DE102008034997A1 - Object and/or obstacle azimuth angle determining method for car, involves determining assumed azimuth angle as azimuth angles of objects when peak of phase shifted, received and reflected portion of reference signal meet cycle load in plane - Google Patents

Abstract

The method involves transmitting reference signals i.e. radar signal, by a transmitting antenna (10) and receiving a portion, which is reflected by objects, of the signals by 3 receiving antennas (11-13) i.e. radar antenna. Phase shift associated to assumed azimuth angle is determined. A part of the received reflected portion of the signals is phase shifted depending on the phase shift. The assumed azimuth angle is determined as azimuth angles of the objects when a peak of the phase shifted, received and reflected portion of the reference signal meet cycle load in imaginary complex plane.

Description

The The invention relates to a method for determining the azimuth angle of obstacles or objects in relation to a measuring device.

The DE 103 57 704 A1 discloses a measuring device for measuring an angle between a beam direction of the measuring device and an object, wherein the measuring device comprises a emitting device for emitting a transmission signal, a first receiving device for receiving a reflection signal of the emitted transmitted signal reflected by the object, at least a second receiving device for receiving the object reflected reflection signal of the radiated transmission signal, at least a first mixer for mixing the transmission signal with the received by the first receiving means reflection signal and at least a second mixer for mixing the transmission signal with the reflection means received by the second receiving means.

The DE 103 47 976 A1 discloses a measuring device for measuring a distance between the measuring device and an object and / or for measuring a speed difference between the measuring device and the object, wherein the measuring device has a signal generator for generating a transmission signal with a time-variant frequency and a phase shifter for delaying the transmission signal.

The DE 103 49 919 A1 discloses a measuring device for measuring a distance between the measuring device and an object and / or for measuring a speed difference between the measuring device and the object, wherein the measuring device has a radiation device for transmitting a transmission signal having at least two signal sequence sections, a first signal section sequence and a second signal segment sequence , comprising at least two temporally alternating signal sections, wherein at least two signal sections of a signal section sequence differ in their frequency by one difference frequency, wherein the difference frequency of the first signal section sequence is different from the difference frequency of the second signal section sequence.

The DE 195 43 813 A1 discloses a three-beam automotive radar system wherein at an angle a wavefront impinges on a lens of a lens antenna. In the focal plane of this lens, indicated by the distance, three receiving elements, each with a lateral distance from each other, arranged for the reception of radar signals. In three envisaged mixers, the high-frequency signal generated in the receiving elements is mixed in the respectively supplied by an oscillator frequency.

The WO01 / 26183 discloses a multi-beam radar sensor having at least two transmit and receive patches on a carrier with associated polyrods and / or with a dielectric lens, wherein the radar sensor is constructed monostatically and configured such that the transmit or receive beams have asymmetrical beam paths with respect to a center plane of the radar sensor.

The use of a radar device in the automotive sector is also from the publications "Automotive 24 GHz Short Range Radar (SRR) Sensors with Smart Antennas" by M. Schneider et al., Proceedings of the German Radar Symposium DRS 2002, pages 175 to 179 . C. Koelen, M.-M. Meinecke, T. Teubner: "High resolution DOA automotive radar with four receiving antennae", International Radar Symposium 2006, Krakow / Poland, May 2006 ; C. Koelen, M.-M. Meinecke, R. Mende, M. Behrens: "Far Distance 24GHz Radar Sensors for Autonomous Driving in Unknown Desert Environment - Equipment of the" Stanley "Touareg", 13th ITS World Congress and Exhibition, London, UK, October 2006 ; C. Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 ; M.-M. Meinecke, "On the optimized transmission signal design for automotive radars" Dissertation, Hamburg University of Technology, 2001 ; and R. Mende, "Driver Assistance Applications Using 24 GHz Radar", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 as well as, the dissertation "Radar systems for automatic distance control in automobiles" by R. Mende, Technical University Carolo-Wilhelmina zu Braunschweig, 1999 as well as from the DE 100 50 278 A1 , of the DE 199 22 411 A1 , of the DE 42 44 608 C2 and the DE 100 25 844 A1 known.

