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
  • 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
• • 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
  • G01S13/50—Systems of measurement based on relative movement of target
  • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
  • G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
  • G01S13/584—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets adapted for simultaneous range and velocity measurements
• • 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
  • G01S13/08—Systems for measuring distance only
  • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
  • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
  • G01S13/343—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using sawtooth modulation
• • 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
  • G01S7/356—Receivers involving particularities of FFT processing

Definitions

• the invention relates to a method for operating a radar device.
• the invention further relates to a radar device.
• radar systems are increasingly being used to support advanced driver assistance systems of motor vehicles.
• One of the main tasks of said radar systems is to determine a distance to objects and a speed of the objects (for example, vehicles, pedestrians, stationary obstacles, etc.) in the vicinity of the motor vehicles. This is important for the driver assistance system "Adaptive Cruise Control", for example.
• ACC where an accurate estimate of a distance and a relative speed of the vehicle is used to determine appropriate actions of the motor vehicle.
• said radar systems can also be used to implement safety functions, such as warning the driver in critical situations or causing an emergency stop when a collision can no longer be avoided.
• CS modulation chirp sequence modulation
• a sequence of so-called chirp signals linear frequency-modulated electromagnetic signals
• the current frequency of the signals is linearly time-variable.
• the reflected time signals are typically stored in a two-dimensional array, each column of the matrix containing values of received signals of a chirp, with a number of columns of the matrix being a number of chirps. Signals of a transmission sequence corresponds.
• a discrete Fourier transform (DFT) for data elements of a chirp along a column of the data matrix allows an estimate of a distance (or range) of targets in a footprint of the radar.
• the data elements of the columns of the matrix represent distances of target objects.
• Performing a second discrete Fourier transformation along the lines of the resulting matrix allows an estimate of the relative velocity of the target objects.
• DFT discrete Fourier transform
• Performing a two-dimensional discrete Fourier transform produces a distance-speed-power (d-v) matrix, wherein amplitude values of the elements of the d-v matrix in a third dimension represent estimates of the reflected signal energy for the corresponding distance and velocity of the target object.
• a fast Fourier transform is typically performed for this purpose that realizes an efficient implementation of the discrete Fourier transform.
• the object is achieved according to a first aspect with a method for operating a radar device, comprising the steps:
• a radar device comprising:
• a generator for generating elements of a distance-speed-power matrix of a radar target; and an evaluation device for evaluating the elements of the distance-speed-power-matrix, wherein by means of the evaluation device elements of the distance-speed-power-matrix are equally evaluable in a first dimension, and wherein by means of the evaluation device elements of the distance-speed- Performance matrix in a second dimension mathematically defined offset evaluable.
• Speed space is a continuous two-dimensional space in which values at each point of the dv space correspond to an amplitude of a received radar signal generated by an object of defined distance and speed relative to the radar. Since only a limited number of input data is available, the "real" dv space can thus only be “scanned” at certain points. As a result, an increase of a "granularity" of the matrix can advantageously be provided, which advantageously supports an improved estimation of distance and relative speed of targets.
• Preferred embodiments of the method according to the invention are the subject of dependent claims.
• Modulation can be generated. In this way, a favorable in the automotive field modulation is used, which is particularly suitable for high real-time requirements.
• An advantageous development of the method provides that first of all the discrete Fourier transformation is carried out for all elements of columns of the distance-speed-power matrix, wherein the discrete
• a further advantageous development of the method provides that first of all the discrete Fourier transformation is carried out for all elements of lines of the distance-speed-power matrix, wherein the discrete
• Speed performance matrix is performed. Thereby, the order of performing the discrete Fourier transform for the entire matrix may be reversed, thereby providing a mathematically equivalent effect which may be particularly useful for less time critical applications (e.g., in astronomy, geodesy, etc.).
• a further advantageous development of the method provides that each element of every second row of the distance-speed-power matrix is multiplied by the factor e jM / N , with the parameters: n column number of the distance-speed-power matrix N .... Total number of columns of the distance-speed-power matrix In this way, a mathematically defined technical realization of the method is provided.
• Fig. 1 shows a conventional sampling scheme for a d-v matrix with a
• Fig. 2 shows a known arrangement scheme of telecommunication devices
• FIG. 3 shows a sampling scheme according to the invention for a d-v matrix with a test cell
• FIG. 5 shows a worst-case scenario of an inventive sampling scheme for a d-v matrix
• FIG. 6 shows a conventional scanning scheme for a d-v matrix with an elongate target object
• FIG. 7 shows a scanning scheme according to the invention for a d-v matrix with an elongate target object
• Fig. 8 is a principle flowchart of an embodiment
• FIG. 1 shows a schematic representation of a conventional sampling scheme for a distance-speed-power-matrix (d-v-matrix) in the d-v-plane.
• the d-v plane scales a speed v in the x direction and a distance d of a radar device of a motor vehicle one to a target object (not shown) in the y direction. It is necessary for a reliable determination of the target object to obtain peak values of elements of the distance-speed-power matrix, each peak value representing a potential target object, provided that its power amplitude, which is plotted in a third dimension, is above Noise is lying.
