Abstract: A LIDAR sensor assembly includes a laser light source to emit laser light, and a light sensor to produce a light signal in response to sensing reflections of the laser light emitted by the laser light source from a reference surface that is fixed in relation to the LIDAR sensor assembly. A controller of the LIDAR sensor assembly can process a plurality of samples of reflected light signals, process the samples to remove erroneous readings, and then provide accurate distance measurement. The system can use low-pass filters, or other components, to filter the plurality of samples to enable the “actual,” or primary, reflected light signal (i.e., light signal reflected off of a surface in an environment external to the sensor assembly, as opposed to extraneous, internal reflections off of lenses or other components or noise) to be identified and an accurate time of flight to be calculated.

Abstract: A device can accurately discriminate an active pulse from noise by setting a dynamic noise floor that adjusts according to environmental conditions. For example, the device may discriminate, as the active pulse, a light pulse emitted by a light emitter of the system and reflected off an object to a light sensor, from noise such as sunlight glare by determining a dynamic noise floor and identifying, as an active pulse, at least a portion of the received signal that exceeds the dynamic noise floor for a threshold number of samples. The dynamic noise floor may be determined, for example, using a moving average of the received signal and/or shifting or scaling the noise floor based on other properties of the return signal.

Abstract: A LIDAR device can accurately calculate distances to objects in an environment by classifying a signal received from a sensor as being a particular type of signal (e.g., saturated or unsaturated) and selecting, based on the type of signal, a detector for processing the received signal from among multiple detectors. For example, the multiple detectors may include different programming and/or circuitry for determining a time delay of arrival (TDOA) between a time that a light pulse was emitted to a time that a pulse reflected off an object was received at a light sensor. The output of the selected detector may then be used to calculate a distance to the object from which the received signal was reflected.

Abstract: A LIDAR system emits laser bursts, wherein each burst has at least a pair of pulses. The pulses of each pair are spaced by a time interval having a variable duration to reduce effects of cross-talk. For example, certain embodiments may have multiple emitter/sensor channels that are used sequentially, and each channel may use a different duration for inter-pulse spacing to reduce the effects of cross-talk between channels. The durations may also be varied over time. The emitters and sensors are physically arranged in a two-dimensional array to achieve a relatively fine vertical pitch. The array has staggered rows that are packed using a hexagonal packing arrangement. The channels are used in a sequential order that is selected to maximize spacing between consecutively used channels, further reducing possibilities for inter-channel cross-talk.

Abstract: A time delay of arrival (TDOA) between a time that a light pulse was emitted to a time that a pulse reflected off an object was received at a light sensor may be determined for saturated signals by using an edge of the saturated signal, rather than a peak of the signal, for the TDOA calculation. The edge of the saturated signal may be accurately estimated by fitting a first polynomial curve to data points of the saturated signal, defining an intermediate magnitude threshold based on the polynomial curve, fitting a second polynomial curve to data points near an intersection of the first polynomial curve and the intermediate threshold, and identifying an intersection of the second polynomial curve and the intermediate threshold as the rising edge of the saturated signal.

Abstract: A support assembly for supporting a rotating body may include first and second supports defining first and second longitudinal support axes and configured to support the rotating body, such that the rotating body is rotatable relative to the first and second supports. A rotation axis about which the rotating body rotates may be transverse to the first and second longitudinal support axes. The support assembly may also include a spine coupled to the first and second supports. The support assembly may also include a motor associated with at least one of the first or second supports and configured to supply torque to rotate the rotating body. At least one of the spine, the first support, or the second support may define a recess configured to receive at least one of an electrical conductor or a data signals link associated with operation of the rotating body.

Abstract: A LIDAR system emits laser pulses, wherein each pulse is associated with a power level. A laser emitter is adjusted during operation of a LIDAR system using power profile data associated with the laser. The power profile data is obtained during a calibration procedure and includes information that associates charge duration for a laser power supply with the actual power output by laser. The power profiles can be used during operation of the LIDAR system. A laser pulse can be emitted, the reflected light from the pulse received and analyzed, and the power of the next pulse can be adjusted based on a lookup within the power profile for the laser. For instance, if the power returned from a pulse is too high (e.g., above some specified threshold), the power of the next pulse is reduced to a specific value based on the power profile.