So revealed the DE 100 50 278 A1 the determination of a distance and a relative speed of at least one distant object from an observation point by means of electromagnetic signals emitted from the observation point in the form of alternately emitted signal portions of a first frequency and a second frequency which are received and evaluated after a reflection at the object, wherein the Signal portions of the two frequencies during a measurement interval are shifted by one frequency step shifted.

The DE 199 22 411 A1 discloses a CW radar method for measuring distances and relative speeds between a vehicle and one or more obstacles in which a transmission signal consists of at least four consecutive blocks each having different slopes. In a distance-relative velocity diagram, first the intersections of all lines from two blocks of all found frequency positions are calculated. In order to validate these intersections, they are checked to see if there is a peak at a frequency position in the Fourier spectrum of a third block whose associated line intersects a surrounding area of the intersection in the distance-relative velocity diagram.

The DE 42 44 608 C2 discloses a radar method for measuring distances and relative velocities between a vehicle and obstacles located therewith, emitting continuous transmission signals, while receiving the continuous transmission signals, simultaneously receiving at the obstacles reflected signals, mixing the reflected signals with the continuous transmission signals to obtain in-phase signals. and Quadrature signals and processing these signals to output signals for the distances and relative speeds of the obstacles.

The DE 100 25 844 A1 discloses a transmitting unit for emitting a pulse-shaped transmission signal, which is controlled clocked with a first drive signal, and serving for detecting the resulting reflection signal receiving unit, which is clocked with a second drive signal to sample the reflection signal at certain sampling times. The second drive signal is phase-shifted relative to the first drive signal in such a way that the distance deviation between the distance to the target object determined by the travel-time measurement and the actual distance to the target object becomes minimal.

Moreover, from the DE 43 31 440 A1 it is known to form I / Q signal pairs for the signal evaluation for radar devices, wherein a phase shifter is connected between a radar antenna and a radar front end, an evaluation circuit having two signal channels on the input side, the radar front end being connectable to one of the two signal channels via a channel selector switch, wherein the phase shifter and the channel switch are synchronously clocked, and wherein the phase shifter switches the phase between 0 ° and 45 ° with each clock.

From the DE 689 13 423 T2 For example, a Doppler radar apparatus for a vehicle for indicating a distance between the vehicle and an obstacle is known.

Methods for the evaluation of radar signals can the book P. Stoica, R. Moses "Introduction to spectral analysis" Prentice-Hall, 1997, ISBN 0-13-258419-0 be removed.

It Object of the invention, the location of objects or obstacles to improve in traffic.

The aforementioned The object is achieved by a method for determining the azimuth angle of obstacles or objects in relation to one, in particular in a measuring device implemented in a motor vehicle, the one transmitting device for transmitting a reference signal and at least three receiving devices each for receiving one of the obstacles or objects of reflected portion of the reference signal, where a phase shift associated with an assumed azimuth angle is determined, wherein at least a part of the received reflected Proportions of the reference signal as a function of the phase shift, and in particular a distance of two receiving devices, phase-shifted and assuming the azimuth angle as the azimuth angle of Obstruction or object is determined when the tips of the phase-shifted received reflected portions of the reference signal of a circular condition suffice in the imaginary number plane.

In particular, a circle condition in the sense of the invention is a criterion for determining whether the peaks of the phase-shifted received reflected portions of the reference signal are (at least substantially) located on a circle in the imaginary number plane. This can be done, for example, by estimating a possible circle center and satisfying the circle condition when the distances of the peaks of the phase-shifted received reflected components of the reference signal in the imaginary plane of the estimated circle center are substantially equal Deviation of the lengths of the distances from each other does not exceed a certain threshold. However, it can also be provided that a function of the phase-shifted received reflected portions of the reference signal for a plurality of different assumed azimuth angle Characteristic is formed such that the azimuth angle at which the characteristic value function has their maxima, are determined or regarded as the azimuth angles that satisfy a circular condition. A suitable characteristic value function is, for example, the function of an inverted TMSE value (see, for example, FIG. C. Koelen, M.-M. Meinecke: "De tection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 ).

