A near object detection (NOD) system includes a plurality of sensors, each of the sensors for providing detection coverage in a predetermined coverage zone and each of the sensors including a transmit antenna for transmitting a first RF signal, a receive antenna for receiving a second RF signal and means for sharing information between each of the plurality of sensors in the NOD system.

Near object detection system

A continuous wave Doppler radar system having a transmitter module and a receiver module is provided for automotive vehicles. Each module includes an antenna system, including a horn, a lens, and a waveguide system, which is attached to a monolithic microwave integrated circuit (MMIC) chip that provides all necessary electronic functions. Each MMIC chip may be attached to a metal base heat sink, which may be conveniently connected to a base plate heat sink that holds the entire radar assembly. The transmitter module includes a voltage controlled oscillator (VCO) that generates a VCO frequency signal which is amplified and switched sequentially to three multiplier chains for transmission in three different directions. Each transmit signal is taken off the MMIC chip by a dielectric waveguide and directed to the antenna system. The receiver module includes three receivers that are selected sequentially to provide a beam azimuth scanning function. A reference local oscillator is provided at the VCO frequency by electromagnetic radiative coupling from the VCO of the transmitter module. Information on the location and relative speed of a radar target are obtained by comparing the frequency of the signal reflected by the target with the frequency of the signal radiated by the transmitter module. Quadrature mixers are used for each receiver channel to output low frequency data signals containing amplitude and phase information on the received reflected signal. Radar directional discrimination is achieved by sequential selection of the mixer output signals.

Doppler radar system for automotive vehicles

A relatively narrow beam of either RF or optical electromagnetic radiation is scanned over a relatively wide azimuthal range. The return signal is processed to detect the range and velocity of each point of reflection. Individual targets are identified by clustering analysis (102) and are tracked (106) in a Cartesian coordinate system using a Kalman filter. The threat to the vehicle for a given target is assessed (116) from estimates of the relative distance, velocity, and size of each target, and one or more vehicular devices are controlled (120) responsive to the assessment of threat so as to enhance the safety of the vehicle occupant. In a preferred embodiment, a quantized linear frequency modulated continuous wave RF signal is transmitted from and received by a multi-beam antenna having an azimuthal range of at least +/- 100 degrees and an individual beam width of approximately 10 degrees.

Predictive collision sensing system

A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone.

Radar detection method and apparatus

A system for monitoring operation and location of a moving first vehicle relative to a second vehicle. A minimum separation distance between the first and second vehicles is estimated, based on the first vehicle velocity, and optionally on the second vehicle velocity, using location determination (LD) signals received from satellite-based transmitters from GPS, GLONASS and LEO satellites, or from ground-based signal sources such as LORAN signal towers, and using ranging signals from SONAR, RADAR or a similar system. The minimum separation distance is compared with the actual separation distance at selected times, and a vehicle driver is advised if the actual separation distance is too small, if the separation distance is decreasing too quickly, or if the second vehicle velocity is decreasing too quickly. The second vehicle may travel in the same traffic lane, in an adjacent lane, or on a road that intersects the road used by the first vehicle. Where the first and second vehicles travel on separate roads that will intersect, the system estimates whether the second vehicle will stop, or will be able to stop, at the intersection. The second vehicle may be a railroad car, such as a locomotive, or a road vehicle, such as an automobile, bus or truck. A maximum vehicle clear-view velocity, consistent with vehicle stopping within a selected distance, is estimated. Road conditions are estimated and compensated for in estimating the minimum separation distance and/or the maximum vehicle clear-view velocity.

Dynamic monitoring of vehicle separation

An FM/CW radar system is disclosed for determining a safe stopping distance between a moving vehicle and a potential obstacle. The radar signal is modulated linearly over several slopes. A microstrip phased array transmit/receive antenna is also disclosed having a hybrid tap, corporate feed structure. Signals from the antenna are amplified and filtered, and passed through an analog to digital converter to a signal processor, which performs a Fast Fourier Transform on the signals to convert them from time domain data to frequency domain data. The frequency domain data is then used to solve target range and doppler equations, determine safe stopping distances, and sound or display alarms if the safe stopping distance has been violated. A sensitivity control adjusts for road conditions or operator reaction time variations.

Safe stopping distance detector, antenna and method

A frequency modulated/continuous wave (FM/cw) radar developed for automotive applications is described in this paper. The objective of this effort was to design a low-cost automotive collision warning radar that could be operated under Part 15 of the U.S. Federal Communications Commission regulations regarding intentional radiators including proximity sensors. In this paper, we describe a forward looking homodyne FM/cw 24.125 GHz radar with a digital signal processor (DSP). The data is collected while the FM/cw transceiver is modulated with several linear chirps of differing bandwidths and modulation slopes. The processor uses this data to calculate the range and Doppler velocity of multiple targets for the purpose of finding the safe following distance that should be kept between the host vehicle and targets. The system specifications and the effects of power and bandwidth on radar performance are shown. The ambiguity function of the homodyne transceiver and FFT spectral processor are shown along with the method of resolving these ambiguities for multiple targets. Data are presented showing radar measurements of a conducting sphere and test vehicle.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Wojciech Klimkiewicz

Papers

Safe stopping distance detector, antenna and method

24-GHz frequency modulated/continuous wave automotive radar designed for collision warning