Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
  • G01S17/06—Systems determining position data of a target
  • G01S17/42—Simultaneous measurement of distance and other co-ordinates
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
  • G01S17/06—Systems determining position data of a target
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/88—Lidar systems specially adapted for specific applications
  • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
  • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/481—Constructional features, e.g. arrangements of optical elements
  • G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/481—Constructional features, e.g. arrangements of optical elements
  • G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
  • G01S7/4815—Constructional features, e.g. arrangements of optical elements of transmitters alone using multiple transmitters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/481—Constructional features, e.g. arrangements of optical elements
  • G01S7/4816—Constructional features, e.g. arrangements of optical elements of receivers alone
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/483—Details of pulse systems
  • G01S7/486—Receivers
  • G01S7/487—Extracting wanted echo signals, e.g. pulse detection
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/499—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using polarisation effects

Definitions

• the present invention relates to an apparatus for determining a position of at least one object, the apparatus having at least one first emitter configured to emit a first transmission light signal traveling from the apparatus to the object, and wherein the apparatus comprises at least one A detector configured to detect a received light signal passing from the object to the detector, wherein the detector comprises at least one pixel matrix having at least one pixel.
• the present invention further relates to a method for determining a position of at least one object by means of such a device.
• Such a device is also referred to as LiDAR (originally a port mount of light and radar).
• a LiDAR can be used to determine a position of an object relative to itself and other objects. Possible applications arise, for example, in the automotive sector.
• the functional principle of a LiDAR is known.
• the laser source for example, a laser beam
• Edge emitter emits systemic usually linearly polarized light as transmitted light signal.
• This is not a system requirement of the LiDAR, but a "parasitic" phenomenon, which is due to the emitter used.
• the linear polarization of the transmitted light signal now has an influence on the
• SNR signal-to-noise ratio
• Ambient brightness ie the ambient light signal
• Ambient brightness represents therein “interference or ambient light” which depends on the environment of use of the device (LiDAR) as well as the time of day.
• the majority polarization of the ambient light signal changes depending on the time of day.
• SNR signal-to-noise ratio
• the change in the majority polarization of the ambient light with the time of day is due to the scattering of sunlight on the air molecules of the atmosphere. If the sun is close to the zenith, one observes a majority parallel polarization of the ambient light signal. If the sun is close to the horizon, a predominantly vertical polarization of the ambient light signal is observed.
• the system performance of the device thus varies depending on the
• US Pat. No. 5,054,464 B2 discloses a polarizable LiDAR, in particular for the detection and characterization of particles distributed in the air, comprising an actively controlled phase retarder, which has two states with different phase delays for changing the
• both an active control of the polarization direction in the transmission path and an additional active global polarization control in the reception path can be present.
• a detector for the optical detection of at least one individual object is known. It is proposed to use a Bayer filter with different absorption properties at the pixel level of the detector. Disclosure of the invention
• a device which has at least one passive polarization adaptation unit which is set up to control a polarization of the received light signal in dependence on an ambient light signal
• the device according to the invention has the advantage that on the one hand a clear improvement of a signal-to-noise ratio can be achieved by an efficient elimination of the ambient light signal.
• a stable system performance of the device can be achieved over the course of the day (and during the course of the day changing majority polarizations of the ambient light signal). This means a higher range of the device or a more stable availability of the range.
• the position of objects farther from the device can be more reliably determined by the device.
• a passive control of the polarization by means of the passive polarization adaptation unit is used. This one is in one
• the polarization of the received light signal reflected from the object is controlled in response to the ambient light signal.
• the passive polarization adaptation unit has a polarization filter matrix, the at least one static
• Polarizing filter is disposed between the detector and the object.
• Polarization filter is tuned to a position of the pixel.
• the static polarizing filter is used in this embodiment at the pixel level in the receiving path of the device.
• the polarization filter matrix is a passive polarization filter array with static polarization filtering, that is, static transmission and
• Filter levels It can be a 1: 1 assignment of a polarizing filter of
• Polarization filter matrix to be provided to a pixel of the pixel matrix of the detector.
• the filter effect can be realized, for example, by the use of small metal filaments.
• the polarization filter matrix is constructed similar to a "Bayer filter" known from image processing. In this there is a 1: 1 assignment of a polarizing filter to a pixel.
• the alternating arrangement of a polarizing filter and a transmission space produces a "checkerboard pattern".
