals. A combination of distance and relative speed values is assigned to the mixer output frequencies of each frequency ramp for each object, and the distance and relative speed of a possible object are determined from points of intersection of a plurality of distance and relative speed combinations. The apparent (unreal) objects are eliminated by modifying the frequency slope of at least one frequency ramp according to the random principle in a subsequent measurement cycle.

Abstract: A computer implemented method for fusing position and range measurements to determine the position of at least one node of a plurality of distributed nodes is disclosed.

Abstract: Disclosed is a signal processing method for an FM-CW radar that can accurately detect the relative distance, relative velocity, etc. with respect to a target approaching or receding at a high relative velocity, wherein predicted values for peak frequencies currently detected in upsweep and downsweep sections are computed from the previously detected relative distance and relative velocity, and it is determined whether any of the predicted values exceeds a detection frequency range and, if there is a peak frequency that exceeds the detection frequency range, the frequency is folded and the folded frequency is taken as one of the predicted values, the method then proceeding to search the currently detected peak frequencies to determine whether there are upsweep and downsweep peak frequencies approximately equal to the predicted values and, if such upsweep and downsweep peak frequency are found, the peak frequency approximately equal to the folded predicted value is folded and the folded peak frequency is used.

Abstract: The invention provides a novel, low-cost, spin-stabilized lander architecture capable (with appropriate system scaling tailored to the attributes of the target) of performing a soft-landing on a solar-system body such as Earth's Moon, Mars, Venus, the moons of Mars, Jupiter, Saturn, Uranus and Neptune, selected near-Earth and main-belt asteroids, comets and Kuiper belt objects and even large human-made objects, and also moving about on the surface of the target solar-system body after the initial landing in movement akin to hopping.

Abstract: A method and a radar sensor for transmitting frequency-modulated transmitted signals and receiving partial waves reflected by objects in the sensor detection range. A frequency shift of the received signal relative to the transmitted signal is determined for each object reflecting in each frequency ramp, it being possible to determine the relative speeds and the distances of the detected objects from the combination of frequency shifts of a plurality of ramps. The objects detected in preceding measurement cycles are stored in a memory, their relative speed and their distance being computed in advance for a future measurement cycle. The expected frequency shifts are determined and the frequency shifts of a plurality of ramps are combined in order to determine the relative speeds and the distances for objects that have not yet been stored in the memory.

Abstract: A radar fall detector system. The radar fall detector system includes transmitter and receiver antennae and a signal processor that processes a reflected signal. Doppler analysis of the reflected signal determines a subject's moving body segment and its distance to a floor.

Abstract: An integrated circuit for measuring the distance and/or velocity of objects, having: a high-frequency signal generating device for generating a first HF signal having a predefined frequency and a predefined modulation curve from at least one LF signal; a diplex/mixing device, which is coupled to the high-frequency signal generating device for determining a frequency offset between the first HF signal and a reflected second HF signal; a transceiver device, which is coupled to the diplex/mixing device, for sending the first HF signal and simultaneously receiving the reflected second HF signal, which is a function of a predefined modulation curve of the first HF signal and a distance to a reflecting object; and an adapter device, which is coupled between the diplex/mixing device and the transceiver device, for adapting the impedance of the transceiver device as a function of the frequency of the first HF signal.

Abstract: It is an object of the present invention to prevent the sensitivity of radar apparatus from falling. A spread spectrum radar apparatus which detects an object, includes a carrier wave oscillator which generates a carrier wave, transmission unit which transmits a spread signal which is the carrier wave spread using a first PN code, an intermediate demodulated signal generating unit which receives a reflected wave which is the spread signal reflected from the object, and despreads the reflected wave using a delayed second PN code that has a cyclically reversed logical value of the first PN code, to generate an intermediate demodulated signal, a low-pass filter through which a specific frequency component of the intermediate demodulated signal passes, and a sampling unit which samples an output signal from the low-pass filter, and the sampling unit samples the output signal in synchronization with the cycle of the reversal.