EP3710866A1

EP3710866A1 - Method for determining a position of a motor vehicle

Info

Publication number: EP3710866A1
Application number: EP18808242.4A
Authority: EP
Inventors: Marcus Wagner
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-11-17
Filing date: 2018-11-14
Publication date: 2020-09-23
Also published as: WO2019096825A1; US20200341155A1; JP7060689B2; CN111344600B; CN111344600A; DE102017220551A1; KR20200088324A; US11269083B2; JP2021503600A; KR102686224B1

Abstract

The invention relates to a method for determining a position of a motor vehicle, comprising at least the following steps: a) receiving a first signal (1) containing an absolute position of the motor vehicle; b) receiving a second signal (2) containing a change in the position of the motor vehicle; c) generating first position information (3) corresponding to the absolute position from the first signal (1) if the first signal (1) is available, and continued from the second signal (2) according to the change in position if the first signal (1) is not available; d) generating second position information (4) corresponding to the first position information (3) at the beginning of first time segments (5) and continued over the first time segments (5) from the second signal (2) according to the change in position; and e) determining an error (7) in the first position information (3) generated in step c) using the second position information (4) generated in step d).

Description

description

title

Method for determining a position of a motor vehicle

State of the art

There are various ways known to determine the position of a motor vehicle. In particular, methods of satellite navigation are used. However, if a corresponding satellite signal is not available, for example when driving through a tunnel, the position of the vehicle can not be determined with such methods or only insufficiently determined.

Disclosure of the invention

Here, a particularly advantageous method for determining a position of a motor vehicle is presented. The dependent claims specify particularly advantageous developments of the method.

In the described method, in particular, a device for highly accurate position determination can be used. Inertialsensorik (especially for yaw rates and

Accelerations in three directions) with GNSS (for satellite navigation) to obtain highly accurate position information. Such accurate position information can be used in particular for highly automated driving (HAF). The described method can be applied to inertial signals with GNSS support, but also to any other sensor output with derived and integrated signals.

With the described method, the position of the motor vehicle is preferably determined by satellite navigation, if a corresponding Signal is available. For this purpose, in step a) of the described method, a first signal is received which comprises an absolute position of the motor vehicle.

The first signal may in particular be a signal for satellite navigation, in particular in the manner of the GPS (Global Positioning System). In that case, for example, the first signal may be generated by a GNSS receiver and delivered to a controller that is intended and arranged to perform the described method. Alternatively, however, it is also possible for the first signal to determine the absolute value in another way

Position allows, for example, by the first signal indicating the distance from one or preferably several (relative to the earth's surface) fixed points. The absolute position is the position of the motor vehicle in one

Reference system in which the earth's surface (ie, for example, the road on which the motor vehicle is driving) is at rest. The absolute position can be specified in particular in GPS coordinates.

With the first signal, the position of the motor vehicle can already be determined in principle. However, this is only possible if the first signal is available. When driving in a tunnel, for example, the reception of a GNSS receiver is often limited or completely prevented. The determination of the position of the motor vehicle with the first signal is then not possible. The fact that the first signal is not available means, in particular, that the first signal can not be created as desired, for example, for lack of GNSS reception. The GNSS receiver may then enter, for example

output the corresponding error signal. Also, the GNSS receiver may continue to output a signal containing the last known position as the position of the motor vehicle. Also in this case, according to the interpretation of the concept of unavailability used here, the first signal is not available. If the first signal is not available, the

Position determination in the control unit in particular be assumed that the first signal specifies the absolute position on the last known value.

With the method described, the position of the motor vehicle can also be determined when the first signal is not available. For this purpose, in step b) of the method described, a second signal is received which comprises a change in the position of the motor vehicle. Also the second signal is preferably received by the control unit which is intended and arranged for carrying out the described method.

The second signal can be obtained in particular from the vehicle's own data. For example, the rotational movement of the tires can be detected. From this, the movement of the motor vehicle can be determined. In particular, a speed can be determined with which the motor vehicle moves. In addition, the steering wheel angle can be detected, so that a change in direction can be detected. If the steering wheel is not detected, for example, it can be assumed that the

Moved motor vehicle with the detected speed in a constant direction.