In Further advantageous embodiment of the invention includes Measuring device at least four receiving devices each for receiving a portion of the object reflected from the obstacles or objects Reference signal. In a further advantageous embodiment of the invention the reference signal is a radar signal. In further advantageous Embodiment of the invention, the meter is a radar device. In a further advantageous embodiment of the invention, the Receiving devices radar antennas or receiving antennas.

The aforementioned The object is also achieved by a method for determining the azimuth angle of obstacles or objects in relation to one, in particular in a measuring device implemented in a motor vehicle, the one transmitting device for transmitting a reference signal and at least three receiving devices each for receiving one of the obstacles or objects of reflected portion of the reference signal, where a phase shift associated with an assumed azimuth angle is determined, wherein at least a part of the received reflected Proportions of the reference signal as a function of the phase shift, and in particular a distance of two receiving devices, is phase-shifted, depending on the phase-shifted received reflected portions of the reference signal for a plurality different assumed azimuth angle a characteristic function is formed, and wherein the assigned to the maximums of the characteristic function (assumed) azimuth angle as the azimuth angle of obstacles or Objects are determined.

In Advantageous embodiment of the invention, the phase-shifted received reflected portions of the reference signal by subtraction a circle center vector, wherein the circle center vector is a vector to the center of an assumed circle which reflected the peaks of the phase shifted received Shares of the reference signal are, and wherein the characteristic function depending on the transformed phase-shifted received reflected portions of the reference signal for various assumed azimuth angles and their mean value formed becomes.

In Furthermore advantageous embodiment of the invention, the phase-shifted received reflected portions of the reference signal by subtraction a circle center vector, wherein the circle center vector is a vector to the center of an assumed circle which the tips of the phase-shifted received re flexed Shares of the reference signal are, and wherein the characteristic function for different assumed azimuth angles depending the differences of transformed phase shifted received reflected Proportions of the reference signal and the mean of these transformed phase-shifted received reflected portions of the reference signal is formed.

wobei S →_{shift,Rxn,DOA} der phasenverschobene von einer n-ten Empfangseinrichtung empfangene reflektierte Anteil des Referenzsignals ist. N ist die Anzahl der Empfangseinrichtungen bzw. der ausgewerteten Empfangseinrichtungen. S →_circle ist ein Kreismittelpunktvektor zu dem Mittelpunkt eines angenommenen Kreises, auf dem die Spitzen der phasenverschobenen empfangenen reflektierten Anteile des Referenzsignals liegen.In a further advantageous embodiment of the invention is the characteristic value function (corresponding to an inverted TMSE value)

where S → _{shift, Rxn, DOA is} the phase-shifted reflected component of the reference signal received by an nth receiving device. N is the number of receiving devices or the evaluated receiving devices. S → _circle is a circle center vector to the center of an assumed circle on which lie the peaks of the phase-shifted received reflected portions of the reference signal.

In Further advantageous embodiment of the invention includes Measuring device at least four receiving devices each for receiving a portion of the object reflected from the obstacles or objects Reference signal. In a further advantageous embodiment of the invention the reference signal is a radar signal. In further advantageous Embodiment of the invention, the meter is a radar device. In a further advantageous embodiment of the invention, the Receiving devices radar antennas or receiving antennas.

motor vehicle in the context of the invention is in particular an individual on the road usable land vehicle. Motor vehicles in the context of the invention especially not on land vehicles with internal combustion engine limited.