• a perpendicular polarization polarization filter or a polarization parallel polarization filter alternates with an unfiltered pixel. Its position is on the position of
• Polarization filter for example, for vertical polarization, a vertically polarized transmitted light signal (and thus received light signal) can be used. This can be done, for example, by using a vertical
• emissive Kantenemitters be achieved as the first emitter. Alternatively, it can be achieved with another corresponding laser type in the transmission path, ie for the transmitted light signal. Then the incident
• Ambient light signal at least during one half of the day (here: sun in the zenith, mostly parallel polarized ambient light signal) optimally blocked by the polarization filter.
• the signal-to-noise ratio improves by 50% in the daily average with a signal-to-noise ratio of 50%.
• a device is furthermore provided which has an active polarization adaptation unit which is set up Polarization of the first transmitted light signal in dependence on the
• System performance of the device can be achieved. This means a higher range of the device. The position of objects farther from the device can be more reliably determined by the device.
• an additional active in the present embodiment, an additional active
• Controlling the polarization used by the active polarization adaptation unit This is used in a transmission path.
• the polarization of the first transmission light signal emitted by the first emitter is controlled in response to the ambient light signal.
• the active polarization adaptation unit has a second emitter which is set up to emit a second transmitted light signal, which runs from the device to the object, and wherein the second polarization adaptation unit
• Transmission light signal is polarized orthogonal to the first transmission light signal.
• the first emitter and the second emitter can be designed as orthogonally polarized lasers. For example, the use of two mutually orthogonal rotated edge emitter is possible.
• a first transmitted light signal and a second transmitted light signal of the device are available with the first emitter and the second emitter.
• This first transmitted light signal and the second transmitted light signal are polarized orthogonal to each other, so that a suitable transmission light signal can be selected both for a majority parallel and a majority vertically polarized ambient light signal.
• the active polarization adaptation unit has a measurement control element which is set up to measure a signal-to-noise ratio of the device and to connect the first emitter and / or the second emitter as a function of the signal-to-noise ratio. To control the noise ratio.
• a measurement control element which is set up to measure a signal-to-noise ratio of the device and to connect the first emitter and / or the second emitter as a function of the signal-to-noise ratio.
• an "adaptive switching" between the first emitter and the second emitter can be done. This adaptive switching can be done in
• a measurement of the signal-to-noise ratio can be carried out continuously by means of the measurement control element.
• the latter can then activate the respective inactive emitter in good time, so that it emits a transmitted light signal.
• the other active emitter can be deactivated according to this time by means of the measurement control element.
• the first emitter is the first transmitted light signal with a direction perpendicular to the ambient light signal
• Ambient light signal at the beginning of operation of the device mostly vertical polarization convert. Simultaneously with this "rotation" of the polarization of the ambient light signal, the measured signal-to-noise ratio will become worse. Once such degradation occurs, the gauging control element may deactivate the first emitter. The emission of the first transmitted light signal ends with it. At the same time the measuring control element will activate the second emitter. This starts the emission of the second
• Transmission light signal which is polarized orthogonal to the first transmission light signal.
• the second transmitted light signal is now better tuned to the changed polarization of the ambient light signal.
• the signal-to-noise ratio improves.
• the transmitted light signal is therefore polarized at any time of day, orthogonal to the majority polarization of the ambient light signal.
• the signal-to-noise ratio of 50% results in an improvement of the signal-to-noise ratio of 50% at any time of day.
• Polarizations of the first transmitted light signal and the second transmitted light signal may be achieved by using more lasers (for example, rotated by 30 °) or, alternatively, by actively polarizing elements in the transmit path (for example, liquid crystal, Pockels cell or rotatable
• Wave plate can be achieved.
• the active polarization adaptation unit has at least one controllable
• Polarization rotating element and wherein the polarization filter matrix is disposed between the detector and the controllable polarization rotating element.
• the polarization filter matrix has only uniform polarization filters (that is, for example, only in parallel
• the polarization filter matrix may be formed as a uniform polarization filter. This one uniform polarization filter is then the controllable polarization rotation element in the reception path
• upstream It can for example consist of an electrically controllable
• Liquid crystal, a Pockels cell or a rotatable wave plate may be formed.
• the received light signal arriving in the device is mostly aligned perpendicular to the ambient light signal.
• the received light signal arriving in the device is mostly aligned perpendicular to the ambient light signal.
• Now can be controlled by adaptive rotation of the polarization of the incoming received light signal so that it is always optimally located in the transmission plane of the uniform, static polarizing filter, while the incoming ambient light signal is optimally located in the absorption plane of the polarizing filter.
