U.S. patent application number 17/548413 was filed with the patent office on 2022-06-16 for calibration of vehicle object detection radar with inertial measurement unit (imu).
The applicant listed for this patent is PRECO ELECTRONICS, LLC. Invention is credited to JONATHAN PAUL COLE, JONATHAN EDWARD FIX.
Application Number | 20220187421 17/548413 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-16 |
United States Patent
Application |
20220187421 |
Kind Code |
A1 |
COLE; JONATHAN PAUL ; et
al. |
June 16, 2022 |
CALIBRATION OF VEHICLE OBJECT DETECTION RADAR WITH INERTIAL
MEASUREMENT UNIT (IMU)
Abstract
The disclosed technology is a vehicle object detection radar
system incorporating an inertial measurement unit (IMU). The IMU
may obtain input signals of, or relating to, for example, relative
motion, acceleration, object detection angle, sway and vibration of
the vehicle and/or any towed trailer, and process them for relay to
the vehicle operator as operating information and possibly alarms.
Also, the obtained IMU signals may be relayed directly to the
vehicle's object detection radar systems and central control for
automatic adjustment and control thereof.
Inventors: |
COLE; JONATHAN PAUL;
(CALDWELL, ID) ; FIX; JONATHAN EDWARD; (BOISE,
ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PRECO ELECTRONICS, LLC |
Boise |
ID |
US |
|
|
Appl. No.: |
17/548413 |
Filed: |
December 10, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63123730 |
Dec 10, 2020 |
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63123777 |
Dec 10, 2020 |
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International
Class: |
G01S 7/40 20060101
G01S007/40; G01S 13/931 20060101 G01S013/931; G01C 21/16 20060101
G01C021/16 |
Claims
1. A dynamic misalignment error correction system for a
vehicle-mounted side-directed object-detection radar system
comprising: an integral, self-contained radar object-detection
sensor package adapted for after-market installation on a side of a
vehicle or on a side of a trailer adapted to be towed by a vehicle,
the radar object-detection sensor package comprising a radar
sensor; the radar sensor comprising a beam face with x, y and z
Cartesian coordinate axes orientation, with said beam face being
attached to the radar object-detection sensor package so that the
x-axis of the beam face is generally parallel to a straight line
approximating the straight, go-ahead or go-back movement direction
of the vehicle or trailer, the beam face y-axis is generally
parallel to a straight line approximating the horizon, and the beam
face z-axis is generally parallel to a straight line approximating
the direction of the earth's gravitational field; said radar sensor
also being adapted, when installed on a side of a vehicle or
trailer, to maintain a wide antenna pattern with a main lobe
directed perpendicularly to the side of the vehicle or trailer so
as to maintain radar coverage principally in next-adjacent,
generally-parallel road lanes and next-far-adjacent,
generally-parallel road lanes thereof; said radar sensor also
comprising an incorporated Inertial Measurement Unit (IMU)
containing accelerometer, gyroscope, and magnetometer components
integrated together with said radar sensor in the self-contained
radar object-detection sensor package; the IMU being adapted to
observe, by a first of the components of the IMU, an observed first
x-axis of the radar sensor face, during a straight, go-ahead or
go-back movement direction of the vehicle or trailer along a
vehicle movement observed second x-axis, in order to determine an
offset angle .alpha. that is the difference between the radar
sensor face observed first x-axis and the observed second x-axis;
the straight, go-ahead or go-back movement of the vehicle being
confirmed by a second of the components of the IMU adapted to
detect any movement of the vehicle or trailer along the y-axis; and
said self-contained radar object-detection sensor package being
adapted to enter and save to send for future consideration the
offset angle .alpha. for correction of any relevant radar sensor
measurement.
2. The dynamic misalignment error correction system of claim 1,
wherein the first component of the IMU is adapted to observe
acceleration or deceleration in movement along the observed second
x-axis in order to determine the offset angle .alpha. and is the
x-axis accelerometer component within the IMU.
3. The dynamic misalignment error correction system of claim 1,
wherein the second component of the IMU that is adapted to detect
any movement of the vehicle or trailer along the y-axis, is the
gyroscope component within the IMU.
4. A dynamic misalignment error correction system for a
vehicle-mounted side-directed object-detection radar system
comprising: an integral, self-contained radar object-detection
sensor package adapted for after-market installation on a side of a
vehicle or on a side of a trailer adapted to be towed by a vehicle,
said radar object-detection sensor package comprising a radar
sensor; said radar sensor comprising a beam face with x, y and z
Cartesian coordinate axes orientation, with said beam face being
attached to said radar object-detection sensor package so that the
x-axis of the beam face is generally parallel to a straight line
approximating the straight, go-ahead or go-back movement direction
of the vehicle or trailer, the y-axis of the beam face is generally
parallel to a straight line approximating the horizon, and the
z-axis of the beam face is generally parallel to a straight line
approximating the direction of the earth's gravitational field;
said radar sensor being adapted, when said radar object-detection
sensor package is installed on a side of a vehicle or trailer, to
maintain a wide antenna pattern with a main lobe directed
perpendicularly to the side of the vehicle or trailer so as to
maintain radar coverage principally in next-adjacent,
generally-parallel road lanes and the next-far-adjacent,
generally-parallel road lanes thereof; said radar sensor also
having an incorporated Inertial Measurement Unit (IMU) containing
accelerometer, gyroscope, and magnetometer components integrated
together with said radar sensor in said self-contained radar sensor
package; the IMU being adapted to observe by a first component of
the IMU an observed first z-axis of the radar sensor face, in order
to determine an offset angle .beta. that is the difference between
the radar sensor face observed first z-axis and a gravitational
field direction that is an observed second z-axis; and said
self-contained radar object-detection sensor package being adapted
to enter and save to send for future consideration the offset angle
.beta. for correction of any relevant radar sensor measurement.