The second signal can be generated, for example, by one or more sensors for the rotational speed of a wheel or by a corresponding one

Electronics to which such sensors are connected. If the steering wheel angle is also taken into account, corresponding sensors are preferably also connected to the corresponding electronics. Also, the second signal can be output from another controller. In particular, the second signal may be a signal available via a bus system of the motor vehicle. For example, the second signal may be the signal that also allows the current speed to be displayed via the tachometer.

From the speed of the motor vehicle and optionally also from the

Steering gear can be determined a change in the position of the motor vehicle relative to a known starting position. In particular, it is possible to override the home position (as an absolute position)

Satellite navigation with the first signal to determine and at

Unavailability of the first signal to fall back on the second signal. In particular, starting from a last position known from satellite navigation (at which the reception was lost), the second signal can be used to determine how the motor vehicle has moved from this last known position. In particular, it may be assumed that the motor vehicle is moving in the direction last detected via GNSS. A change of direction by turning the steering wheel can be taken into account. Also, one detected before loss of GNSS reception Direction change (for example, when cornering) considered and continued.

For this purpose, in step c) of the described method, a first

Position information is created which corresponds to the absolute position of the first signal, if the first signal is available, and which is continued according to the change of position from the second signal, if the first signal is not available.

The first position information is thus basically obtained from the first signal and possibly also from the second signal. The second signal can be considered always available. The continuation of the position determination with the second signal can therefore enable, for example, the determination of the position of the motor vehicle even when driving in a tunnel. However, with the use of the second signal, an error, in particular due to integrations to be performed, build up over time and greatly increase.

This is due in particular to the fact that any inaccuracies in the change in position contained in the second signal accumulate over the duration of the continuation. Even small inaccuracies in the second signal can lead to a large error, if the continuation of the position determination on the second signal over a long time (for example when driving in a long tunnel) is necessary.

It can be assumed that the first signal is not always available, but most of the time. The first signal can therefore be used to support the second signal. This means that with the first signal, the absolute position of the motor vehicle is determined, if possible. If the first signal is not available, the absolute position determined last from this signal can be used as a support, from which it is continued with the second signal.

The method presented here serves in particular to improve the quality of the first position information. Thus, the accuracy of the method determined by the position of the motor vehicle is improved. For this purpose, the signals described above are used and their errors minimized. In step d) of the described method, a second position information is generated, which corresponds to the beginning of first time periods of the first position information, and over the first time intervals according to the

Change in position from the second signal is continued.

The second position information is introduced as an auxiliary quantity. Like the first position information, the second position information is also determined both using the first signal and using the second signal. In contrast to the first position information, however, the second signal is not used for the second position information due to

Unavailability of the first signal used. Instead, regardless of the availability of the first signal in the given first

Periods resorted to the second signal. Thus, if necessary, the unavailability of the first signal is simulated.

The first time segments preferably each have the same length. It is also preferred that the first time periods are arranged at the same time interval from each other. In particular, in the determination of the second position information periodically, the first signal or the second signal can be used. The first time segments may in particular be specified via an enable signal (which may also be referred to as a flag signal). In particular, the enable signal may be designed such that it assumes only two discrete values. Depending on the value of the enable signal, the determination of the second position information at a specific time then takes place via the first signal or via the second signal. The enable signal is preferably automatically set at regular intervals and acts as a signal for suppressing the support. The enable signal therefore forces an error in the second position information.

With the second position information, a new position information is thus obtained, whose error increases over time (at least over the first time periods). With the second position information, an error of the first position information can be determined. This is done in step e) of the method described, in which an error of the first created according to step c)

Position information is determined using the second position information created according to step d). In an embodiment variant, the second signal (2) received in step b) comprises a first derivative of the position. A first derivative of the position is in particular a speed information. In another

In an alternative embodiment, the second signal received in step b) can also comprise a second derivative of a position plus a value of a first derivative at a specific point in time. From this combination of information, a change in the position of the motor vehicle can be determined. A radar or laser system may be a potential source for the second signal.

This can be done in particular according to the following two embodiments.

In a preferred embodiment of the method, the error in step e) becomes a difference between the first

Position information position information and the second one

Position information determines position information.

In a further preferred embodiment of the method, the error in step e) is determined as a difference between the absolute position of the first signal and the second position information.

The first position information differs from the absolute position of the first signal only if the first signal is not available. This difference may be considered small for the present purposes. Therefore, the comparison can be made with the first position information as well as the absolute position from the first signal. The exact one is

Use of the first position information, while the use of the first signal may be simpler. The deviation between the second position information and the first position information or the absolute position from the first signal is the error to be determined in step e).

