DE102004051690A1 - Motor vehicle e.g. land vehicle, has parking space detector to determine length and width of parking space with respect to nearby objects based on vehicle speed, distance from vehicle side to object, and angle of such distance - Google Patents

Abstract

A measuring device (1) measures the distance (R) from the side of the vehicle (1) to a nearby object e.g. a curb (5), as well as the angle (alpha ) of the distance with respect to a horizontal plane (HSR). The plane passes through the measuring device location. A parking space detector determines the length and width of the parking space with respect to the nearby objects based on the measured distance and angle as well as vehicle speed.

Description

The The invention relates to a motor vehicle having a parking space detector for determining the size of a parking space.

From the DE 101 14 932 A1 For example, there is known a parking space detection apparatus for a road vehicle which stores from a distance sensor which generates a succession of two-dimensional distance profiles from a data processing unit and a storage unit which processes successive distance profiles, and from a sequence of a consecutive set of distance profiles Generates a three-dimensional image of the environment, and consists of a means for determining the distance traveled by the road vehicle between each individual generated distance profile.

From the EP 0 305 907 B1 is a Einparkhilfsvorrichtung for motor vehicles with at least one arranged on a vehicle outer side transmitter for a toward a parking space limiting body radiated transmission signal and an associated receiver for the reflex signal known, wherein the transmission signal is limited to a small beam angle and emitted transversely to the longitudinal axis of the motor vehicle in which the reflex signal obtained in the parking space during passage past the parking space differs markedly from the reflex signal outside the parking space, and wherein the reflex signal is fed to a comparison device which receives as a further input variable a characteristic value for the traveled distance.

The EP 0 936 471 A2 discloses a vehicle having an object detection device for detecting objects in an observation region of predetermined horizontal extent with means for radiation-based scanning of the observation area and an evaluation unit downstream of the scanning means, wherein the evaluation unit the scanning information of two or more stripe-shaped portions of the observation area with the vehicle longitudinal direction differently inclined or in the vehicle longitudinal direction mutually offset horizontal components evaluated time-resolved and based on the response order of the observation sub-ranges in the direction of travel of the vehicle moving objects differs from stationary and oncoming objects.

The DE 101 46 712 A1 discloses a Einparkhilfsvorrichtung for motor vehicles with at least one arranged on a vehicle outside transmitter for at least approximately perpendicular to the vehicle longitudinal axis radiated, limited to a small beam angle range transmission signal and an associated receiver for the reflex signal, the transmission signal is formed of two partial beams having an approximately areal radiation characteristic possess, wherein the two surfaces are at least approximately perpendicular to each other.

From the DE 199 20 090 A1 and the DE 298 04 296 U1 is an electronic car parking aid to facilitate the parking next to a curb known by warning of the contact, wherein ultrasonic sensors are mounted on the side of the vehicle, wherein a control system is provided which detects the distances reported by the ultrasonic sensors curb or calculated and after reaching fixed Distances a signal signals, with far-reaching sensors only signal a signal in the lower speed range, the control system detects when the sensors are approximately the same distance to the curb, and signals no signal when the long-range sensors are broken at the same time, and where the range of less far-reaching sensors is shortened at higher speeds.

The DE 697 10 579 T2 discloses an apparatus for measuring parking spaces intended for equipping a motor vehicle, wherein the apparatus for measuring parking spaces emits a proximity sensor emitting a measuring beam towards a series of parked vehicles to detect the presence or absence of a vehicle adjacent to the equipped vehicle and includes an odometer coupled to the proximity sensor to measure the length of a free space separating two vehicles already parked, the proximity sensor being configured to emit at least one measurement beam that is directed toward the ground in the area is directed to the row of parked vehicles, so that the bundle in the event that a vehicle is parked, hits the vehicle or in the absence of a parked vehicle on the ground.

From the DE 101 51 965 A1 a method for operating a proximity detection system of a vehicle is known, wherein the height of a in the detection range of at least one sensor of an object or the height difference between object and sensor from at least one of the measured height of the sensor, the radial distance of the sensor in a position to the Object, the radial distance of the sensor to the object in a further position and covered distance of the vehicle between the aforementioned sensor positions is determined.

Another parking aid is from the US 701 122 known.

It object of the invention, the parking of a motor vehicle on to facilitate.