5. The dynamic misalignment error correction system of claim 4,
wherein the first component of the IMU that is adapted to observe
the first z-axis in order to determine the offset angle .beta. is
the z-axis accelerometer component within the IMU.
6. The dynamic misalignment error correction system of claim 4,
wherein the vehicle or trailer is parked on a flat surface during
observation of the observed first z-axis and the observed second
z-axis, so that the vehicle or trailer is not tilted and not
turning.
7. A dynamic misalignment error correction system for a
vehicle-mounted side-directed object-detection radar system
comprising: an integral, self-contained radar sensor package
adapted for after-market installation on a side of a vehicle or on
a side of a trailer adapted to be towed by a vehicle, said radar
sensor package having a radar sensor; said radar sensor comprising
a beam face with x, y and z Cartesian coordinate axes orientation,
with said beam face being attached to said radar object-detection
package so that the x-axis of the beam face is generally parallel
to a straight line approximating the straight, go-ahead or go-back
movement direction of the vehicle or trailer, the y-axis of the
beam-face is generally parallel to a straight line approximating
the horizon, and the z-axis of the beam face is generally parallel
to a straight line approximating the direction of the earths'
gravitational field; said radar sensor being adapted, when said
radar object-detection sensor package is installed on a side of a
vehicle or trailer, to maintain a wide antenna pattern with a main
lobe directed perpendicularly to the side of the vehicle or
trailer, so as to maintain radar coverage principally in
next-adjacent, generally-parallel road lanes and next-far-adjacent,
generally-parallel road lanes thereof; said radar sensor also
comprising an incorporated IMU (Inertial Measurement Unit)
containing accelerometer, gyroscope, and magnetometer components
integrated together with said radar sensor in said self-contained
radar sensor package; the IMU being adapted to observe, by a first
of the components of the IMU, an observed first x-axis of the radar
sensor face, during a straight, go-ahead or go-back movement
direction of the vehicle or trailer along an observed second
x-axis, in order to determine an offset angle .alpha. that is the
difference between the radar sensor face observed first x-axis and
the vehicle movement direction observed second x-axis; the
straight, go-ahead or go-back movement of the vehicle or trailer
being confirmed by a second component of said IMU adapted to detect
any movement of the vehicle or trailer along the y-axis; said radar
sensor further comprising a third component of said IMU adapted to
observe an observed first z-axis of the radar sensor face, in order
to determine an offset angle .beta. that is the difference between
the radar sensor face observed first z-axis and a gravitational
field direction that is an observed second z-axis generally
corresponding to the downward and upward direction of the trailer
in the earth's gravitational field; and said self-contained radar
object-detection sensor package being adapted to enter and save to
send for future consideration the first offset angle .alpha. and
the second offset angle .beta. for correction of any relevant
sensor measurement.
8. The dynamic misalignment error correction system of claim 7,
wherein said first component of the IMU is adapted to observe
acceleration or deceleration of movement along the observed second
x-axis in order to determine offset angle .alpha. and is the x-axis
accelerometer component within the IMU.
9. The dynamic misalignment error correction system of claim 7,
wherein said second component of said IMU that is adapted to detect
any movement of the vehicle or trailer along the y-axis, is the
gyroscope component within said IMU.
10. The dynamic misalignment error correction system of claim 7,
wherein said third component of said IMU that is adapted to observe
the observed first z-axis in order to determine the offset angle
.beta. is the z-axis accelerometer component within the IMU.
11. The dynamic misalignment error correction system of claim 7,
wherein the vehicle or trailer is parked on a flat surface during
observation of the observed first z-axis and the observed second
z-axis, so that the vehicle or trailer is not tilted and not
turning.
Description
DESCRIPTION
[0001] This application claims benefit of Provisional Application
Ser. No. 63/123,730, filed Dec. 10, 2020, entitled Calibration of
Vehicle Object Detection Radar With Inertial Measurement Unit
(IMU), and claims benefit of Provisional Application Ser. No.
63/123,777, filed Dec. 10, 2020, entitled Operation of Vehicle
Object Detection Radar With Inertial Measurement Unit (IMU), the
entire disclosures of both Provisional Applications being
incorporated herein by this reference.
