CA2255115C - Method and device for determining correction parameters - Google Patents
Method and device for determining correction parameters Download PDFInfo
- Publication number
- CA2255115C CA2255115C CA002255115A CA2255115A CA2255115C CA 2255115 C CA2255115 C CA 2255115C CA 002255115 A CA002255115 A CA 002255115A CA 2255115 A CA2255115 A CA 2255115A CA 2255115 C CA2255115 C CA 2255115C
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- CA
- Canada
- Prior art keywords
- vehicle
- correction parameters
- azimuth
- values
- elevation
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- Expired - Fee Related
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/26—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network
- G01C21/28—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network with correlation of data from several navigational instruments
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C17/00—Compasses; Devices for ascertaining true or magnetic north for navigation or surveying purposes
- G01C17/38—Testing, calibrating, or compensating of compasses
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- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Navigation (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Stereophonic System (AREA)
- Gyroscopes (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention relates to a method for determining correction parameters for the measured values of a magnetic compass, which is built into a land craft for navigation purposes, and gives the azimuth a of the direction of motion of the vehicle; of a gradiometer giving the elevation e of the direction of motion of the vehicle in relation to the horizon; and of an odometer, giving the distance s travelled. In this method, two visually navigated test drives are carried out in different directions between known point of departure and arrival. The measured values (a, e, s) are replaced by corrected values (a', e', s') in accordance with the following: a' = a + A + B . sin a + C . cos a; e' = e - A2; S' = p. The correction parameters are determined by performing a vectorial comparison of the known direction and distance values (a', e', s') with the measured values. The correction parameters are as follows: A for declination and compass mounting errors in azimuth; B, C for hard and soft magnetic vehicle magnetism; A2 for mounting errors of the gradiometer in elevation; and p for a scale error of the odometer.
Description
Method and Device for Determining Correction Parameters Field of the Invention The invention is related to a method for determining correction parameters for the measured values of land craft magnetic compass, gradiometer, and odometer.
Rebated Art When navigating a land vehicle by means of an electronic compass for indicating the azimuth, a gradiometer for indicating the elevation or height, and an odometer for indicating the distance, errors occur in terms of the calculated position. The reasons are as follows:
- the difference between magnetic north and the grid north of the map used for navigation, - the geometric differences bet~rveen mounting direction of the compass or gradiometer and the direction of vehicle travel, - soft and hard magnetic effects of the vehicle on the compass, and - scale errors when measuring distance by means of the odometer.
For navigation; the direction of vehi~;le travel, expressed in coordinates of the grid north system, is used, which is additionally twisted horizontally about the declination in reference to the magnetic north system. The declination can be found in the tables. However, a t,~rn of the compass coordinate system , whose direction is unknown, is superimposed to it in relation to the direction of vehicle travel.
In case of a land vehicle, the direction of vehicle travel is not given from the start by the geometrical or optical construction in terms of the vehicle chassis, and it cannot be easily calculated according to the manufacturer's specifications. It can only be determined empirically from the difference between actual and calculated direction of travel.
From DE 4.1 25 369 A1, a navigational system mounted on a motor vehicle is known which contains an earth magnetism sensor as an azimuth sensor. To compensate for nil reports of this sensor due to the effect of a magnetic environment, a comparison with additionally obtained GPS [global positioning system] navigation data is provided. However, this can serve only to correct a zero point shift of the coordinate system.
In DE 31 41 439 A1, an azimuth determination device is described with which the vehicle is aligned exactly to north and east by means of an azimuth sensor mounted on the vehicle. The deviation detected from the two-component measuring signals of the azimuth sensor in comparison with the given direction is compensated for by adjusting the measuring signals with an adjustment circuit. Thus, the distortion of the output signals based on the residual magnetism is also corrected by means of zero point shift.