Further Advantages and details will become apparent from the following description of exemplary embodiments. Showing:

1 an embodiment of a motor vehicle,

2 an embodiment of a sensor plate,

3 an embodiment of a method for determining the azimuth angle of obstacles or objects with respect to the sensor plate according to 2 .

4 an exemplary embodiment of an LFMSK signal,

5 Azimuth angle,

6 received portions of a reference signal,

7 phase shifted received portions of a reference signal,

8th an embodiment of a characteristic value function,

9 an experimental setup in a plan view,

10 the experimental setup according to 9 from the perspective of a motor vehicle and

11 by means of with reference to 3 described inverted TMSE values at different times.

1 shows a motor vehicle 1 with a transmitting antenna 10 and four receiving antennas 11 . 12 . 13 and 14 , The transmitting antenna 10 is an embodiment of a transmitting device in the sense of the claims, the receiving antennas 11 . 12 . 13 . 14 are exemplary embodiments of receiving devices within the meaning of the claims. The transmitting antenna 10 and the receiving antennas 11 . 12 . 13 and 14 form an embodiment of a measuring device or a radar device in the sense of the claims. In an advantageous embodiment, the transmitting antenna 10 and the receiving antennas 11 . 12 . 13 . 14 in a sensor plate 15 as they are in 2 is shown integrated. The sensor plate 15 forms an exemplary embodiment of a measuring device or a radar device in the sense of the claims.

3 shows an embodiment of a method for determining the azimuth angle of obstacles or objects with respect to the sensor plate 15 , It is first in one step 21 sent out a reference signal. The reference signal is in an advantageous embodiment, a 24 GHz signal, which is advantageously designed as an LFMSK signal. Details of an LFMSK signal can be found, for example, in the dissertation of M.-M. Meinecke, "On the optimized transmission signal design for automotive radars", Hamburg University of Technology, 2001 be removed.

4 shows an embodiment of such an LFMSK signal. In doing so, they will gradually (for example in 512 Steps) frequency-modulated signals A, B, C generated containing alternating so-called up and down chirps whose microstructure in 4 is shown. In the step 21 is also provided to receive the portions of the reference signal, which are reflected by obstacles or objects. In addition, in the step 21 the evaluation of these reflected portions of the reference signal.

The step 21 follows a step 22 in which an assumed azimuth angle is assigned a value f _{s, m, DOA} for an assumed object. Although not a phase in itself, f _{s, m, DOA is} an embodiment of a phase shift in the sense of the claims. As azimuth angle should - as in 5 shown below - the deviation of an angle from the measuring device 15 to an object 31 respectively. 32 opposite to the 5 dotted illustrated longitudinal axis of the motor vehicle 1 be understood. For example, θ _{1 is} the azimuth angle with respect to the object 31 and θ ₂ the azimuth angle with respect to the object 32 , In the present embodiment, first f s, m, DOA = -180 ° set, which corresponds to an assumed azimuth angle DOA of -25 ° in the present embodiment. Assumed azimuth angles are hereinafter referred to as DOA (Direction of Arrival).

verschoben werden. Dabei bezeichnet n den Index einer Empfangsantenne und d den Abstand zwischen zwei Empfangsantennen. f_s,m,DOAd ist ebenfalls ein Ausführungsbeispiel für eine Phasenverschiebung im Sinne der Ansprüche.The step 22 follows a step 23 in which the portions of the reference signal received by the receiving antennas - as described below with reference to 6 and 7 explained - according to the context

be moved. Where n is the index of a receiving antenna and d is the distance between two receiving antennas. f _{s, m, DOA} d is also an exemplary embodiment of a phase shift in the sense of the claims.

S → _Rx1 , S → _Rx2 , S → _Rx3 , S → _Rx4 denote those of the four receiving antennas of the sensor plate 15 received reflected portions of the reference signal, wherein the received portions of the reference signal are shown as vectors in the imaginary number plane. In each case, a received signal is composed in the illustrated embodiment of a portion (dash-dotted lines), which is reflected by a first object, and a second portion (dashed), which is received by a second object together.

