Leica Geosystems Ag

Safran Vectronix Ag

Vectronix Ag

Silvio Gnepf

Ivo Annen

Frank Dittrich

Peter Nachbaur

Holger Kirschner

Ernst Ramseier

Juerg Weilenmann

Jürg Gees

Optoelectronic measuring device having an electronic magnetic compass and a compensation device assigned to the magnetic compass for compensating device-fixed interference fields and is designed to occupy at least two defined, repeatable operating states and generates a different device-fixed interference field in each of the operating states. The measuring device is designed to occupy at least two defined, repeatable application states, the magnetic compass being exposed to a different external magnetic interference field in each of the application states. The compensation device being designed to measure a first, second and third magnetic field set in a first, second and third overall state of the measuring device, and to determine by means of the processing unit a first, second and third set of parameters based on the first, second and third magnetic field set respectively, and to derive a fourth parameter set based on the first, second and third parameter set.

Optoelectronic measuring device with magnetic compass and compensation functionality

Disclosed is an optoelectronic measuring device having an electronic magnetic compass for determining an azimuthal alignment of the measuring device and a compensation unit, which is associated with the magnetic compass, for compensating for device-fixed interference fields, wherein the measuring device assumes at least two defined, repeatable operating states, has a different device-fixed interference field in each of the operating states, and the compensation unit carries out an initial compensation of the electronic magnetic compass in a first operating state of the measuring device, wherein the compensation unit has a detection unit for detecting a present operating state, a memory unit for storing a magnetic offset resulting from the different device-fixed interference fields between the first and a second operating state of the measuring device, and a computer unit for computing the azimuthal alignment of the measuring device depending on an ascertained operating state and based on the magnetic offset.

Optoelectronic measuring device having magnetic compass and compensation functionality

The invention relates to a method for a field compensation of an electronic compass for influences to a geomagnetic field by magnetic objects in the vicinity of the compass, that is done with acquiring a magnetic field value by a magnetic field sensor and acquiring an inclination with respect to level plane by an accelerometer, in a discrete set of multiple orientations of the compass. Therein, a user guidance for subsequently orienting the compass into a predetermined desired range of orientation is provided to the user. In the following, compensation data are calculated from those magnetic sensor acquisitions to compensate for the influences in such a way, that a magnetic north heading is determinable based on the compensated magnetic field values. Therein, the user guidance for the compensation is done with a gathering of directional information based on rotary rate readings from a gyroscope for an azimuthal component of the orientation.

Digital magnetic compass compensation

The invention relates to a handheld observation device including a digital magnetic compass for measuring a magnetic field direction of a magnetic field present, a gravitation sensor for measuring a gravitational field direction of a gravitational field present, and a control and evaluation unit configured for determining an externally referenced orientation of the observation device depending on a measured magnetic field direction and a measured gravitational field direction and with application of an algorithmic disturbance suppression, for which compensation parameters are stored. The observation device can also include a video tracking system () for recording an image sequence and for deriving orientation changes of the observation device.

Handheld observation device comprising a digital magnetic compass

A north-referenceable goniometer for azimuthal orientation determination of a sighting device has a base, a rotary part, a rotation angle encoder for determining a rotational position of the rotary part about an upright axis, a gyroscope fixed on the rotary part and having a measuring device oriented orthogonally to the upright axis for determining a component of the Earth rotation vector, and an evaluation unit for determining the azimuthal angle of the geographical north pole. The goniometer also includes an acceleration sensor, and the evaluation unit is formed such that, using the evaluation unit, the determined component of the Earth rotation vector is corrected by a sink rate of the goniometer, determined with the aid of the acceleration sensor, and a systematic measurement error of the gyroscope is corrected by determining measurement values of the component of the Earth rotation vector in at least three different rotational positions.

Geographically north-referenced azimuth determination

In a method according to the invention for estimating the accuracy of azimuthal orientations (a) of a measuring device () having an electronic magnetic compass (), a plurality of determinations of an azimuthal orientation (a, a', a&#x2033;, a&#x2032;&#x2033;, a&#x2033;&#x2033;) are carried out, in which the measuring device is aligned with one and the same measuring points at different measuring locations (P, P&#x2032;, P&#x2033;, P&#x2032;&#x2033;, P&#x2033;&#x2033;) adjacent to one another. On the basis of these determined azimuthal orientations (a, a&#x2032;, a&#x2033;, a&#x2032;&#x2033;, a&#x2033;&#x2033;), the value of the accuracy is automatically estimated by the measuring device () by means of a computational method. The adjacent measuring locations (P, P&#x2032;, P&#x2033;, P&#x2032;&#x2033;) are advantageously located one above the other or along a straight line to the measuring point. By means of this method, stationary stray fields of local scale can be detected and the effects thereof on the accuracy can be estimated. Further methods according to the invention are designed in each case specifically for further types of stray fields.

Method for estimating the accuracy of azimuthal orientations and portable sighting device

An arrangement for measuring the direction of the geomagnetic field {right arrow over (B)} , in the proximity of a magnetic jamming device with a magnetic field direction variable as a function of time, which is distinguished by the fact that at least two magnetic field measuring devices are provided, each of which measures all three vector components of the total magnetic field ({right arrow over (B)} ,{right arrow over (B)} ), the magnetic field measuring devices have a position, ({right arrow over (r)} ,{right arrow over (r)} ,{right arrow over (r)} ) which is invariable as a function of time and is fixed relative to one another and relative to the jamming device, and the measured values can be called up synchronously and can be evaluated according to {right arrow over (B)} &equals;({right arrow over (B)} &plus;{right arrow over (B)} )/2&plus;P&middot;({right arrow over (B)} &minus;{right arrow over (B)} ), P({right arrow over (r)} ,{right arrow over (r)} ,{right arrow over (r)} ) describing the geometric position of the magnetic field measuring devices relative to one another and relative to the jamming device.

Geomagnetic field direction measuring system

Process for determining the direction of the earth's magnetic field

Method of stabilizing the horizon of magnetic compasses

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.multidot.sin a+C.multidot.cos a; e'=e-A.sub.2 ; S'=.rho.. 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; A.sub.2 for mounting errors of the gradiometer in elevation; and .rho. for a scale error of the odometer.

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Heerbrugg, Switzerland

Silvio Gnepf