The aforementioned Task is by a motor vehicle with a measuring device for measuring an object distance between the measuring device and an object and a Object angle between a reference direction and a straight line between the object and the measuring device, wherein the motor vehicle a parking space detector to determine the size of a parking lot dependent on the object distance and in dependence the object angle and advantageously in dependence having the speed of the motor vehicle. The speed of the motor vehicle in the context of the invention is also intended to be a Radumdrehung and similar Include sizes, which indicate the speed of the motor vehicle.

In Further advantageous embodiment of the invention, the meter has a radiating device for Emitting a transmission signal. It is in further advantageous Embodiment of the invention, the reference direction a main radiation direction the radiating device. Emitting a transmission signal (in the main beam direction) For the purposes of the invention, in particular, a beam shape of a club In particular, it is provided that a sufficient Part of the transmission power hits the object. The main beam direction can be the center of the club.

In Furthermore, an advantageous embodiment of the invention, the meter has a first Receiving means for receiving a reflected from the object Reflection signal of the radiated transmission signal and at least one second receiving means for receiving the reflected from the object Reflection signal of the emitted transmission signal.

In Furthermore, an advantageous embodiment of the invention is the reference direction substantially orthogonal to a plane through the first receiving means and the second receiving device.

In Furthermore, the measuring device has at least an advantageous embodiment of the invention a first mixer for mixing the transmission signal with the means the first receiving device received reflection signal and at least a second mixer for mixing the transmission signal with the received by the second receiving means reflection signal on.

In Furthermore, an advantageous embodiment of the invention is the reference direction essentially orthogonal to the longitudinal axis of the motor vehicle.

In Furthermore, advantageous embodiment of the invention is by means of of the measuring device the object distance and the object angle with respect to an object with a height less than 25cm, in particular with a height of less than 10cm.

In Furthermore, an advantageous embodiment of the invention, the motor vehicle a parking assistant for independent parking of the motor vehicle and / or to specify a steering angle for parking in dependence the size of the parking space.

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 embodiments, wherein like reference numerals in different figures, the same or similar counter states. Showing:

1 an embodiment of a motor vehicle,

2 an example of a traffic situation,

3 an example of another traffic situation,

4 an example of another traffic situation,

5 an embodiment of a parking space detector,

6 Another embodiment of a parking space detector,

7 an exemplary embodiment of a radar device in a schematic representation,

8th an embodiment of a frequency-time diagram,

9 an embodiment of an arrangement of antennas,

10 a further embodiment of an arrangement of antennas and

11 a further embodiment of a radar device in a schematic representation.

1 shows an embodiment of a motor vehicle 1 with an arranged in a mounting height H measuring device 2 for measuring an object distance R between the measuring device 2 and an object like one in 1 curb shown 5 and an object angle α between a reference direction or main beam direction HSR and a straight line between the object and the measuring device 2 , The reference direction or main beam direction HSR is in the present embodiment substantially orthogonal to the longitudinal axis of the motor vehicle 1 ,

The car 1 also has a parking space detector for determining the size of a -. In 2 between two vehicles 10 and 11 formed - parking space 12 depending on the speed of the motor vehicle 1 , in dependence of the object distance R and in dependence of the object angle α.

3 shows an example of another traffic situation, wherein between the motor vehicles 10 and 11 a bollard 18 is arranged, in cooperation of the parking space detector with the measuring device 2 as well as the curb 5 and the motor vehicle 10 as the one with reference numerals 14 designated parking space limiting object is detected. 4 shows an example of another traffic situation, where a parking space 15 between a bollard 19 and the motor vehicle 11 is recognized. In the present embodiment, the size of the parking space 12 . 14 or 15 through the parking space length LPL of the parking space 12 . 14 respectively. 15 and the parking space depth TPL of the parking space 12 . 14 respectively. 15 Are defined.

5 and 6 show exemplary embodiments each of a parking space detector 20 respectively. 23 for determining the size of a parking space in the form of a parking space length LPL and a parking space depth TPL. The parking space detector 20 respectively. 23 determines the parking space length LPL and the parking space depth TPL thereby depending on the speed vFZG of the motor vehicle 1 and depending on the meter 2 output object distance R and object angle α.

7 shows a radar device 30 as a measuring device 2 for determining the object distance R and the object angle α is usable. The radar device 30 has a radar sensor 40 and an evaluation device 41 on. The radar device 30 has an oscillator or a signal generator 31 for generating a transmission signal s (t), a transmission antenna 35 for emitting the transmission signal s (t) and a receiving antenna 36 to receive one from an object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 reflected reflection signal r1 (t) of the radiated transmission signal s (t). t denotes the time.

