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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
  • G01S13/06—Systems determining position data of a target
  • G01S13/42—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
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/40—Means for monitoring or calibrating
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/003—Bistatic radar systems; Multistatic radar systems
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
  • G01S13/878—Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/88—Radar or analogous systems specially adapted for specific applications
  • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
• • 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
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/88—Radar or analogous systems specially adapted for specific applications
  • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
  • G01S13/931—Radar or analogous 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
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/35—Details of non-pulse systems
  • G01S7/352—Receivers
  • G01S7/354—Extracting wanted echo-signals

Definitions

• the invention relates to a method and a device for evaluating, in particular thinned, radar systems.
• the object of the invention is to propose a comparatively simple and yet precise method for evaluating, in particular for imaging and / or for a MIMO method, of signals from a radar system, in particular a thinned out radar system. Furthermore, a corresponding evaluation device, a corresponding radar system and a corresponding mobile device should be proposed.
• the object is achieved by a method for evaluating (possibly for imaging and / or for a MIMO method and / or for target recognition or localization and / or for target speed determination) of signals from an, in particular thinned, radar system (Spare radar array) and / or a radar system with a large aperture, comprising at least one first radar unit for transmitting and / or receiving signals and at least one second radar unit for transmitting and / or receiving signals that have a (virtual) overall Forming a radar array (with antenna channels or physical channels and virtual channels), whereby only a partial radar array of the overall radar array is used in the (for) evaluation.
• Each radar unit can have at least two (or at least three or at least four) receiving antennas and / or at least (or at least three) two transmitting antennas. Several, possibly all, antennas can be arranged on a (straight) line.
• the respective radar unit can also be referred to as a transceiver unit.
• the sub-radar array includes only virtual channels.
• the partial radar array used is preferably (completely) between the first and the second radar unit.
• all virtual channels between the first and the second radar unit can possibly be taken into account.
• the sub-radar array is preferably selected such that a
• At least one target is preferably in the near field of the overall radar array and / or in the far field of the partial radar array.
• the evaluation preferably includes beamforming (literally translated:
• a position of the target lies on an ellipse with the radar positions in the ellipse focal points.
• the ellipse is not a circle.
• the radar positions can be approximated by a center point of the antennas of the respective radar unit. The fact that an error in the radar position due to the curvature of the ellipse has only a minor influence (or only becomes relevant at a multiple of the wavelength) is thereby advantageously used.
• the evaluation in particular the beamforming, can include the use of a window function, in particular a Hann window.
• beamformer weights can be used, which if necessary can be determined in advance, in particular calculated, if necessary from
• Hypothesis vectors and / or can be stored, in which case they are determined, in particular calculated, only once in the latter case and used for various radar measurements.
• the evaluation, in particular the beamforming, is preferably adapted in such a way that it is taken into account that the far-field approximation does not apply to the entire radar array, but to the partial radar array.
• a transmission frequency of at least one transmission antenna, possibly all transmission antennas, is preferably at least 1 GHz, preferably at least 10 GHz, for example 77 GHz.
• an evaluation device in particular for performing the method described above or below, for evaluation (possibly for imaging and / or for a MIMO method and / or for target recognition or localization and / or for a target speed determination) of signals from a, in particular thinned, radar system, comprising at least one first radar unit for transmitting and receiving signals and at least one second radar unit for transmitting and receiving signals that form a (virtual) overall radar array (with Antenna channels or physical channels and virtual
• the evaluation device can have at least one (electronic) memory and / or at least one (micro) processor and / or at least one connection for power transmission and / or at least one connection for data transmission.
• a radar system comprising at least one first radar unit for transmitting and receiving signals and at least one second radar unit for transmitting and receiving signals that form a (virtual) overall radar array, as well as the