7 shows the corresponding phase-shifted received portions of the reference signal in the event that an assumed azimuth angle DOA actually indicates the direction from which a signal is reflected. In this case, the peaks of the phase-shifted received components of the reference signal S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA lie} on a circle in the imaginary plane ,

_{shift,Rx2,DOA,circle},

_{shift,Rx3,DOA,circle}, S →_{shift,Rx4,DOA,circle} bezeichnet und wie folgt berechnet: S →shift,Rxn,DOA,circle = S →shift,Rxn,DOA – S →circle wobei S →_circle ein Vektor zum Mittelpunkt des angenommenen Kreises ist und/oder wie folgt berechnet werden kann:

wobei gilt

b1 = a2

The step 23 follows a step 24 in which the phase-shifted received portions of the reference signal S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} as a function of the center of an assumed circle, on the the peaks of the phase-shifted received components of the reference signal S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} lie, are transformed. The transformed phase-shifted received portions of the reference signal are hereinafter referred to as S → _{shift, Rx1, DOA, circle} ,

_{shift, Rx2, DOA, circle} ,

_{shift, Rx3, DOA, circle} , S → _{shift, Rx4, DOA, circle} and calculated as follows: S → shift, Rxn, DOA, circle = S → shift, Rxn DOA - S → circle where S → _{circle is} a vector to the center of the assumed circle and / or can be calculated as follows:

where is true

b 1 = a 2

Here, S → _{shift, Rxn, Re} denotes the real part of S → _{shift, Rxn, DOA} and S → _{shift, Rxn, Im} the imaginary part of S → _{shift, Rxn, DOA} .

In addition, the mean value of the transformed phase-shifted received portions of the reference signal is formed:

bzw. dessen inverser Wert gebildet. Einzelheiten zum TMSE-Wert können zum Beispiel dem Artikel C. Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points within one Range/Velocity Resolution Cell", 4th International Workshop an Intelligent Transportation, Hamburg, 2007 entnommen werden.Subsequently, in one step 25 a so-called TMSE value according to

or its inverse value formed. Details of the TMSE value can be found, for example, in the article C. Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 be removed.

This is followed by a query 26 whether all assumed azimuth angles have been traversed. For the present embodiment, this corresponds to the query

If the above condition is not met, the query follows 26 a step 27 in which the value f _{s, m, DOA is} incremented. Then follow the step 27 turn the step 23 , If, on the other hand, the corresponding inverse TMSE values are determined for all assumed azimuth angles, then a function is involved, as described, for example, in US Pat 8th is shown, and it follows the query 26 a step 28 in which the maxima of the inverted TMSE values are determined. In the 8th Function shown is an embodiment of a characteristic value function in the sense of the claims. The maxima in the inverse TMSE function reflect the position of detected obstacles or objects. Thus, in the present exemplary embodiment, an object or obstacle has been detected at the azimuth angle -6 ° and another object or obstacle at the azimuth angle 10 °.

9 . 10 and 11 show the results of one with the sensor plate 15 carried out according to the experiment with reference to 3 described method. It shows 9 the experimental setup in a plan view, wherein in front of the motor vehicle 1 with the sensor plate 15 two cars 41 and 42 are arranged. 10 shows the experimental setup from the perspective of the motor vehicle 1 , 11 shows the means of referring to 3 described inverted TMSE values at different times, while the motor vehicle 1 on the motor vehicles 41 and 42 zufährt. At about -4 ° and 6 ° distinct maxima in the inverted TMSE function are apparent, which is the position of the motor vehicles 41 and 42 equivalent.

erfolgen, wobei a₁, a₂, b₁, b₂, c₁ und c₂ wie oben beschrieben ermittelt werden.In an alternative procedure for generating TMSE values and their evaluation, it can also be determined for different assumed azimuth angles whether the phase-shifted received reflected components of the reference signal satisfy a circular condition. For this purpose, for example, for each assumed azimuth angle, a circle center of the peaks of the phase-shifted received reflected components of the reference signal in the imaginary plane of the numbers can be determined, and the distance of these peaks from the circle center can be determined. The determination of such a center of the circle (S ~ _{center, Re} ; S ~ _{center, Im} ) can be determined, for example, by means of the formula

be carried out, wherein a ₁ , a ₂ , b ₁ , b ₂ , c ₁ and c _{2 are determined} as described above.

