LIGHT DETECTION AND RANGING SYSTEM, OPTICAL RECEIVER SYSTEM FOR A LIGHT DETECTION AND RANGING SYSTEM AND METHOD FOR OPERATING A LIGHT DETECTION AND RANGING SYSTEM

Abstract

A light detection and ranging system having a reference receiver channel and at least one comparator for comparing the output of the reference receiver channel and the output of each of the separate receiver channels to a second emitted light signal, the reference receiver channel having a reference optical sensor and a reference amplifier, wherein the at least one comparator can adjust the gain of the amplifiers of each separate receiver channels based on the result of the comparison of the output of the reference receiver channel and the output of the corresponding separate receiver channel. An optical receiver system and a method for operating a light detection and ranging system are also provided.

Claims

1. A light detection and ranging system comprising: at least one first light source for emitting a light signal to the surroundings of the light detection and ranging system, multiple receiving optical sensors for receiving a light signal from surroundings of the light detection and ranging system; an optical receiver system for processing the signals of the multiple receiving optical sensors, wherein the optical receiver system comprises a separate receiver channel for each of the multiple receiving optical sensors, each separate receiver channel comprising an amplifier with an adjustable gain for amplifying the signal of the corresponding receiving optical sensor; and a second light source for emitting a light signal directly to a reference receiver channel and the multiple receiving optical sensors, wherein the optical receiver system comprises the reference receiver channel and at least one comparator for comparing the output of the reference receiver channel and the output of each of the separate receiver channels, the reference receiver channel comprising a reference optical sensor and a reference amplifier, and wherein the at least one comparator can adjust the gain of the amplifiers of each separate receiver channel based on the result of the comparison of the output of the reference receiver channel and the output of the corresponding separate receiver channel.

2. The light detection and ranging system according to claim 1, wherein the multiple receiver channels and the reference receiver channel further comprise a buffer, an analog-to-digital converter and/or a signal processing unit, particularly a digital signal processing unit.

3. The light detection and ranging system according to claim 1, wherein the at least one first light source and the second light source are controlled by the light detection and ranging system and do not emit light simultaneously.

4. The light detection and ranging system according to claim 1, comprising a separate comparator for each separate receiver channel, for comparing the output of the reference receiver channel to the output of the corresponding receiver channel.

5. The light detection and ranging system according to claim 1, wherein the amplifier of each optical receiver channel and the reference receiver channel is a transimpedance amplifier.

6. The light detection and ranging system according to claim 1, wherein the receiving optical sensors of the multiple optical receiver channels and the reference receiver channel are photodiodes and/or the first light source and/or the second light source is a laser source.

7. The light detection and ranging system according to claim 1, further comprising sender optics and/or receiver optics for adjusting light emitting characteristics and/or light receiving characteristics of the light detection and ranging system.

8. The light detection and ranging system according to claim 1, wherein the optical receiver system is implemented in an integrated circuit.

9. An optical receiver system for a light detection and ranging system, the light detection and ranging system comprising: at least one first light source for emitting a light signal to surroundings of the light detection and ranging system, multiple receiving optical sensors for receiving a light signal from surroundings of the light detection and ranging system; and a second light source for emitting a light signal directly to a reference receiver channel and the multiple receiving optical sensors, wherein the optical receiver system comprises: a separate receiver channel for each of the multiple receiving optical sensors, each separate receiver channel comprising an amplifier with an adjustable gain for amplifying the signal of the corresponding receiving optical sensor; the reference receiver channel; and at least one comparator for comparing the output of the reference receiver channel and the output of each of the separate receiver channels, wherein the reference receiver channel comprises a reference optical sensor and a reference amplifier, and wherein the at least one comparator can adjust the gain of the amplifiers of each separate receiver channel based on the result of the comparison of the output of the reference receiver channel and the output of the corresponding separate receiver channel.

10. A method for operating a light detection and ranging system comprising: emitting a first light signal to the surroundings of the light detection and ranging system; receiving a light signal from the surroundings of the light detection and ranging system using multiple receiving optical sensors; processing the signal of the receiving optical sensors by separate receiver channels of an optical receiver system of the light detection and ranging system, wherein the processing comprises at least amplifying the signal of the receiving optical sensors by the separate receiver channels; emitting a second light signal directly to a reference receiver channel and the multiple receiving optical sensors; comparing the output of the reference receiver channel and the output of each of the separate receiver channels; and adjusting the gain of the amplifiers of each separate receiver channel based on the result of the comparison of the output of the reference receiver channel and the output of the corresponding separate receiver channel.

11. The method according to claim 10, wherein the processing of the signal of the receiving optical sensors further comprises buffering the signal, converting the signal from an analog domain to the digital domain and/or digitally processing the signal.

12. The method according to claim 10, wherein the first light signal and the second light signal are not emitted simultaneously.

13. The method according to claim 10, wherein the signal of the reference receiver channel and each optical receiver channel are compared in parallel by separate comparators.

14. The method according to claim 10, wherein the method is performed continuously during operation of the light detection and ranging system.

15. The method according to claim 10, wherein the steps of the characterizing portion are performed in predetermined intervals.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0044] FIG. 1 shows a block diagram of a light detection and ranging system according to an embodiment.

