Data resolution in lidar systems

Abstract

A system output signal is transmitted from the lidar system such that the sample region is illuminated by the system output signal. Different portions of the system output signal are transmitted during different data periods. Light returned from the system output signal to the lidar system is combined with light from the reference signal to generate beat signals each associated with a different one of the data periods. A set of multiple candidate frequencies is generated for each data period. Each candidate frequency of the data period represents a possible beat frequency of the beat signal associated with the data period. The candidate frequency of the check data period of the data periods is also used to identify which of the candidate frequencies of the object data period of the data periods is the beat frequency of the beat signal associated with the object data period.

Description

Related applications

[0001] This application is a continuation-to-file of U.S. Patent Application No. 18 / 119,274, entitled “Data Resolution in Lidar Systems,” filed March 8, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to imaging systems. In particular, this invention relates to data refinement in imaging systems. Background Technology

[0003] A lidar (LiDAR) system outputs a system output signal reflected by an object located outside the lidar system. The reflected light returns to the lidar system as a system return signal. The lidar system combines the light from the system return signal with a reference signal from a local oscillator to generate a beat signal. The lidar system includes electronics that use the beat frequency of the beat signal to determine lidar data (radial velocity and / or distance between the lidar system and the object) of the sample area illuminated by the system output signal.

[0004] Identifying the beat frequency of a real beat signal can be difficult because there is usually more than one possible solution for the beat frequency. This ambiguity is typically avoided by converting the beat signal from its real form to a complex form that combines the in-phase representation of the beat signal with its quadrature signal. Since the beat signal is represented by two distinct signals, multiple analog-to-digital converters (ADCs) are usually required to process these complex signals. However, ADCs are expensive and increase the complexity of LiDAR systems. Therefore, there is a need for LiDAR systems with reduced cost and complexity. Summary of the Invention

[0005] Operating a lidar system involves transmitting a system output signal from the lidar system such that a sample area is illuminated by the system output signal. Different portions of the system output signal are transmitted during different data periods. The light returning from the system output signal to the lidar system is combined with light from a reference signal to generate beat signals that are associated with different data periods within the data period. For each data period, a set of multiple candidate frequencies is generated. Each candidate frequency for a data period represents a possible beat frequency of the beat signal associated with that data period. The candidate frequencies of the target data period within the data period are used to identify which of the candidate frequencies of the target data period is the beat frequency of the beat signal associated with that target data period.

[0006] Operating a lidar system involves transmitting a system output signal from the lidar system such that a sample area is illuminated by the system output signal. This includes an object portion of the system output signal being transmitted during the object data period and an inspection portion during the inspection data period. The frequency of the system output signal varies at different rates during the object data and inspection data periods. Light returning from the object portion of the system output signal to the lidar system is combined with light from an object reference signal to generate an object beat signal with a beat frequency difference. Light returning from the inspection portion of the system output signal to the lidar system is combined with light from an inspection reference signal to generate an inspection beat signal with an inspection beat frequency difference. Multiple object candidate frequencies are identified, including the object target frequency at the object beat frequency and the object image frequency at the inverse of the object beat frequency. Multiple inspection candidate frequencies are identified, including the inspection target frequency at the inspection beat frequency and the inspection image frequency at the inverse of the inspection beat frequency. The inspection candidate frequencies are used to identify which of the object candidate frequencies is the object target frequency.

[0007] The lidar system is configured to transmit system output signals such that a sample area is illuminated by the system output signals. The object portion of the system output signals is transmitted during the object data period. The inspection portion of the system output signals is transmitted during the inspection data period. The frequency of the system output signals varies at different rates during the object data period and the inspection data period. The lidar system includes an optical combiner that combines light returned from the object portion of the system output signals to the lidar system with light from an object reference signal to generate an object beat signal with a beat frequency difference. The optical combiner combines light returned from the inspection portion of the system output signals to the lidar system with light from an inspection reference signal to generate an inspection beat signal with a beat frequency difference. The lidar system includes electronics for identifying multiple object candidate frequencies and multiple inspection candidate frequencies. The multiple object candidate frequencies include the object target frequency at the object beat frequency and the object image frequency at the inverse of the object beat frequency. The multiple inspection candidate frequencies include the inspection target frequency at the inspection beat frequency and the inspection image frequency at the inverse of the inspection beat frequency. The electronics are configured to use the inspection candidate frequencies to identify which of the object candidate frequencies is the object target frequency.

[0008] The operating system includes transmitting system output signals from the lidar system, illuminating a sample area with the system output signals. Multiple distinct candidate lidar data results are calculated for the sample area. Each of the distinct candidate lidar data results is a candidate for the radial velocity and / or distance between the lidar system and an object in the sample area. Candidate lidar data results representing valid lidar data for the sample area are identified.

[0009] Operating the lidar system includes transmitting a system output signal from the lidar system such that a sample area is illuminated by the system output signal. A first object portion of the system output signal is transmitted during a first object data period. A second object portion of the system output signal is transmitted during a second object data period. An inspection portion of the system output signal is transmitted during an inspection data period. The frequency of the system output signal changes at different rates during the first and second object data periods. Light returning from the first object portion of the system output signal to the lidar system is combined with light from a first reference signal to generate a first object beat signal with a beat frequency difference of the first object. Light returning from the second portion of the system output signal to the lidar system is combined with light from a second reference signal to generate a second object beat signal with a beat frequency difference of the second object. Light returning from the inspection portion of the system output signal to the lidar system is combined with light from an inspection reference signal to generate an inspection beat signal with a beat frequency difference of the inspection. Multiple first object candidate frequencies are identified. The first object candidate frequencies include a first object target frequency at the first object beat frequency and a first image frequency at the inverse of the sum of the first object beat frequencies. Multiple second object candidate frequencies are identified. The second object candidate frequency includes the second target frequency at the second object beat frequency and the second image frequency at the inverse additive element of the second beat frequency. Multiple inspection candidate frequencies are identified. Inspection candidate frequencies include the inspection target frequency at the inspection beat frequency and the inspection image frequency at the inverse additive element of the inspection beat frequency. Multiple candidate frequency pairs are identified. Each candidate frequency pair includes a pairing of one of the second object candidate frequencies with one of the first object candidate frequencies. For each candidate frequency pair, a candidate LiDAR data result is calculated. The candidate LiDAR data result for each candidate frequency pair is calculated from the first and second object target frequencies in the candidate frequency pair. The candidate LiDAR data result for each candidate frequency pair is a candidate for the radial velocity and / or distance between the LiDAR system and the object in the sample area. The candidate LiDAR data results calculated from the first and second target frequencies are identified.

[0010] A system includes a lidar system configured to transmit a system output signal such that a sample area is illuminated by the system output signal. A first object portion of the system output signal is transmitted during a first object data period within a data period. A second object portion of the system output signal is transmitted during a second object data period within a data period. A check portion of the system output signal is transmitted during a check data period within a data period. The frequency of the system output signal varies at different rates during the first and second object data periods. An optical signal combiner combines light returned from the first object portion of the system output signal to the lidar system with light from the first object portion of a reference signal to generate a first object beat signal with a first object beat frequency difference. The optical signal combiner also combines light returned from the second object portion of the system output signal to the lidar system with light from the second object portion of the reference signal to generate a second object beat signal with a second object beat frequency difference. The optical signal combiner also combines light returned from the check portion of the system output signal to the lidar system with light from the check portion of the reference signal to generate a check beat signal with a check beat frequency difference. Electronic devices identify a plurality of first candidate frequencies, a plurality of second candidate frequencies, and a plurality of check candidate frequencies. The first candidate frequency includes the first target frequency at the first target beat frequency and the first image frequency at the inverse additive element of the first target beat frequency. The second candidate frequency includes the second target frequency at the second beat frequency and the second image frequency at the inverse additive element of the second beat frequency. The third candidate frequency includes the third target frequency at the third beat frequency and the third image frequency at the inverse additive element of the third beat frequency. The electronics identify multiple candidate frequency pairs and calculate candidate LiDAR data results from each candidate frequency pair. Each candidate frequency pair includes a pairing of one of the second candidate frequencies with one of the first candidate frequencies. The candidate LiDAR data results for each candidate frequency pair are candidates for the radial velocity and / or distance between the LiDAR system and an object in the sample area. The electronics identify which of the candidate LiDAR data results was calculated from the first target frequency and the second target frequency. The identified candidate LiDAR data results can be used as valid LiDAR data for the sample area. Attached Figure Description

[0011] Figure 1A It is a top view of a schematic diagram including a lidar chip or a lidar system composed of lidar chips, wherein the lidar chip outputs lidar output signals and receives lidar input signals on a common waveguide; Figure 1B It is a top view of a schematic diagram including a lidar chip or a lidar system composed of lidar chips, wherein the lidar chip outputs lidar output signals and receives lidar input signals on different waveguides; Figure 1CThis is a top view of another embodiment of a lidar system including a lidar chip or composed of lidar chips, wherein the lidar chip outputs lidar output signals on different waveguides and receives multiple lidar input signals. Figure 2 Is it suitable for and Figure 1B A top view of an example of a lidar adapter used with a lidar chip; Figure 3 Is it suitable for and Figure 1C A top view of an example of a lidar adapter used with a lidar chip; Figure 4 Included in public support components Figure 1A LiDAR chips and Figure 2 A top view of an example of a lidar system with a lidar adapter; Figure 5A An example of a processing component suitable for use with a lidar system is shown; Figure 5B Provided suitable and based on Figure 5A A schematic diagram of the electronic devices used in the constructed processing components; Figure 5C It is a graph of the frequency of the system output signal versus time; Figure 5D The spectrum with corresponding frequency peaks at +f and -f is shown; Figure 5E The spectrum with multiple pairs of corresponding frequency peaks is shown, each corresponding frequency peak being generated due to the presence of different objects in the sample region of the field of view of the lidar system; Figure 6 The flowchart for refining lidar data is shown. Figure 7 It is a cross-section of a portion of a lidar chip that includes a waveguide on a silicon-on-insulator platform. Detailed Implementation

[0012] The lidar system emits its output signal, illuminating a sample area. Different portions of the output signal are emitted during different data periods. The light returning from the output signal is combined with light from a reference signal to generate beat signals associated with different data periods within the same data period. For each data period, a set of multiple candidate frequencies is calculated. Each candidate frequency represents a possible beat frequency of the beat signal associated with that data period. The candidate frequencies of the check data periods are used to identify which candidate frequency of the target data period is the correct beat frequency of the beat signal associated with that target data period. LiDAR data for the sample area is calculated from the candidate frequencies identified as the correct beat frequencies of the beat signals.