BACKGROUND OF THE DISCLOSED TECHNOLOGY
Field of the Disclosed Technology
[0002] This disclosed technology relates generally to vehicle
object detection radar systems. More specifically, this disclosed
technology relates to such radar systems incorporating an inertial
measurement unit (IMU) to detect, and if necessary, enable the
vehicle's operator or the vehicle's automatic monitoring and
control systems to adjust to issues resulting from inaccurate
installation of, or impact damage to, for example, the radar
system.
Related Art
[0003] An exemplary conventional inertial measurement unit (IMU) is
Delphi's Electronically Scanning Radar (ESR)
(https://www.delphi.com). Another exemplary conventional IMU is the
VN-100 IMU/AHRS of VectorNav of Dallas, Tex., USA
(https://www.vectornav.com/products).
SUMMARY OF THE DISCLOSED TECHNOLOGY
[0004] The present invention is a vehicle object detection radar
system incorporating an IMU. The IMU may obtain input signals of,
or relating to, for example, range, relative motion, acceleration,
object detection angles, plus vehicle sway, bounce and vibration.
The IMU may share or send these input signals to the vehicle object
detection radar system and/or operator, or to other of the
vehicle's monitoring/control systems, or even remotely to other
receiver(s) as data.
[0005] Typically, precise mounting is required for proper operation
of such radar systems. According to the presently disclosed
technology, on the other hand, with an IMU the system may be
conveniently and effectively calibrated for mounting error. Also,
this way, the radar system need not be mounted on the vehicle
within very small tolerances, which is the current practice. The
presently-disclosed technology allows the radar to be mounted
instead with wider tolerances, resulting in savings of time, effort
and expense.
[0006] In one embodiment, the presently-disclosed technology is a
vehicle-mounted, preferably side-directed, object-detection radar
system including a radar sensor incorporating an IMU. In another
embodiment, the presently-disclosed technology is an integral,
self-contained radar object-detection package, including a radar
sensor and an incorporated IMU, for after-market installation on a
side of a vehicle or a to-be-towed trailer. In another embodiment,
the presently-disclosed technology is a radar object-detection
package having an IMU that contains accelerometer, gyroscope and
magnetometer components integrated together within a radar sensor
package.
[0007] This way, the presently-disclosed technology may exist in
multiple embodiments, for example, to account for errors during
installation of the radar object-detection package. Also, it may
account for errors due to movement/displacement of the radar
object-detection package resulting from impact damage, or errors
resulting from wear-and-tear or failure of any of the securement
components for the radar package on a side of the vehicle or
trailer. Also, it may account for errors resulting from a change of
height of the vehicle due to different suspensions, different
tires, or adjustable height settings for the vehicle or trailer or
their suspensions.
[0008] To provide one or more or all of these features is an
objective of the presently-disclosed technology.
[0009] For example, embodiments of the presently-disclosed
technology may be described by the following: [0010] 1.
(Calibration for angle .alpha.) A dynamic misalignment error
correction system for a vehicle-mounted side-directed
object-detection radar system having:
[0011] an integral, self-contained radar object-detection sensor
package adapted for after-market installation on a side of a
vehicle or on a side of a trailer adapted to be towed by a vehicle,
the radar object-detection sensor package having a radar
sensor;
[0012] the radar sensor having a beam face (also, "exterior face"
or "radar sensor face") with x, y and z Cartesian coordinate axes
orientation, with the beam face being attached so that the x-axis
is generally parallel to a straight line approximating the
straight, go-ahead or go-back movement direction of the vehicle or
trailer, the y-axis is generally parallel to a straight line
approximating the horizon, and the z-axis is generally parallel to
a straight line approximating the direction of the earth's
gravitational field;
[0013] the radar sensor also being adapted, when installed on a
side of a vehicle or trailer, to maintain a wide antenna pattern
with a main lobe directed perpendicularly to the side of the
vehicle or trailer so as to maintain radar coverage principally in
next-adjacent, generally-parallel road lanes and next-far-adjacent,
generally-parallel road lanes thereof;
[0014] the radar sensor also having an Inertial Measurement Unit
(IMU) containing accelerometer (preferably each of a x-axis
accelerometer, a y-axis accelerometer, and a z-accelerometer),
gyroscope, and magnetometer components integrated together with the
radar sensor in the self-contained radar object-detection sensor
package;
[0015] the IMU being adapted to observe, by a first of the
components of the IMU, an observed first x-axis of the radar sensor
face, during a straight, go-ahead or go-back movement direction of
the vehicle or trailer along an observed second x-axis, in order to
determine an offset angle .alpha. that is the difference between
the radar sensor face observed first x-axis and the observed
vehicle movement direction observed second x-axis;
[0016] the straight, go-ahead or go-back movement of the vehicle or
trailer being confirmed by a second component of the IMU adapted to
detect any movement of the vehicle or trailer along the y-axis;
and
[0017] the self-contained radar object-detection package being
adapted to enter and save for future consideration the offset angle
.alpha. for correction of any relevant radar sensor measurement.
