Abstract: In one embodiment, a lidar system includes a light source configured to emit optical pulses using multiple pulse intervals (PIs) that include a first PI and a second PI, where the first PI and the second PI are not equal. The lidar system also includes a receiver configured to detect multiple input optical pulses. The lidar system further includes a processor configured to generate multiple pixels, where each pixel of the multiple pixels corresponds to one of the multiple input optical pulses and is associated with one of the PIs. The processor is further configured to (i) determine, for a particular pixel of the multiple pixels, a group of nearby pixels and (ii) determine whether the particular pixel is range-wrapped based at least in part on the PI associated with each pixel of the group of nearby pixels.

Abstract: In one embodiment, a lidar system includes a light source configured to emit a first set of optical signals that include a first optical signal. The lidar system also includes a scanner that includes a polygon mirror configured to: rotate around an axis of rotation at a rotation rate, and direct the first set of emitted optical signals into a field of regard of the lidar system with the polygon mirror rotating at a first rotation rate. The lidar system further includes a receiver configured to detect a first received optical signal that includes a portion of the first optical signal that is scattered by a target located a distance from the lidar system. The lidar system also includes a controller configured to adjust the rotation rate of the polygon mirror for a second set of optical signals emitted by the light source.

Abstract: In one embodiment, a lidar system includes a light source configured to emit optical pulses using multiple pulse intervals (PIs) that include a first PI and a second PI, where the first PI and the second PI are not equal. The lidar system also includes a receiver configured to detect multiple input optical pulses. The lidar system further includes a processor configured to generate multiple pixels, where each pixel of the multiple pixels corresponds to one of the multiple input optical pulses and is associated with one of the PIs. The processor is further configured to (i) determine, for a particular pixel of the multiple pixels, a group of nearby pixels and (ii) determine whether the particular pixel is range-wrapped based at least in part on the PI associated with each pixel of the group of nearby pixels.

Abstract: A system includes a signal transmitter configured to emit a signal pulse and a signal receiver configured to receive one or more reflected pulses of the emitted signal pulse, wherein the signal receiver includes a plurality of comparators configured to sample the one or more reflected pulses at different intensity threshold levels to determine a group of slices representative of the received one or more reflected pulses, wherein each slice of at least a portion of the group of slices identifies a corresponding timing of when at least a portion of the received one or more reflected pulses met a corresponding intensity threshold level. The system further includes one or more processors configured to use the determined slices to reconstruct the one or more reflected pulses.

Abstract: In one embodiment, a method includes emitting, by a light source of a lidar system, multiple optical pulses using multiple alternating pulse repetition intervals (PRIs) that include a first PRI and a second PRI, where the first PRI and the second PRI are not equal. The method also includes detecting, by a receiver of the lidar system, multiple input optical pulses and generating, by a processor of the lidar system, multiple pixels. Each pixel of the multiple pixels corresponds to one of the input optical pulses, and each pixel includes a PRI associated with a most recently emitted optical pulse of the multiple optical pulses. The method also includes determining a group of neighboring pixels for a particular pixel of the multiple pixels and determining whether the particular pixel is range-wrapped based at least in part on the PRI associated with each pixel of the group of neighboring pixels.

Abstract: Methods, systems, and apparatus for transmitting a first set of continuous wave (CW) signals, where each CW signal of the first set of CW signals has a first signal frequency and the transmitter is turned off between transmission of each CW signal of the first set of CW signals. For each CW signal of the first set of CW signals, receiving a reflection of the CW signal, and selecting an analog to digital (A/D) sample of the reflection of the CW signal that does not contain ground reflections by selecting the A/D sample based on timing from the transmitter being turned off after transmission of the CW signal. Integrating the selected A/D samples from each of the CW signals of the first set of CW signals to obtain a single A/D sample for the first set of CW signals.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: Methods, systems, and apparatus for transmitting a first set of continuous wave (CW) signals, where each CW signal of the first set of CW signals has a first signal frequency and the transmitter is turned off between transmission of each CW signal of the first set of CW signals. For each CW signal of the first set of CW signals, receiving a reflection of the CW signal, and selecting an analog to digital (A/D) sample of the reflection of the CW signal that does not contain ground reflections by selecting the A/D sample based on timing from the transmitter being turned off after transmission of the CW signal. Integrating the selected A/D samples from each of the CW signals of the first set of CW signals to obtain a single A/D sample for the first set of CW signals.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: An apparatus for detecting objects includes a transceiver configured to generate a radar signal, a radar having a transmit antenna configured to transmit the radar signal, and a receive antenna configured to sense a return signal in response to a transmission of the radar signal. The apparatus also includes a processor configured to detect an object based on the return signal. One or more of the transmit antenna or the receive antenna include offset spiral feed antennas.