[0013] The existence of multiple frequencies, each a candidate for the actual beat frequency, allows for processing the real form of the beat signal instead of its complex form. Since the real form of the beat signal does not include its quadrature components, a single analog-to-digital converter (ADC) can replace the multiple ADCs required to process its complex representation. This reduces the cost and complexity of the lidar system.

[0014] Figure 1A This is a top view of a schematic diagram of a lidar chip, which can be used as part of a lidar system or can be included in a lidar system that includes components other than the lidar chip. The lidar chip can include a photonic integrated circuit (PIC) and can be a photonic integrated circuit chip. The lidar chip includes a light source 4 that outputs an initial lidar signal. Suitable light sources 4 include, but are not limited to, semiconductor lasers, such as external cavity lasers (ECL), distributed feedback lasers (DFB), discrete mode (DM) lasers, and distributed Bragg reflector lasers (DBR).

[0015] The lidar chip includes a utility waveguide 12 that receives the output lidar signal from the light source 4. The utility waveguide 12 terminates at an end face 14 and carries the output lidar signal thereto. The end face 14 can be positioned such that the output lidar signal traveling through the end face 14 leaves the lidar chip and is used as a lidar output signal. For example, the end face 14 can be positioned at the edge of the chip such that the output lidar signal traveling through the end face 14 leaves the chip and is used as a lidar output signal. In some cases, a portion of the lidar output signal that has left the lidar chip can also be considered the system output signal. As an example, when the departure of the lidar output signal from the lidar chip also means the departure of the lidar output signal from the lidar system, the lidar output signal can also be considered the system output signal.

[0016] The lidar output signal travels away from the lidar system through free space in the atmosphere. The lidar output signal can be reflected by one or more objects in its path. When the lidar output signal is reflected, at least a portion of the reflected light travels back towards the lidar chip as the lidar input signal. In some cases, the lidar input signal can also be considered a system return signal. As an example, when the lidar output signal leaving the lidar chip also means the lidar output signal leaving the lidar system, the lidar input signal can also be considered a system return signal.

[0017] The lidar input signal can enter the utility waveguide 12 through end face 14. A portion of the lidar input signal entering the utility waveguide 12 serves as the incoming lidar signal. The utility waveguide 12 carries the incoming lidar signal to a splitter 16, which moves a portion of the outgoing lidar signal from the utility waveguide 12 onto a comparison waveguide 18 as a comparison signal. The comparison waveguide 18 carries the comparison signal to a processing unit 22 for further processing. Although... Figure 1A A directional coupler operating as splitter 16 is shown, but other signal tapping components can also be used as splitter 16. Suitable splitters 16 include, but are not limited to, directional couplers, optical couplers, Y-junctions, tapered couplers, and multimode interference (MMI) devices.

[0018] The utility waveguide 12 also carries the outgoing lidar signal to the splitter 16. The splitter 16 moves a portion of the outgoing lidar signal from the utility waveguide 12 onto the reference waveguide 20 as a reference signal. The reference waveguide 20 carries the reference signal to the processing unit 22 for further processing.

[0019] The percentage of light transmitted from the utility waveguide 12 by the splitter 16 can be fixed or substantially fixed. For example, the splitter 16 can be configured such that the power of the reference signal transmitted to the reference waveguide 20 is an outgoing percentage of the power of the outgoing lidar signal, or that the power of the comparison signal transmitted to the comparison waveguide 18 is an incoming percentage of the power of the incoming lidar signal. In many splitters 16, such as directional couplers and multimode interferometers (MMIs), the outgoing percentage is equal to or substantially equal to the incoming percentage. In some cases, the outgoing percentage is greater than 30%, 40%, or 49% and / or less than 51%, 60%, or 70%, and / or the incoming percentage is greater than 30%, 40%, or 49% and / or less than 51%, 60%, or 70%. Splitters 16, such as multimode interferometers (MMIs), typically provide 50% or about 50% outgoing and incoming percentages. However, multimode interferometers (MMIs) can be more easily fabricated in platforms such as silicon-on-insulator platforms than some alternatives. In one example, the separator 16 is a multimode interferometer (MMI), and the outgoing and incoming percentages are 50% or approximately 50%. As will be described in more detail below, the processing unit 22 combines the comparison signal with the reference signal to form a composite signal carrying lidar data for a sample area in the field of view. Therefore, the composite signal can be processed to extract lidar data for the sample area (radial velocity and / or distance between the lidar system and objects outside the lidar system).

[0020] The lidar chip may include a control branch for controlling the operation of the light source 4. The control branch includes a splitter 26 that moves a portion of the outgoing lidar signal from the utility waveguide 12 onto the control waveguide 28. The coupled portion of the outgoing lidar signal serves as a tap signal. Although Figure 1A A directional coupler operating as splitter 26 is shown, but other signal tapping components can also be used as splitter 26. Suitable splitters 26 include, but are not limited to, directional couplers, optical couplers, Y-junctions, tapered couplers, and multimode interference (MMI) devices.

[0021] Control waveguide 28 carries the tap signal to control component 30. The control component may be electrically connected to electronics 32. All or part of the control component may be included in electronics 32. During operation, the electronics may utilize the output from control component 30 in a control loop configured to control one, two, or three loop-controlled optical signals selected from the group consisting of tap signals, system output signals, and output lidar signals. Examples of suitable process variables include the frequency and / or phase of the loop-controlled optical signals.

[0022] The lidar system can be modified so that the incoming and outgoing lidar signals can be carried on different waveguides. For example, Figure 1B yes Figure 1A A top view of a lidar chip modified such that the incoming and outgoing lidar signals are carried on different waveguides. The outgoing lidar signal leaves the lidar chip through end face 14 and is used as the lidar output signal. When light from the lidar output signal is reflected by an object outside the lidar system, at least a portion of the reflected light returns to the lidar chip as a first lidar input signal. The first lidar input signal enters the comparison waveguide 18 through end face 35 and is used as a comparison signal. The comparison waveguide 18 carries the comparison signal to the processing unit 22 for further processing. Figure 1A As described in the context, reference waveguide 20 carries a reference signal to processing unit 22 for further processing. As will be described in more detail below, processing unit 22 combines the comparison signal with the reference signal to form a composite signal that carries lidar data of a sample area in the field of view.

[0023] The lidar chip can be modified to receive input signals from multiple lidar systems. For example, Figure 1C The diagram shows a modification to receive input signals from two lidar sensors. Figure 1B The LiDAR chip. The splitter 40 is configured to place a portion of the reference signal carried on the reference waveguide 20 onto a first reference waveguide 42, and another portion of the reference signal onto a second reference waveguide 44. Therefore, the first reference waveguide 42 carries the first reference signal, and the second reference waveguide 44 carries the second reference signal. The first reference waveguide 42 carries the first reference signal to a first processing unit 46, and the second reference waveguide 44 carries the second reference signal to a second processing unit 48. Examples of suitable splitters 40 include, but are not limited to, Y-junctions, optical couplers, and multimode interference couplers (MMIs).

[0024] The output lidar signal leaves the lidar chip through end face 14 and is used as the lidar output signal. When light from the lidar output signal is reflected by one or more objects located outside the lidar system, at least a portion of the reflected light returns to the lidar chip as a first lidar input signal. The first lidar input signal enters the comparison waveguide 18 through end face 35 and is used as a first comparison signal. The comparison waveguide 18 carries the first comparison signal to the first processing unit 46 for further processing.

[0025] Additionally, when light from the lidar output signal is reflected by one or more objects located outside the lidar system, at least a portion of the reflected signal is returned to the lidar chip as a second lidar input signal. The second lidar input signal enters the second comparison waveguide 50 through end face 52 and is used as a second comparison signal carried by the second comparison waveguide 50. The second comparison waveguide 50 carries the second comparison signal to the second processing unit 48 for further processing.

[0026] Although the light source 4 is shown as being positioned on the lidar chip, it can be located outside the lidar chip. For example, the utility waveguide 12 can terminate at a second end face through which the lidar signal can enter the utility waveguide 12 from the light source 4 located outside the lidar chip.

[0027] In some cases, according to Figure 1B or Figure 1C The constructed lidar chip is used in conjunction with a lidar adapter. In some cases, the lidar adapter can be physically and optically positioned between the lidar chip and one or more reflective objects and / or the field of view, because the optical path of the first lidar input signal and / or lidar output signal from the lidar chip to the field of view passes through the lidar adapter. Alternatively, the lidar adapter can be configured to operate the first lidar input signal and lidar output signal such that they travel on different optical paths between the lidar adapter and the lidar chip, but on the same optical path between the lidar adapter and the reflective object in the field of view.

[0028] Suitable for Figure 1B An example of a lidar adapter used with a lidar chip is shown in Figure 2 As shown in the diagram, the lidar adapter includes multiple components positioned on a base. For example, the lidar adapter includes a circulator 100 positioned on the base 102. The illustrated optical circulator 100 includes three ports and is configured such that light entering one port exits through the next port. For example, the illustrated optical circulator includes a first port 104, a second port 106, and a third port 108. The lidar output signal enters from the utility waveguide 12 of the lidar chip at the first port 104 and exits from the second port 106.

[0029] The lidar adapter can be configured such that the output of the lidar output signal from the second port 106 can also be used as the output of the lidar output signal from the lidar adapter and therefore from the lidar system. Thus, the lidar output signal can be output from the lidar adapter, causing the lidar output signal to travel towards the sample area in the field of view. Therefore, in some cases, a portion of the lidar output signal that has left the lidar adapter can also be considered the system output signal. As an example, when the departure of the lidar output signal from the lidar adapter is also the departure of the lidar output signal from the lidar system, the lidar output signal can also be considered the system output signal.

[0030] The lidar output signal from the lidar adapter includes, constitutes, or substantially constitutes the light received from the lidar output signal from the lidar chip. Therefore, the lidar output signal from the lidar adapter can be the same as or substantially the same as the lidar output signal received from the lidar chip. However, there may be differences between the lidar output signal from the lidar adapter and the lidar output signal received from the lidar chip. For example, the lidar output signal may experience optical losses as it travels through the lidar adapter, and / or the lidar adapter may optionally include an amplifier configured to amplify the lidar output signal as it travels through the lidar adapter.

[0031] When one or more objects in the sample area reflect the lidar output signal, at least a portion of the reflected light is returned to the circulator 100 as a system return signal. The system return signal enters the circulator 100 through the second port 106. Figure 2 The lidar output signal and system return signal are shown traveling along the same optical path between the lidar adapter and the sample area.

[0032] The system return signal leaves the circulator 100 through the third port 108 and is guided to the comparison waveguide 18 on the lidar chip. Therefore, all or part of the system return signal can be used as the first lidar input signal, and the first lidar input signal includes or is composed of light from the system return signal. Thus, the lidar output signal and the first lidar input signal travel along different optical paths between the lidar adapter and the lidar chip.