[0018] 2. The dynamic misalignment error correction system of item
#1 above, wherein the first component of the IMU is adapted to
observe acceleration and/or deceleration of movement (due to
vehicle or trailer acceleration or deceleration) along the observed
second x-axis in order to determine offset angle .alpha. and is the
x-axis accelerometer component within the IMU. [0019] 3. The
dynamic misalignment error correction system of item #1 above,
wherein the second component of the IMU adapted to detect any
movement of the vehicle or trailer along the y-axis is the
gyroscope component within the IMU.
[0020] Therefore, to calibrate for error, for example due to radar
packaging mounting error or radar package or vehicle side surface
damage that changes the position/orientation of the radar package,
an IMU is preferably built into the printed circuit assembly (PCA)
of a radar system such that one axis aligns parallel to the x-axis
of the face of the sensor, and another axis aligns perpendicular to
the face of the sensor (the z-axis). Then, to calculate an offset
angle .alpha. between the actual moving straight go-ahead or
go-back direction and the IMU's accelerometer's x-axis, its
position is monitored while accelerating and/or decelerating the
vehicle in a straight line. To ensure that the vehicle is being
driven in a straight line at this time, the gyroscope component of
the IMU is monitored while accelerating/decelerating for any motion
that indicates turning.
[0021] Or, example embodiments of the presently-disclosed
technology may also be described by the following: [0022] 4.
(Calibration for angle .beta.) A dynamic misalignment error
correction system for a vehicle-mounted side-directed
object-detection radar system having:
[0023] an integral, self-contained radar object-detection sensor
package adapted for after-market installation on a side of a
vehicle or on a side of a trailer adapted to be towed by a vehicle,
the package having a radar sensor;
[0024] the radar sensor having a beam face (also, "radar sensor
face") with a x, y and z Cartesian coordinate axes orientation,
with the beam face being attached so that the x-axis is generally
parallel to a straight line approximating the straight, go-ahead or
go-back movement direction of the vehicle or trailer, the y-axis is
generally parallel to a straight line approximating the horizon,
and the z-axis is generally parallel to a straight line
approximating the direction of the earth's gravitational field;
[0025] the radar sensor being adapted, when the radar
object-detection package is installed on a side of a vehicle or
trailer, to maintain a wide antenna pattern with a main lobe
directed perpendicularly to the side of the vehicle or trailer so
as to maintain radar coverage principally in next-adjacent,
generally-parallel road lanes and the next-far-adjacent,
generally-parallel road lanes thereof;
[0026] the radar sensor also having an Inertial Measurement Unit
(IMU) containing accelerometer (preferably each of a x-axis
accelerometer, a y-axis accelerometer, and a z-accelerometer),
gyroscope, and magnetometer components integrated together with the
radar sensor in the self-contained radar sensor package;
[0027] the IMU being adapted to observe by a first component of the
IMU an observed first z-axis of the radar sensor face, in order to
determine an offset angle .beta. that is the difference between the
radar sensor face observed first z-axis and an observed
gravitational field direction that is an observed second z-axis
generally corresponding to the downward and upward direction of the
trailer in the earth's gravitational field; and
[0028] the self-contained radar sensor object-detection package
being adapted to enter and save for future consideration the offset
angle .beta. for correction of any relevant radar sensor
measurement. [0029] 5. The dynamic misalignment error correction
system of item #4 above, wherein the first component of the IMU
that is adapted to observe the first z-axis in order to determine
the offset angle .beta. is the z-axis accelerometer component
within the IMU. [0030] 6. The dynamic misalignment error correction
system of item #4 above, wherein the vehicle or trailer is parked
on a flat surface during observation of the first z-axis and the
second z-axis, so that the vehicle or trailer is not tilted or
turning and the second z-axis is perpendicular to the flat
surface.