The effects of the wrong alignment of a magnetic compass in terms of the direction of travel and of hard and soft magnetic fields on the reading accuracy are known from marine applications. To compensate the deviation of the compass, coefficients A, B, C, D, E are defined and determined separately. For example, A takes a constant nil report into account by mounting the compass twisted in the longitudinal direction of the ship, B takes into account the effect of the ship's longitudinal magnetism, C the effect of the athwartship magnetism, D the effect of magnetism induced in soft-iron parts, and E an asymmetry of distribution of iron masses in the ship's hull (A. Heine: Kompaf3 ABC [Compass ABC], published by Verlag Klasing + Co., 1983, pages 43-45).
Since the D and E effects are usually smaller, their coefficients are neglected as a rule.
To determine the coefficients, the ship is held at known courses to north, east, south and west, and the respective deviation of the compass reading from the known courses is observed. The individual coefficients are calculated from the mean of the deviation values in comparison with the selected courses.
The deviations from the distances plotted on the map, which in the case of land navigation result from an inaccurate measuring of the distance, do not play a role in marine applications. However, for the autonomous navigation of land vehicles it is necessary to equip the vehicles not only with a magnetic - _,, compass for measuring the direction, but also with an odometer for measuring the distance and with a gradiometer, which allows the conversion of distances measured in uphill or downhill travel into values that correspond to the map level.
To calibrate the compass reading, it is customary to drive in a circle and to record measured values at several defined angular positions in relation to the centre of the circle. In some cases, the magnetic bearing indication for the horizontal planes is obtained with incline sensors. In a digital magnetic compass (DMC) made by the firm of Leica AG in Heerbrugg, Switzerland, not only three magnetic-field sensors for the three space coordinates, but also two incline sensors for elevation and tank are integrated. Distance measuring, which together with directional measuring results in the position of the vehicle, .
can be verified and if need be corrected by means of independently obtained satellite navigation signals (GPS). Direction measuring, distance measuring and position measuring are treated as separate independent systems (Information brochure published by the firm of KVH Industries, Inc., USA, 1995, TACNAV
. System).
Backctround of the Invention Object of the invention is to create a simple method with which the correction parameters for the readings of integrated measuring devices for azimuth, elevation and distance can be dE;termined in a land vehicle; achieving a considerably increased accuracy in navigation and m-aki~ng a GPS review unnecessary.
For the evaluation, it is a special adva stage when the run in both directions is carried out between two points whose geographical coordinates are known.
Summar7i of them Invention The present invention seeks to overcome the disadvantages of the prior art associated with method and device for determining correction parameters.
According to one aspect of the invention, a method for determining correction parameters for measured values of a magnetic compass, which is built into a land vehicle for navigation purposes, and gives the azimuth 'a' of a direction of motion of the vehicle, of a gradiometer giving the elevation 'e' of the direction of motion of the vehicle ir~ relation to. the horizon, and of an odometer giving a distance 's' traveled, an instantaneous direction vector of the vehicle being given by formula 2 where L~ =direction of motion of the vehicle in a horizontal plane and s~=distance interval between two measurement instances 'j' and Q-1), characterized in that a first test drive is carried out with visual navigation from a departure point with known geographical coordinates to a first cestination point also with known geographical coordinates, in that a subsequent test drive with a change in direction is carried out under visual navigation to a second destination point with known geographical coordinates, in that, during the .test drives, the measured values (a~, e~, s~~ are recorded at instances t~ (j=1, . . . N), and corresponding values (a'~, e'~, s'~~ are calculated from the known geographical coordinates, and in that the calculated direction vectors are related to the direction vectors determined by measurement according to:
a'=a+A+B~sin a+C~cos a e,=e-A2 s'=p.s and the correction parameters.
The "Summary of the Invention" ~~oes not necessarily disclose all the inventive features. The inventions may reside in a sub-combination of the disclosed features.
Rebated Art When navigating a land vehicle by means of an electronic compass for indicating the azimuth, a gradiometer for indicating the elevation or height, and an odometer for indicating the distance, errors occur in terms of the calculated position. The reasons are as follows:
- the difference between magnetic north and the grid north of the map used for navigation, - the geometric differences bet~rveen mounting direction of the compass or gradiometer and the direction of vehicle travel, - soft and hard magnetic effects of the vehicle on the compass, and - scale errors when measuring distance by means of the odometer.