[0033] from Figure 2 It is evident that, in addition to the circulator 100, the lidar adapter may also include optical components. For example, the lidar adapter may include components for guiding and controlling the optical path of the lidar output signal and the system return signal. As an example, Figure 2The adapter includes an optional amplifier 110, which is configured to receive and amplify the lidar output signal before it enters the circulator 100. Amplifier 110 can be operated by electronics 32, allowing electronics 32 to control the power of the lidar output signal.

[0034] Figure 2 A lidar adapter including an optional first lens 112 and an optional second lens 114 is also shown. The first lens 112 can be configured to couple the lidar output signal to a desired location. In some cases, the first lens 112 is configured to focus or collimate the lidar output signal at the desired location. In one example, when the lidar adapter does not include amplifier 110, the first lens 112 is configured to couple the lidar output signal to a first port 104. As another example, when the lidar adapter includes amplifier 110, the first lens 112 can be configured to couple the lidar output signal at the input port to amplifier 110. The second lens 114 can be configured to couple the lidar output signal to a desired location. In some cases, the second lens 114 is configured to focus or collimate the lidar output signal at the desired location. For example, the second lens 114 can be configured to couple the lidar output signal to the end face 35 of the comparison waveguide 18.

[0035] The lidar adapter may also include one or more orientation-changing components, such as a reflector. Figure 2 A lidar adapter is shown, which includes a mirror as a direction-changing component 116 that redirects the system return signal from the circulator 100 to the end face 20 of the comparison waveguide 18.

[0036] A lidar chip includes one or more waveguides that constrain the optical path of one or more optical signals. Although a lidar adapter may include waveguides, the optical paths of the system return signal and lidar output signal traveling between components on the lidar adapter and / or between the lidar chip and components on the lidar adapter can be free space. For example, when traveling between different components on the lidar adapter and / or between components on the lidar adapter and the lidar chip, the system return signal and / or lidar output signal can travel through the atmosphere in which the lidar chip, lidar adapter, and / or base 102 are located. Therefore, optical components such as lenses and orientation-changing components can be used to control the characteristics of the optical paths of the system return signal and lidar output signal traveling on, to, and from the lidar adapter.

[0037] Suitable base 102 for a lidar adapter includes, but is not limited to, substrates, platforms, and boards. Suitable substrates include, but are not limited to, glass, silicon, and ceramic. Components may be discrete components attached to the substrate. Suitable techniques for attaching discrete components to base 102 include, but are not limited to, epoxy resins, solder, and mechanical clamping. In one example, one or more of the components are integrated components, and the remaining components are discrete components. In another example, the lidar adapter includes one or more integrated amplifiers, and the remaining components are discrete components.

[0038] LiDAR systems can be configured to compensate for polarization. Light from a laser source is typically linearly polarized, and therefore the LiDAR output signal is also typically linearly polarized. Reflection from an object can alter the polarization angle of the returning light. Therefore, the system's returned signal can include light in different linear polarization states. For example, a first portion of the system's returned signal may include light in a first linear polarization state, and a second portion may include light in a second linear polarization state. The intensity of the resulting composite signal is proportional to the square of the cosine of the angle between the polarization fields of the comparison and reference signals. If the angle is 90 degrees, LiDAR data may be lost in the resulting composite signal. However, the LiDAR system can be modified to compensate for changes in the polarization state of the LiDAR output signal.

[0039] Figure 3 It shows Figure 3 The lidar system was modified to make the lidar adapter compatible with... Figure 1C The lidar adapter is used in conjunction with a lidar chip. It includes a beam splitter 120 that receives the system return signal from the circulator 100. The beam splitter 120 splits the system return signal into a first part and a second part. Suitable beam splitters include, but are not limited to, Wollaston prisms and MEMS-based beam splitters.

[0040] The first part of the system return signal is guided to the comparison waveguide 18 on the lidar chip and used as a reference for... Figure 1C The first lidar input signal is described in the context of the above. A second portion of the system return signal is directed to polarization rotator 122. Polarization rotator 122 outputs a second lidar input signal, which is directed to a second input waveguide 76 on the lidar chip and used as the second lidar input signal.

[0041] Beam splitter 120 can be a polarization beam splitter. An example of a polarization beam splitter is configured such that a first portion of the system-returned signal has a first polarization state but has no or substantially no second polarization state, and a second portion of the system-returned signal has a second polarization state but has no or substantially no first polarization state. The first and second polarization states can be linear polarization states, and the second polarization state differs from the first polarization state. For example, the first polarization state can be TE and the second polarization state can be TM, or the first polarization state can be TM and the second polarization state can be TE. In some cases, the laser source can be linearly polarized, such that the lidar output signal has a first polarization state. Suitable beam splitters include, but are not limited to, Wollaston prisms and MEM-based polarization beam splitters.

[0042] A polarization rotator can be configured to change the polarization state of a first portion and / or a second portion of the system return signal. For example, Figure 3 The polarization rotator 122 shown can be configured to change the polarization state of a second portion of the system-returned signal from a second polarization state to a first polarization state. Therefore, the second lidar input signal has a first polarization state but does not have, or substantially does not have, a second polarization state. Thus, both the first and second lidar input signals have the same polarization state (the first polarization state in this example). Although carrying light with the same polarization state, the first and second lidar input signals are associated with different polarization states due to the use of a polarization beam splitter. For example, the first lidar input signal carries light reflected in the first polarization state, and the second lidar input signal carries light reflected in the second polarization state. Therefore, the first lidar input signal is associated with the first polarization state, and the second lidar input signal is associated with the second polarization state.

[0043] Since the first lidar input signal and the second lidar input signal carry light with the same polarization state, the comparison signal generated by the first lidar input signal has the same polarization angle as the comparison signal generated by the second lidar input signal.

[0044] Suitable polarization rotators include, but are not limited to, polarization-preserving fiber rotation, Faraday rotators, half-wave plates, MEM-based polarization rotators and integrated optical polarization rotators using asymmetric y-branching, Mach-Zehnder interferometers and multimode interference couplers.

[0045] Since the transmitted lidar signal is linearly polarized, the first reference signal can have the same linear polarization state as the second reference signal. Alternatively, components on the lidar adapter can be selected such that the first reference signal, the second reference signal, the comparison signal, and the second comparison signal all have the same polarization state. Figure 3 In the examples disclosed in the context, the first comparison signal, the second comparison signal, the first reference signal, and the second reference signal can all be light with a first polarization state.

[0046] As a result of the above configuration, both the first composite signal generated by the first processing unit 46 and the second composite signal generated by the second processing unit 48 are generated by combining a reference signal and a comparison signal with the same polarization state, and will correspondingly provide the desired beat difference between the reference signal and the comparison signal. For example, the composite signal is generated by combining a first reference signal and a first comparison signal with the first polarization state and does not include or substantially does not include light with the second polarization state, or the composite signal is generated by combining a first reference signal and a first comparison signal with the second polarization state and does not include or substantially does not include light with the first polarization state. Similarly, the second composite signal includes a second reference signal and a second comparison signal with the same polarization state and will correspondingly provide the desired beat difference between the reference signal and the comparison signal. For example, the second composite signal is generated by combining a second reference signal and a second comparison signal with the first polarization state and does not include or substantially does not include light with the second polarization state, or the second composite signal is generated by combining a second reference signal and a second comparison signal with the second polarization state and does not include or substantially does not include light with the first polarization state.

[0047] The above configuration results in lidar data for a single sample region in the field of view being generated from multiple different composite signals (i.e., a first composite signal and a second composite signal) from that sample region. In some cases, determining the lidar data for the sample region involves electronic devices combining lidar data from the different composite signals (i.e., a first composite signal and a second composite signal). Combining lidar data may include taking the average, median, or mode of the lidar data generated from the different composite signals. For example, the electronic devices may average the distance between the lidar system and the reflecting object determined from the composite signal with the distance determined from the second composite signal, and / or the electronic devices may average the radial velocity between the lidar system and the reflecting object determined from the composite signal with the radial velocity determined from the second composite signal.

[0048] In some cases, determining the LiDAR data for a sample area involves the electronics identifying one or more composite signals (i.e., a composite signal and / or a second composite signal) as the source of LiDAR data that best represents reality (representative LiDAR data). The electronics can then use the LiDAR data from the identified composite signals as representative LiDAR data for further processing. For example, the electronics can identify signals with larger amplitudes (composite signals or second composite signals) as representative LiDAR data and can use the LiDAR data from the identified signals for further processing by the LiDAR system. In some cases, the electronics combine composite signals identified as having representative LiDAR data with LiDAR data from combinations of different LiDAR signals. For example, the electronics can identify each composite signal with an amplitude above an amplitude threshold as having representative LiDAR data, and when more than two composite signals are identified as having representative LiDAR data, the electronics can combine the LiDAR data from each identified composite signal. When a composite signal is identified as having representative LiDAR data, the electronics can use the LiDAR data from that composite signal as representative LiDAR data. When no composite signal is identified as representative lidar data, the electronics can discard lidar data for sample regions associated with those composite signals.

[0049] although Figure 3 The description is made in the context of the components being arranged such that the first comparison signal, the second comparison signal, the first reference signal, and the second reference signal all have a first polarization state, but Figure 3 Other configurations of the components can be arranged such that the composite signal is generated by combining a reference signal and a comparison signal with the same linear polarization state, and the second composite signal is generated by combining a reference signal and a comparison signal with the same linear polarization state. For example, the beam splitter 120 can be configured such that a second portion of the system return signal has a first polarization state, and a first portion of the system return signal has a second polarization state, the polarization rotator receives the first portion of the system return signal, and the output lidar signal can have a second polarization state. In this example, both the first lidar input signal and the second lidar input signal have a second polarization state.

[0050] The above system configuration results in the first and second portions of the system return signal being directed into different composite signals. Therefore, since both the first and second portions of the system return signal are associated with different polarization states, but the electronics can process each composite signal, the lidar system compensates for the change in polarization state of the lidar output signal in response to the reflection of the lidar output signal.

[0051] Figure 3The lidar adapter may include additional optical components, including passive optics. For example, the lidar adapter may include an optional third lens 126. The third lens 126 may be configured to couple the second lidar output signal at a desired location. In some cases, the third lens 126 focuses or collimates the second lidar output signal at the desired location. For example, the third lens 126 may be configured to focus or collimate the second lidar output signal onto the end face 52 of the second comparison waveguide 50. The lidar adapter also includes one or more orientation-changing components 124, such as mirrors and prisms. Figure 3 A lidar adapter is shown, which includes a mirror as a direction-changing component 124 that redirects a second portion of the system-returned signal from the circulator 100 to the end face 52 of the second comparison waveguide 50 and / or the third lens 126.