That by means of the signal generator 31 generated transmission signal s (t) comprises in an exemplary embodiment, at least two signal sequence sections, a first signal section sequence and a second Signalab cut sequence, with at least two temporally alternating signal sections, wherein the at least two signal sections of a signal section sequence differ in their frequency by a difference frequency, and wherein the difference frequency of the first signal section sequence of the difference frequency of the second signal section sequence, in particular by at least 5%, advantageously by at least 10%, is different. An embodiment of such a transmission signal is in 8th shown in a frequency-time diagram.

In this case, A1, A2, A3,... Designate the signal sections of a first signal section sequence A (t) and B1, B2, B3,... The signal sections of a second signal section sequence B (t). Such signal sections are also referred to as chirps. In the present exemplary embodiment, the durations T _burst for the signal sections A1, A2, A3,... And B1, B2, B3,... Are the same length. The durations T _{Burst of} the signal sections A1, A2, A3,... Are in 8th represented by a solid line and the durations T _{burst of} the signal sections B1, B2, B3,... by a broken line.

The difference frequency of the stages within a signal section A1, A2, A3,... Or B1, B2, B3,... Can be a constant frequency f _T (t), but it can also be modulated.

The individual signal sections A1, A2, A3,... Of the first signal section sequence A (t) differ in their instantaneous frequency by a difference frequency f _{Hub, A} / (N-1), where f _{Hub, A is} the difference between the carrier frequency of the first signal section A1 of the first signal section sequence A (t) and the carrier frequency of the Nth signal section of the first signal section sequence A (t) and N is the number of signal sections A1, A2, A3,... of the first signal section sequence A (t). The individual signal sections B1, B2, B3,... Of the first signal section sequence B (t) differ in their instantaneous frequency by a difference frequency f _{Hub, B} / (N-1), where f _{Hub, B is} the difference between the carrier frequency of the first signal section B1 of the second signal section sequence B (t) and the carrier frequency of the Nth signal section of the second signal section sequence B (t) and N is also the number of signal sections B1, B2, B3,... of the first signal section sequence B (t). It has proved to be particularly advantageous, the difference frequency f _{Hub, A} / (N-1) and the first signal section sequence A (t), in particular by at least 5%, advantageously by at least 10%, different from the difference frequency f _{Hub, B} / (N-1) of the second signal sequence B (t).

In addition, a frequency offset f _Shift between the signal section A1 of the first signal section sequence A (t) and the signal section B1 of the second signal section sequence B (t) can be provided.

und die zweite Signalabschnittsfolge B(t) zu

wobei f_TA1 die Trägerfrequenz des Signalabschnitts A1 und rect die Rechteckfunktion bezeichnet.Accordingly, the first signal section sequence A (t) results

and the second signal sequence B (t)

where f _{TA1 denotes} the carrier frequency of the signal section A1 and rect the rectangular function.

The transmission signal s (t) thus results s (t) = A (t) + B (t)

Of course, other transmission signals are possible. Among other things, it may be provided a transmission signal according to the DE 100 50 278 A1 to create. The pulse radar principle can also be used.

The transmission signal s (t) is transmitted by means of a coupler 32 a mixer 38 for mixing the transmission signal s (t) and the reflection signal r1 (t). The mixer 38 outputs an in-phase signal I1 (t).

The transmission signal s (t) is also by means of another coupler 33 a phase shifter 37 fed, by means of which the phase of the transmission signal s (t) relative to the carrier frequency by 90 °, ie π / 2, is shifted. The phase-shifted transmission signal becomes a mixer 39 for mixing the phase-shifted transmission signal and the reflection signal r1 (t) supplied to the mixer 39 by means of a coupler 34 is forwarded. The mixer 39 outputs a quadrature signal Q1 (t).

The radar device 30 has a multiplier 42 by means of which the quadrature signal Q1 (t) is multiplied by the complex number j to jQ1 (t). I1 (t) and j1Q (t) are added to form a complex mixing signal m1 (t). The complex mixed signal m1 (t) is also a mixed signal in the sense of the claims. The radar device 30 also has a frequency analyzer 43 on, by means of which - for example by an FFT - a spectrum M1 (κ) of the complex mixed signal m1 (t) over the frequency κ is formed.

The radar device 30 also has a receiving antenna 56 to receive one from an object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 reflected reflection signal r2 (t) of the radiated transmission signal s (t). The transmission signal s (t) is transmitted by means of a coupler 52 a mixer 58 for mixing the transmission signal s (t) and the reflection signal r2 (t). The mixer 58 outputs an in-phase signal I2 (t).

