Abstract: Described herein are systems and methods for improving detection of multi-return light signals, and more particularly to the mitigation of optical crosstalk in a Light Detection And Ranging (LIDAR) system. The methods may include cycling a passive state, where the LIDAR system receives returns from other optical sources, and in an active state, where the LIDAR system receives returns from its laser firing and from the other optical sources. By comparing the returns from the passive state and active state, crosstalk from the other optical sources may be removed. Other methods may include (1) phase locking intra LIDAR systems to fire their laser in different directions from one another; and (2) when two inter LIDAR system are firing a laser beam at one another within a field of view threshold, each inter LIDAR system may ignore the signal return from the other inter LIDAR system.

Abstract: A two-dimensional (2D) lidar scanner includes a scan mirror assembly and rotary component. The scan mirror assembly includes a scan mirror and a mirror-tilting apparatus coupled to the scan mirror. The rotary component is coupled to the scan mirror assembly and can drive a rotary motion of the scan mirror assembly about a first axis. The mirror-tilting apparatus is configured to tilt the scan mirror about a second axis substantially perpendicular to the first axis in response to the rotary component driving the rotary motion of the scan mirror assembly. An orientation of the scan mirror is operable to control a first angle of reflection of a laser beam in a first dimension and a second angle of reflection of the laser beam in a second dimension during a lidar scanning process.

Abstract: Described herein are systems and methods that may efficiently detect multi-return light signals. A light detection and ranging system, such as a LIDAR system, may fire a laser beam that may hit multiple objects with a different distance in one line, causing multi-return light signals to be received by the system. Multi-return detectors may be able to analyze the peak magnitude of a plurality of peaks in the return signals and determine a multitude of peaks, such as the first peak, the last peak and the maximum peak. One embodiment to detect the multi-return light signals may be a multi-return recursive matched filter detector. This detector comprises a matched filter, peak detector, centroid calculation and a zeroing out function. Other embodiments may be based on a maximum finder that algorithmically selects the highest magnitude peaks from samples of the return signal and buffers for regions of interests peaks.

Abstract: Motion and video data from vehicle sensors and camera arrays attached to a vehicle collect video and sensor data along a path driven by the vehicle. A system processes such data to produce high-accuracy structured map data, as might be used to precisely locate a moving vehicle in its environment. Positions are calculated from the sensor data. The positions are updated based on the video data. Positions of features in the video are used to create or update structured map data.

Abstract: Described herein are systems and methods that that mitigate avalanche photodiode (APD) blinding and allow for improved accuracy in the detection of a multi-return light signal. A blinding spot may occur due to saturation of a primary APD. The systems and methods include the incorporation of a redundant APD and the utilization of time diversity and space diversity. Detection by the APDs is activated by a bias signal. The redundant APD receives a time delayed bias signal compared to the primary APD. Additionally, the redundant APD is positioned off the main focal plane in order to attenuate an output of the redundant APD. With attenuation, the redundant APD may not saturate and may have a successful detection during the blinding spot of the primary APD. Embodiments may include multiple primary APDs and multiple secondary APDs.

Abstract: Methods, apparatus, and systems related to light detection and ranging (LIDAR) are described. In one example aspect, a LIDAR apparatus includes a light emitter configured to generate, according to a first electrical pulse signal, a pulse light signal. The first electrical pulse signal comprises a first set of non-uniformly spaced pulses. The apparatus includes a receiver configured to convert returned light signals from the object into electrical signals and a filtering subsystem in communication with the receiver, configured to receive the electrical signals from the receiver and remove a point from a set of points representing at least a partial surface of the object as noise by determining whether there is a coherence between the point and corresponding neighboring points of the point along at least a first direction and a second direction of the set of points.

Abstract: Methods and systems for improved simultaneous localization and mapping based on 3-D LIDAR image data are presented herein. In one aspect, LIDAR image frames are segmented and clustered before feature detection to improve computational efficiency while maintaining both mapping and localization accuracy. Segmentation involves removing redundant data before feature extraction. Clustering involves grouping pixels associated with similar objects together before feature extraction. In another aspect, features are extracted from LIDAR image frames based on a measured optical property associated with each measured point. The pools of feature points comprise a low resolution feature map associated with each image frame. Low resolution feature maps are aggregated over time to generate high resolution feature maps.