[0052] When a lidar system includes a lidar chip and a lidar adapter, the lidar chip, electronics, and lidar adapter can be positioned on a common mounting bracket. Suitable common mounting brackets include, but are not limited to, glass plates, metal plates, silicon plates, and ceramic plates. As an example, Figure 4 Included on the common support 140 Figure 1A LiDAR chips and electronic devices 32 and Figure 2 A top view of the lidar system with a lidar adapter. Although electronics 32 is shown as being located on a common support, all or part of the electronics may be located outside the common support. When the light source 4 is located outside the lidar chip, the light source may be located on or outside the common support 140. Suitable methods for mounting the lidar chip, electronics, and / or lidar adapter on the common support include, but are not limited to, epoxy resin, solder, and mechanical clamping.

[0053] A lidar system may include components containing additional passive and / or active optical elements. For example, a lidar system may include one or more components that receive lidar output signals from a lidar chip or a lidar adapter. A portion of the lidar output signal exiting from one or more components may be used as the system output signal. As an example, a lidar system may include one or more beam steering components that receive lidar output signals from a lidar chip or a lidar adapter and output all or a portion of the lidar output signal as the system output signal. For example, Figure 4 A beam steering component 142 is shown that receives the lidar output signal from the lidar adapter. Although Figure 4A beam steering component positioned on the common support 140 is shown, but the beam steering component may be positioned on the lidar chip, on the lidar adapter, outside the lidar chip, or outside the common support 140. Suitable beam steering components include, but are not limited to, movable mirrors, MEMS mirrors, optical phased arrays (OPAs), and actuators for moving the lidar chip, lidar adapter, and / or common support.

[0054] Electronic devices can operate one or more beam steering components 142 to direct the system output signal to different sample regions 144. The sample regions can extend remotely from the lidar system to the maximum distance configured to provide reliable lidar data. Sample regions can be stitched together to define the field of view. For example, the lidar system's field of view may include or consist of the space occupied by a combination of sample regions.

[0055] Figures 5A to 5C An example of a suitable processing unit, selected from the group consisting of processing unit 22, first processing unit 46, and second processing unit 48, is shown. The processing unit receives a comparison signal from comparison waveguide 196 and a reference signal from reference waveguide 198. Figure 1A and Figure 1B The comparison waveguide 18 and reference waveguide 20 shown can be used as comparison waveguide 196 and reference waveguide 198, Figure 1C The comparison waveguide 18 and the first reference waveguide 42 shown can be used as comparison waveguide 196 and reference waveguide 198, or Figure 1C The second comparison waveguide 50 and the second reference waveguide 44 shown can be used as comparison waveguide 196 and reference waveguide 198.

[0056] Comparison waveguide 196 carries the comparison signal to optical signal combiner 211. Reference waveguide 198 carries the reference signal to optical signal combiner 211. First optical signal combiner 211 combines the comparison signal and the reference signal into a first composite signal. Due to the frequency difference between the comparison signal and the reference signal, the first composite signal beats between the comparison signal and the reference signal.

[0057] The first optical signal combiner 211 also separates the first composite signal onto a first detector waveguide 221 and a second detector waveguide 222. The first detector waveguide 221 carries a first portion of the first composite signal to a first optical sensor 223, which converts the first portion of the second composite signal into a first electrical signal. The second detector waveguide 222 carries a second portion of the second composite signal to a second optical sensor 224, which converts the second portion of the second composite signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0058] In some cases, the optical signal combiner 211 separates the first composite signal such that a portion of the comparison signal included in the first part of the composite signal is phase-shifted by 180° relative to a portion of the comparison signal in the second part of the composite signal, but the portion of the reference signal in the first part of the composite signal is not phase-shifted relative to a portion of the reference signal in the second part of the composite signal. Alternatively, the optical signal combiner 211 separates the composite signal such that a portion of the reference signal in the first part of the composite signal is phase-shifted by 180° relative to a portion of the reference signal in the second part of the composite signal, but the portion of the comparison signal in the first part of the composite signal is not phase-shifted relative to a portion of the comparison signal in the second part of the composite signal.

[0059] The first optical sensor 223 and the second optical sensor 224 can be connected as a balance detector. For example, Figure 5B A schematic diagram illustrating the relationship between the electronic components, the first light sensor 223, and the second light sensor 224 is provided. The symbol for a photodiode is used to represent the first light sensor 223 and the second light sensor 224; however, one or more of these sensors may have other configurations. In some cases, Figure 5B All the components shown in the schematic diagram are included on the lidar chip. In some cases, Figure 5B The components shown in the schematic diagram are distributed between the lidar chip and the electronic devices located outside the lidar chip.

[0060] Electronic devices connect a first optical sensor 223 and a second optical sensor 224 as a first balanced detector 225. Specifically, the first optical sensor 223 and the second optical sensor 224 are connected in series. This series connection in the first balanced detector communicates with a first data line 228, which carries the output from the first balanced detector as a first data signal. The first data signal is an electrical representation of a first composite signal. Therefore, the first data signal includes contributions from both the first and second waveforms. The first data signal is beat-dependent due to the beat difference between the comparison signal and the reference signal. Other optical detectors can be used instead of the balanced detector. For example, a single photodiode can replace the balanced detector.

[0061] Electronic device 32 includes a transformation mechanism 238 configured to perform a mathematical transformation on the first data signal. For example, the mathematical transformation could be a real Fourier transform with the first data signal as a real input. Since the transformation operates on real signals rather than complex signals, the first data signal could be an electrically in-phase representation of a composite signal, and quadrature signals could be excluded.

[0062] The conversion mechanism 238 includes a first analog-to-digital converter (ADC) 264 that receives a first data signal from a first data line 228. The first ADC 264 converts the first data signal from analog to digital form and outputs a first digital data signal. The first digital data signal is a digital representation of the first data signal.

[0063] The transformation mechanism 238 includes a transformation component 268 that receives a first data signal as input from a first analog-to-digital converter (ADC) 264. The transformation component 268 can be configured to perform a mathematical transformation on the first data signal to convert it from the time domain to the frequency domain. The mathematical transformation can be a real transformation, such as a real fast Fourier transform (FFT). A real transformation, such as a real fast Fourier transform (FFT), provides an output with one or more frequency peaks. Electronic devices use one or more frequency peaks output from the transformation component 268 for further processing to generate lidar data (distance and / or radial velocity between a reflecting object and a lidar chip or lidar system). The transformation component 268 can execute attribute functions using firmware, hardware, or software, or a combination thereof.

[0064] Electronic device 32 includes a peak finder 270 that receives the output from conversion unit 268. Peak finder 270 is configured to find peaks in the output of conversion unit 268 to identify the beat frequency of the composite optical signal. In some cases, the peak finder is configured such that the identified peak frequencies all have an amplitude above a threshold, which is selected to reduce noise and / or prevent spurious peak frequencies. In some cases, peak finder 270 may store the peak frequencies in memory 271 for later use by lidar data generator 274. LiDAR data generator 274 uses the peak frequencies to generate lidar data (distance and / or radial velocity between a reflecting object and the lidar chip or lidar system). Suitable memory 271 includes, but is not limited to, buffers. Peak finder 270 may use firmware, hardware, or software, or a combination thereof, to perform attribute functions.

[0065] The frequency of the system output signal is tuned by the electronic device over time. The system output signal has a frequency-time pattern with a repetitive period. Figure 5C An example of a suitable frequency-time pattern for the system output signal is shown. The fundamental frequency (f) of the system output signal. o () can be the frequency of the system output signal at the beginning of the cycle.

[0066] Figure 5C The image labeled Cycle is shown. j and Cycle j+1 The relationship between the frequency and time of a two-period sequence, where j represents the period index. In some cases, the frequency repeats in each period in relation to the time pattern, such as... Figure 5CAs shown in the diagram. The cycles shown do not include repositioning periods and / or repositioning periods that do not fall between cycles. Therefore, Figure 5C The results of continuous scanning are shown.

[0067] Each period consists of M data time slots, each data time slot is associated with a time slot index m and is labeled DP. m Suitable values ​​for M include M ≥ 2. Figure 5C In the example, M=3. Therefore, each cycle includes a label DP. m The three data periods are m=1, 2, and 3. In some cases, the frequency-time pattern is the same for data periods that correspond to each other in different periods, such as... Figure 5C As shown in the diagram, the corresponding data periods are those with the same periodic index. Therefore, each data period DP1 can be considered as the corresponding data period, and the associated frequency-pair time pattern is... Figure 5C The process is the same. At the end of the cycle, the electronics return the frequency to the same level as the previous cycle.

[0068] DP during data period m During this period, electronic devices can manipulate the light source, causing the frequency of the system output signal to change linearly as a function of time. For example, during the data period DP... m During this period, the frequency of the system output signal can be at a constant or substantially constant rate α. m The chirp rate changes. The chirp rate can persist for all or part of the duration of a data period. For example, during a data period labeled DP1, the electronics operate the light source, causing the frequency of the system output signal to change at a linear rate α1; during a data period labeled DP2, the electronics operate the light source, causing the frequency of the system output signal to change at a linear rate α2; and during a data period labeled DP3, the electronics operate the light source, causing the frequency of the system output signal to change at a linear rate α3.

[0069] The data periods associated with the sample area include multiple object data periods and at least one inspection data period. Figure 5C In this context, DP1 and DP2, associated with each sample region, can be used as the object sample region, and DP3, associated with the sample region, can be used as the data period to be examined. The rate of change of the system output signal frequency (α) during data period m... m The time period for each object's data can be different. In some cases, α1 to α2 can be selected. M , such that α1 to α M The sum is zero. For example, when M equals three, we can choose α1, α2, and α3 such that α1 + α2 + α3 = 0, as shown below. Figure 5CAs shown in the diagram. When α1 + α2 + α3 = 0, the frequency returns to the same frequency level as the previous cycle. In some cases, α1 > 0, α2 < 0 and α3 ≠ 0, or α11 < 0, α2 > 0 and α3 ≠ 0, or α3 = 0. In some examples, the rate of change of the system output signal frequency is non-zero during the data checking period.