[0031] Or embodiments of the presently-disclosed technology may
also be described by the following: [0032] 7. (Calibration, for
angles .alpha. and .beta.) A dynamic misalignment error correction
system for a vehicle-mounted side-directed object-detection radar
system having:
[0033] an integral, self-contained radar sensor package adapted for
after-market installation on a side of a vehicle or on a side of a
trailer adapted to be towed by a vehicle, the radar sensor package
having a radar sensor;
[0034] the radar sensor having a beam face (also, "exterior face"
or "radar sensor face") with x, y and z Cartesian coordinate axes
orientation, with the beam face being attached so that the x-axis
is generally parallel to a straight line approximating the
straight, go-ahead or go-back movement direction of the vehicle or
trailer, the y-axis is generally parallel to a straight line
approximating the horizon, and the z-axis is generally parallel to
a straight line approximating the direction of the earths'
gravitational field;
[0035] the radar sensor being adapted, when the package is
installed on a side of a vehicle or trailer, to maintain a wide
antenna pattern with a main lobe directed perpendicularly to the
side of the vehicle or trailer, so as to maintain radar coverage
principally in next-adjacent, generally-parallel road lanes and the
next-far-adjacent, generally-parallel road lanes thereof;
[0036] the radar sensor also having an IMU (Inertial Measurement
Unit) containing accelerometer (preferably each of a x-axis
accelerometer, a y-axis accelerometer, and a z-accelerometer),
gyroscope, and magnetometer components integrated together with the
radar sensor in the self-contained radar sensor package;
[0037] the IMU being adapted to observe, by a first of the
components of the IMU, an observed first x-axis of the radar sensor
face, during a straight, go-ahead or go-back movement direction of
the vehicle or trailer along an observed second x-axis, in order to
determine an offset angle .alpha. that is the difference between
the radar sensor face observed first x-axis and the vehicle
movement direction observed second x-axis;
[0038] the straight, go-ahead or go-back movement of the vehicle or
trailer being confirmed by a second component of the IMU adapted to
detect any movement of the vehicle or trailer along the y-axis;
[0039] the IMU being adapted to observe by a third component of the
IMU an observed first z-axis of the radar sensor face, in order to
determine an offset angle .beta. that is the difference between the
radar sensor face observed first z-axis and a gravitational field
direction that is an observed second z-axis; and
[0040] the self-contained radar object-detection package sensor
being adapted to enter and save for future consideration the first
offset angle .alpha. and the second offset angle .beta. for
correction of any relevant sensor measurement. [0041] 8. The
dynamic misalignment error correction system of item #7 above,
wherein the first component of the IMU is adapted to observe
acceleration and/or deceleration along the observed second x-axis
in order to determine offset angle .alpha. and is the x-axis
accelerometer component within the IMU. [0042] 9. The dynamic
misalignment error correction system of item #7 above, wherein the
second component of the IMU that is adapted to detect any movement
of the vehicle or trailer along the y-axis, is the gyroscope
component within the IMU. [0043] 10. The dynamic misalignment error
correction system of item #7 above, wherein the third component of
the IMU that is adapted to observe the first z-axis in order to
determine the offset angle .beta. is the z-axis accelerometer
component within the IMU. [0044] 11. The dynamic misalignment error
correction system of item #7 above, wherein the vehicle or trailer
is parked on a flat surface during observation of the first z-axis
and the second z-axis, so that the vehicle or trailer is not tilted
or turning and the vehicle/trailer z-axis is perpendicular to the
flat surface, wherein the vehicle z-axis and the observed second
z-axis that is the gravitational force direction are parallel.
[0045] This way, the installed radar object-detection and IMU
package may observe a straight, go-ahead or go-back movement
direction of the vehicle or trailer along an observed second x-axis
in order to determine a first offset angle .alpha., the difference
between the radar sensor face first x-axis and the observed vehicle
straight-ahead or go-back movement direction, that is, the second
x-axis. Then, upon calculating the angle between the straight
direction of the vehicle/trailer (which direction is also the
x-axis of the truck/trailer side surface upon which the radar
package is mounted, if the side surface is planar and parallel to
said straight direction of the vehicle/trailer, as it typically for
many undamaged truck/trailer sidewalls) and the radar sensor face
first x-axis, any measured deviation from 0.degree. is angle
.alpha., the mounting error. The first x-axis location and
resulting angle .alpha., detected during calibration, then becomes
the "expected" position/angle of the radar sensor face x-axis.
Then, upon subsequent operation of the radar object detection
system comprising measurement(s) of angle .alpha., deviations from
the expected angle .alpha. may be taken into account in
object/target detection and/or signaled as an error, depending on
the amount/extent of the deviation.
[0046] Also, this way the installed radar object-detection and IMU
package may confirm said straight, go-ahead or go-back, movement of
the vehicle by the gyroscope component of the IMU being adapted to
detect turning and/or any direction of the vehicle or trailer along
the first y-axis. In certain embodiments, alternatively or
additionally to a gyroscope component, GPS heading information
and/or vehicle CAN (controller area network) steering position
data, may be used to indicate moving-straight condition or a
turning condition, or in certain circumstances or environments, a
magnetometer may be instead or additionally used.
[0047] Also, this way the installed radar object-detection IMU
package may observe a downward and/or upward movement direction of
the vehicle or trailer principally in the earth's gravitational
field along an observed second z-axis in order to determine a
second offset angle .beta., the difference between the radar sensor
face first z-axis and the observed gravitational field direction,
that is, the second z-axis.
[0048] Then, to calculate .beta., the angle between a line
perpendicular to the ground (and approximately parallel to the
acceleration of the earth's gravitational field) and the face of
the radar sensor, the IMU' s z-axis accelerometer position is
monitored, and any measured deviation from 0.degree. is .beta., the
mounting error. Similarly as with the detection of angle .alpha.
during calibration, the first z-axis location and resulting angle
.beta. detected during calibration, becomes the "expected" position
of the radar sensor face z-axis. Upon subsequent operation,
deviations from the expected may be taken into account in
object/target detection and/or signaled as an error, depending on
the amount/extent of the deviation.
[0049] The calibration process may be completed once, and the
.alpha. and .beta. values stored in memory. Or, the calibration
process may also be done periodically, or even continuously for
.alpha. wherein updated .alpha. values may in certain embodiments
be calculated every time a moving-straight condition of the
vehicle/trailer is detected.
