Abstract: A complex frequency shift keyed homodyned diplexed radar system and method that can accurately determine the range of one or more targets where the targets have little or no velocity relative to the radar system. The system and method generates a FSK electromagnetic wave that is reflected off the one or more targets and converted into a delayed or phase shifted baseband signal and undelayed baseband signal where the delayed and an undelayed baseband signal may be analyzed to determine the range of the one or more targets.

Abstract: A method and apparatus for calibrating range in a radar system. Due mainly to temperature changes in a radar system which cause frequency deviation error, range errors can be introduced into the radar system, thus adversely affecting the determination of the position of targets relative to the host platform. These range errors can be corrected by detecting and accurately estimating the frequency deviation error of a radar system. The present invention improves target position determination performance in a radar system by reducing errors introduced by the frequency deviation error. The present invention relies upon the observation that the Doppler range rate is largely unaffected by frequency deviation error, and thus, is approximately equal to the actual range rate. In accordance with a first range calibration technique of the present invention, the radar system measures the range, Doppler range rate, and azimuth angle of a target during at least two successive time instances.

Abstract: A heterodyned double side band diplex radar system determines the range of targets as a function of the amplitude variation of reflected target Doppler signals. The present invention includes a real radar system that accurately determines the range of fading targets and the magnitude of the velocity of the targets. The present invention also includes a complex radar system that determines the relative velocity of targets in addition to the range of targets. In either embodiment, the transmitted signal may be modulated with a pseudo-random number (“PN”) sequence to attenuate or decorrelate signals reflected from targets beyond some maximum range. The modulation of the pseudo-random sequence may also attenuate or decorrelate signals reflected from targets closer than some minimum range. The present invention also includes a real radar system having BPSK modulation with PN coding. The selection of BPSK modulation enables or facilitates the implementation of a portion of the system in digital form.

Abstract: A method and apparatus for detecting the presence of objects in a vehicle operator's blind spots. The apparatus comprises a side-facing Doppler radar system using continuous wave (CW) transmission with frequency modulation (FM) operation from a frequency modulation switching technique. The radar system determines the presence, range and closing rate of detected targets. The radar system detects targets even when operated in adverse weather conditions and will not generate false warnings due to rain clutter caused by wet roads and other wet surroundings. The radar system uses ranging techniques to reject false targets that are detected outside of a predetermined target detection zone. In accordance with the present invention, the radar system indicates that a target is detected if and only if any part of the target is within the detection zone and it: (1) remains in front of the antenna for at least TH1 seconds; (2) is at a range between Range.sub.min and Range.sub.

Abstract: A method and apparatus for calibrating range in a radar system. Due mainly to temperature changes in a radar system which cause frequency deviation error, range errors can be introduced into the radar system, thus adversely affecting the determination of the position of targets relative to the host platform. These range errors can be corrected by detecting and accurately estimating the frequency deviation error of a radar system. The present invention improves target position determination performance in a radar system by reducing errors introduced by the frequency deviation error. The present invention relies upon the observation that the Doppler range rate is largely unaffected by frequency deviation error, and thus, is approximately equal to the actual range rate. In accordance with a first range calibration technique of the present invention, the radar system measures the range, Doppler range rate, and azimuth angle of a target during at least two successive time instances.

Abstract: A radar system including a means for distinguishing signals returned from (i.e., reflected by) objects that are stationary with respect to earth (i.e., "stationary objects") from signals returned from objects that are moving along with a host vehicle (i.e., the vehicle upon which the radar system is mounted). The system includes a radar antenna having a relatively narrow beam width centered at a "squint" angle .theta.. When the antenna is aimed such that the center of the beam is at a squint angle of .theta.=60.degree., the Doppler frequency of signals that are reflected from targets that are stationary along the roadside is significantly higher than the frequency of signals reflected from targets that are in the blind spot to the right-rear of the host vehicle and which are moving along with the host vehicle.

Abstract: A method and apparatus for calibrating azimuth boresight in a radar system. Antenna boresight misalignment can cause radar systems to inaccurately determine the position of targets relative to a platform vehicle. These errors can be corrected by detecting and accurately measuring a boresight offset angle defined as the angle between the radar antenna boresight and the direction of travel of the host platform vehicle. Several antenna boresight calibration techniques are described. A first technique calculates the boresight offset angle by obtaining target range and azimuth angle measurements at two instants in time. The boresight offset angle is determined by the geometric relationship of the offset angle, target range and azimuth values obtained at two successive time instants. A refined approach obtains target range and azimuth values at several successive time instants, calculating interim boresight offset angles at each time instant.

Abstract: The present invention concerns a method, an apparatus and an article of manufacture that satisfies the need for determining whether or not an obstacle vehicle is in the path of a host vehicle. Specifically, the present invention satisfies the above stated regardless of whether or not the host vehicle is moving in a straight path or along a curved path. Preferably, input data ("input") is collected from instruments mounted to a host vehicle. The input is used to calculate for the host vehicle the average turn rate, the radius of curvature of the path being traveled, the velocity, and a range from the host vehicle to a obstacle vehicle. Additionally, the input is used to determine the deviation of an obstacle from a 0.degree. reference azimuth extending through the center of a radar beamating from a radar unit mounted to the host vehicle. An obstacle azimuth angle .varies..sub.i is calculated and used to determine whether or not the obstacle is in the path of the host vehicle.