[0070] Different portions of the system output signal are transmitted from the lidar system during different data periods. For example, the first object portion of the system output signal may be transmitted during the first object data period (in... Figure 5C In the example, m=1) it is transmitted during the second object data period. The second object portion of the system output signal can be transmitted during the second object data period (in Figure 5C In the example, m=2) is emitted during the period. The check portion of the system output signal is emitted during the data check period (in Figure 5C In the example (m=2), light is emitted during this period. Different portions of the system output signal can be combined with different portions of the reference signal to generate a composite signal with beat frequency differences. For example, light returning to the lidar system from the first object portion of the system output signal can be combined with light from the first object portion of the reference signal to generate a first object beat signal with a first object beat frequency difference. Light returning to the lidar system from the second object portion of the system output signal can be combined with light from the second object portion of the reference signal to generate a second object beat signal with a second object beat frequency difference. Light returning to the lidar system from the inspection portion of the system output signal can be combined with light from the inspection portion of the reference signal to generate an inspection beat signal with an inspection beat frequency difference.

[0071] although Figure 5C Two object data periods are shown, but the sample area may be illuminated by the system output signal for more than two object data periods. Therefore, in some cases, the period may include more than two object data periods or as few as one. The rate of change of the system output signal frequency during the examined data period may differ from the rate of change of the system output signal frequency during all or part of the object data periods. Therefore, the rate of change of the system output signal frequency may be different during each data period associated with the same sample area.

[0072] from Figure 5C It is evident from data period DP1 that the frequency of the system output signal can be increased during a period of the object data period associated with the sample region. The beat frequency of the composite signal during the object data period (increased data period) in which the frequency of the system output signal increases can be determined by f. ub This indicates that the rate of increase can be written as α. ub Therefore, in Figure 5C In the example, f1=f ub And α1=α ub.from Figure 5C As clearly seen in data period DP2, the frequency of the system output signal can decrease during a period of the object data associated with the same sample region. The beat frequency of the composite signal during the data period in which the frequency of the system output signal decreases can be determined by f. db This indicates that the rate of decrease can be written as α. db Therefore, in Figure 5C In the example, f2=f db And α2=α db .

[0073] Figure 5C Label the sample regions, each sample region is associated with a sample region index k and labeled as SR. k . Figure 5C The sample region SR was marked k To SR k+1 .exist Figure 5C The diagram shows how each sample region is illuminated with the system output signal during the data periods associated with it. For example, during the data periods labeled DP1, DP2, and DP3 within period j+1, the sample region SR is illuminated with the system output signal. k+1 Therefore, it is labeled as SR. k+1 The sample region is associated with the data periods marked DP1 to DP3 within period j+1. The sample region index k can be assigned relative to time. For example, the sample region can be illuminated by the system output signal in the sequence indicated by index k. Therefore, the sample region can be located after SR9 and within SR... 11 Previously irradiated sample area SR 10 .although Figure 5C The diagram shows a single sample region irradiated during one cycle, but multiple different sample regions can be irradiated during one cycle.

[0074] Each object illuminated by the system's output signal results in a set of frequency peaks in the spectrum. For example, a composite signal can result in a real Fourier transform with multiple distinct peak frequencies, each peak frequency separated from the DC frequency by the same amount. As an example, Figure 5D This is an exemplary spectrum output from a mathematical transformation. The spectrum shows the relationship between power and frequency. The spectrum shows a frequency peak at +f relative to the DC frequency and another corresponding frequency peak at -f relative to the DC frequency. One of these frequency peaks is at the beat frequency of the composite signal and is used as the target beat frequency. Another of these frequency peaks is at the inverse of the addendum of the beat frequency of the composite signal and is used as the image beat frequency. It is usually unclear which of the beat frequencies represents the target beat frequency and which of the beat frequencies represents the image beat frequency. As will be described below, the beat frequency during a period of data examination in each cycle can be used to identify which frequency peak represents the target beat frequency.

[0075] When multiple distinct objects exist within a sample region, the peak finder can output multiple sets of frequency peaks, each associated with a different object. Therefore, the spectrum can include multiple target beat frequencies and multiple image beat frequencies. Each peak frequency output from the peak finder can be a candidate among the target beat frequencies. Candidate frequencies can be determined by f... m,n This indicates that m represents the periodic index and n represents the index of the frequency peak within the data period m. As an example, Figure 5E The possible spectrum is shown. The spectrum in f m,1 f m,2 f m,3 and f m,4 It has four frequency peaks. m,1 and f m,2 The frequency peak at that point is the corresponding frequency peak, and f m,3 and f m,4 The frequency peak at that location is the corresponding frequency peak.

[0076] From candidate frequency (f m,n The period index m in the data clearly shows that when one or more objects are present in the sample region illuminated during data period m, each data period is associated with a set of candidate frequencies including at least one target beat frequency and at least one image beat frequency. For example, when the system output signal has a period index m according to the data period index m, the data period is associated with a set of candidate frequencies including at least one target beat frequency and at least one image beat frequency. Figure 5C In frequency-to-time mode, the first object data period (m=1) can be associated with multiple first object candidate frequencies, including the first object target frequency at the first object beat frequency and the first object image frequency at the additive inverse of the first object beat frequency. The second object data period (m=2) can be associated with multiple second object candidate frequencies, including the second object target frequency at the second object beat frequency and the second object image frequency at the additive inverse of the second object beat frequency. The inspection data period (m=3) can be associated with multiple inspection candidate frequencies, including the inspection target frequency at the inspection beat frequency and the inspection image frequency at the additive inverse of the inspection beat frequency.

[0077] The candidate frequencies that appear in data period m (i.e., Figure 5E f in m,1 f m,2 f m,3 and f m,4 The number of objects in the sample area is equal to the number of objects that may exist in the sample area. Figure 5E N in o =2) twice. Candidate frequencies from different object data periods can be grouped into candidate frequency pairs. (2(N)) o )) 2 There are N candidate frequency pairs, where No This indicates the number of objects considered to be in the sample region, as indicated by the output of a peak finder. Each candidate frequency pair includes candidate frequencies from two different object data periods. For example, when object data period m=1 results in f 1,1 f 1,2 f 1,3 and f 1,4 When the candidate frequency is at a certain point, the object data time period m=2 causes the frequency at f to be lower than that at a certain point. 2,1 f 2,2 f 2,3 and f 2,4 Candidate frequencies at N; o =2 and in (f 1,1 f 2,1 ), (f 1,1 f 2,2 ), (f 1,1 f 2,3 ), (f 1,1 f 2,4 ), (f 1,2 f 2,1 ), (f 1,2 f 2,2 ), (f 1,2 f 2,3 ), (f 1,2 f 2,4 ), (f 1,3 f 2,1 ), (f 1,3 f 2,2 ), (f 1,3 f 2,3 ), (f 1,3 f 2,4 ), (f 1,4 f 2,1 ), (f 1,4 f 2,2 ), (f 1,4 f 2,3 ) and (f 1,4 f 2,4 There are 16 candidate frequency pairs at index i'. Each candidate frequency pair can be associated with a pair of indices i'. For example, each candidate frequency pair can be written as P i’ , where i' has values ​​from 1 to (2 (N) o )) 2 The value of . As an example, the above candidate frequency pairs can be obtained from P1=(f 1,1 f 2,1 Extended to P I’ =(f 1,1 f 2,1 ), where I' = (2 (N o )) 2Each candidate frequency pair is potentially a pair of correct beat frequencies caused by the object during data period m=1 and correct beat frequencies caused by the same object during data period m=2. Therefore, there is no N pairs that can all be used as valid frequency pairs. o One effective candidate frequency pair.

[0078] Beat frequencies from two or more different data periods associated with the same sample area can be combined to generate lidar data for that sample area. For example, in the SR illumination sample area k The beat frequency determined from DP1 during this period can be compared with the SR in the irradiated sample area. k The beat frequency combination determined from DP2 during the period is used to determine the SR of the sample region. k The LiDAR data. As an example, the data period DP... m The beat frequency during this period can be written as the following equation 1: f m =2α m R / c-2ν / λ, where m is the time period index, R represents the distance between the lidar system and the object, c represents the speed of light, ν represents the radial velocity between the reflecting object and the lidar system, λ represents the wavelength of the system output signal, and the direction from the reflecting object toward the lidar system is assumed to be the positive direction.

[0079] In equation 1 (f) above m =2α m In (R / c-2ν / λ), the values ​​of ν and R are unknown. Therefore, the results of Equation 1 from two different data periods associated with the sample region can be used to calculate the values ​​of ν and R for the sample region. Solving these equations to obtain the distance (R) between the lidar system and the object provides Equation 2: R=c(f ub -f db ) / (2(α) ub -α db Additionally, solving these equations to obtain the radial velocity (ν) between the reflecting object and the lidar system provides equation 3: ν = λ(α) db f ub -α ub f db ) / (2(α) ub -α db )).

[0080] like Figure 5B As shown, the electronic device includes a lidar data generator 274 that receives beat frequencies from memory 271 and / or peak seeker 270. The lidar data generator 274 can use equations 2 and 3 to calculate lidar data for each candidate frequency pair. For example, when the system output signal has a beat frequency according to... Figure 5C In frequency-to-time mode, f in each candidate frequency pair 1,nThe value (m=1) can be used as f in equation 2 and / or equation 3. ub And f in the candidate frequency pair 2,n The value (m=1) can be used as f in equation 2 and / or equation 3. db Therefore, the lidar data generator 274 can calculate the candidate range and / or candidate radial velocity (R and / or ν) for each candidate frequency pair. Thus, each candidate frequency pair (P) in the sample region... i’ ) and candidate distance (R i’ ) and / or candidate radial velocity (ν i’ Correlation. Candidate distance and / or candidate radial velocity (R) of candidate frequency pairs. i’ and / or ν i’ () can represent candidate lidar data for a sample region. Candidate lidar data potentially exists as f ub f db and f chk The source data is the lidar data of the sample area illuminated during the data period. The lidar data generator 274 can perform attribute functions using firmware, hardware, software, or a combination thereof.

[0081] The electronic device may include a lidar data verifier 276 that receives candidate lidar data from the lidar data generator 274. The lidar data verifier 276 may also receive peak frequencies, such as the peak frequency of the check period (f), from the memory 271 and / or the peak seeker 270. chk,n When the system output signal has according to Figure 5C When the frequency is relative to the time pattern, the data period marked DP3 can be used as the inspection data period. Therefore, f 3,n (m=3) values ​​can all be used as the beat frequency (f) during the inspection period. chk,n When there may be two objects in the sample region (N) o =2), there are four peak frequencies (f) during the inspection period. chk,1 f chk,2 and f chk,3 and f chk,4 ).