From the difference of the second position information and the first

Position information or the absolute position from the first signal can be closed on the type and size of the error. Preferably, the Determination of the error at a plurality of times (if

Admission conditions permit this). For example, the error for each of the first time periods and thus in particular be determined periodically. At the beginning of each first period, the first one is correct

Position information with the absolute position of the first signal match.

Preferably, at the end of each first time period, the error becomes the difference between the second position information and the first one

Position information or the absolute position determined from the first signal. The error thus indicates the deviation that has accumulated over a first period of time. If all first time periods are the same length, the errors determined at the end of the first time periods can be compared with one another. So the error can be checked and re-evaluated over and over again.

In particular, it can be determined by step e) how exactly the second signal is currently.

The stated process steps can be carried out in any order and also overlapping in time, provided that at least steps c) and d) do not start before the beginning of steps a) and b) and if step e) does not start before the beginning of steps c) and d) starts.

In a further preferred embodiment of the method, the second position information corresponds to the first one in second time segments

Position information.

The second time segments preferably each have the same length.

It is also preferred that the second time periods are arranged at the same time interval from each other. Preferably, first and second time intervals alternate. This can be done in particular periodically. For example, the second time periods may be the same length as the first time periods. In particular, it is preferable that there are only first and second time periods.

In a further preferred embodiment, the method further comprises the following method step: f) outputting an output signal comprising the position of the motor vehicle, which from the first determined according to step c)

Position information is obtained by correction with the error determined in step e).

The execution of step f) does not begin before the beginning of step e).

The output signal is preferably generated and output by the control unit, which is intended and configured for carrying out the described method. The position of the signal contained in the output signal

Motor vehicle can be considered in particular as a final result of the described method.

Basically, the output signal comprises the first position information as the determined position of the motor vehicle. However, the error determined according to step e) is taken into account. The error can therefore be eliminated before the final output signal is output.

In a further preferred embodiment of the method, the correction in step f) is carried out using a current value of the error determined according to step e).

In particular, it can be assumed that the type and size of the error does not change rapidly. The error can therefore be assumed to be constant between two points in time of the determination (ie in particular the ends of the first time segments).

Due to the recurrent determination of the error but also a temporal change of the error can be detected or taken into account.

In particular, therefore, in a further preferred embodiment of the method, a time profile of the error determined according to step e) is determined, wherein the correction in step f) takes place with extrapolation of the time profile of the error.

In this embodiment, the error between two points in time of the determination (ie in particular the ends of the first time segments) is not assumed to be constant per se. Instead, it is believed that the temporal Development of the error corresponds to an extrapolatable course. If, for example, a linear increase in the error was determined for past determination times, it can be assumed that the error will continue to increase linearly in the future. The same applies, for example, even with a quadratic or exponential behavior. By extrapolation according to a recognized history, the instantaneous error between two

Determination times are particularly well estimated. In the case of a previous course which has been identified as constant, the extrapolation can also consist in considering the error to be constant, as in the previous embodiment.

As a further aspect, a control unit is presented, which for

Implementation of the described method is set up. The particular advantages and design features described above for the method are applicable to the controller and transferable.

Furthermore, a computer program is presented, which is set up to carry out all steps of the described method. In addition, a

machine-readable storage medium presented on which the computer program described is stored. The particular advantages and design features described above for the method and the controller are applicable to the computer program and the machine-readable storage medium and transferable.

Further details of the invention and embodiments, to which the invention is not limited, will be explained in more detail with reference to the drawings. They show schematically:

1 shows an illustration of a first example of a method for

Determination of the position of a motor vehicle,

2 shows a representation of a second example of a method for

Determination of the position of a motor vehicle,

3 is an enlarged view of the method of Fig. 2,

4 to 6: three examples of a time course of an error, 7 shows a first representation of a sequence of the method from FIGS. 2 and 3, and FIG

8 shows a second representation of a sequence of the method from the

Fig. 2, 3 and 7.

Fig. 1 shows an illustration of a first example of a method for

Determining the position of a motor vehicle. For this purpose, a position x of a motor vehicle is plotted against the time t. Both the position x and the time t are represented in arbitrary units, which is indicated by the abbreviation "a.u" (arbitrary units). The position x is an instantaneous absolute position of the motor vehicle. This is indicated by the one-dimensional coordinate x in this example. A transfer to two or three dimensions is readily possible.

