Method and device for determining correction parameters
First Claim
1. Method for determining correction parameters for the measured values of a magnetic compass, which is built into a land vehicle 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 traveled, the instantaneous direction vector of the vehicle being given by ##EQU3## where Lj =direction of motion of the vehicle in the horizontal plane and sj =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 known by its geographical coordinates to a destination point also known by its geographical coordinates,in that a subsequent test drive with a change in direction is carried out under visual navigation to a second destination point known by its geographical coordinates, in that, during the test drives, the measured values aj, ej, sj are recorded at instances tj :
- j=1 . . . N, and the corresponding values a'"'"'j, e'"'"'j, s'"'"'j are calculated from the known coordinates of the departure point and destination point, 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 ae'"'"'=e-A2s'"'"'=ρ
·
sand the correction parametersA 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, andρ
for a scale error of the odometer are determined therefrom.
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Accused Products
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'"'"'=ρ. The correction parameters are determined by performing a vertorial 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 ρ for a scale error of the odometer.
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Citations
4 Claims
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1. Method for determining correction parameters for the measured values of a magnetic compass, which is built into a land vehicle 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 traveled, the instantaneous direction vector of the vehicle being given by ##EQU3## where Lj =direction of motion of the vehicle in the horizontal plane and sj =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 known by its geographical coordinates to a destination point also known by its geographical coordinates,
in that a subsequent test drive with a change in direction is carried out under visual navigation to a second destination point known by its geographical coordinates, in that, during the test drives, the measured values aj, ej, sj are recorded at instances tj : - j=1 . . . N, and the corresponding values a'"'"'j, e'"'"'j, s'"'"'j are calculated from the known coordinates of the departure point and destination point, 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 ae'"'"'=e-A2 s'"'"'=ρ
·
sand 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 ρ
for a scale error of the odometer are determined therefrom. - View Dependent Claims (2, 3, 4)
- j=1 . . . N, and the corresponding values a'"'"'j, e'"'"'j, s'"'"'j are calculated from the known coordinates of the departure point and destination point, and in that the calculated direction vectors are related to the direction vectors determined by measurement according to;
Specification