[0082] The lidar data validator 276 can use the inspection data period associated with a sample area to identify which candidate lidar data values ​​associated with that sample area are correct. For example, the lidar data validator 276 can identify which candidate lidar data values ​​are correct based on the relationship between the candidate frequency and the P-value. i’ The associated candidate lidar data is used to calculate the beat frequency (cf) of each candidate frequency pair during the comparison check period. chk,i’ (This can be achieved by examining the data period α) chk Substituting the rate of change of frequency during the period into Equation 1 yields Equation 4: cf chk =2αchk R / c-2ν / λ is used to determine the beat frequency during the comparative examination period (cf). chk When the system output signal has according to Figure 5C When the frequency is relative to the time pattern, the data period marked DP3 can be used as the check data period. Therefore, the value of α3 can be used as α. chk The lidar data verifier 276 can be derived from equation 5: cf chk,i’ =2α chk R i’ / c-2ν i’ / λ calculates candidate frequencies for P i’ The comparison of the capture frequency during the inspection period, where R i’ Represents the candidate frequency with respect to P i’ The candidate distance, and ν i’ Represents the candidate frequency with respect to P i’ Candidate radial velocities.

[0083] The lidar data verifier 276 can use the comparison of candidate frequency pairs to check the beat frequency during the time period (cf). chk,i’ To identify N o The system identifies one or more valid candidate frequency pairs (one or more valid frequency pairs) and thus identifies the LiDAR data for one or more valid frequency pairs. For example, the LiDAR data verifier 276 can apply one or more inspection criteria to each candidate frequency pair P. i’ As an example, the lidar data verifier 276 can compare 2N samples from the same sample region. o The frequency of each inspection period (f) chk,n ) and comparison of the beat frequency during the examination period (cf) chk,i’ The value of ) is used to identify matching values. As a more specific example, in some examples, the beat frequency (f) is calculated for each examination period for the sample region. chk,n The value of ) is compared with the beat frequency (cf) calculated for the region during the inspection period. chk,i’ The match is identified by comparing one of the values ​​in the sample region with the beat frequency (cf) of each comparison check period. chk,i’ One of the comparisons. For example, the lidar data verifier 276 can be compared from the beat frequency (cf) of each comparison check period. chk,i’ Subtract each data period from the inspection data (f) chk,n The number of matching indicators can be equal to 2N. o *(2(N o )) 2 The lidar data verifier 276 can identify N with the smallest absolute value. o A matching indicator. As an example, the lidar data verifier 276 can be configured for a range of 1 to (2 (N) o)) 2 The sum of all values ​​of i' from 1 to 2N o Calculate all values ​​of n to match indicator X i’,n =|cf chk,i’ -f chk,n The value of |. The lidar data verifier 276 can determine the minimum value of X. i’,n The result N o Identified as a match value. A match value indicates the beat frequency (cf) estimated from the candidate pair's data for the examined data period. chk,i’ ) and the actual measured beat frequency (f chk,n A match between one of the following (N). o Each value of the identified matching indicator i' indicates a candidate frequency pair P that is associated with one of the objects in the sample region. i’ For example, when the LiDAR data verifier 276 identifies a matching indicator X 5,3 and X 9,1 At that time, the candidate frequency pairs associated with i'=5 and i'=9 are identified as valid frequency pairs in sample region m, i.e., P5=(f m,n f m,n ) and P9 = (f m,n f m,n Therefore, each identified candidate pair P i’ The peak frequencies in the sample are identified as valid beat frequencies occurring during the object data period and generated by the same objects in the sample region. For example, if the candidate frequencies are P5 = (f 1,1 f 2,4 If ) is identified, then the peak frequency f 1,1 and f 2,4 The frequency is identified as the actual beat frequency generated by the reflection of the system output signal by the same object in the sample region during object data periods m=1 and m=2. Similarly, candidate lidar data associated with the identified i' value is also assigned as lidar data for sample region m. For example, the sample region is considered to contain an object with a radial velocity ν5 at a distance R5 and an object with a radial velocity ν9 at a distance R9. LiDAR data verifier 276 can discard frequency pairs with pair indices (i') associated with matching indicators not identified by lidar data verifier 276. Similarly, lidar data verifier 276 can discard lidar data (R') associated with matching indicators not identified by lidar data verifier 276. i’ and / or ν i’ The lidar data verifier 276 can perform attribute functions using firmware, hardware, software, or a combination thereof.

[0084] Comparative examination time period (cf) chk,i’All of these are the frequency of the inspection period (f) chk,n The approximation of one of the values ​​in the test period (cf) is used instead of a function of the beat frequency values ​​within the test period. chk,i’ The comparison beat frequency (cf) is a function of beat frequencies from multiple different object data periods. The comparison beat frequency for each candidate frequency pair represents the value that the beat frequency associated with the checked data period will have if the first object beat frequency equals the candidate frequency from the first object data period in the candidate frequency pair and the second object beat frequency equals the candidate frequency from the second object data period in the candidate frequency pair. chk,i’ The beat frequencies (cf) are calculated from multiple different object data time periods. For example, in the example above, the beat frequency (cf) of the comparison check period is used. chk,i’ The beat frequency is calculated from the time periods during which the object data is increased and decreased. Therefore, the beat frequency (cf) of the comparison check period is used. chk,i’ The beat frequency (f) is a function of the distance (R) and radial velocity (ν) values ​​during data periods other than the inspection data period. Conversely, the beat frequency (f) during the inspection period is a function of the distance (R) and radial velocity (ν) values ​​during the inspection data period. chk,n The beat frequency (f) is a function of the distance (R) and radial velocity (ν) values ​​during the data period being examined. Therefore, when the distance (R) and radial velocity (ν) values ​​match during both the data period being examined and the associated object data period, the beat frequency (f) for each examination period is... chk,n The value of ) is compared with the beat frequency (cf) during the inspection period. chk,i’ The value of one of them matches. For example, when the distance (R) and radial velocity (ν) remain constant or substantially constant during the inspection data period, the associated increasing data period, and the associated decreasing data period, the beat frequency (f) for each inspection period. chk,n The value of ) is compared with the beat frequency (cf) during the inspection period. chk,i’ A value in one of the comparison checks is matched. Values ​​that do not result in a match are discarded. The comparison check period beat frequency (cf) is checked. chk,i’ ) and associated candidate lidar data.

[0085] Figure 6 This is a flowchart of LiDAR data refinement processing that can be used to identify valid LiDAR data. In processing box 310, the received sample area (SR)... k The beat frequency of the object sample region in the image. For example, the lidar data generator 274 can receive the beat frequency from the memory 271 and / or the peak finder 270. As described above, the received beat frequency includes beat frequencies from two or more object data periods and at least one inspection data period. For example, when the system output signal has a beat frequency according to... Figure 5C When the frequency is relative to the time pattern, the received beat frequency can be included in the object sample region SR. kThe beat frequency generated by the system output signal during data periods DP1, DP2, and DP3. In some cases, DP1 and DP2 can be used as the object data period and DP3 can be used as the check data period. As another example, DP1 and DP3 can be used as the object data period and DP2 can be used as the check data period.

[0086] At processing box 312, the lidar data generator can identify candidate frequencies (f... m,n A set of (). This can be related to the sample region SR. k Candidate frequencies (f) are determined for each associated data period. m,n A set of ). For example, if the system output signal has according to Figure 5C The frequency-to-time pattern can identify a set of first candidate frequencies, which includes one or more first target frequencies all at the first object beat frequency and one or more first image frequencies all at the additive inverse of one of the first object beat frequencies; it can identify a set of second candidate frequencies, which includes one or more second target frequencies all at the second object beat frequency and one or more second image frequencies all at the additive inverse of one of the second object beat frequencies; and it can identify a set of inspection candidate frequencies, which includes one or more inspection target frequencies all at the inspection beat frequency and one or more inspection image frequencies all at the additive inverse of one of the inspection beat frequencies.

[0087] In order to find candidate frequencies (f) m,n The peak finder 270 can search for frequency peaks across the entire spectrum. Alternatively, the peak finder 270 can search the positive side (>DC) or the negative side of the spectrum. When the peak finder 270 searches the positive side (>DC) or the negative side of the spectrum, the peak finder identifies N. o The LiDAR data generator 274 can receive only the SR data from the sample area, but does not identify the corresponding frequency. Therefore, the LiDAR data generator 274 can receive only the SR data from the sample area. k Candidate frequency (f) m,n Part of the process. When the lidar data generator 274 only receives the sample area SR k Candidate frequency (f) m,n When a portion of the received candidate frequency is received, the lidar data generator 274 can add the corresponding frequency to the received candidate frequency (f). m,n To identify the sample region SR k Candidate frequency (f) m,n The complete set of ). When the peak seeker 270 searches for frequency peaks throughout the entire spectrum, the received candidate frequencies (f m,n ) can be used as a sample region SR k Candidate frequency (f) m,n The complete set of ).

[0088] At processing block 314, lidar data generator 274 can identify candidate frequency pairs from the candidate frequencies identified at processing block 312.

[0089] At processing block 316, the lidar data generator 274 can calculate the beat frequency for the comparison check period for each candidate frequency pair. In some cases, the lidar data generator 274 also calculates candidate lidar data for each candidate frequency pair. For example, the lidar data generator 274 can use Equation 2 and / or Equation 3 to calculate the candidate distance (R). i’ ) and / or candidate radial velocity (ν i’ For each candidate frequency, P i’ Calculate candidate distance and / or candidate radial velocity (R i’ and / or ν i’ When the lidar data generator 274 calculates each candidate frequency pair P i’ Candidate distance and / or candidate radial velocity (R i’ and / or ν i’ When this is the case, each candidate frequency can be calculated from Equation 5 for P. i’ Comparative examination time period capture frequency (cf) chk,i’ When the lidar data generator 274 does not calculate each candidate frequency pair P i’ Candidate distance and candidate radial velocity (R i’ and / or ν i’ When ), by substituting equations 2 and 3 into equation 5, we can directly obtain f ub and f db The value of each candidate frequency is calculated for P. i’ Comparative examination time period capture frequency (cf) chk,i’ ).