Shown is a first signal 1 or an absolute position of the motor vehicle contained therein. For example, the first signal 1 can be obtained via satellite navigation. The first signal 1 is not always available. This is indicated by an also shown 11 availability. With the availability 11, shown as a rectangular signal, it is indicated when the very precise first signal 1 is available. If the availability 11 is at its higher value (which may correspond, for example, to a logical one), the first signal 1 is available. In that case, the absolute position contained in the first signal 1 corresponds to the instantaneous absolute position of the motor vehicle. If the availability 11 is at its lower value (which may correspond, for example, to a logic zero), the first signal 1 is not available. In that case, the last known value is assumed for the absolute position of the motor vehicle. This can be seen from the fact that the first signal 1 is constantly drawn in these areas. The values of the first signal 1 only change if the availability is "up". If the availability is "down", the last value is retained.

Furthermore, a second signal 2 or a change in the position of the motor vehicle contained therein is shown. This is shown insofar as that the second signal 2 in the temporal origin (that is to say the far left in the illustration) coincides with the instantaneous absolute position of the motor vehicle. from Based on temporal origin, the position x is continued according to the change in position contained in the second signal 2. It can be seen that over time a (here for clarification especially large) error is built up. The second signal 2 is always available in contrast to the first signal 1.

From the first signal 1 and the second signal 2 is a first

Position information 3 determined. This is the final output position information in this example. The first position information 3 is composed of the precise first signal 1 when values are present and is otherwise continued by the always-available second signal 2. The slope of the first position information 3 and the second signal 2 is the same when the first signal 1 is not available. In the moments in which the first signal 1 is not available, the first position information 3 (still) coincides with the first signal 1. By this support of the first

Position information 3, an accumulated error is eliminated again and again, as soon as the first signal 1 is available again. This is the first one

Position information 3 much more accurate than the second signal 2, because an error does not accumulate permanently.

2 shows an illustration of a second example of a method for determining the position of a motor vehicle. As in Fig. 1, the position x of the motor vehicle is plotted against time in Fig. 2. The first signal 1, the second signal 2, the first position information 3 and the

Availability 11 is similar to that shown in FIG.

Furthermore, a second position information 4 is shown in FIG. The second position information 4 corresponds to the beginning of first time sections 5 of the first position information 3. Over the first time sections 5, the second position information 4 is continued according to the change in position from the second signal 2. In second time intervals 6, the second position information 4 corresponds to the first position information 3.

The first time sections 5 and the second time sections 6 are predetermined by an enable signal 12. If the enable signal 12 is at its higher value (which may, for example, correspond to a logic one), the second position information item 4 is determined using the second signal 2. That is in the first periods 5 of the case. If the enable signal is at its lower value (which may correspond, for example, to a logical zero), the second one becomes

Position information 4 with the first signal 1 determined. This is the case in the second time periods 6.

In the example of FIG. 2, the second position information 4 is partially not supported by the first signal 1. This can be jumps in the waveform avoided.

It can be seen that in the first position information 3, the accuracy decreases with time. Nevertheless, the first signal 1 can not be the final one

Position information can be used because in some cases jumps are to be avoided.

The user can determine when to support and when not to. This can be done in particular by specifying the enable signal 12. The second position information 4 deviates from the first position information 3 as soon as the support is no longer considered. If support is again allowed (ie if the release signal 12 is down), then the second position information 4 again becomes equal to the first position information 3. The release signal 12 can be predefined in particular as shown in FIG. 2 as a periodic square wave signal his.

FIG. 3 shows an enlarged representation of the method from FIG. 2. Thick lines particularly highlight the first signal 1 and the second position information 4. By a comparison between the first signal 1 and the second position information 4, an error can be determined, which results from the continuation of the position determination via the second signal 2. This error can be used as an error of the first position information 3.

FIGS. 4 to 6 show three examples of a time characteristic of an error 7. This error 7 can be determined in particular as described with reference to FIG. 3.

