Lidar system design to mitigate Lidar cross-talk
Aspects of the present disclosure involve systems, methods, and devices for mitigating Lidar cross-talk. Consistent with some embodiments, a Lidar system is configured to include one or more noise source detectors that detect noise signals that may produce noise in return signals received at the Lidar system. A noise source detector comprises a light sensor to receive a noise signal produced by a noise source and a timing circuit to provide a timing signal indicative of a direction of the noise source relative to an autonomous vehicle on which the Lidar system is mounted. A noise source may be an external Lidar system or a surface in the surrounding environment that is reflecting light signals such as those emitted by an external Lidar system.
1. A Lidar system comprising:
an array of channels to provide ranging information for an autonomous vehicle (AV), a channel of the array of channels comprising a emitter paired with a receiver, the emitter to emit light signals into a surrounding environment, the receiver to receive return signals corresponding to reflections of the light signals off the surrounding environment; and
a noise source detector coupled to the array of channels, the noise source detector to detect a noise signal producing noise in one or more of the return signals, the noise source detector comprising:
a light sensor to receive the noise signal; and
a first timing circuit coupled to the light sensor, the first timing circuit to provide an indication of a direction of a noise source relative to the AV, the noise source corresponding to the noise signal,
wherein the array of channels includes a second timing circuit to measure a time of flight of one or more of the return signals, wherein the first timing circuit operates at a first level of precision and the second timing circuit operates at a second level of precision, and wherein the first level of precision is lower than the second level of precision.
2. The Lidar system of claim 1 , wherein:
the array of channels and the light sensor continuously rotate around a central axis of the Lidar system, the indication of the direction of the noise source comprises an indication of a position of the light sensor within a spin cycle, the spin cycle corresponding to a complete rotation of the array of channels and the light sensor around the central axis.
3. The Lidar system of claim 2 , wherein the indication of the position of the light sensor within the spin cycle comprises a timestamp that correlates to the position of the light sensor based on a duration of the spin cycle.
4. The Lidar system of claim 3 , wherein the providing of the indication of the position of the noise source by the first timing circuit comprises:
generating the timestamp by measuring a time at which the noise signal is received at the light sensor.
5. The Lidar system of claim 1 , wherein the light sensor is positioned at about 180 degrees from a center of a scanning direction of the array of channels.
6. The Lidar system of claim 1 , wherein the light sensor is tuned to a wavelength of the array of channels.
7. The Lidar system of claim 1 , wherein the light sensor comprises a light sensor having a wider vertical field of view relative to a horizontal field of view.
8. The Lidar system of claim 1 , wherein the light sensor measures an intensity of the noise signal produced by the noise source.
9. The Lidar system of claim 1 , wherein the noise source is one of:
an external Lidar system or a surface reflecting a light signal produced by the external Lidar system.
10. The Lidar system of claim 1 , wherein the autonomous vehicle is a truck.
11. A noise source detector to detect a noise signal producing noise in one or more return signals received at a Lidar unit comprising a first timing circuit to measure a time of flight of one of more of the return signals, the noise source detector comprising:
a light sensor to receive a noise signal; and
a second timing circuit coupled to the light sensor, the second timing circuit to provide an indication of a direction of a noise source corresponding to the noise signal relative to an autonomous vehicle (AV) system,
wherein the second timing circuit operates at a first level of precision and the first timing circuit operates at a second level of precision, and wherein the first level of precision is lower than the second level of precision.
12. The noise source detector of claim 11 , wherein the indication of the direction of the noise source comprises an indication of a position of the light sensor within a spin cycle of the Lidar unit.
13. The noise source detector of claim 12 , wherein the timing circuit provides the indication of the position of the light sensor within a spin cycle of the Lidar unit by:
maintaining a clock signal;
measuring, using the clock signal, a time at which the noise signal is received at the light sensor; and
correlating the time to the position of the light sensor in the spin cycle of the Lidar unit based on a spin rate of the Lidar unit.
14. The noise source detector of claim 12 , wherein the light sensor is positioned at about 180 degrees from a center of a scanning direction of the Lidar unit.
15. The noise source detector of claim 11 , wherein the light sensor is tuned to a wavelength of the Lidar unit.
16. The noise source detector of claim 11 , wherein the noise source is a surface in a surrounding environment.
17. A Lidar system comprising:
an array of channels to provide ranging information for an autonomous vehicle (AV), a channel of the array of channels comprising a emitter paired with a receiver, the emitter to emit light signals into a surrounding environment, the receiver to receive return signals corresponding to reflections of the light signals off the surrounding environment; and
a plurality of noise source detectors coupled to the array of channels, the plurality of noise source detectors to detect noise signals producing noise in one or more return signals, each noise source detector comprising:
a light sensor to receive a noise signal; and
a first timing circuit coupled to the light sensor, the first timing circuit to provide an indication of a direction of a noise source corresponding to the noise signal,
wherein the array of channels includes a second timing circuit to measure a time of flight of one or more of the return signals, wherein the first timing circuit operates at a first level of precision and the second timing circuit operates at a second level of precision, and wherein the first level of precision is lower than the second level of precision.
18. The Lidar system of claim 17 , wherein:
the plurality of noise source detectors are positioned around a central axis of the Lidar system; and
the array of channels and the plurality of noise source detectors are rotated around the central axis of the Lidar system.
19. The Lidar system of claim 17 , wherein the providing of the indication of the direction of the noise source by the first timing circuit comprises:
generating a timestamp by measuring a time at which the noise signal is received at the light sensor.
20. The Lidar system of claim 17 , wherein the noise source is another Lidar system.