U.S. patent application number 12/016405 was filed with the patent office on 2008-05-15 for apparatus for creating a navigation map.
Invention is credited to Philipp Harald Nagel.
Application Number | 20080114540 12/016405 |
Document ID | / |
Family ID | 7662440 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080114540 |
Kind Code |
A1 |
Nagel; Philipp Harald |
May 15, 2008 |
APPARATUS FOR CREATING A NAVIGATION MAP
Abstract
To display a navigation map for a navigation device more
accurately and realistically and with less memory capacity, roads,
railroad lines, rivers, lakes, and similar cartographic parameters
are composed not of straight lines but of Cornu spirals. A Cornu
spiral is defined by its curvature and its length.
Inventors: |
Nagel; Philipp Harald;
(Seevetal, DE) |
Correspondence
Address: |
Patrick J. O'Shea, Esq.;Samuels, Gauthier & Stevens, LLP
Suite 3300
225 Franklin Street
Boston
MA
02110
US
|
Family ID: |
7662440 |
Appl. No.: |
12/016405 |
Filed: |
January 18, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10037303 |
Nov 7, 2001 |
7324895 |
|
|
12016405 |
Jan 18, 2008 |
|
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Current U.S.
Class: |
701/532 |
Current CPC
Class: |
G01C 21/32 20130101;
G09B 29/007 20130101; G06T 11/203 20130101 |
Class at
Publication: |
701/208 |
International
Class: |
G01C 21/32 20060101
G01C021/32 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2000 |
DE |
100 55 156.4 |
Claims
1. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and a navigation
processing unit that receives the sensor data, and requests map
data from the navigation map data memory associated with the sensor
data, and computes the map image from the map data, where terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral, where the Cornu spiral is of the
form l=Ka.sup.2, where l is indicative of arc length and K is
indicative of curvature.
2. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and a navigation
processing unit that receives the sensor data, and requests map
data from the navigation map data memory associated with the sensor
data, and computes the map image from the map data, where terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral, where the navigation map data
memory includes coordinates of the unit Cornu spiral stored in a
table, from which the Cornu spirals of the navigation map are
derived.
3. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and a navigation
processing unit that receives the sensor data, and requests map
data from the navigation map data memory associated with the sensor
data, and computes the map image from the map data, where terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral, where the navigation map data
memory includes coordinates of the unit Cornu spiral stored in a
table, from which the Cornu spirals of the navigation map are
derived for roads, railroad lines, rivers, lakes, and similar
cartographic parameters defined as Cornu spirals.
4. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and means for
receiving the sensor data, for requesting map data from the
navigation map data memory associated with the sensor data, and for
computing the map image from the map data, where the means for
computing computes the map image using Cornu spiral polynomial
coefficients stored in the navigation map data memory, and terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral and the Cornu spiral is of the form
l=Ka.sup.2, where l is indicative of arc length and K is indicative
of curvature.
5. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and means for
receiving the sensor data, for requesting map data from the
navigation map data memory associated with the sensor data, and for
computing the map image from the map data, where the means for
computing computes the map image using Cornu spiral polynomial
coefficients stored in the navigation map data memory, and terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral and the navigation map data memory
includes coordinates of the unit Cornu spiral stored in a table,
from which the Cornu spirals of the navigation map are derived.
6. A vehicle navigation system that receives sensor data from a
plurality of sensors, and provides a map image that is presented on
a display, the system comprising: a navigation map data memory that
includes map data indicative of roadways stored in Cornu spiral
form and data indicative of a unit Cornu spiral; and means for
receiving the sensor data, for requesting map data from the
navigation map data memory associated with the sensor data, and for
computing the map image from the map data, where the means for
computing computes the map image using Cornu spiral polynomial
coefficients stored in the navigation map data memory, and terms of
polynomials of the unit Cornu spiral are stored in the navigation
map data memory and the map image is computed using the terms of
polynomials of the unit Cornu spiral, where the terms of
polynomials are associated with Taylor series expressions
indicative of the Cornu spiral and the navigation map data memory
includes coordinates of the unit Cornu spiral stored in a table,
from which the Cornu spirals of the navigation map are derived for
roads, railroad lines, rivers, lakes, and similar cartographic
parameters defined as Cornu spirals.