The The invention will be particularly advantageous in connection with a driver assistance system used for a motor vehicle.

1, 41, 42

motor vehicle

10

transmitting antenna

11 12, 13, 14

receiving antenna

15

sensor plate

21 22, 23, 24

25 27, 28

step

26

query

31 32

object or obstacle

DOA

accepted azimuth angle

S → _Rx1 , S → _Rx2 , S → _Rx3 , S → _Rx4

received reflected portion of a reference signal

S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA}

phase-shifted received reflected portion of a reference signal

1 / TMSE

Map function

Θ ₁ , Θ ₂

azimuth angle

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10357704 A1 [0002]
• DE 10347976 A1 [0003]
• - DE 10349919 A1 [0004]
• DE 19543813 A1 [0005]
• WO 01/26183 [0006]
• - DE 10050278 A1 [0007, 0008]
• - DE 19922411 A1 [0007, 0009]
• - DE 4244608 C2 [0007, 0010]
• - DE 10025844 A1 [0007, 0011]
• DE 4331440 A1 [0012]
• - DE 68913423 T2 [0013]

Cited non-patent literature

• "Automotive 24 GHz Short Range Radar (SRR) Sensors with Smart Antennas" by M. Schneider et al., Proceedings of the German Radar Symposium DRS 2002, pages 175 to 179 [0007]
• C.Koelen, M.-M. Meinecke, T. Teubner: "High resolution DOA automotive radar with four receiving antennae", International Radar Symposium 2006, Krakow / Poland, May 2006 [0007]
• C.Koelen, M.-M. Meinecke, R. Mende, M. Behrens: "Far Distance 24GHz Radar Sensors for Autonomous Driving in Unknown Desert Environment - Equipment of the" Stanley "Touareg", 13th ITS World Congress and Exhibition, London, UK, October 2006 [0007]
• C.Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 [0007]
• - M.-M. Meinecke, "On the optimized transmission signal design for automotive radars" Dissertation, Hamburg University of Technology, 2001 [0007]
• R. Mende, "Driver Assistance Applications Using 24 GHz Radar", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 [0007]
• - "Radar systems for automatic distance control in automobiles" by R. Mende, Technische Universität Carolo-Wilhelmina zu Braunschweig, 1999 [0007]
• P. Stoica, R. Moses "Introduction to spectral analysis" Prentice-Hall, 1997, ISBN 0-13-258419-0 [0014]
• C.Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 [0017]
• - M.-M. Meinecke, "On the optimized transmission signal design for automotive radars", Hamburg-Harburg University of Technology, 2001 [0038]
• C.Koelen, M.-M. Meinecke: "Detection and Analysis of Multiple Reflection Points in One Range / Velocity Resolution Cell", 4th International Workshop on Intelligent Transportation, Hamburg, 2007 [0047]

Claims (11)

Method for determining the azimuth angles (Θ ₁ , Θ ₂ ) of objects ( 31 . 32 . 41 . 42 ) in relation to a measuring device ( 15 ) comprising a transmitting device for transmitting a reference signal and at least three receiving devices each for receiving one of the objects ( 31 . 32 . 41 . 42 ) reflected portion of the reference signal, wherein an assumed azimuth angle (DOA) associated phase shift is determined, wherein at least a portion of the received reflected portions of the reference signal (S → _Rx1 ,