For navigation; the direction of vehi~;le travel, expressed in coordinates of the grid north system, is used, which is additionally twisted horizontally about the declination in reference to the magnetic north system. The declination can be found in the tables. However, a t,~rn of the compass coordinate system , whose direction is unknown, is superimposed to it in relation to the direction of vehicle travel.
In case of a land vehicle, the direction of vehicle travel is not given from the start by the geometrical or optical construction in terms of the vehicle chassis, and it cannot be easily calculated according to the manufacturer's specifications. It can only be determined empirically from the difference between actual and calculated direction of travel.
From DE 4.1 25 369 A1, a navigational system mounted on a motor vehicle is known which contains an earth magnetism sensor as an azimuth sensor. To compensate for nil reports of this sensor due to the effect of a magnetic environment, a comparison with additionally obtained GPS [global positioning system] navigation data is provided. However, this can serve only to correct a zero point shift of the coordinate system.
In DE 31 41 439 A1, an azimuth determination device is described with which the vehicle is aligned exactly to north and east by means of an azimuth sensor mounted on the vehicle. The deviation detected from the two-component measuring signals of the azimuth sensor in comparison with the given direction is compensated for by adjusting the measuring signals with an adjustment circuit. Thus, the distortion of the output signals based on the residual magnetism is also corrected by means of zero point shift.
The effects of the wrong alignment of a magnetic compass in terms of the direction of travel and of hard and soft magnetic fields on the reading accuracy are known from marine applications. To compensate the deviation of the compass, coefficients A, B, C, D, E are defined and determined separately. For example, A takes a constant nil report into account by mounting the compass twisted in the longitudinal direction of the ship, B takes into account the effect of the ship's longitudinal magnetism, C the effect of the athwartship magnetism, D the effect of magnetism induced in soft-iron parts, and E an asymmetry of distribution of iron masses in the ship's hull (A. Heine: Kompaf3 ABC [Compass ABC], published by Verlag Klasing + Co., 1983, pages 43-45).
Since the D and E effects are usually smaller, their coefficients are neglected as a rule.
To determine the coefficients, the ship is held at known courses to north, east, south and west, and the respective deviation of the compass reading from the known courses is observed. The individual coefficients are calculated from the mean of the deviation values in comparison with the selected courses.
The deviations from the distances plotted on the map, which in the case of land navigation result from an inaccurate measuring of the distance, do not play a role in marine applications. However, for the autonomous navigation of land vehicles it is necessary to equip the vehicles not only with a magnetic - _,, compass for measuring the direction, but also with an odometer for measuring the distance and with a gradiometer, which allows the conversion of distances measured in uphill or downhill travel into values that correspond to the map level.
To calibrate the compass reading, it is customary to drive in a circle and to record measured values at several defined angular positions in relation to the centre of the circle. In some cases, the magnetic bearing indication for the horizontal planes is obtained with incline sensors. In a digital magnetic compass (DMC) made by the firm of Leica AG in Heerbrugg, Switzerland, not only three magnetic-field sensors for the three space coordinates, but also two incline sensors for elevation and tank are integrated. Distance measuring, which together with directional measuring results in the position of the vehicle, .
can be verified and if need be corrected by means of independently obtained satellite navigation signals (GPS). Direction measuring, distance measuring and position measuring are treated as separate independent systems (Information brochure published by the firm of KVH Industries, Inc., USA, 1995, TACNAV
. System).
Backctround of the Invention Object of the invention is to create a simple method with which the correction parameters for the readings of integrated measuring devices for azimuth, elevation and distance can be dE;termined in a land vehicle; achieving a considerably increased accuracy in navigation and m-aki~ng a GPS review unnecessary.
For the evaluation, it is a special adva stage when the run in both directions is carried out between two points whose geographical coordinates are known.