Description
PRIORITY INFORMATION
[0001] This application is a continuation of co-pending Ser. No.
10/037,303 filed Nov. 7, 2001.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the field of navigation
systems, and in particular to a vehicle navigation system that
stores map data using Cornu spiral data.
[0003] Conventional navigation systems typically represent roads
and rivers to be displayed on a navigation system display unit as
straight lines. However, this type of simplified cartographic
reproduction has a number of disadvantages. For example, roads and
rivers are not straight lines. As a result, a navigation map
displayed on the navigation system display unit does not accurately
represent the features of roads and rivers. In an attempt to more
accurately represent roads and rivers, the number of straight line
segments used to define the roads and rivers can be increased.
However, this leads to a large increase in the amount of data that
must be stored to accurately represent features such as roads,
rivers and railroad lines.
[0004] Therefore, there is a need for a navigation system that
accurately models and displays information indicative of features
such as for example roads and rivers without requiring large
amounts of memory.
SUMMARY OF THE INVENTION
[0005] Briefly, according to an aspect of the present invention, a
vehicle navigation system includes navigation map data memory
comprising map data composed of Cornu spirals indicative of
cartographic features such as roads, railroad lines, rivers and
lakes.
[0006] Rather than representing roads, railroad lines, rivers, and
similar cartographic parameters by a sequence of straight lines,
the present invention specifies that these cartographic parameters
are provided as Cornu spirals.
[0007] In one embodiment, a vehicle navigation system that receives
sensor data from a plurality of sensors, and provides a map image
that is presented on a display, includes a navigation map data
memory that includes map data indicative of roadways stored in
Cornu spiral form. The system also includes a navigation processing
unit that receives the sensor data, and requests map data from the
navigation map data memory associated with the sensor data, and
computes the map image from the map data.
[0008] Advantageously, the amount of memory required to store the
parameters of the navigation map is reduced, while the accuracy of
the navigation map is increased.
[0009] These and other objects, features and advantages of the
present invention will become more apparent in light of the
following detailed description of preferred embodiments thereof, as
illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIG. 1 is a pictorial illustration of a road in Cornu spiral
representation;
[0011] FIG. 2 is a block diagram illustration of a vehicle
navigation system comprising a navigation map memory device that
includes map data stored as Cornu spiral representations;
[0012] FIG. 3 is a pictorial illustration of the same road
illustrated in FIG. 1, but represented by the prior art technique
of straight line segments.
DETAILED DESCRIPTION OF THE INVENTION
[0013] FIG. 1 is a pictorial illustration of a road 10 in Cornu
spiral representation. A Cornu spiral is defined as a curve whose
curvature is proportional to its arc length. A Cornu spiral can be
calculated by the following formula: l=Ka.sup.2 EQ. 1 where l
represents the arc length and K the curvature. In parameter form,
the equations of a Cornu spiral can be expressed as coordinates as
follows: x = a .times. .pi. .times. .intg. .tau. = 0 t .times. cos
.function. ( .pi. 2 .times. .tau. 2 ) .times. d .tau. EQ . .times.
2 y = a .times. .pi. .times. .intg. .tau. = 0 t .times. sin
.function. ( .pi. 2 .times. .tau. 2 ) .times. d .tau. .times.
.times. with .times. .times. t = l a .times. .pi. EQ . .times. 3
##EQU1## Since these integrals cannot easily be solved, an
embodiment of the invention makes use of a Taylor series
development, which can be expressed as follows: X k .function. ( t
) = a .times. .pi. .times. ( 1 0 ! .times. .pi. 0 2 0 .times. 1 1
.times. t 1 - 1 2 ! .times. .pi. 2 2 2 .times. 1 5 .times. t 5 + 1
4 ! .times. .pi. 4 2 4 .times. 1 9 .times. t 9 - 1 6 ! .times. .pi.
6 2 6 .times. 1 13 .times. t 13 + .times. ) .times. .times. and EQ
. .times. 4 Y k .function. ( t ) = a .times. .pi. .times. ( 1 1 !