Abstract: A LIDAR system may include a laser diode that emits a beam having a slow axis and a fast axis so that a cross-section of the beam has a width substantially greater than a height. A first three-element lens may be optically aligned with a photodetector of the LIDAR system. A second three-element lens may be optically aligned with the diode laser. The second three-element lens may include at least one lens having a predetermined astigmatism that reduces the width of the beam with respect to the height.

Abstract: A LIDAR system includes a laser emitter configured to emit a laser pulse in a sample direction of a sample area of a scene. A sensor element of the LIDAR system is configured to sense a return pulse, which is a reflection from the sample area corresponding to the emitted laser pulse. The LIDAR system may compare a width of the emitted laser pulse to a width of the return pulse in the time-domain. The comparison of the width of the emitted pulse to the width of the return pulse may be used to determine an orientation or surface normal of the sample area relative to the sample direction. Such a comparison leads to a measurement of the change of pulse width, referred to as pulse broadening or pulse stretching, from the emitted pulse to the return pulse.

Abstract: A LIDAR system includes one or more LIDAR sensor assemblies, which may be mounted to a vehicle or other object. Each LIDAR sensor assembly includes a laser light source to emit laser light, and a light sensor to produce a light signal in response to sensing reflected light corresponding to reflection of the laser light emitted by the laser light source from a reference surface that is fixed in relation to the LIDAR sensor assembly. A controller of the LIDAR sensor assembly may calibrate the LIDAR sensor assembly based at least in part on a signal from the light sensor indicating detection of reflected light corresponding to reflection of a pulse of laser light reflected from the reference surface.

Abstract: Techniques are described for aligning optical components within a LIDAR assembly. The techniques may be performed to align the optical components during manufacturing or assembly of the LIDAR assembly. For example, a first optical element (e.g., one of a light source or light sensor) may be installed in the LIDAR assembly. An optimal alignment for a second optical element (e.g., the other of the light source or light sensor) may be determined and the second optical element may be installed at the optimal alignment. The optimal alignment for the second optical element may be determined based on detected signals, for example, which may correspond to an alignment resulting in a strongest return signal, highest quality return signal, and/or minimal interference. Additionally, or alternatively, techniques may be used to align optical components at runtime by using an actuator to move one or more components of the LIDAR assembly during operation.

Abstract: An interface for transferring power and data between a non-rotating body and a rotating body may include a power transfer device coupled to the non-rotating body, and a power receiver coupled to the rotating body and configured to receive electrical power from the power transfer device. The interface may further include a first data transmitter coupled to the rotating body, and a first data receiver coupled to the non-rotating body and configured to receive data signals from the first data transmitter. The interface may also include a second data transmitter coupled to the non-rotating body, and a second data receiver coupled to the rotating body and configured to receive data signals from the second data transmitter. The wireless coupling between the power transfer device and the power receiver may include an inductive coupling, and the first data transmitter and the first data receiver may each include an optical communication device.

Abstract: An interface for transferring data between a non-rotating body and a rotating body of a sensor assembly using a bidirectional communication link. For instance, the interface may include a first data transmitter coupled to the rotating body and configured to transmit first data signals representing sensor signals generated by the sensor assembly. A first data receiver is coupled to the non-rotating body and configured to receive the first data signals via a first wireless coupling. The interface further includes a second data transmitter coupled to the non-rotating body and configured to transmit second data signals. A second data receiver is coupled to the rotating body and configured to receive the second data signals via a second wireless coupling. In some instances, the first data signals may be transmitted using a first wavelength and the second data signals may be transmitted using a second, different wavelength.

Abstract: A LIDAR system emits laser pulses, wherein each pulse is associated with a power level. A laser emitter is adjusted during operation of a LIDAR system using power profile data associated with the laser. The power profile data is obtained during a calibration procedure and includes information that associates charge duration for a laser power supply with the actual power output by laser. The power profiles can be used during operation of the LIDAR system. A laser pulse can be emitted, the reflected light from the pulse received and analyzed, and the power of the next pulse can be adjusted based on a lookup within the power profile for the laser. For instance, if the power returned from a pulse is too high (e.g., above some specified threshold), the power of the next pulse is reduced to a specific value based on the power profile.