• the number of pixels, and therefore the image resolution is doubled by not necessarily alternating the transmission plane. Furthermore, after this
• Ambient light signal is always optimally blocked in front of the detector.
• the invention will also specify a method in which the measurement control element has a first signal-to-noise ratio to a first
• Measuring time measures; and the measurement control element measures a second signal-to-noise ratio at a second measurement time; and the measurement control element controls the second emitter to emit the second transmit light signal if the second signal-to-noise ratio is less than the first signal-to-noise ratio.
• Polarization of the incoming received light signal is always majority orthogonal to the incoming ambient light signal. As soon as the polarization of the ambient light signal relative to, for example, the polarization of the first transmitted light signal from the optimum vertical position of the two
• the measurement control element will deactivate the active emitter. It will also activate the inactive emitter. This emits a transmission light signal perpendicular to the transmitted light signal of the now inactive emitter.
• Ambient light signal again optimized, that is, a possible orthogonal relationship between them produced.
• the measurement control element controls the second emitter to emit the second transmission light signal at temporally periodic intervals; and the measurement control element determines a third signal-to-noise ratio at the time of emission of the second transmission light signal.
• the measurement of the signal-to-noise ratio can thus take place periodically. It can be checked periodically for the possible improvement with the third signal-to-noise ratio of the second emitter.
• the second emitter carries out a test emission at specific time intervals.
• FIG. 1 shows a device for determining a position of at least one object with a passive polarization adaptation unit
• FIG. 2 shows a device for determining a position of at least one object with an active polarization adaptation unit
• FIG. 3 shows a device for determining a position of at least one object with a passive polarization adaptation unit and an active polarization adaptation unit;
• FIG. 4 shows a method for determining a position of an object by means of a device with an active polarization adaptation unit
• FIG. 5 shows a method for determining a position of an object by means of a device with a passive polarization unit and an active polarization unit;
• FIG. 6 shows the method according to FIG. 5, wherein the polarization is adaptively rotated by a polarization rotation angle.
• the device according to the invention has a first emitter 1, which is set up to emit a first transmitted light signal 2.
• Transmission light signal 2 is reflected on an object whose position is to be determined and travels back to the device as a reception light signal 3. Here it encounters a detector 4 which has a pixel matrix 5 which has at least one pixel 6.
• FIG. 1 shows a device which is a passive one
• Polarization adaptation unit 7 which is arranged, a polarization of the reception light signal 3 in response to an ambient light signal 8 to control.
• the passive polarization adaptation unit 7 has a
• Polarization filter matrix 9 on.
• This polarization filter matrix 9 has a multiplicity of static polarization filters 10.
• polarization filters for vertical polarization 11 and polarization filters for parallel polarization 12 "checkerboard pattern-like" alternate.
• a passage space 13 is provided in each case.
• the individual polarization filters 10 are arranged in a 1: 1 association with the pixels 6 of the pixel matrix 5. This is similar to one from the
• the polarizing filters 10 may be formed, for example, by means of small metal filaments.
• vertically polarized reception light signal 3 may be used. This can be achieved, for example, by means of a vertical edge emitter as the first emitter 1 or another corresponding laser type in the transmission path.
• the ambient light signal 8 is then optimally blocked at the pixels 6 with the polarization filter 10, at least during one half of the day (in this case, the sun at zenith, parallel polarized ambient light signal 8).
• FIG. 2 shows a device with an active polarization adaptation unit 14. This active polarization adaptation unit 14 is shown in FIG. 2
• a second emitter 15 is configured to emit a second transmitted light signal 16.
• the first emitter 1 emits a first transmitted light signal 2 with a parallel polarization 17.
• the second emitter 15 emits a second transmitted light signal 16 with a vertical polarization 18.
• the polarization of the first transmitted light signal 2 is therefore orthogonal to the polarization of the second transmitted light signal 16 set.
• These polarizations can be achieved by more lasers (as first emitter 1 and second emitter 15), for example, rotated by 30 °, or alternatively by actively polarization rotating elements (not shown) in the transmit path (for example a liquid crystal, a Pockels cell or a rotatable wave plate).
• FIG. 1 shows a) the first transmitted light signal 2, for example, in the vertical polarization 18.
• the ambient light signal 8 has the parallel polarization 17.
• the alignment of the majority parallel polarization 17 of the ambient light signal 8 is set optimally with respect to the vertical polarization 18 of the first transmitted light signal 2.