[0090] At processing box 318, lidar data verifier 276 identifies valid frequency pairs and / or valid lidar data for the sample region. For example, lidar data verifier 276 can apply one or more inspection criteria to each candidate frequency pair P. i’ This is to identify valid frequency pairs and / or valid lidar data. In one example, lidar data verifier 276 targets frequencies from 1 to (2 (N) o )) 2 The sum of all values ​​of i' from 1 to 2N o Calculate all values ​​of n to match indicator X i’,n =|cf chk,i’ -f chk,n The value of |. The lidar data verifier 276 will have the minimum value of X. i’,n The result N o Recognized as a matching value. The N of the recognized matching indicator i' oThe value belongs to the effective candidate frequency pair P i’ (Effective frequency pairs). In some cases, the lidar data verifier 276 identifies valid lidar data at processing box 318. For example, candidate lidar data associated with the identified i' value is identified as valid lidar data for sample region m. For example, for each identified i' value, the sample region is considered to be contained within a distance R. i At and / or with radial velocity ν i The object. Therefore, when the lidar data generator 274 calculates candidate lidar data for each candidate frequency pair at processing block 316, the candidate lidar data associated with the identified i' value can be used as valid lidar data for the sample area. For example, when the lidar data generator 274 calculates each candidate frequency pair P at processing block 316 i’ Candidate distance and / or candidate radial velocity (R i’ and / or ν i’ When ), the candidate distance (R) for each identified i' value i’ The values ​​and / or candidate radial velocities (ν) for each identified i' value i’ The value can be used as the effective distance (R) of one or more objects in the sample region. i’ ) value and / or (one or more) effective radial velocities (ν) i’ The effective distance (R) with the same i' index value when the sample region includes more than one object. i’ ) and effective radial velocity (ν) i’ The i' value is used for the same object. Therefore, the LiDAR data for each different object in the sample area can be identified. Since effective LiDAR data is associated with the identified i' value, identifying effective LiDAR data also involves identifying which of the candidate LiDAR data results is calculated from a candidate frequency pair that includes the first target frequency and the second target frequency associated with the same object, thus identifying the effective frequency pair.

[0091] When the lidar data generator 274 does not calculate candidate lidar data for each candidate frequency pair at processing box 316, the lidar data verifier 276 can use the identified i' value to calculate the effective lidar data for the sample area. For example, the lidar data verifier 276 can use Equation 2 and / or Equation 3 to calculate the effective distance and / or effective radial velocity (R) for each identified i' value. i’ and / or ν i’ When the sample region includes more than one object, the effective distance (R) with the same i' index value is... i’ ) and effective radial velocity (ν) i’ The values ​​correspond to the same object. Therefore, it is possible to identify the LiDAR data for each different object in the sample area.

[0092] At processing block 320, the lidar data verifier 276 can retain valid lidar data for the sample area and / or make it available to the application for further processing. For example, valid lidar data for the sample area can be stored in a storage device such as a memory and / or can be further processed. In some cases, further processing includes filtering valid lidar data for errors. After further processing, filtered lidar data for the sample area can be stored in a storage device such as a memory and / or can be further processed. The application can access the valid and / or filtered lidar data for the sample area from the storage device or directly from the electronics 32. At processing block 320, the lidar data verifier 276 can optionally discard any candidate frequency pairs and / or candidate lidar data for the sample area and / or mark them as invalid. Thus, a first portion of the candidate frequency pairs and / or candidate lidar data is classified as valid, while a second portion of the candidate frequency pairs and / or candidate lidar data is classified as invalid.

[0093] Although lidar systems are disclosed as having a system output signal with a frequency-to-time pattern comprising two object data periods for each sample region, the system output signal can also have a frequency-to-time pattern with a single object data period. For example, for a stationary field of view, there is a radial velocity equal to zero for each sample region. Therefore, a single object data period can be used to resolve the range (R). In these cases, candidate frequencies of the object data period can be used as candidate frequency pairs, f db or f ub The time pattern can be set to zero based on the frequency, and ν in the above equation i’ The value can be set to zero.

[0094] Although lidar systems are described as generating composite signals with multiple different beat frequencies when multiple objects are present in a sample area and / or illuminated by the system output signal, composite signals with multiple different beat frequencies can also be generated by different surfaces of the same physical entity. Therefore, multiple objects present in the sample area and / or illuminated by the system output signal can also include multiple surfaces of the same physical entity.

[0095] Suitable electronic devices 32 may include, but are not limited to, controllers, which include analog circuitry, digital circuitry, processors, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), computers, microcomputers, or combinations thereof suitable for performing the aforementioned operations, monitoring, and control functions. In some cases, the controller may access memory containing instructions executed by the controller during the performance of the operations, control, and monitoring functions. In some cases, the functions of the lidar data generator and peak finder may be performed by a field-programmable gate array (FPGA), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), firmware, software, hardware, or combinations thereof. Although electronic devices are shown as a single component in a single location, electronic devices may include multiple different components that are independent of each other and / or placed in different locations. Additionally, as described above, all or part of the disclosed electronic devices may be included on a chip, which includes electronic devices integrated with the chip.

[0096] Suitable platforms for LiDAR chips include, but are not limited to, silicon dioxide, indium phosphide, and silicon-on-insulator wafers. Figure 7 This is a cross-section of a portion of a chip made of silicon-on-insulator (SOI) wafers. SOI wafers include a buried layer 410 between a substrate 412 and a light transmission medium 414. In SOI wafers, the buried layer 410 is silicon dioxide, while the substrate 412 and the light transmission medium 414 are silicon. The substrate 412 of an optical platform such as an SOI wafer can serve as the base for the entire lidar chip. For example, Figures 1A to 1C The optical components shown on the lidar chip can be positioned on or above the top and / or lateral sides of the substrate 412.

[0097] Figure 7 The portion of the chip shown includes a waveguide structure suitable for use in a lidar chip constructed from silicon-on-insulator wafers. A ridge 416 of the optical transmission medium 414 extends away from the planar region 418 of the optical transmission medium. The optical signal is confined between the top of the ridge 416 and the buried oxide layer 410.

[0098] The dimensions of the ridge waveguide are Figure 7The dimensions are denoted as follows. For example, a ridge has a width denoted as w and a height denoted as h. The thickness of the planar region is denoted as T. For lidar applications, these dimensions may be more important than others because higher levels of optical power are required than in other applications. The ridge width (denoted as w) is greater than 1 μm and less than 4 μm, the ridge height (denoted as h) is greater than 1 μm and less than 4 μm, and the planar region thickness is greater than 0.5 μm and less than 3 μm. These dimensions can be applied to straight or substantially straight portions of the waveguide, curved portions of the waveguide, and tapered portions(one or more) of the waveguide. Thus, these portions of the waveguide will be single-mode. However, in some cases, these dimensions are suitable for straight or substantially straight portions of the waveguide. Additionally or alternatively, curved portions of the waveguide may have a reduced planar thickness to reduce optical losses in the curved portions of the waveguide. For example, curved portions of the waveguide may have ridges extending away from the planar region with a thickness greater than or equal to 0.0 μm and less than 0.5 μm. While the dimensions described above typically provide straight or substantially straight sections of waveguides with a single-mode configuration, they can result in multimode (one or more) tapered sections and / or (one or more) bent sections. Coupling between the multimode and single-mode geometries can be accomplished using tapered sections that substantially do not excite higher-order modes. Therefore, waveguides can be constructed such that even when carried in waveguide sections with multimode dimensions, the signal carried in the waveguide is carried in single-mode mode. Figure 7 The waveguide construction disclosed in the context is suitable for use according to Figures 1A to 1C All or part of the waveguide on the constructed lidar chip.

[0099] The optical sensor that interfaces with the waveguide on the LiDAR chip can be a component that is separate from and then attached to the chip. For example, the optical sensor can be a photodiode or an avalanche photodiode. Examples of suitable optical sensor components include, but are not limited to, InGaAs PIN photodiodes manufactured by Hamamatsu in Hamamatsu, Japan, or InGaAs APDs (avalanche photodiodes) manufactured by Hamamatsu in Hamamatsu, Japan. These optical sensors can be centrally located on the LiDAR chip. Alternatively, all or part of the waveguide terminating at the optical sensor can terminate at an end face located at the edge of the chip, and the optical sensor can be attached above the end face to the edge of the chip, such that the optical sensor receives light passing through the end face. The use of an optical sensor as a component separate from the chip is suitable for all or part of an optical sensor selected from the group consisting of a first auxiliary optical sensor 218, a second auxiliary optical sensor 220, a first optical sensor 223, and a second optical sensor 224.

[0100] As an alternative to a standalone optical sensor, all or part of the optical sensor can be integrated with a chip. Examples of optical sensors with an on-chip ridge waveguide interface constructed from silicon-on-insulator wafers can be found in: Optics Express, Vol. 15, No. 21, 13965-13971 (2007); U.S. Patent No. 8,093,080, published January 10, 2012; U.S. Patent No. 8,242,432, published August 14, 2012; and U.S. Patent No. 6,108,8472, published August 22, 2000, all of which are incorporated herein by reference in their entirety. The use of a chip-integrated optical sensor is suitable for all or part of an optical sensor selected from the group consisting of an auxiliary optical sensor 218, a second auxiliary optical sensor 220, a first optical sensor 223, and a second optical sensor 224.

[0101] The light source 4, which interfaces with the utility waveguide 12, can be a laser chip that is separate from and then attached to the lidar chip. For example, the light source 4 can be a laser chip attached to the chip using a flip-chip arrangement. A flip-chip arrangement is suitable when the light source 4 is to be coupled to a ridge waveguide on a chip constructed of silicon on insulator. Alternatively, the utility waveguide 12 can include a grating (not shown), such as a Bragg grating, which serves as a reflector for an external cavity laser. In these cases, the light source 4 can include a gain element that is separate from and then attached to the lidar chip in a flip-chip arrangement. Examples of suitable interfaces between flip-chip gain elements and ridge waveguides on chips constructed of silicon on insulator can be found in U.S. Patent No. 9,705,278, published July 11, 2017, and U.S. Patent No. 5,991,484, published November 23, 1999; each of these patents is incorporated herein by reference in its entirety. When the light source 4 is a gain element or a laser chip, the electronic device 32 can change the frequency of the emitted lidar signal by changing the level of the current applied through the gain element or the laser cavity.

[0102] The aforementioned lidar system includes multiple optical components, such as lidar chips, lidar adapters, light sources, optical sensors, waveguides, and amplifiers. In some cases, in addition to or as a replacement for the optical components shown, the lidar system includes one or more passive optical components. Passive optical components can be solid-state components that do not involve moving parts. Suitable passive optical components include, but are not limited to, lenses, mirrors, gratings, reflective surfaces, splitters, demultiplexers, multiplexers, polarizers, polarization separators, and polarization rotators. In some cases, in addition to or as a replacement for the optical components shown, the lidar system includes one or more active optical components. Suitable active optical components include, but are not limited to, optical switches, phase tuners, attenuators, steerable mirrors, steerable lenses, tunable demultiplexers, and tunable multiplexers.

[0103] In view of these teachings, other embodiments, combinations, and modifications of the invention will readily occur to those skilled in the art. Therefore, the invention is limited only to the following claims, which, when viewed in conjunction with the foregoing description and drawings, encompass all such embodiments and modifications.