[0050] Many commercial IMU's are now manufactured in excellent
quality and large quantities. As a result, they tend to be
currently available at reasonable prices. This way, as in some
embodiments of the presently-disclosed technology, it is economical
to design for, specify, and use commercially-available IMUs, even
if not all available functions of the commercially-available IMU
are planned to be used. In some of the present embodiments, for
example, the magnetometer component may not be used. The
accelerometer and gyroscope components, however, are used for their
respective functions. Still, it may be economically advantageous to
install a current, commercial, "off-the-shelf" IMU in many
embodiments of the presently-disclosed technology.
[0051] In some circumstances however, singular, stand-alone
accelerometer and gyroscope components of high quality and
low-price may become available and economically attractive for use
in the presently-disclosed technology. Then, a current, classic
IMU, with possibly more than needed components/functions as
discussed above, may not be necessary, and the stand-alone
accelerometer and gyroscope components may be designed for,
specified, and/or manufactured, and used, either separately or
together to practice the presently-disclosed technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 is a schematic flow diagram which depicts simply and
generally a radar object-detection process which may be utilized
according to embodiments of the presently-disclosed technology.
[0053] FIG. 2 is a top detail perspective left side view of a radar
object-detection package according to one embodiment of the
invention being attached to the left side of a trailer, for
example.
[0054] FIG. 3 is a schematic side view of a truck-tractor pulling a
trailer, the trailer being equipped with a radar object-detection
sensor package on a right side of the trailer according to one
embodiment of the presently-disclosed technology.
[0055] FIG. 4 is a top view of the side view depicted in FIG.
3.
[0056] FIG. 4A is an enlarged detail view of the top view depicted
in FIG. 4, but with the radar object-detection sensor package in
FIG. 4A being installed at an angle (.alpha.) from the truck
trailer body in the enlarged detail view.
[0057] FIG. 5 is a rear view of the trailer depicted in FIGS. 3, 4
and 4A.
[0058] FIG. 5A is an enlarged detail view of the rear view depicted
in FIG. 5, but with the radar object-detection sensor package in
FIG. 5A being installed at an angle (.beta.) from the truck trailer
body in the enlarged detail view.
[0059] FIG. 6 is a schematic flow diagram, .alpha. Angle Initial
Calibration, showing the steps to determine the alpha (.alpha.)
angle according to an embodiment of the presently-disclosed
technology.
[0060] FIG. 7 is a schematic flow diagram, .beta. Angle Initial
Calibration, showing the steps to determine the beta (.beta.) angle
according to an embodiment of the presently-disclosed
technology.
[0061] FIG. 8 is a schematic flow diagram showing one embodiment of
steps according to the invention that may be included as a portion
of a radar object detection process, such as that in FIG. 1,
wherein the steps include continued verification of vehicle/trailer
direction, continued measurement of sensor angle alpha (.alpha.)
and sensor angle beta (.beta.) and comparison of the newly-measured
sensor angles to the respective sensor angles expected from the
calibration according to the presently-disclosed technology, and
determining whether the comparison is within normal tolerances or
whether angle compensation to the target detection signals/data
should be made or whether an alarm/error is warranted.
DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS
Referring to the Figures:
[0062] In the generalized schematic flow-chart diagram of FIG. 1,
there are depicted in outline form several process steps, which a
reasonably-skilled person in the art of vehicle object detection
radar systems may understand and utilize for radar-based object
detection. Said reasonably-skilled person in the art also will
understand, once this document and the drawings have been reviewed,
how to incorporate, into the process of FIG. 1 and the equipment
represented by FIG. 1 and/or known in this field, methods and
apparatus according to embodiments of the invention for practicing
improved calibration of a radar sensor system and the resulting
improved on-going operation of the radar sensor system.
[0063] In the schematic top detail perspective left side view of
FIG. 2, radar object-detection sensor package (or "unit") 10 with
built-in IMU 12 is attached to vehicle left side surface 15. The
package 10 comprises IMU 12 having exterior face 16 and being
operatively incorporated into a radar object detection printed
circuit assembly (PCA) 11, the PCA 11 having exterior PCA face 17
and beam face 18, with x-y-z Cartesian coordinate's axes--the
x-axis points generally/approximately towards the front of the
vehicle (front-to-back), the y-axis points generally/approximately
perpendicularly out from and into the body of the vehicle
(left-side-to-right-side), and the z-axis points
generally/approximately perpendicularly up to the sky and down to
the ground (up-and-down).
[0064] The use of "generally" and/or "approximately" herein to
describe the axes will be understood to indicate the general
orientation of the axes, without limiting each axis of the
vehicle/trailer or the radar object-detection package to only a
single location. This is especially important in this disclosure
that focuses on observing/measuring/determining a radar
object-detection sensor's actual, as-mounted position relative to a
vehicle/trailer for calibration, and, after calibration, the
sensor's actual in-operation position at any given time during
continued operation wherein the dynamic driving of the
vehicle/trailer, road conditions, and changing sensor package and
vehicle/trailer condition (such as resulting from impact, damage,
or wear) may change the position of the sensor relative to
vehicle/trailer, gravity, the ground, and the driving direction,
for example. As the position of the radar sensor and the direction
of the radar signals are key factors in the accuracy of the
detection signals, these methods may greatly enhance the accuracy
of radar object-detection, by allowing compensation for mounting
errors and undesirable dynamic motions, and/or by allowing
mitigation or at least the sending of alerts regarding equipment
problems.