Summar7i of them Invention The present invention seeks to overcome the disadvantages of the prior art associated with method and device for determining correction parameters.
According to one aspect of the invention, a method for determining correction parameters for measured values of a magnetic compass, which is built into a land vehicle for navigation purposes, and gives the azimuth 'a' of a direction of motion of the vehicle, of a gradiometer giving the elevation 'e' of the direction of motion of the vehicle ir~ relation to. the horizon, and of an odometer giving a distance 's' traveled, an instantaneous direction vector of the vehicle being given by formula 2 where L~ =direction of motion of the vehicle in a horizontal plane and s~=distance interval between two measurement instances 'j' and Q-1), characterized in that a first test drive is carried out with visual navigation from a departure point with known geographical coordinates to a first cestination point also with known geographical coordinates, in that a subsequent test drive with a change in direction is carried out under visual navigation to a second destination point with known geographical coordinates, in that, during the .test drives, the measured values (a~, e~, s~~ are recorded at instances t~ (j=1, . . . N), and corresponding values (a'~, e'~, s'~~ are calculated from the known geographical coordinates, and in that the calculated direction vectors are related to the direction vectors determined by measurement according to:
a'=a+A+B~sin a+C~cos a e,=e-A2 s'=p.s and the correction parameters.
The "Summary of the Invention" ~~oes not necessarily disclose all the inventive features. The inventions may reside in a sub-combination of the disclosed features.
Brief Description of the Drawings In the drawing, the direction of vehicle travel is shown as a vector of the horizontal plane, or map plane, in which Fig. 1 shows azimuth and elevations, and Fig. 2 shows the effect.of an az muth error on the elevation readings.
Detailed Description of the Preferred Embodiments Below, the invention is described by means of an example, whereby azimuth measurement and elevation measurement are performed with a mutually coupled system (17MC).
Starting with the values for azimuth and elevation, the direction of vehicle travel LF is shown as a unit vector in the. horizontal plane and related to magnetic north. Fig. 1 shows the interrelations; where eF is the elevation angle between the actual direction of vehicle travel LF and the horizontal plane, and aF is the azimuth angle between magnetic north and the projection of LF upon the horizontal plane. Multiplying this with the travelled distance SF, the result in general representation is the position in the horizontal plane:
cos eF ~ cos a~
SF ~ LF = SF COS eF ., Sln aF
SIt1 eF
In practice, the resulting position is determined starting from a starting point by adding many interim values L~ , s~; j =1...N. In marine applications, this method is known dead-reckoning navigation. It therefore follows, by neglecting the indices N and F for the achieved position along the direction of vehicle travel in the horizontal plane cos e~ ~ cos a~
jL ds ~ ~L~ -sj = ~ cns ej -sin a~ -s~
o i=~ ~ i=~
sin e~
Detailed Description of the Preferred Embodiments Below, the invention is described by means of an example, whereby azimuth measurement and elevation measurement are performed with a mutually coupled system (17MC).
Starting with the values for azimuth and elevation, the direction of vehicle travel LF is shown as a unit vector in the. horizontal plane and related to magnetic north. Fig. 1 shows the interrelations; where eF is the elevation angle between the actual direction of vehicle travel LF and the horizontal plane, and aF is the azimuth angle between magnetic north and the projection of LF upon the horizontal plane. Multiplying this with the travelled distance SF, the result in general representation is the position in the horizontal plane:
cos eF ~ cos a~
SF ~ LF = SF COS eF ., Sln aF
SIt1 eF
In practice, the resulting position is determined starting from a starting point by adding many interim values L~ , s~; j =1...N. In marine applications, this method is known dead-reckoning navigation. It therefore follows, by neglecting the indices N and F for the achieved position along the direction of vehicle travel in the horizontal plane cos e~ ~ cos a~
jL ds ~ ~L~ -sj = ~ cns ej -sin a~ -s~
o i=~ ~ i=~
sin e~
Other forms of an approximated integration are possible and lie within reach of a person skilled in the art.