It should be noted that in FIGS. 4 to 6, the first signal 1 and the second position information 4-unlike in FIG. 3 -are not themselves shown as a time characteristic. Rather, in FIGS. 4 to 6 in each case for a plurality of discrete determination times (for example, each at the end of a the first time period 5) indicated how large the error is 7. Thus, the error 7 results from the time evolution of the distance between the first signal 1 and the second position information 4 at the determination times. In Figs. 4 to 6 so are the

Determination times plotted on the time axis. An (almost) continuous representation of the time course of the error 7 as in FIGS. 4 to 6 can be obtained by a sufficiently large number of destination points. FIG. 4 shows a linear time evolution of the error 7, in FIG. 5 a quadratic and in FIG. 6 an exponential one. Shown in FIGS. 4 to 6 are only three types of errors. Of course, with the method, other types of errors (eg, with a drift and / or offset) and

Combinations of different types of errors are recorded and treated.

FIG. 7 shows a first representation of a sequence of the method from FIGS. 2 and 3. For this purpose, the mode of operation is shown with reference to a simplified block diagram. The first signal 1 and the second signal 2 are in each case passed to a first determination element 14 and a second determination element 15. In the first determination element 14, the first

Position information 3 determines, in the second determination element 15, the second position information 4. The second determination element 15 receives a command 13 for calculating an error 7 from a

corresponding control element 16. In a comparison element 17, the first position information 3 and the second position information 4 are compared. As a result, the error 7 is obtained. From the error 7 and the first

Position information 3, an output signal 8 is detected.

8 shows a second illustration of a sequence of the method from FIGS. 2, 3 and 7. The method comprises the following method steps:

a) receiving the first signal 1, which is an absolute position of the

Motor vehicle comprises,

b) receiving the second signal 2, which comprises a change in the position of the motor vehicle,

c) Creating the first position information 3, which corresponds to the absolute position of the first signal 1, if the first signal 1 is available, and which is continued according to the change of position from the second signal 2, if the first signal 1 is not available . d) preparing the second position information 4, which corresponds to the first position information 3 at the beginning of the first time segments 5, and which is continued over the first time segments 5 in accordance with the change in position from the second signal 2,

e) determining the error 7 of the first created according to step c)

Position information 3 using the second position information 4, prepared in accordance with step d), and

f) outputting the output signal 8, which is the position of the motor vehicle

comprising, which from the first determined according to step c)

Position information 3 is obtained by correction with the error 7 determined in step e).

In the example shown, steps a) and b) as well as steps c) and d) are carried out at the same time.

Claims

claims

1. A method for determining a position of a motor vehicle comprising at least the following method steps:

a) receiving a first signal (1) comprising an absolute position of the motor vehicle,

b) receiving a second signal (2) representing a change in the

Includes position of the motor vehicle,

c) creating a first position information (3), the absolute

Position from the first signal (1) corresponds, if the first signal (1) is available, and which is continued according to the change of position from the second signal (2), if the first signal (1) is not available,

d) creating a second position information (4) at the beginning of

first time portions (5) of the first position information (3), and over the first time periods (5) across according to

Changing the position from the second signal (2) is continued, e) determining an error (7) of the first created according to step c)

Position information (3) using the second position information (4) prepared according to step d).

2. The method of claim 1, wherein the received in step b) second

Signal (2) comprises a first derivative of the position.

3. The method of claim 1 or 2, wherein in step b) received

second signal (2) comprises a position.

4. The method according to any one of claims 1 to 3, wherein the error (7) in step e) is determined as a difference between the first position information (3) and the second position information (4).

5. The method according to any one of claims 1 to 3, wherein the error (7) in step e) is determined as a difference between the absolute position of the first signal (1) and the second position information (4).

6. The method according to any one of the preceding claims, wherein the second position information (4) in second time periods (6) of the first

Position information (3) corresponds.

7. The method according to any one of the preceding claims, further comprising the following method step:

f) outputting an output signal (8) representing the position of the

Motor vehicle comprises, which is obtained from the determined according to step c) first position information (3) by correction with the determined in step e) error (7).

8. The method of claim 7, wherein the correction in step f) under

Use of a current value of the detected according to step e) error (7).

9. The method of claim 7, wherein a time course (9) of the detected according to step e) error (7) is determined, and wherein the correction in step f) with extrapolation of the time course (9) of the error (7).

10. Control device (10) for a motor vehicle, which is set up to carry out a method according to one of the preceding claims.

11. Computer program which is set up to carry out all the steps of the method according to one of claims 1 to 9.

12. A machine-readable storage medium on which the computer program according to claim 11 is stored.