Apparatus and method for mitigating LiDAR interference through pulse coding and frequency shifting

1. An apparatus, comprising:

a first emitter emitting at a first frequency a first plurality of optical pulses that form a first pulse collection with a first pattern;

a second emitter emitting at a second frequency different than the first frequency a second plurality of optical pulses that form a second pulse collection with a second pattern different than the first pattern;

a first receiver to collect during a time of flight time window a first reflected pulse collection corresponding to the first pulse collection reflected from a sensed object;

a second receiver to collect during the time of flight time window a second reflected pulse collection corresponding to the second pulse collection reflected from the sensed object; and

a processor to analyze the first reflected pulse collection and the second reflected pulse collection to produce first reflected pulse collection metrics and second reflected pulse collection metrics, wherein the first reflected pulse collection and the second reflected pulse collection are each analyzed to form a detected signal histogram that plots reflected pulse collections as a function of time of flight where an interfering signal contributes to a noise floor, but does not substantially impact the detected signal histogram.

2. The apparatus of claim 1 wherein the first plurality of optical pulses includes a first plurality of optical pulse codes and the second plurality of optical pulses includes a second plurality of optical pulse codes.

3. The apparatus of claim 2 wherein each optical pulse code of the first plurality of optical pulse codes and the second plurality of optical pulse codes has off-peak autocorrelation coefficients that are less than one.

4. The apparatus of claim 2 wherein each optical pulse code of the first plurality of optical pulse codes and the second plurality of optical pulse codes has complementary sequences that cancel side lobes when summed.

5. The apparatus of claim 1 wherein the first reflected pulse collection metrics include a first detected signal histogram that plots the first reflected pulse collection as a function of the time of flight time window and the second reflected pulse collection metrics include a second detected signal histogram that plots the second reflected pulse collection as a function of the time of flight time window.

6. The apparatus of claim 1 wherein the first reflected pulse collection metrics include a first average detected signal for the first reflected pulse collection and a second average detected signal for the second reflected pulse collection.

7. The apparatus of claim 1 wherein the first reflected pulse collection metrics include a first weighted average detected signal for the first reflected pulse collection and a second weighted average detected signal for the second reflected pulse collection.

8. The apparatus of claim 1 wherein the first reflected pulse collection metrics include a first detected signal standard deviation for the first reflected pulse collection and a second detected signal standard deviation for the second reflected pulse collection.

9. The apparatus of claim 1 further comprising a reference clock connected to a first frequency divider to form the first frequency and a second frequency divider to form the second frequency.

10. The apparatus of claim 1 wherein the first plurality of optical pulses are formed from a first pulse pattern modulator responsive to a first stored pulse code and the second plurality of optical pulses are formed from a second pulse code pattern modulator responsive to a second stored pulse code.

11. The apparatus of claim 1 wherein the first receiver is connected to a first memory that stores first reflected pulses for the duration of the time of flight time window and the second receiver is connected to a second memory that stores second reflected pulses for the duration of the time of flight time window.