.times. .pi. 1 2 1 .times. 1 3 .times. t 3 - 1 3 ! .times. .pi. 3 2
3 .times. 1 7 .times. t 7 + 1 5 ! .times. .pi. 5 2 5 .times. 1 11
.times. t 11 - 1 7 ! .times. .pi. 7 2 7 .times. 1 15 .times. t 15 +
.times. ) EQ . .times. 5 ##EQU2## The series is truncated after a
given term, so that a polynomial remains. The terms of the
polynomials are preferably stored in a table.
[0014] Since all Cornu spirals are similar, there exists a unit
Cornu spiral with parameter value a that is equal to one (i.e.,
a=1). In a preferred embodiment, the terms of the polynomials of
the unit Cornu spiral are stored in a table and the actual Cornu
spirals are calculated from these values. The coordinates of the
unit Cornu spiral are stored in a table and the actual Cornu
spirals are calculated from these values.
[0015] Compared to the conventional representation of roads by
sequential straight lines, the present inventive provides a number
of advantages. For example, the accuracy of the image is
substantially increased, because an exact position exists not only
at the points where two straight lines join, but rather over the
course of the curve. The reproduction of roads, rivers, and the
like is much more realistic. In addition, the representation of the
indicated cartographic parameters by Cornu spirals requires fewer
parameters than the prior art technique of using sequential
straight lines. This saves considerable storage space in a
navigation device that creates the inventive navigation map.
[0016] Because a navigation map with a Cornu spiral representation
reproduces the actual pattern of roads and the like much more
accurately than a representation with sequential straight lines,
locations can be determined much better. Thus, for example, the
route of a traveled road, measured by sensors, can be recovered
more easily in a navigation map with a Cornu spiral representation,
because the parameters can be calculated over the entire course of
the curve.
[0017] A navigation map in Cornu spiral representation is suited
both for navigation and for display. Consequently, a navigation
device that creates the inventive navigation map no longer needs
two navigation maps, as is the case in prior art systems. That is,
in the prior art one of these two navigation maps is used for
navigation, while the other is used for display.
[0018] Predictive route data describe the future route, for example
for the next one to two kilometers. With a representation by Cornu
spirals, predictive route data, for example, can be taken directly
from the navigation map and are not required to be calculated
online, which saves computing time.
[0019] In Germany, and also in other countries where geography
permits, roads are constructed as Cornu spirals for the sake of
higher traffic safety. As a result, the inventive representation of
Cornu spirals is thus especially realistic. The quality of this
representation approaches that of an aerial photograph.
[0020] FIG. 2 is a block diagram illustration of a vehicle
navigation system 20 comprising a navigation map memory device 22
that includes map data stored as Cornu spiral representations. The
navigation system 20 also includes a navigation processing unit 24
that receives data from a plurality of sensors 26-28 and input
commands from a user input interface 30. The components may be
connected via a MOST bus. The system 20 also includes a display 32,
which is used to display the navigation map and other navigation
information. Significantly, the navigation map data memory 22
includes map data stored as Cornu spiral data.
[0021] FIG. 3 is a pictorial illustration of the prior art
technique for representing the same road as illustrated in FIG. 1.
Specifically, a section of a road 40 is represented by five
straight lines 41-44 and six points 46-51. In contrast, the same
road illustrated in FIG. 1 is represented by two Cornu spirals
62-63 and three points 64-66. Despite using only two Cornu spirals
and three points, the inventive representation illustrated in FIG.
1 is more accurate and realistic than the prior art representation
with five straight lines and six points as shown in FIG. 3. The six
points 46-51 illustrated in FIG. 3 require six x-coordinates and
six y-coordinates, for a total of twelve coordinates. In contrast,
referring to FIG. 1, the technique of the present invention
requires the x- and y-coordinates of three points and the curvature
K for the three points 64-66, for a total of nine coordinates.
[0022] Although the present invention has been shown and described
with respect to several preferred embodiments thereof, various
changes, omissions and additions to the form and detail thereof,
may be made therein, without departing from the spirit and scope of
the invention.
* * * * *