[0065] Further, as schematically shown in FIG. 2, the IMU face 16,
PCA face 17, and beam face 18, may be understood to all be
co-planar, or parallel and very close to each other so as to be
nearly co-planar, and, therefore, the terms "exterior face" or
"radar sensor face" or "beam face" are used herein to represent a
plane/face from which radar waves are emitted and to which
radar-return-waves/signals are received, and from which same
plane/face (the same "exterior face" or "radar sensor face" or
"beam face") the IMU incorporated into the PCA will observe (or
determine, measure, or sense) during embodiments of the
herein-disclosed calibration and continuing radar object detection
operation. While the radar object-detection sensor package will
typically have a housing for protection of the PCA and other
components, the outer surface of the housing will be slightly
outward from the PCA and is not the "plane/face" described herein.
Therefore, in the figures, the radar object-detection sensor
package is portrayed schematically as an elongated rectangular box
not showing any housing, and the outer side (outer-left in the
left-side-mounting of FIG. 2, or outer-right in the
right-side-mounting of FIGS. 3-5A) of that schematic box is the
"exterior face" or "radar sensor face" or "beam face".
[0066] Radar object-detection sensor package 10 may be attached
both to the left and right sides of the vehicle, with the
right-side package (also "unit") being a mirror image of the left
side package ("unit") pictured in FIG. 2. Also, for tractor-truck
and trailer vehicle combinations, sensor package 10 may be placed
on one or both sides of either, and near the front or back of, the
tractor-truck or trailer.
[0067] In the schematic side view of FIG. 3, a tractor-truck 22
pulling a trailer 24 has radar object-detection sensor package 26,
similar or the same as package 10 of FIG. 2, attached to the front
right lower side surface 25 of the trailer 24.
[0068] In the schematic top view of FIG. 3 depicted as FIG. 4,
tractor-truck 22, trailer 24 and radar object-detection sensor
package 26 are shown also. In both FIGS. 3 and 4, the relevant
Cartesian axes x-z for the side view and x-y for the top view are
shown, as well as a bold arrow 23 showing the go-ahead movement
direction of vehicle 20 generally along the x-axis. For calibration
of angle alpha (.alpha.), the go-ahead movement direction (23) is
preferably straight with no turning and no movement in the y-axis
direction.
[0069] In the enlarged detail view FIG. 4A, radar object-detection
package 26A has exterior face 28, there being an offset angle
.alpha. between exterior face 28 of package 26A and arrow 30, which
is understood to be the straight, go-ahead movement direction 23
along the x-axis of vehicle 20, and, if the side wall 25 is planar
and parallel to direction 23, also it may also be thought of as the
x-axis of the outer wall 25 of trailer 24 where the package 26A is
mounted. Angle a may be called a first offset angle and may be
described as rotation around axis Z that has moved the package
exterior face 28 away from being perfectly parallel to the x-axis
of the vehicle/trailer, frequently as a result of mounting error
that places the exterior face 28 at an angle, rather than parallel,
to the side surface 25.
[0070] Angle alpha (.alpha.) may be described as an angle observed
(or determined, measured, or sensed) between: 1) the observed
position of radar sensor face or "exterior face 28" of the radar
object detection package, and 2) the go-ahead movement direction of
the vehicle/trailer 23. In other words, said observing of the angle
alpha (.alpha.) is preferably done by observing (or determining,
measuring, or sensing) and comparing the x-axis of the radar sensor
face and the x-axis of the vehicle/trailer straight forward or
rearward movement.
[0071] The direction 23 of the vehicle/trailer, the side surface
25, and the x-axis of the exterior face 28 should all be parallel
if the package 26 is mounted perfectly to a perfectly flat, planar
surface 25 that is perfectly parallel to the x-axis of the
vehicle/trailer, and, if this is the case, the observed x-axis
would result in a calibration offset angle alpha (.alpha.) of 0
degrees. But, given that such perfect conditions frequently do not
exist or happen, observing the x-axis of the calibration according
to embodiments disclosed herein will allow the imperfections to be
accounted for during radar object detection operation of the
imperfectly mounted package 26, and/or after the mounted package 10
is loosened from the side surface 25 due to long use, or the
package or vehicle/trailer side surface is impacted, damaged, or
worn. Even if a package 10 is well-mounted to a flat, planar side
surface, the imperfections often inherent in manual installations
are expected to result in certain embodiments in a calibration
offset angle alpha (.alpha.) of up to 2 degrees, for example, or,
in a superior installation, up to 1 degree for example, which could
result in significant errors in object detection. In less accurate
installations, or in said loosened, impacted, damaged, or worn
situations, the calibration offset angle alpha (.alpha.) may be
larger, and may be so large as to deserve an error alarm that calls
for reinstallation or repair.