The transmission signal s (t) is also by means of another coupler 53 a phase shifter 57 fed, by means of which the phase of the transmission signal s (t) relative to the carrier frequency by 90 °, ie π / 2, is shifted. The phase-shifted transmission signal becomes a mixer 59 for mixing the phase-shifted transmission signal and the reflection signal r2 (t) supplied to the mixer 59 by means of a coupler 54 is forwarded. The mixer 59 outputs a quadrature signal Q2 (t). The in-phase signal I2 (t) and the quadrature signal Q2 (t) are mixed signals in the sense of the claims.

The radar device 30 has a multiplier 62 by means of which the quadrature signal Q2 (t) is multiplied by the complex number j to jQ2 (t). I2 (t) and j2Q (t) are added to a complex mixing signal m2 (t). The complex mixed signal m2 (t) is also a mixed signal in the sense of the claims. The radar device 30 also has a frequency analyzer 63 , by means of which - for example by an FFT - a spectrum M2 (κ) of the complex mixed signal m2 (t) over the frequency κ is formed.

By means of an analyzer 44 a difference Δψ12 of the phase of the complex mixing signal m1 (t) and the phase of the complex complex signal m2 (t) is formed.

auf, wobei ΔEA – wie in 9 dargestellt – der Abstand zwischen der Empfangsantenne 36 und der Empfangsantenne 56 ist, und wobei λ die (mittlere) Wellenlänge des Sendesignals s(t) ist.The radar device 30 has an evaluator 45 for determining the angle α between the beam direction HSR of the radar device 30 and the object like the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 according to the context

on, where ΔEA - as in 9 shown - the distance between the receiving antenna 36 and the receiving antenna 56 where λ is the (average) wavelength of the transmission signal s (t).

By means of the analyzer 44 Optionally, the dominant frequency κ1 _{A of} the composite signal m1 (t) and the dominant frequency κ2 _{A of} the composite signal m2 (t) with respect to the first signal sequence A (t) and the dominant frequency κ1 _{B of} the composite signal m1 (t) and the dominating Frequency κ2 _{B of} the mixed signal m2 (t) with respect to the second signal sequence B (t) determined.

The processing of the individual signal sequences A (t) and B (t) takes place advantageously by temporal separation separately, so that by means of the mixer 38 and 39 respectively. 58 and 59 the first signal sequence A (t) with one of the object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 reflected portion of the first signal section sequence A (t) (the reflection signal r1 (t) or r2 (t)) to a first mixed signal I1 _A (t), Q1 _A (t) and m1 _A (t) and I2 _A ( t), Q2 _A (t) and m2 _A (t) and the second signal sequence B (t) with one of the object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 reflected portion of the second signal sequence B (t) (the reflection signal r1 (t) and r2 (t)) to a second mixed signal I1 _B (t), Q1 _B (t) and m1 _B (t) and I2 _B ( t), Q2 _B (t) and m2 _B (t), respectively. By means of the frequency analyzer 43 is a spectrum M1 _A (κ) or M2 _A (κ) of the complex mixed signal m1 _A (t) or m2 _A (t) over the frequency κ and a spectrum M1 _B (κ) or M2 _B (κ) of the complex mixed signal m1 _B (t) or m2 _B (t) over the frequency κ. By means of the analyzer 44 become the dominant frequency κ1 _{A of} the complex complex signal m1 _A (t) and the dominant frequency κ2 _{A of} the complex complex signal m2 _A (t) (ie with respect to the first signal sequence A (t)) and the dominant frequency κ1 _{B of} the complex composite signal m1 _B (t) and the dominant frequency κ2 _{B of} the complex complex signal m2 _B (t) (ie with respect to the second signal sequence B (t)) determined.

wobei c die Lichtgeschwindigkeit ist.By means of the evaluator 45 becomes the distance R and optionally the differential speed v between the motor vehicle 1 and an object like the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 by solving the following overdetermined equation system, eg by a least-square algorithm, determines:

where c is the speed of light.