• the majority polarization of the ambient light signal 8 will change. It will change in the course of time from the parallel polarization 17 (tableau a)) into the vertical polarization 18 (tableau e)). As a result of this change, the optimum orthogonal alignment of the polarization of the ambient light signal 8 with the first transmitted light signal 2 will also deteriorate.
• the signal-to-noise ratio will increase.
• the signal-to-noise ratio can be determined by means of a measurement control element (not shown). As soon as the signal-to-noise ratio thus deteriorates, the measurement control element can drive the second emitter 15, which then emits the second transmitted light signal 16.
• the second transmitted light signal 16 has a parallel polarization 17.
• Transmission light signal 16 is orthogonal to the polarization of the first
• the first emitter 1 can be deactivated by means of the measurement control element.
• the polarization of the transmitted light signal 2, 16 is thus orthogonal to the daytime at all times
• An adaptive switching between the first emitter 1 and the second emitter 15 is performed as a function of the polarization of the ambient light signal 8. The adaptive switching takes place when the measuring control element has a
• Deterioration of the signal-to-noise ratio measures.
• the measurement of the signal-to-noise ratio periodically with the signal-to-noise ratio of the second emitter 15 to a possible
• Improvement can be checked by the second emitter 15 at certain intervals performs a test emission.
• a combination of the transmitted light signals 2, 16 with static, alternating perpendicular and parallel transmitting pixels 6 (as described above) orthogonal to the majority polarization of the ambient light signal 8 results in a signal-to-noise ratio of 50% Improvement of the signal-to-noise ratio of 50% at any time of day.
• FIG. 3 shows a device with an active polarization adaptation unit 14 (not shown here, see FIG.
• Polarization rotating element 19 has.
• the passive polarization adaptation unit 7 is here designed as a static, uniform (here: only parallel transmitting) polarization filter for vertical polarization 1 1. This is preceded by the controllable polarization rotating element 19 in the receiving path.
• the controllable polarization rotating element 19 may, for example, as a
• Liquid crystal, a Pockels cell or a rotatable wave plate may be formed.
• Figure 5 shows the method before active rotation of the polarization in the receiving path by means of the controllable polarization rotating element 19.
• the polarization of the transmitted light signal 2, 16 held orthogonal to the polarization of the ambient light signal 8.
• the first transmitted light signal 2 has, for example, the vertical polarization 18.
• the ambient light signal 8 has the parallel polarization 17.
• Ambient light signal 8 is adaptively received by first transmitted light signal 2 of FIG first emitter 1 switched to the second transmitted light signal 16 of the second emitter 15.
• the polarization can be adaptively rotated by a polarization rotation angle 20. This ensures that the received light signal 3 is always optimally oriented to the transmission plane of the uniform, static polarizing filter 10. At the same time is the
• Polarization of the ambient light 8 is also optimally oriented to the absorption plane of the uniform, static polarizing filter 10.
• transmitted light signals 2, 16 are used which are orthogonal to the majority polarization of the ambient light signal 8 at any time of the day. This is achieved by means of the controllable polarization rotating element 19. This can then on the checkerboard structure of the polarization filter matrix 9 of polarization filters for vertical polarization 1 1 or
• Polarization filters for parallel polarization 12 and the passage space 13 are dispensed with. This results in a doubling of the number of pixels; the
• Image resolution is doubled. Also, “slow” rotations of the polarization can be used depending on the time of day. The use of cheaper
• Liquid crystals as controllable polarization rotating elements 19 becomes possible.
• the "switching times" of such liquid crystals can be in the ms range, since the change in the position of the sun, and thus the change in the polarization of the ambient light signal 8, again takes place much more slowly in the hourly range.
• the signal-to-noise ratio improves by 100% at any time of day.
• Ambient light signal 8 is optimally blocked at any time of the day.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Electromagnetism (AREA)
• Optical Communication System (AREA)
• Optical Radar Systems And Details Thereof (AREA)

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• 2018
  • 2018-04-19 DE DE102018205984.5A patent/DE102018205984A1/de active Pending
• 2019
  • 2019-04-11 WO PCT/EP2019/059178 patent/WO2019201719A1/de active Application Filing
  • 2019-04-11 EP EP19717840.3A patent/EP3781966A1/de active Pending
  • 2019-04-11 CN CN201980026894.2A patent/CN112041701B/zh active Active
  • 2019-04-11 US US17/045,584 patent/US20210026010A1/en active Pending

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