• the illustrated sampling scheme with rectangularly arranged test cells 1 and sampling points respectively, local peaks can be found by comparing each matrix element with eight adjacent matrix elements. 1 shows, with a square framing, that a test cell 1 (English, cell under test, CUT) is surrounded in the d-v plane by eight potential neighboring elements or test cells 1.
• a d-v spectrum of a target object has a two-dimensional pattern due to effects of limited window sizes, which may include a main lobe and several side lobes. This has the effect of spreading electromagnetic signal energy across several adjacent cells. If only the main lobe is considered, the closer the test cell 1 is to the peak value of the d-v spectrum, the higher the signal energy. Although the four closest neighboring test cells 1 (in the "north”, "south”,
• cell towers or other wireless telecommunications devices are often located locally in a hexagonal pattern, as shown in principle in the diagram of FIG. 2 with the x and y axes.
• the two-dimensional area to be scanned is a physical area of a ground surface in which both dimensions have the same physical unit length. It is proposed to use a conventional two-dimensional matrix with chirp
• Sequence data of a discrete two-dimensional digital or discrete Fourier transform wherein the Fourier transform is applied according to a hexagonal sampling scheme.
• a two-dimensional dV matrix is initially generated, in which each data element corresponds to a signal energy of a temporal chirp sequence signal.
• a d-v matrix of 512 rows and 32 columns can be generated.
• a one-dimensional digital Fourier transform (preferably using Fast Fourier Transform, FFT) is performed along each column of the dv matrix. Thereafter, for every other line (eg, every even-numbered line) of the dv matrix, the one-dimensional digital Fourier transform is performed for all elements of the entire line.
• FFT Fast Fourier Transform
• N number of columns of the d-v matrix
• the digital Fourier transform is evaluated at lobes of (k + 1/2) / N cycles per sample.
• the method can also be realized by first performing the digital one-dimensional Fourier transform over all rows of the dv matrix until all elements of the dv matrix have been transformed. Then the multiplication of the elements of each second column is performed with the factor e ⁇ -j * ⁇ * m / M with the parameters:
• X1 (ii,:) X1 (ii,:). * Exp (-1j * pi * (0: (N-1)) / N);
• FIG. 3 indicates this with a hexagonal border of the test cell 1.
• Table 1 below shows that a number of neighboring elements to the test cell 1 has decreased in the following way:
• a conventional scanning scheme has the following distances from neighboring cells to test cell 1, as shown in the following Table 2: Number of post-speed domain Distance domain barzellen
• FIG. 5 shows an advantage of such a sampling of the distance-speed-power-matrix compared to FIG. 4.
• FIG. 5 it can be seen from FIG. 5 with the modified sampling scheme that in a worst-case scenario, a sampling point has only three adjacent sampling points, each having the same spacing, the distances to the adjacent sampling points being reduced in comparison to FIG.
• a process of evaluating target objects can be significantly simplified and improved because a distance of a peak in the d-v space to the nearest sampling point is reduced.
• FIG. 3 it can be seen that in this case only six comparisons with adjacent sampling points are required, instead of eight, as can be seen from FIG.
• FIG. 6 shows a conventional rectangular scanning scheme of a d-v matrix, wherein an elongate target object 200 is to be detected. It can be seen that, due to the regular structure of the sampling scheme, a distance of the target object 200 from all sampling points or test cells 1 is substantially the same size.
• FIG. 7 shows that with a hexagonal sampling scheme, individual sampling points or test cells 1 of the dv matrix are closer to the target object 200 than others.
• detection of the elongate target 200 may be easier and more accurate.
• the Target object 200 is weak (eg, a low-reflectivity pedestrian), since a contribution of the signal peak value of the target object 200 to the amplitude of the nearest dv matrix element is stronger, the closer the sampling point is to the peak value of the target object 200.
• a distance of a "true" target in the dv space to the next sample point is only about half as large as when using the conventional sampling scheme of FIG. 6.
• Fig. 8 shows in principle a sequence of an embodiment of the method according to the invention.
• a determination of a matrix with time signals of reflected radar radiation and determination of elements of a distance-speed-power matrix of a radar target are performed.
• a first discrete one-dimensional Fourier transform is performed for the elements of the distance-speed power matrix in a first dimension.
• a second discrete one-dimensional Fourier transform is performed for the elements of the distance-speed-power matrix in a second dimension such that the second discrete one-dimensional Fourier transform defines mathematically for every other element of the distance-speed-power matrix offset is performed.
• Fig. 9 greatly illustrates a radar apparatus 100 having a generating means 10 for generating elements of a distance-speed-power matrix of a radar target 200.
• the radar apparatus 100 further comprises an evaluator 20 for evaluating the elements of the pitch-speed-power matrix in which elements of the distance-speed-power matrix can be uniformly evaluated in a first dimension by means of the evaluation device 20, and elements of the distance-speed-power-matrix in a second dimension can be mathematically defined and evaluated in a defined manner by means of the evaluation device 20.
• the radar device 100 may be formed as a conventional electronic hardware, wherein by means of software, a configuration of the hardware can be performed, for example, an implementation of the Fast Fourier transform and other radar signal processing steps.
• the method may also be fully implemented in software.
• the inventive method can also be used for other applications, such as an ultrasonic device, if a chirp sequence modulation is used.
• the person skilled in the art can suitably modify and combine the described features of the invention without departing from the essence of the invention.

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

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• 2015
  • 2015-06-22 DE DE102015211490.2A patent/DE102015211490A1/de active Pending
• 2016
  • 2016-04-29 US US15/738,502 patent/US10684364B2/en active Active
  • 2016-04-29 WO PCT/EP2016/059608 patent/WO2016206841A1/de active Application Filing
  • 2016-04-29 EP EP16719095.8A patent/EP3311189A1/de not_active Ceased
  • 2016-04-29 CN CN201680037002.5A patent/CN107787460B/zh active Active

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