Assuming that correct values are available for elevation e, azimuth a and travel s, and that the starting point is known, a precise position can be determined by evaluating the given sum, or an accurate navigation can be achieved by inserting values taken from the map for a and s. In fact, however, the values given by the measuring devices are distorted, as mentioned above and a s shown in Fig. 2.
Elevation a and azimuth a are measured in the coordinate system of the DMC.
Its x axis must correspond to the direction of vehicle travel. Fig, 2 shows the azimuth distortion ~aF of the projection of the direction of vehicle travel LF
in relation to the projection of the x axis and the difference in elevation a of the x axis in relation to elevation eF in the direction of vehicle travel.
According to the invention, the measured values a, e, s are replaced by corrected values a', e', s' according to the following formula:
a' - a + A + B ~ sin a + C ~ cos a e' = e-A2 s' =p~s The parameters take the following into consideration:
A the declination with regard to magnetic north and a compass mounting error in azimuth.
B, C a hard and soft magnetic vehicle magnetism.
A2 a mounting error of the gradiometer in elevation, and p a scale error of the odometer.
Assuming that correct values are available for elevation e, azimuth a and travel s, and that the starting point is known, a precise position can be determined by evaluating the given sum, or an accurate navigation can be achieved by inserting values taken from the map for a and s. In fact, however, the values given by the measuring devices are distorted, as mentioned above and a s shown in Fig. 2.
Elevation a and azimuth a are measured in the coordinate system of the DMC.
Its x axis must correspond to the direction of vehicle travel. Fig, 2 shows the azimuth distortion ~aF of the projection of the direction of vehicle travel LF
in relation to the projection of the x axis and the difference in elevation a of the x axis in relation to elevation eF in the direction of vehicle travel.
According to the invention, the measured values a, e, s are replaced by corrected values a', e', s' according to the following formula:
a' - a + A + B ~ sin a + C ~ cos a e' = e-A2 s' =p~s The parameters take the following into consideration:
A the declination with regard to magnetic north and a compass mounting error in azimuth.
B, C a hard and soft magnetic vehicle magnetism.
A2 a mounting error of the gradiometer in elevation, and p a scale error of the odometer.
According to the invention, the unknown correction parameters are determined in two test runs with visual navigation, where the corrected values a', e' and s' between the start and finish positions are known and the actual values a, e, s are measured. Each test run results in a sufficient number of independent conditional equations according to the measured values for the three space coordinates x, y, z, so that the correction parameters are clearly definable and can be taken into consideration in the measuring system during subsequent runs with instrumental navigation.
It is particularly advantageous to simply reverse the direction in the two test runs. In that case, only two points and their geographic coordinates must be known, and the actual travel difference equals zero, so that the system of the conditional equations is simplified.
When a vehicle is driven only in the plane, gradiometers are unnecessary. This reduces the number of correction parameters and also simplifies the solution of the conditional equations. This specialization does not diminish the inventive idea. The important finding is that the corrected azimuth can be described as indicated and that in the simplest case if two test runs between two known points, all necessary correction parameters can be determined.
It is particularly advantageous to simply reverse the direction in the two test runs. In that case, only two points and their geographic coordinates must be known, and the actual travel difference equals zero, so that the system of the conditional equations is simplified.
When a vehicle is driven only in the plane, gradiometers are unnecessary. This reduces the number of correction parameters and also simplifies the solution of the conditional equations. This specialization does not diminish the inventive idea. The important finding is that the corrected azimuth can be described as indicated and that in the simplest case if two test runs between two known points, all necessary correction parameters can be determined.