Abstract: A stepped-frequency radar signal is transmitted through a barrier. A transmitter of the stepped-frequency radar is on a first side of the barrier, a first object is on a second side of the barrier, and a second object that is distinct from the first object is on the second side of the barrier. A signal including a reflection of the transmitted signal from the first object and a reflection of the transmitted signal from the second object is sensed. The sensed signal is analyzed to determine that a first detection is associated with the first object and a second detection is associated with a second object.

Abstract: Systems and methods for sensing targets on an opposite side of a wall are disclosed. In some aspects, the techniques include providing an indication to a user that portions of reflected radar signals were blocked by radiofrequency-blocking material at the wall. In some aspects, the techniques include identifying candidate targets as multipath echoes or motion-induced errors based on a correlation map.

Abstract: A stepped-frequency radar signal is transmitted through a barrier. A transmitter of the stepped-frequency radar is on a first side of the barrier, a first object is on a second side of the barrier, and a second object that is distinct from the first object is on the second side of the barrier. A signal including a reflection of the transmitted signal from the first object and a reflection of the transmitted signal from the second object is sensed. The sensed signal is analyzed to determine that a first detection is associated with the first object and a second detection is associated with a second object.

Abstract: A device includes a radar system configured to be placed in a hiding mechanism, the radar system having one or more transmit antennas oriented within the hiding mechanism and configured to transmit one or more radar signals toward a barrier, one or more receive antennas oriented within the hiding mechanism and configured to receive reflection signals of the transmitted radar signal back through the barrier and back through the hiding mechanism, one or more transceivers coupled to the one or more transmit antennas and the one or more receive antennas, and an electronic processor to analyze the received reflection signals of the transmitted one or more radar signals, and determine, based on the analyzed received reflection signals, locations of the one or more individuals within a region at a side of the barrier.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: A stepped-frequency radar signal is transmitted through a barrier. A transmitter of the stepped-frequency radar is on a first side of the barrier, a first object is on a second side of the barrier, and a second object that is distinct from the first object is on the second side of the barrier. A signal including a reflection of the transmitted signal from the first object and a reflection of the transmitted signal from the second object is sensed. The sensed signal is analyzed to determine that a first detection is associated with the first object and a second detection is associated with a second object.

Abstract: An apparatus includes an extendable wand, and a sensor head coupled to the wand. The sensor head includes a continuous wave metal detector (CWMD) and a radar. When the wand is collapsed, the wand and the sensor head collapse to fill a volume that is smaller than a volume filled by the sensor head and the wand when the wand is extended. Frequency-domain data from a sensor configured to sense a region is accessed, the frequency-domain data is transformed to generate a time-domain representation of the region, a first model is determined based on the accessed frequency-domain data, a second model is determined based on the generated time-domain representation, the second model being associated with a particular region within the sensed region, and a background model that represents a background of the region is determined based on the first model and the second model.

Abstract: A stepped-frequency radar signal is transmitted through a barrier. A transmitter of the stepped-frequency radar is on a first side of the barrier, a first object is on a second side of the barrier, and a second object that is distinct from the first object is on the second side of the barrier. A signal including a reflection of the transmitted signal from the first object and a reflection of the transmitted signal from the second object is sensed. The sensed signal is analyzed to determine that a first detection is associated with the first object and a second detection is associated with a second object.