Abstract: Pulsed radar detects the presence and range of very short-range objects via small perturbations in phase and/or amplitude of relatively long duration coherently related transmit pulses. In one embodiment, echoes forming a received signal waveform from a sampling baseband radar receiver are processed at audio frequency to look for perturbations of the phase of the time-stretched received radar signal while the radar is still transmitting a long-duration pulse. In a second embodiment, the time-stretched received signal is processed to look for perturbations in the amplitude of the received radar signal. Small amplitude perturbations due to constructive and destructive interference of the transmitted and reflected signals occur in the receiver when objects are very close to the radar if the receiver is not heavily saturated. These same techniques can also be used to achieve highly accurate ranging of long-distance objects and detection of overlapping echoes from multiple objects.

Abstract: Apparatus and methods for adjusting or “hopping” the center frequency or the pulse repetition frequency of a radar system improve the co-locatability of multiple radars commonly located in a region. In a Time Domain Downconversion (TDDC) or Ultra-Wideband (UWB) radar system having a display update period between range sweeps, the preferred device comprises a frequency variable oscillator for adjusting the radar's internal timing reference frequency during a plurality of the display update periods. Radar frequency hopping methods and apparatus may result in improvements in interference immunity compared to other interference reduction techniques and may achieve cost reduction. In frequency hopping radar, if an actual target is present, the receiver waveform will repeat at the newly adjusted center frequency. Confirmation of a target is realized as an ongoing reflection and not interference.

Abstract: In an object detection radar system, dynamically adjusting the gain of a radar during its range sweep cycle, either by tuning its transmitter power or its receiver sensitivity or both, allows a variety of detection pattern shapes to be realized. Adjusting the gain is done by using a plurality of different gain corrections, which are applied in the sweep cycle at different ranges. Thus, certain types of detection patterns, as controlled through a setting feature or via a user interface, may be realized by incorporation of an internal microcontroller and associated embedded program into an object detection radar system.

Abstract: Apparatus and methods for adjusting or “hopping” the center frequency or the pulse repetition frequency of a radar system improve the co-locatability of multiple radars commonly located in a region. In a Time Domain Downconversion (TDDC) or Ultra-Wideband (UWB) radar system having a display update period between range sweeps, the preferred device comprises a frequency variable oscillator for adjusting the radar's internal timing reference frequency during a plurality of the display update periods. Radar frequency hopping methods and apparatus may result in improvements in interference immunity compared to other interference reduction techniques and may achieve cost reduction. In frequency hopping radar, if an actual target is present, the receiver waveform will repeat at the newly adjusted center frequency. Confirmation of a target is realized as an ongoing reflection and not interference.