Claims (4)
1. Method for determining correction parameters for measured values of a magnetic compass, which is built into a land vehicle for navigation purposes, and gives the azimuth 'a' of a direction of motion of the vehicle, of a gradiometer giving the elevation 'e' of the direction of motion of the vehicle in relation to the horizon, and of an odometer giving a distance 's' traveled; an instantaneous direction vector of the vehicle being given by where L j =direction of motion of the vehicle in a horizontal plane and s j=distance interval between two measurement instances 'j' and (j-1), characterized in that a first test drive is carried out with visual navigation from a departure point with known geographical coordinates to a first destination point also with known geographical coordinates, in that a subsequent test drive with a change in direction is carried out under visual navigation to a second destination point with known geographical coordinates, in that, during the test drives, the measured values (a j, e j, s j) are recorded at instances t j (j=1, . . . N), and corresponding values (a'j, e'j; s'j) are calculated from the known geographical coordinates, and in that the calculated direction vectors are related to the direction vectors determined by measurement according to:
a'=a+A+B-sin a+C-cos a.
e'=e-A2 s'=p-s and the correction parameters A for declination and compass mounting error in azimuth, B, C for hard and soft magnetic magnetism in the vehicle, A2 for mounting errors of the gradiometer in elevation, and p for a scale error of the odometer are determined therefrom.
a'=a+A+B-sin a+C-cos a.
e'=e-A2 s'=p-s and the correction parameters A for declination and compass mounting error in azimuth, B, C for hard and soft magnetic magnetism in the vehicle, A2 for mounting errors of the gradiometer in elevation, and p for a scale error of the odometer are determined therefrom.
2. Method according to claim 1, characterized in that the second test drive takes place from the first destination point back to the departure point.
3. Method according to claim 1, characterized in that the geographical data of the departure point and the destination points are determined using a GPS
measuring system built into the vehicle.
measuring system built into the vehicle.
4. Method according to claim 3, characterized in that, during the test drives, GPS
coordinate determinations are carried out continuously and the accuracy of the GPS
coordinate values is determined as a ratio to the distance traveled s, and the destination point is established on the basis of the ratio obtained.
coordinate determinations are carried out continuously and the accuracy of the GPS
coordinate values is determined as a ratio to the distance traveled s, and the destination point is established on the basis of the ratio obtained.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19704853.6 | 1997-02-10 | ||
| DE19704853A DE19704853C1 (en) | 1997-02-10 | 1997-02-10 | Correction parameter evaluation method for on-board vehicle navigation system |
| PCT/EP1998/000627 WO1998035206A1 (en) | 1997-02-10 | 1998-02-05 | Method and device for determining correction parameters |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2255115A1 CA2255115A1 (en) | 1998-08-13 |
| CA2255115C true CA2255115C (en) | 2006-04-11 |
Family
ID=7819729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002255115A Expired - Fee Related CA2255115C (en) | 1997-02-10 | 1998-02-05 | Method and device for determining correction parameters |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0901609B8 (en) |
| JP (1) | JP3774753B2 (en) |
| KR (1) | KR100550944B1 (en) |
| CN (1) | CN1103910C (en) |
| AT (1) | ATE308028T1 (en) |
| AU (1) | AU723107B2 (en) |
| CA (1) | CA2255115C (en) |
| DE (2) | DE19704853C1 (en) |
| NO (1) | NO324073B1 (en) |