[0072] In the rear view of FIG. 5 of the vehicle 20, trailer 24
depicted in FIGS. 3, 4 and 4A, and radar object-detection sensor
package 26 is shown attached to the outer wall 25 of trailer
24.
[0073] In the enlarged detail view of FIG. 5A of the rear view
depicted in FIG. 5, radar object-detection sensor package 26B is
shown as being installed at an angle .beta. from the vertical line
32, which represents 1) the direction of gravitational force; 2)
because the calibration is preferably done with the vehicle/trailer
parked on flat ground or surface, the z-axis of the
vehicle/trailer; and 3) if the side surface 25 is planar and
parallel to the z-axis of the vehicle/trailer, the side surface 25.
Angle .beta. may be called a second offset angle, and may be
described as rotation around axis X, which has moved the package
exterior face 28 away from being perfectly parallel to the Z-axis
of the vehicle/trailer, frequently as a result of mounting error
that places the exterior face 28 at an angle, rather than parallel,
to the side surface 25.
[0074] Angle beta (.beta.) may be described as an angle observed
(or determined, measured, or sensed) angle between: 1) the radar
sensor face or "exterior face 28" of the radar object detection
package/unit, and 2) the gravitational direction of the earth's
gravitational field and/or the up and down, z-axis of
vehicle/trailer when the vehicle is on a flat surface. Said
observing of the angle beta (.beta.) is preferably done by
observing (or determining, measuring, or sensing) and comparing the
z-axis of the radar sensor face and the gravitation field direction
and/or z-axis of the vehicle/trailer when the vehicle/trailer is
parked on flat ground and so the z-axis of the vehicle/trailer and
the gravitational field should be the same or extremely close to
the same.
[0075] Similarly as described above for the first offset angle
alpha (.alpha.), the z-axis of the vehicle/trailer, the side
surface 25, and the z-axis of the exterior face 28 should all be
parallel if the package 26 is mounted perfectly to a perfectly
flat, planar surface 25 that is perfectly parallel to the z-axis of
the vehicle/trailer, and, if this is the case, the calibration
offset angle beta (.beta.) would be 0 degrees. But, given
imperfections of mounting error, loosening, impact, damage or wear,
as discussed above, calibration for beta (.beta.), preferably in
addition to calibration for alpha (.alpha.), according to
embodiments disclosed herein, will allow the imperfections to be
accounted for during radar object detection operation of the
package 26. Said mounting imperfections are expected to result in
certain embodiments in a calibration offset angle beta (.beta.) of
up to 2 degrees, for example, or, in a superior installation, up to
1 degree, which may result in significant errors in object
detection. And, also as discussed above, less accurate
installations, or in said loosened, impacted, damaged, or worn
situations, the calibration offset angle beta (.beta.) may be
larger, and may be so large as to deserve an error alarm that calls
for reinstallation or repair.
[0076] It may be noted that certain embodiments may include
calibration for mounting error caused by installing the package 26
in a position that is rotated around the y-axis. However, due to
the preferred box-like shape of certain embodiments of the radar
package/unit and the ability of personal to put a level on the top
surface of the package/unit to prevent it from said rotation around
the y-axis, such a mounting error, if any, is typically small.
[0077] In the schematic flow chart diagram of FIG. 6, there are
depicted the steps of certain embodiments to initially calibrate
angle .alpha., the first offset angle.
[0078] In the schematic flow chart diagram of FIG. 7, there are
depicted the steps of certain embodiments to initially calibrate
angle .beta., the second offset angle.
[0079] In the schematic flow chart diagram of FIG. 8, there is
depicted one embodiment for utilizing the disclosed apparatus and
methods, after calibration, as part of ongoing radar objection
detection. Thus, FIG. 8 shows one embodiment of steps according to
the invention that may be included as a feature/portion of an
ongoing radar object detection process such as that in FIG. 1, for
example. FIG. 8 illustrates steps, ongoing after calibration,
include the continued verification of vehicle/trailer direction,
continued measurement of sensor angle alpha (.alpha.) and sensor
angle beta (.beta.) and comparison of the newly-measured sensor
angles to the respective sensor angles expected from the
calibration according to the presently-disclosed technology, and
determining whether the comparison is within normal tolerances or
whether compensation should be applied to the target detection
signals/data or whether an alarm/error is warranted. It should be
noted that, the alpha angles indicate angles of the sensor face
resulting from rotation around the z-axis, and the beta angles
indicate angles of the sensor face resulting from rotation around
the x-axis. In certain embodiments of ongoing operation such as
schematically represented in FIG. 8, the alpha and beta angles may
be observed using different apparatus/methods compared to the
apparatus/methods in calibration, for example, different IMU
components compared to those listed herein for calibration.
[0080] Although this disclosed technology has been described above
with reference to particular means, materials, and embodiments of
apparatus and methods, it is to be understood that the
presently-disclosed technology is not limited to these disclosed
particulars, but extends instead to all equivalents within the
broad scope of this disclosure, and the Figures and Claims
herein.
* * * * *
References