Abstract: Described herein are systems and methods that implement a dual axis resonant scanning mirror to support a sensor system such as a LIDAR system. The scanning mirror may comprise: 1) a small dual axis mirror, in which each axis is moving by similar electromagnetic mechanisms can generate crosstalk between each of these electromagnetic mechanisms causing perturbations in the motion; 2) a primary axis that may need to be driven independently of the motion of a secondary axis and vice versa; 3) an optical position sensor; 4) a scanning mirror assembly that may be mounted to a scanner base via the secondary axis. The scanning mirror assembly may comprise resonant spring, resonant spring assembly, the rocking chair (with electromagnetic drive coils), the scanner base with a set of two secondary axis propulsion magnets, the mirror with a spacer and primary axis propulsion magnets, and the optical sense board.

Abstract: Described herein are systems and methods for improving detection of a return signal in a light ranging and detection system. The system comprises a transmitter and a receiver. A first sequence of pulses may be encoded with an anti-spoof signature and transmitted in a laser beam. A return signal, comprising a second sequence of pulses, may be received by the receiver and the anti-spoof signature extracted from the second sequence of pulses. If based on the extraction, the first and second sequences of pulses match, the receiver outputs return signal data. If based on the extraction, the first and second sequence of pulses do not match, the return signal is disregarded. The system may dynamically change the anti-spoofing signature for subsequent sequences of pulses. Additionally, the first sequence of pulses may be randomized relative to a prior sequence of pulses.

Abstract: Methods and systems for performing three-dimensional (3-D) LIDAR measurements with multiple illumination beams scanned over a 3-D environment are described herein. In one aspect, illumination light from each LIDAR measurement channel is emitted to the surrounding environment in a different direction by a beam scanning device. The beam scanning device also directs each amount of return measurement light onto a corresponding photodetector. In some embodiments, a beam scanning device includes a scanning mirror rotated in an oscillatory manner about an axis of rotation by an actuator in accordance with command signals generated by a master controller. In some embodiments, the light source and photodetector associated with each LIDAR measurement channel are moved in two dimensions relative to beam shaping optics employed to collimate light emitted from the light source. The relative motion causes the illumination beams to sweep over a range of the 3-D environment under measurement.

Abstract: A plurality of beams of illumination light are emitted from a LIDAR device over a range of angles and scanned about an axis of rotation. The range of angles includes the axis of rotation. Intermediate electronics boards provide mechanical support and electrical connectivity between a rotating electronics board and various elements of a light emission and collection engine. One or more of the optical elements of the collection optics, the illumination optics, or both, is constructed from one or more materials that absorb light outside of a predetermined wavelength range. An overmolded lens is fixedly coupled to one or more of the light detecting elements to collect incoming light over a larger range of angles. A lens element is disposed in the light path between a light emitting element and the illumination optics to flatten the intensity distribution of light emitted from the light emitting element to reduce peak intensity.

Abstract: Apparatus and methods for aligning circuit boards (e.g., for LIDAR systems) are disclosed. According to one embodiment, an electronic device comprises a secondary device and a coupling device coupled to the secondary device. The coupling device comprises a plurality of conductive members, including a first conductive member and a second conductive member. Each of the conductive members comprises a first end configured to electrically and mechanically couple to a primary circuit board and a second end electrically and mechanically coupled to the secondary device. Each of the plurality of conductive members has an attribute adjustable in response to a condition being added to the respective conductive member, and is configured to maintain the adjusted attribute after the condition is removed.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with a highly integrated LIDAR measurement device are described herein. In one aspect, the illumination source, detector, and illumination drive are integrated onto a single printed circuit board. In addition, in some embodiments, the associated control and signal conditioning electronics are also integrated onto the common printed circuit board. Furthermore, in some embodiments, the illumination drive and the illumination source are integrated onto a common Gallium Nitride substrate that is independently packaged and attached to the printed circuit board. In another aspect, the illumination light emitted from the illumination source and the return light directed toward the detector share a common optical path within the integrated LIDAR measurement device. In some embodiments, the return light is separated from the illumination light by a beam splitter.

Abstract: Described herein are systems and methods that detect an electromagnetic signal in a constant interference environment. In one embodiment, the electromagnetic signal is a light signal. A constant interference detector may detect false signal “hits” generated by constant interference, such as bright light saturation, from valid signals. The constant interference detector determines if there is constant interference for a time period that is greater than a time period of the valid signal. In one embodiment, if a received signal exceeds a programmable threshold value for a programmable period of time, when compared to previously stored ambient light, a control signal is generated to inform the next higher network layer of a sudden change in ambient light. This control signal can be used to either discard the present return or process the signal in a different way. A constant interference detector may be a component of a LIDAR system.