| WO (1) | WO1998035206A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000052661A1 (en) * | 1999-03-02 | 2000-09-08 | Gentex Corporation | Rearview mirror assembly with internally mounted compass sensor |
| JP4698087B2 (en) * | 2001-08-15 | 2011-06-08 | 富士通テン株式会社 | Radar horizontal axis deviation occurrence detection apparatus, axis deviation determination apparatus, and axis deviation correction apparatus |
| GB0329959D0 (en) * | 2003-12-24 | 2004-01-28 | Qinetiq Ltd | Magnetic field sensor |
| KR100809352B1 (en) | 2006-11-16 | 2008-03-05 | 삼성전자주식회사 | Method and apparatus of pose estimation in a mobile robot based on particle filter |
| CN101241009B (en) * | 2007-12-28 | 2010-06-09 | 北京科技大学 | Magneto- electronic compass error compensation method |
| CN105717325A (en) * | 2016-04-15 | 2016-06-29 | 江西中船航海仪器有限公司 | Magnetic azimuth sensor used for wind direction measurement |
| CN107473092B (en) * | 2017-10-10 | 2019-06-14 | 三一海洋重工有限公司 | Suspender swing angle acquisition methods and device and crane are prevented shaking method and device |
| CN109933093A (en) * | 2017-12-18 | 2019-06-25 | 华创车电技术中心股份有限公司 | Automatic following device and automatic following system |
| EP3667355A1 (en) * | 2018-12-12 | 2020-06-17 | Rohde & Schwarz GmbH & Co. KG | Method for radio direction finding, direction finding system as well as platform |
| CN114001752A (en) * | 2021-10-27 | 2022-02-01 | 一汽解放汽车有限公司 | Vehicle gradient sensor calibration method and device, sensor calibration equipment and medium |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2042181B (en) * | 1979-01-24 | 1983-03-23 | Nippon Telegraph & Telephone | Determining positional coordinates utilising the terrestrial magnetism as a directional reference |
| JPS6212976Y2 (en) * | 1980-10-20 | 1987-04-03 | ||
| DE3418081A1 (en) * | 1984-05-16 | 1985-11-21 | Teldix Gmbh, 6900 Heidelberg | LOCATION PROCEDURE FOR VEHICLES, ESPECIALLY FOR AGRICULTURAL VEHICLES |
| EP0392448B1 (en) * | 1989-04-13 | 1992-08-19 | Siemens Aktiengesellschaft | Procedure for the determination of the angular error of a magnetic field sensor |
| DE3937160A1 (en) * | 1989-11-08 | 1991-05-16 | Bosch Gmbh Robert | ELECTRONIC COMPASS WITH INCLINATION CORRECTION |
| JP2664800B2 (en) * | 1990-09-19 | 1997-10-22 | 三菱電機株式会社 | Vehicle navigation system |
-
1997
- 1997-02-10 DE DE19704853A patent/DE19704853C1/en not_active Expired - Fee Related
-
1998
- 1998-02-05 CA CA002255115A patent/CA2255115C/en not_active Expired - Fee Related
- 1998-02-05 DE DE59813132T patent/DE59813132D1/en not_active Expired - Lifetime
- 1998-02-05 WO PCT/EP1998/000627 patent/WO1998035206A1/en active IP Right Grant
- 1998-02-05 AT AT98909395T patent/ATE308028T1/en active
- 1998-02-05 AU AU63947/98A patent/AU723107B2/en not_active Ceased
- 1998-02-05 EP EP98909395A patent/EP0901609B8/en not_active Expired - Lifetime
- 1998-02-05 KR KR1019980708064A patent/KR100550944B1/en not_active IP Right Cessation
- 1998-02-05 JP JP53376098A patent/JP3774753B2/en not_active Expired - Fee Related
- 1998-02-05 CN CN98800118.7A patent/CN1103910C/en not_active Expired - Fee Related
- 1998-10-09 NO NO19984744A patent/NO324073B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001506759A (en) | 2001-05-22 |
| CN1216104A (en) | 1999-05-05 |
| DE59813132D1 (en) | 2005-12-01 |
| AU723107B2 (en) | 2000-08-17 |
| EP0901609B1 (en) | 2005-10-26 |
| NO984744D0 (en) | 1998-10-09 |
| EP0901609A1 (en) | 1999-03-17 |
| AU6394798A (en) | 1998-08-26 |
| JP3774753B2 (en) | 2006-05-17 |
| EP0901609B8 (en) | 2005-12-28 |
| KR20000064880A (en) | 2000-11-06 |
| CA2255115A1 (en) | 1998-08-13 |
| NO324073B1 (en) | 2007-08-06 |
| KR100550944B1 (en) | 2006-05-25 |
| DE19704853C1 (en) | 1998-06-18 |
| ATE308028T1 (en) | 2005-11-15 |
| NO984744L (en) | 1998-11-30 |
| CN1103910C (en) | 2003-03-26 |
| WO1998035206A1 (en) | 1998-08-13 |
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