It can also be provided that by means of the analyzer 44 additionally the difference Δψ1 of the phase of the complex mixed signal m1 _A (t) and the phase of the complex mixed signal m1 _B (t) and the difference Δψ2 of the phase of the complex mixed signal m2 _A (t) and the phase of the complex mixed signal m2 _B (t) is determined. In this case, by means of the evaluator 45 - To determine the distance R and / or the speed difference v - the following overdetermined system of equations, for example by a least-square algorithm, are solved:

It can also be provided to use more than two signal sequence sections. For example, three signal sequence sequences A (t), B (t) and C (t) different difference frequency f _{Hub, A} / (N-1), f _{Hub, B} / (N-1) and f _{hub, C} / (N-1) are used and appropriately blasted and processed.

wobei ein ΔPARK ein Grenzwert, z.B. 3cm, und TPLmax die maximal notwendige Parklückentiefe ist, die z.B. die Länge des Kraftfahrzeuges 1 zuzüglich eines Sicherheitsabstandes betragen kann. D bezeichnet – wie in 2 dargestellt – einen Abstand zwischen dem Kraftfahrzeug und einer Linie 6, die durch die Parklücke begrenzende Objekte wie die Kraftfahrzeuge 10 und 11 definiert ist.Depending on the object distance R and the object angle α, the in 5 Parking space detector shown 20 the parking space depth TPL by checking whether

where a ΔPARK is a limit, eg 3cm, and TPLmax is the maximum required parking space depth, eg the length of the motor vehicle 1 plus a safety margin can be. D denotes - as in 2 shown - a distance between the motor vehicle and a line 6 through the parking space bounding objects such as the motor vehicles 10 and 11 is defined.

If no object is detected, the parking space depth TPL is equal to the maximum necessary parking space depth TPLmax. If an object is detected, the parking space depth TPL is equal to R · cos (α) with respect to values for R and α for which no object is currently detected. The determination of the parking space length LPL is effected by integration of the speed vFZG of the motor vehicle 1 in a range of sufficient parking space depth TPL.

The parking space depth TPL and the parking space length LPL can be determined by means of an output device 21 be issued optically or acoustically.

The in 6 Parking space detector shown 23 corresponds largely to the parking space detector 20 However, there is also a relative position POSPL of the motor vehicle 1 to the parking space 12 . 14 . 15 from, for example, by integrating the speed vFZG the motor vehicle 1 possibly taking into account the steering angle δ of the motor vehicle 1 is determined.

In the in 6 illustrated embodiment, the motor vehicle 1 a parking assistant 25 for presetting a steering angle δ for parking as a function of the parking space depth TPL, the parking space length LPL and the relative position POSPL of the motor vehicle 1 to the parking space 12 . 14 . 15 on. It can be a man-machine interface 24 be provided by means of an operator due to the parking space depth TPL and the parking space length LPL a parking position or a selection of parking positions is proposed. From this selection of parking positions, the operator can then select a parking position. It can also be provided that the parking assistant for independent parking of the motor vehicle 1 is trained. For example, it may be provided that the motor vehicle 1 after selecting a parking position by means of the human-machine interface 24 parked independently.

The transmission of the speed difference v to the parking space detector 20 or the parking space detector 23 is optional. It can be provided that the parking space detector 20 or the parking space detector 23 using the speed difference v checks whether a detected object is stationary. It is advantageous, albeit a speed component of a recognized object in the longitudinal direction of the motor vehicle 1 is recognizable. This can - as in 10 and 11 represented - three receiving antennas 36 . 56 and 76 in a radar device 70 be provided, wherein 10 an advantageous arrangement of the receiving antennas 36 . 56 and 76 shows. The radar device 70 has a radar sensor 80 on, the opposite the radar sensor 40 further couplers 72 . 73 . 74 , more mixers 78 . 79 and another phase shifter 77 having. The radar sensor 80 also has the receiving antenna 76 to receive one from an object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 reflected reflection signal r3 (t) of the radiated transmission signal s (t). The radar device 70 has an evaluation device 81 for determining the angle α between the beam direction and the object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 in the plane defined by the coordinates x and z and the angle β between the beam direction and the object such as the curb 5 , the motor vehicle 10 respectively. 11 or the bollard 18 respectively. 19 in the plane spanned by the coordinates y and z and optionally the distance R and the speed difference v as a function of in-phase signals I1 (t), I2 (t), I3 (t) and quadrature signals Q1 (t), Q2 ( t), Q3 (t). This is the evaluation device 81 with appropriate adjustments according to the evaluation device 41 designed.

