Abstract: Described herein are systems and methods for improving detection of a return signal in a light ranging and detection system (LiDAR). The method includes the following steps at the LiDAR system: encoding and transmitting a sequence of pulses based on a user signature. Then, receiving a multi-return signal based on a reflection off objects of the sequences of pulses. The multi-return signal may be decoded based on the user signature, and then authenticated the via a correlation calculation. The user signature may determine an amplitude of a first pulse in the sequence of pulses, an amplitude of a second pulse of the sequence of pulses, and an interval between the first pulse and the second pulse. A bit representation of the user signature is orthogonal to a bit representation of another user signature of another LiDAR system. The user signature may be dynamically adjusted by the LiDAR system.

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: 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: Methods and systems for performing three dimensional LIDAR measurements with an integrated LIDAR measurement device are described herein. In one aspect, a return signal receiver generates a pulse trigger signal that triggers the generation of a pulse of illumination light and data acquisition of a return signal, and also triggers the time of flight calculation by time to digital conversion. In addition, the return signal receiver also estimates the width and peak amplitude of each return pulse, and samples each return pulse waveform individually over a sampling window that includes the peak amplitude of each return pulse waveform. In a further aspect, the time of flight associated with each return pulse is estimated based on a coarse timing estimate and a fine timing estimate. In another aspect, the time of flight is measured from the measured pulse due to internal optical crosstalk and a valid return pulse.

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: Described herein are systems and methods that create a capacitive link based on a rotating cylinder capacitor. A cylindrical rotor rotates around a shaft and maintains an air gap between the cylindrical rotor and the shaft and to create one or more air gap capacitors. A first subsystem, comprising a light detection and ranging components, is coupled to the rotor. A second sub-subsystem, comprising data analysis functions, is coupled to the shaft. The first subsystem and the second subsystem are coupled via capacitive links created by the air gap capacitors. The communication signaling utilized on the capacitive links may be bi-directional and differential signaling. The first subsystem and the second subsystem may comprise a LIDAR light detection and ranging system. The second subsystem may power the first subsystem via inductive coupling.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with multiple illumination beams scanned over a three dimensional 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 three dimensional environment under measurement.

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: 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: Described herein are systems and methods that create a capacitive link based on a rotating cylinder capacitor. A cylindrical rotor rotates around a shaft and maintains an air gap between the cylindrical rotor and the shaft and to create one or more air gap capacitors. A first subsystem, comprising a light detection and ranging components, is coupled to the rotor. A second sub-subsystem, comprising data analysis functions, is coupled to the shaft. The first subsystem and the second subsystem are coupled via capacitive links created by the air gap capacitors. The communication signaling utilized on the capacitive links may be bi-directional and differential signaling. The first subsystem and the second subsystem may comprise a LIDAR light detection and ranging system. The second subsystem may power the first subsystem via inductive coupling.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with multiple illumination beams scanned over a three dimensional environment by one or more optical phase modulation devices are described herein. In one aspect, illumination light from each LIDAR measurement channel is emitted to the surrounding environment in a different direction by an optical phase modulation device. The optical phase modulation device also directs each amount of return measurement light onto a corresponding photodetector. The illumination pulse output of each LIDAR measurement channel is synchronized with commanded changes of state of each corresponding optical phase modulation device. In some embodiments, each optical phase modulation device is associated with a single LIDAR measurement channel. In some embodiments, multiple LIDAR measurement channels are associated with a single modulation device. In some embodiments, a one dimensional optical phase modulation device is employed.

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: 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: Described herein are systems and methods that determines a centroid of a waveform in a high noise environment. In one embodiment, the method may include determining a damping threshold and a noise-exclusion threshold for a waveform that define a three tier dynamic range for the waveform comprising a noise-exclusion region, damping region and a full region. The noise-exclusion threshold may be less than the damping threshold. Weights for each of the mass scalars may be determined based on the three tier dynamic range. The centroid may be determined based on the determined weights and their corresponding position vectors.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with different illumination intensity patterns are described herein. Repetitive sequences of measurement pulses each having different illumination intensity patterns are emitted from a LIDAR system. One or more pulses of each repetitive sequence have a different illumination intensity than another pulse within the sequence. The illumination intensity patterns are varied to reduce total energy consumption and heat generated by the LIDAR system. In some examples, the illumination intensity pattern is varied based on the orientation of the LIDAR device. In some examples, the illumination intensity pattern is varied based on the distance between a detected object and the LIDAR device. In some examples, the illumination intensity pattern is varied based on the presence of an object detected by the LIDAR device or another imaging system.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with different pulse repetition patterns are described herein. Each repetitive pattern is a sequence of measurement pulses that repeat over time. In one aspect, the repetition pattern of a pulsed beam of illumination light emitted from a LIDAR system is varied to reduce total energy consumption and heat generated by the LIDAR system. In some examples, the repetitive pattern is varied by skipping a number of pulses. In some examples, the repetitive pattern of pulses of illumination light emitted from the LIDAR system is varied by changing a repetition rate of the sequence of emitted pulses. In some examples, the pulse repetition pattern is varied based on the orientation of the LIDAR device. In some examples, the repetition pattern is varied based on an object detected by the LIDAR device or another imaging system.

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: A LiDAR-based 3-D point cloud measuring pattern includes a base, a housing, a plurality of photon transmitters and photon detectors contained within the housing, a rotary motor that rotates the housing about the base, and a communication component that allows transmission of signals generated by the photon detectors to external components. In several versions of the invention, the system includes a vertically oriented motherboard, thin circuit boards such as ceramic hybrids for selectively mounting emitters and detectors, a conjoined D-shaped lens array, and preferred firing sequences.