Abstract: Methods and systems for improved simultaneous localization and mapping based on 3-D LIDAR image data are presented herein. In one aspect, LIDAR image frames are segmented and clustered before feature detection to improve computational efficiency while maintaining both mapping and localization accuracy. Segmentation involves removing redundant data before feature extraction. Clustering involves grouping pixels associated with similar objects together before feature extraction. In another aspect, features are extracted from LIDAR image frames based on a measured optical property associated with each measured point. The pools of feature points comprise a low resolution feature map associated with each image frame. Low resolution feature maps are aggregated over time to generate high resolution feature maps.

Abstract: Methods and systems for performing multiple pulse LIDAR measurements are presented herein. In one aspect, each LIDAR measurement beam illuminates a location in a three dimensional environment with a sequence of multiple pulses of illumination light. Light reflected from the location is detected by a photosensitive detector of the LIDAR system during a measurement window having a duration that is greater than or equal to the time of flight of light from the LIDAR system out to the programmed range of the LIDAR system, and back. The pulses in a measurement pulse sequence can vary in magnitude and duration. Furthermore, the delay between pulses and the number of pulses in each measurement pulse sequence can also be varied. In some embodiments, the multi-pulse illumination beam is encoded and the return measurement pulse sequence is decoded to distinguish the measurement pulse sequence from exogenous signals.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with an integrated LIDAR measurement device are described herein. In one aspect, a Gallium Nitride (GaN) based illumination driver integrated circuit (IC), an illumination source, and a return signal receiver IC are mounted to a common substrate. The illumination driver IC provides a pulse of electrical power to the illumination source in response to a pulse trigger signal received from the return signal receiver IC. In another aspect, the GaN based illumination driver IC controls the amplitude, ramp rate, and duration of the pulse of electrical power based on command signals communicated from the return signal receiver IC to the illumination driver IC. In a further aspect, illumination driver IC reduces the amount of electrical power consumed by the illumination driver IC during periods of time when the illumination driver IC is not providing electrical power to the illumination source.

Abstract: Methods and systems for performing three-dimensional (3-D) LIDAR measurements with multiple illumination beams scanned over a 3-D environment are described herein. In one aspect, illumination light from each LIDAR measurement channel is emitted to the surrounding environment in a different direction by a beam scanning device. The beam scanning device also directs each amount of return measurement light onto a corresponding photodetector. In some embodiments, a beam scanning device includes a scanning mirror rotated in an oscillatory manner about an axis of rotation by an actuator in accordance with command signals generated by a master controller. In some embodiments, the light source and photodetector associated with each LIDAR measurement channel are moved in two dimensions relative to beam shaping optics employed to collimate light emitted from the light source. The relative motion causes the illumination beams to sweep over a range of the 3-D environment under measurement.

Abstract: LIDAR measurement systems employing a multiple channel, GaN based illumination driver integrated circuit (IC) are described herein. In one aspect, the multiple channel, GaN based illumination driver IC selectively couples each illumination source associated with each measurement channel to a source of electrical power to generate a measurement pulse of illumination light. In one aspect, each pulse trigger signal associated with each measurement channel is received on a separate node of the IC. In another aspect, additional control signals are received on separate nodes of the IC and communicated to all of the measurement channels. In another aspect, the multiple channel, GaN based illumination driver IC includes a power regulation module that supplies regulated voltage to various elements of each measurement channel only when any pulse trigger signal is in a state that triggers the firing of an illumination pulse.

Abstract: An apparatus may include an energy rate limiter, an electro-optical transmitter, and an energy monitor. The energy rate limiter limits energy transfer, based on an energy control signal, from a power supply to the energy storage module. The energy storage module is charged based on the energy transfer from the power supply. The electro-optical transmitter includes lasers coupled to local energy storage module. Laser firings of the lasers are based on an electrical potential of the energy storage module and laser enable signals corresponding to the lasers. The energy monitor is coupled to the energy storage module and triggers a safety alarm signal if a voltage provided by the energy storage module violates a safety condition related to a threshold voltage. The energy rate limiter terminates the energy transfer from the power supply to the local energy storage module after the safety condition is violated.