Claims

1. A method for operating a lidar system, the method comprising: The laser radar system emits a signal, causing the sample area to be illuminated by the output signal. Different portions of the system output signal are transmitted during different data periods; The light returning from the system output signal to the lidar system is combined with the light from the reference signal to generate beat signals that are associated with different data periods in the data period. Multiple candidate frequencies are generated for each data period, and each candidate frequency for a data period represents a possible beat frequency of the beat signal associated with the data period. as well as The candidate frequencies of the inspection data period in the data period are used to identify which of the candidate frequencies of the object data period in the data period is the beat frequency of the beat signal associated with the object data period.

2. The method according to claim 1, further comprising: The lidar data of the object in the sample area is calculated from the identified target frequency, and the lidar data indicates the radial velocity and / or distance between the lidar system and the object.

3. The method according to claim 2, wherein, The lidar data of the object is not a function of any candidate frequency of the object data period that was not identified as the beat frequency of the beat signal.

4. The method according to claim 1, further comprising: Multiple candidate frequency pairs are identified, each candidate frequency pair including one candidate frequency from the object data period and one second candidate frequency from the second object data period in the data period, and Specifically, using candidate frequencies from the inspection data period to identify which of the candidate frequencies associated with the object data period is at the beat frequency of the beat signal associated with the object data period includes identifying which of the candidate frequency pairs includes a pairing of the beat frequency of the beat signal associated with the object data period and the beat frequency of the beat signal associated with the second object data period.

5. The method according to claim 4, further comprising: The comparison beat frequency of each of the candidate frequency pairs is calculated, wherein the comparison beat frequency of each candidate frequency pair is calculated from the candidate frequencies from the object data period and the candidate frequencies from the second object data period in the candidate frequency pair. If the beat frequency associated with the object data period is equal to the candidate frequency from the object data period in the candidate frequency pair and the beat frequency associated with the second object data period is equal to the candidate frequency from the second object data period in the candidate frequency pair, then the comparison beat frequency of each of the candidate frequency pairs represents the value that the beat frequency associated with the checked data period will have.

6. The method according to claim 5, wherein, Identifying which of the candidate frequency pairs includes pairing the beat frequency of the beat signal associated with the object data period and the beat frequency of the beat signal associated with the second object data period, which involves comparing the candidate frequency of the examined data period with the comparison beat frequency of each of the candidate frequency pairs.

7. The method according to claim 1, wherein, The object portion transmits the system output signal during the object data period, and the check portion transmits the system output signal during the check data period within the data period. The frequency of the system output signal is changed at different rates during the object data period and the inspection data period; The combination of light returning from the system output signal to the lidar system and light from the reference signal includes: The light returning the object portion of the output signal from the system to the lidar system is combined with the light from the object reference signal to generate an object beat signal with the object beat frequency difference. The light returned from the inspection portion of the system output signal to the lidar system is combined with the light from the inspection reference signal to generate an inspection beat signal for inspecting the beat frequency difference. Generating candidate frequencies for each data period includes generating object candidate frequencies comprising the object target frequency at the object beat frequency and the object image frequency at the additive inverse of the object beat frequency, and generating check candidate frequencies comprising the check target frequency at the check beat frequency and the check image frequency at the additive inverse of the check beat frequency; and Using candidate frequencies includes using the check candidate frequencies method to identify which of the object's candidate frequencies is the object's target frequency.

8. The method according to claim 1, wherein, Each of the candidate frequencies is located at the frequency peak in the output spectrum from the real fast Fourier transform (FFT).

9. A method for operating a lidar system, comprising: The laser radar system emits a signal that illuminates the sample area. Calculate multiple different candidate lidar data results for the sample area, each of the different candidate lidar data results being a candidate for radial velocity and / or distance between the lidar system and an object in the sample area; as well as Identify which of the candidate lidar data results represents valid lidar data for the sample area.

10. The method according to claim 9, wherein, The system output signal is transmitted in the first object data period during a first object data period, in the second object data period during a second object data period, and in the check data period during a check data period. The frequency of the system output signal changes at different rates during the first object data period and the second object data period. as well as Also includes: The light returning to the lidar system from the first object portion of the system output signal is combined with the light from the first object portion of the reference signal to generate a first object beat signal with a first object beat frequency difference. The light returning to the lidar system from the second object portion of the system output signal is combined with the light from the second object portion of the reference signal to generate a second object beat signal with a second object beat frequency difference. The light returned to the lidar system from the inspection portion of the system output signal is combined with the light from the inspection reference signal to generate an inspection beat signal for inspecting the beat frequency difference. Multiple candidate frequencies of the first object are identified. The first candidate frequencies include the first target frequency at the first object beat frequency and the first image frequency at the additive inverse of the first object beat frequency. Multiple second candidate frequencies are identified, including the second target frequency at the second object beat frequency and the second image frequency at the additive inverse of the second object beat frequency. Multiple candidate frequencies for inspection are identified, including the target frequency at the inspection beat frequency and the inspection image frequency at the additive inverse of the inspection beat frequency. Identify multiple candidate frequency pairs, each candidate frequency pair including one of the first candidate frequencies and one of the second candidate frequencies; The calculation of multiple distinct candidate lidar data results for the sample region includes calculating candidate lidar data results from each of the candidate frequency pairs; and The process of identifying which candidate lidar data result represents valid lidar data for the sample area includes identifying which candidate lidar data result is calculated from the first target frequency and the second target frequency.

11. The method according to claim 10, wherein, Identify the candidate frequency pairs such that for each possible combination of a first candidate frequency paired with a second candidate frequency, there exists one of the candidate frequency pairs.

12. The method according to claim 10, wherein, The lidar data results for each of the candidate frequency pairs are candidates for the radial velocity and distance between the lidar system and the object in the sample area.

13. The method of claim 10, further comprising: The comparison beat frequency of each of the candidate frequency pairs is calculated, wherein the comparison beat frequency of each candidate frequency pair is calculated from the first candidate frequency and the second candidate frequency of the candidate frequency pair. If the first target frequency is equal to the first candidate frequency in the candidate frequency pair and the second target frequency is equal to the second candidate frequency in the candidate frequency pair, then the comparison beat frequency of each of the candidate frequency pairs is an approximation of the value that the third target frequency will have.

14. The method according to claim 13, wherein, The identification of which candidate lidar data result is calculated from a candidate frequency pair including a first target frequency and a second target frequency, and includes a comparison beat frequency that compares a third target frequency with each of the candidate frequency pairs.

15. The method of claim 14, further comprising: Calculate matching indicators, which are all absolute values ​​of the difference between one of the beat frequencies and one of the third target frequencies. For each possible combination of one of the comparison beat frequencies and one of the third target frequencies, calculate one of the matching indicators, and Candidate lidar data results calculated from candidate frequency pairs associated with the lowest matching indicator are identified as candidate lidar data results calculated from the first target frequency and the second target frequency.

16. A system comprising: A lidar system, configured to emit a system output signal such that a sample area is illuminated by the system output signal. Different portions of the system output signal are transmitted during different data periods; An optical signal combiner configured to combine light returning from the system output signal to the lidar system with light from a reference signal to generate beat signals that are associated with different data periods in the data period; Electronic devices configured to generate multiple candidate frequencies for each data period in a data period. Each candidate frequency of a data period represents a possible beat frequency of the beat signal associated with that data period, and The electronic device uses candidate frequencies of the check data period in the data period to identify which of the candidate frequencies of the object data period is at the beat frequency of the beat signal associated with the object data period.

17. The system according to claim 16, wherein, The electronic device calculates lidar data of an object in the sample area from the identified target frequency, the lidar data indicating the radial velocity and / or distance between the lidar system and the object; and The lidar data of the object is not a function of any candidate frequency of the object data period that was not identified as the beat frequency of the beat signal.

18. The system according to claim 16, wherein, The object portion transmits the system output signal during the object data period, and the check portion transmits the system output signal during the check data period within the data period. The frequency of the system output signal changes at different rates during the object data period and the inspection data period; The optical signal combiner is configured to combine light returning from the system output signal to the lidar system with light from a reference signal, such that... The light returning to the lidar system from the object portion of the system output signal is combined with the light from the object portion of the reference signal to generate an object beat signal with an object beat frequency difference. The light returning from the inspection portion of the system output signal to the lidar system is combined with the light from the inspection portion of the reference signal to generate an inspection beat signal for checking the beat frequency difference. Candidate frequencies include object candidate frequencies and inspection candidate frequencies. The object candidate frequencies include the object target frequency at the object beat frequency and the object image frequency at the additive inverse of the object beat frequency, and The candidate frequencies to be checked include the target frequency at the beat frequency and the image frequency at the additive inverse of the beat frequency; and The electronic device uses candidate frequencies, including checking candidate frequencies to identify which of the candidate frequencies is the target frequency.

19. A system comprising: A lidar system configured to emit a system output signal such that a sample area is illuminated by the system output signal; An electronic device that calculates multiple distinct candidate lidar data results for the sample region, each of the distinct candidate lidar data results being a candidate for radial velocity and / or distance between the lidar system and an object in the sample region. The electronic device identifies which of the candidate lidar data results represents the valid lidar data for the sample area.

20. The system according to claim 19, wherein, The system output signal is transmitted by the object portion during the first object data period in the data period, by the second object data period during the second object data period, and by the check portion during the check data period in the data period. The frequency of the system output signal changes at different rates during the first object data period and the second object data period. as well as Also includes: An optical signal combiner combines light returning from the first object portion of the system output signal to the lidar system with light from the first object portion of a reference signal to generate a first object beat signal with a first object beat frequency difference. The optical signal combiner combines the light returned to the lidar system from the second object portion of the system output signal with the light from the second object portion of the reference signal to generate a second object beat signal with a second object beat frequency difference. The optical signal combiner combines the light returned from the inspection portion of the system output signal to the lidar system with the light from the inspection portion of the reference signal to generate an inspection beat signal for checking the beat frequency difference. Which of the candidate lidar data results represents valid lidar data for the sample region that identified multiple first candidate frequencies, multiple second candidate frequencies, and multiple check candidate frequencies? The first candidate frequencies include the first target frequency at the first object beat frequency and the first image frequency at the additive inverse of the first object beat frequency. The second candidate frequencies include the second target frequency at the second beat frequency and the second image frequency at the additive inverse at the second beat frequency, and The third candidate frequencies include the third target frequency at the third beat frequency and the third image frequency at the additive inverse at the third beat frequency. Identifying which candidate LiDAR data result represents valid LiDAR data for the sample area includes identifying multiple candidate frequency pairs. Each candidate frequency pair includes one of the first candidate frequencies and one of the second candidate frequencies; Calculating multiple distinct candidate lidar data results for the sample region includes calculating candidate lidar data results from each of the candidate frequency pairs; and Identifying which candidate lidar data result represents valid lidar data for the sample area includes identifying which candidate lidar data result was calculated from the first target frequency and the second target frequency.

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