[0045] FIG. 2 shows a detailed view of an optical receiver system of the light detection and ranging system of FIG. 1 according to an embodiment.

[0046] FIG. 3 shows a detailed view of an optical receiver system according to an embodiment.

DETAILED DESCRIPTION

[0047] FIG. 1 shows a block diagram of an exemplary embodiment of a light detection and ranging system 1.

[0048] The light detection and ranging system 1 comprises a first light source 2 for emitting a light signal to the surroundings of the light detection and ranging system 1. The first light source 2 is for example a laser source that emits laser pulses to the surroundings of the light detection and ranging system 1.

[0049] The emitted light signal 3 hits objects 6 in the surroundings of the light detection and ranging system 1 and is reflected or scattered back to the light detection and ranging system 1. These light signals from the surroundings reflected or scattered back to the light detection and ranging system 1 are indicated in FIG. 1 by reference 5.

[0050] The light detection and ranging system 1 further comprises multiple receiving optical sensors 4 for receiving the light signals 5 from the surroundings of the light detection and ranging system 1. These receiving optical sensors 4 are for example photodiodes. The receiving optical sensors 4 are for example arranged in the front part of a vehicle.

[0051] The signals of the multiple receiving optical sensors 4 are processed by an optical receiver system 7 of the light detection and ranging system 1. A detailed view of the optical receiver system 7 of the light detection and ranging system 1 of FIG. 1 is shown in FIG. 2. The optical receiver system 7 can be implemented in a single integrated circuit.

[0052] The optical receiver system 7 comprises a separate receiver channel 8 for each receiving optical sensor 4. In FIGS. 1 and 2, the separate receiver channels 8 are separated by dashed lines. Each separate receiver channel 8 comprises at least an amplifier 9 for amplifying the signal of the corresponding receiving optical sensor 4. The amplifiers 9 have an adjustable gain, to adjust the amplification of the signal of the corresponding receiving optical sensor 4. According to the embodiment shown in FIG. 1, each receiver channel further comprises a signal processing block 16, which for example comprises a buffer, an analog-to-digital converter and/or a signal processing unit.

[0053] According to the present disclosure, the light detection and ranging system 1 further comprises a second light source 10, like a laser source, for emitting a light signal 11 directly to a reference receiver channel 12 of the optical receiver system 7 and the multiple receiving optical sensors 4. The reference receiver channel 12 comprises a reference optical sensor 14 and a reference amplifier 15. Like the separate receiver channels 8, the reference receiver channel 12 also comprises a signal processing block 16 comprising a buffer, an analog-to-digital converter and/or a signal processing unit.

[0054] The optical receiver system 7 further comprises a comparator 13 for comparing the output of the reference receiver channel 12 and the output of each of the separate receiver channels 8. The comparator 13 can adjust the gain of the amplifiers 9 of each separate receiver channel 8 based on the result of the comparison of the output of the reference receiver channel 12 and the output of the corresponding separate receiver channel 8. The comparator 13 adjusts the gain of the amplifiers of the separate receiver channels 8 in such a way, that the output of each separate receiver channel 8 corresponds to the output of the reference receiver channel 12. Thus, each separate receiver channel 8 provides the same output to the same light signal 11, i.e., the light signal 11 emitted by the second light source 10. According to the embodiment shown in FIGS. 1 and 2, the optical receiver system 7 comprises one comparator 13 for comparing the output of the reference receiver channel 12 and the output of each of the separate receiver channels 8. This comparison can be performed serially or at least partially in parallel. The comparator 13 can be part of the optical receiver system 7 but could also be a separate part of the light detection and ranging system 1.

[0055] The first light source 2 and the second light source 10 are controlled by the light detection and ranging system 1 and do not emit light simultaneously. Thus, an interference between the emitted light signals 3 and 11 and processing of the light signals 5 from the surroundings and light signals 11 from the second light source 10 can be avoided.

[0056] The amplifiers 9 of the separate receiver channels 8 and the reference amplifier 15 of the reference receiver channel 12 are for example transimpedance amplifiers. The receiving optical sensors 4 of the separate receiver channels 8 and the reference optical sensor 14 of the reference receiver channel 12 are for example photodiodes. The light detection and ranging system 1 can further comprise sender optics and/or receiver optics (not shown) for adjusting light emitting characteristics and/or light receiving characteristics of the light detection and ranging system 1.

[0057] FIG. 3 shows a detailed view of another embodiment of an optical receiver system 7. The optical receiver system 7 shown in FIG. 3 differs from the optical receiver system 7 shown in FIG. 2 in that the optical receiver system 7 comprises a separate comparator 13 for each separate receiver channel 8. Thus, the outputs of all separate receiver channels 8 can be compared fully in parallel to the output of the reference receiver channel 12 by the multiple comparators 13. Again, the comparators 13 are not necessarily part of the optical receiver system 7 but could also be a separate part of the light detection and ranging system 1. With respect to all other features the optical receiver system 7 of FIG. 3 corresponds to the optical receiver system 7 of FIG. 2 and can be for example used in a light detection and ranging system 1 as shown in FIG. 1.