1, 10, 11

motor vehicle

2

gauge

5

curbstone

6

line

12 14, 15

parking lot

18 19

Bollard

20 23

Parking space detector

21

output device

24

Human-machine interface

25

parking assistant

30 70

radar

31

signal generator

32 33, 34, 52, 53, 54, 72, 73, 74

coupler

35

transmitting antenna

36 56, 76

receiving antenna

37, 57, 77

phase shifter

38 39, 58, 59, 78, 79

mixer

40 80

radar sensor

41 81

evaluation

42 62

multiplier

43 63

frequency analyzer

44

analyzer

45

evaluator

A, B

signal sequence

A1, A2, A3, B1, B2, B3

signal section

D

distance between a motor vehicle and one through the one

Parking space delimiting Objects defined line

f _{stroke, A} , f _{stroke, B}

difference between the carrier frequency of the first signal section

one Signal section sequence and the carrier frequency of the last one

signal section the signal section sequence

_Shift

frequency offset

f _T (t)

carrier frequency

H

installation height

HSR

Boresight

I1 (t), I2 (t), I3 (t)

In-phase signal

LPL

Parking space length

m1 (t), m2 (t)

complex mixed signal

M1 (κ), M2 (κ)

spectrum

POSPL

relative Position of a vehicle to a parking space

Q1 (t), Q2 (t), Q3 (t)

Quadrature signal

R

object distance

r1 (t), r2 (t), r3 (t)

reflection signal

s (t)

send signal

t

Time

T _Burst

time

TPL

Parking space depth

v

speed difference

vFzg

speed of the motor vehicle

x, Y Z

coordinates

α, β

angle

ΔEA

distance between two receiving antennas

Δψ1, Δψ2 Δψ12

phase difference two mixed signals

κ

frequency

κ1 _A , κ1 _B , κ2 _A , κ2 _B

dominant Frequency of a complex mixed signal

δ

steering angle

Claims (10)

Motor vehicle ( 1 ) with a measuring device ( 2 . 30 ) for measuring an object distance (R) between the measuring device ( 2 . 30 ) and an object ( 5 . 10 . 11 . 18 . 19 ) and an object angle (α) between a reference direction (HSR) and a line between the object ( 5 . 10 . 11 . 18 . 19 ) and the measuring device ( 2 . 30 ), wherein the motor vehicle ( 1 ) a parking space detector ( 20 . 23 ) for determining the size (LPL, TPL) of a parking space ( 12 . 14 . 15 ) as a function of the speed (vFZG) of the motor vehicle ( 1 ), depending on the object distance (R) and in dependence of the object angle (α). Motor vehicle ( 1 ) according to claim 1, characterized in that the measuring device ( 2 . 30 ) a radiation device ( 35 ) for emitting a transmission signal (s (t)). Motor vehicle ( 1 ) according to claim 21, characterized in that the reference direction a main beam direction (HSR) of the emitting device ( 35 ). Motor vehicle ( 1 ) according to claim 2 or 3, characterized in that the measuring device ( 2 . 30 ) a first receiving device ( 36 ) for receiving one of the object ( 20 ) reflected reflection signal (r1 (t)) of the radiated transmission signal (s (t)) and at least one second receiving device ( 56 ) for receiving the object ( 20 ) reflected reflection signal (r2 (t)) of the radiated transmission signal (s (t)). Motor vehicle ( 1 ) according to claim 4, characterized in that the reference direction (HSR) substantially orthogonal to a plane through the first receiving device ( 36 ) and the second receiving device ( 56 ). Motor vehicle ( 1 ) according to claim 4 or 5, characterized in that the measuring device ( 2 . 30 ) at least a first mixer ( 38 . 39 ) for mixing the transmission signal (s (t)) with that by means of the first receiving device ( 36 ) received reflection signal (r1 (t)) and at least one second mixer ( 58 . 59 ) for mixing the transmission signal (s (t)) with that by means of the second receiving device ( 56 ) received reflection signal (r2 (t)). Motor vehicle ( 1 ) according to one of the preceding claims, characterized in that the reference direction (HSR) substantially orthogonal to the longitudinal axis of the motor vehicle ( 1 ). Motor vehicle ( 1 ) according to one of the preceding claims, characterized in that by means of the measuring device ( 2 . 30 ) the object distance (R) and the object angle (α) with respect to an object ( 5 . 18 . 19 ) with a height of less than 25cm can be determined. Motor vehicle ( 1 ) according to claim 8, characterized in that by means of the measuring device ( 2 . 30 ) the object distance (R) and the object angle (α) with respect to an object ( 5 ) with a height of less than 10cm can be determined. Motor vehicle ( 1 ) according to one of the preceding claims, characterized in that it has a parking assistant ( 25 ) for independent parking of the motor vehicle ( 1 ) and / or for specifying a steering angle (δ) for parking depending on the size (LPL, TPL) of the parking space ( 12 . 14 . 15 ) having.