• Evaluation device The above object is further achieved by a mobile device, in particular a vehicle, preferably a motor vehicle and / or ship and / or aircraft, more preferably a passenger or truck, comprising the evaluation device and / or the radar system.
• a mobile device in particular a vehicle, preferably a motor vehicle and / or ship and / or aircraft, more preferably a passenger or truck, comprising the evaluation device and / or the radar system.
• the first and / or second radar unit possibly the radar system, can be arranged (integrated) in / on a bumper.
• Fig. 1 is a schematic representation of an inventive
• FIG. 2 shows a detail from FIG. 1;
• Fig. 5 shows a pseudo spectrum
• Fig. 6 shows a pseudo spectrum
• Fig. 7 shows a pseudo spectrum
• Fig. 8 shows a pseudo spectrum
• the first and / or the Second radar units can have several (for example four or more) receiving antennas 15 and / or several (for example three or more) transmitting antennas 16.
• the additional virtual channels can be designed as spatial convolution as long as a far-field approximation is given. Basically only applies from one
• a sub-arrangement is preferably selected which lies between the two arrays and is less thinned out (channel group 12 in FIG. 1).
• the achievable resolution is reduced by the smaller size, but the side lobes are smaller.
• Fig. 4 illustrates this on the basis of two close
• Array elements in the middle of the array as these always come to lie in the middle of the two radars due to the spatial folding of the subarrays.
• the relative distance between the virtual channels in the middle depends (at least essentially or at least in a first approximation) only on that of the antennas in the modules (radar units 10, 11) from one another. This eliminates the need to know the exact distance between the modules and, if necessary, to recalibrate changes due to thermal expansion.
• a comparatively more complex than in the prior art is thus preferably dispensed with Step.
• this distance can also be inconstant, for example in the event of vibrations.
• any type of beamformer can be used on the entire and / or on the partial array.
• extensive (sparse array) antenna arrangements due to the large size and the high transmission and
• Receiving frequency of 77 GHz for example, the far field approximation is no longer given.
• a holographic reconstruction is generally necessary if a target appears in different bins due to the size of the antenna array or the bandwidth used according to the range FFT. Then a hypothesis has to be created for both the target frequency and the target phase, what
• the advantage of the thinned array considered here is that, even if the target lies in the near field of the overall antenna arrangement, it lies in the far field of the partial apertures that are formed from the apertures of the two radar units. It is particularly advantageous here that the target is then at the same range FFT bin in both cross paths. This enables a computationally efficient calculation of cross-path spectra of both radars (radar units) with the help of a suitable beamformer. Although the classic MIMO approach cannot be used here if the target is in the near field of the overall antenna arrangement, the combination of the Tx and Rx antenna arrays can be used to advantage with the help of the beamformer.
• the distance information for the cross path of an arrangement consisting of two radar units limits the position of the target to an ellipse with the
• the linear eccentricity is with the distance between the two radar stations b.
• the minor axis of the ellipse is
• the hypothetical target position p hyp in the Cartesian coordinate system can be calculated as follows:
• 2 With the ramp start frequency and bandwidth f 0 and B or the speed of light c 0 , the phase hypothesis F hyp can be calculated:
• 0.5B takes into account the influence of a (FMCW) bandwidth on the phase.
• the radar image I (d hyp , f hyp ) results from the comparison of the hypothesis with the measurement s m, n (d hyp ):
• FIGS. 5 and 6 A simulation result is shown in FIGS. 5 and 6 for a target in the near field at 15 ° or 40 ° as "NFBF". If the beamforming is expanded by a window w (e.g. a Hann window)
• w e.g. a Hann window
• the window reduces the side lobes in some areas of the spectrum.
• the remaining side lobes of up to -15 dB are, however, inadmissibly high for imaging applications. This is because the combination of two partial apertures not a fully occupied uniform linear array (ULA), but a thinned out array.
• the optimized weights H 0 can be calculated as follows:
• H 0 H (H H H + mI), with the regularization parameter m and the identity matrix I.
• the optimized weights are independent of the measurement data. Therefore they can only be calculated and saved once and then applied to each measurement. The computational effort for the use of the optimized beamformer is consequently the same as that of the simplest delay-and-sum beamformer.
• the main points of the invention are: 1) Use of sub-arrays with better overall properties than the main array.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

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• 2019
  • 2019-04-10 DE DE102019002662.4A patent/DE102019002662A1/de active Pending
• 2020
  • 2020-03-26 WO PCT/EP2020/058574 patent/WO2020207814A1/de unknown
  • 2020-03-26 CN CN202080034836.7A patent/CN113811789A/zh active Pending
  • 2020-03-26 EP EP20715035.0A patent/EP3953728A1/de active Pending
• 2021
  • 2021-10-09 US US17/497,910 patent/US20220043111A1/en active Pending

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