_Rx2 ,

_Rx3 , S → _Rx4 ) is phase-shifted in dependence on the phase shift, and wherein the assumed azimuth angle (DOA) as the azimuth angle (Θ ₁ , Θ ₂ ) of an object ( 31 . 32 . 41 . 42 ) is determined when the peaks of the phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} ,

_{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ) satisfy a circular condition in the imaginary number plane. Method for determining the azimuth angles (Θ ₁ , Θ ₂ ) of objects ( 31 . 32 . 41 . 42 ) in relation to a measuring device ( 15 ) comprising a transmitting device for transmitting a reference signal and at least three receiving devices each for receiving one of the objects ( 31 . 32 . 41 . 42 ) reflected portion of the reference signal, wherein an assumed azimuth angle (DOA) associated phase shift is determined, wherein at least a portion of the received reflected portions of the reference signal (S → _Rx1 ,

_Rx2 ,

_Rx3 , S → _Rx4 ) is phase-shifted as a function of the phase shift, wherein in dependence of the phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} ,

_{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ) a characteristic value function (1 / TMSE) is formed for a plurality of different assumed azimuth angles (DOA), and wherein the azimuth angle (DOA) assigned to the maxima of the characteristic value function (1 / TMSE) as azimuth angle (Θ ₁ , Θ ₂ ) of objects ( 31 . 32 . 41 . 42 ). A method according to claim 2, characterized in that the phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ) by Subtraction of a circle center vector to be transformed, wherein the circle center vector (S → _circle ) is a vector to the center point of an assumed circle on which the peaks of the phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA} , S → _{shift, Rx2 , DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ), and wherein the characteristic function (1 / TMSE) depends on the transformed phase-shifted received reflected components of the reference signal (S → _{shift, Rx1, DOA, circle} , S → _{shift, Rx2, DOA, circle} , S → _{shift, Rx3, DOA, circle} , S → _{shift, Rx4, DOA, circle} ) for different assumed azimuth angles (DOA) as well as the average of the transformed phase-shifted received reflected ones Shares of the reference signal (S → _{shift, Rx1, DOA, circle} , S → _{shift, Rx2, DOA, circle} , S → _{shift, Rx3, DOA, circle} , S → _{shift, Rx4, DOA, circle} ,) is formed. A method according to claim 3, characterized in that the characteristic value function (1 / TMSE) for different assumed azimuth angles (DOA) as a function of the differences of transformed phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA, circle} , S → _{shift, Rx2 , DOA, circle} ,

_{shift, Rx3, DOA, circle} ,

_{shift, Rx4, DOA, circle} ) and the mean of these transformed phase-shifted received reflected components of the reference signal of the phase-shifted received reflected components of the reference signal (S → _{shift, Rx1, DOA, circle} , S → _{shift, Rx2, DOA, circle} , S → _{shift , Rx3, DOA, circle} , S → _{shift, Rx4, DOA, circle} ). Method according to Claim 2, 3 or 4, characterized in that the characteristic value function (1 / TMSE)

where S → _{shift, Rxn, DOA is} the phase-shifted reflected component of the reference signal received from an nth receiving device (S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ) and (S → _circle ) is a circle center _vector to the center of an assumed circle on which the peaks of the phase-shifted received reflected portions of the reference signal (S → _{shift, Rx1, DOA} , S → _{shift, Rx2, DOA} , S → _{shift, Rx3, DOA} , S → _{shift, Rx4, DOA} ). Method according to one of the preceding claims, characterized in that the measuring device at least four receiving devices each for receiving one of the objects ( 31 . 32 . 41 . 42 ) reflected portion of the reference signal. Method according to one of the preceding claims, characterized in that the reference signal is a radar signal is. Method according to one of the preceding claims, characterized in that the measuring device ( 15 ) is a radar device. Method according to one of the preceding claims, characterized in that the receiving devices radar antennas are. Driver assistance system, characterized in that it for carrying out a method according to one of the preceding Claims is designed. Motor vehicle, characterized in that it is a Driver assistance system according to claim 10.