Methods, apparatuses, and computer programs for estimating the heading of an axis of a rigid body

Patent metadata

Field	Value
Publication number	US-11428823-B2
Application number	US-202016995313-A
Country	US
Kind code	B2
Filing date	Aug 17, 2020
Priority date	Sep 22, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

Methods, apparatuses and computer programs are disclosed for estimating, or at least for generating information usable to estimate, the heading of at least one axis of interest of a rigid body. Rigid body is equipped with an antenna of a navigation satellite system (NSS) receiver, and with sensor equipment comprising sensors such as a gyroscope, an angle sensor, and accelerometers, depending on the form of the invention. Rigid body is subject to a known motion comprising causing a point's horizontal position to change, the point being referred to as “point B”, while keeping another point's position, the point being referred to as “point A”, fixed relative to the Earth. Considering the motion constraint, an estimation of the heading is generated using sensor equipment data and NSS receiver data. The estimation of the heading may for example be used to estimate the position of any point of rigid body.

First claim

The invention claimed is:

1. Method for estimating, or at least for generating information usable to estimate, a heading of at least one axis of interest of a rigid body, wherein the rigid body is equipped with an antenna of a navigation satellite system receiver, hereinafter abbreviated as “NSS receiver”, wherein a phase center of the antenna is located at a point, hereinafter referred to as “point B”, which is away from another point, hereinafter referred to as “point A”, wherein point A is either a point of the rigid body or a point being at a fixed position with respect to the rigid body, and wherein the rigid body is further equipped with sensor equipment comprising at least one of:
a gyroscope, and
an angle sensor,
the method comprising:
subjecting the rigid body to a motion causing point B's horizontal position to change while keeping point A's position fixed relative to the Earth; and
observing, by the NSS receiver, a NSS signal from each of a plurality of NSS satellites during said motion;
wherein the method further comprises the following operations, carried out by at least one of: the NSS receiver, the sensor equipment, and a processing entity capable of receiving data from the NSS receiver and sensor equipment:
estimating an orientation, during said motion, of a body frame of the rigid body with respect to a reference frame based on data from the sensor equipment;
computing at least two coordinates of a velocity vector, in the reference frame, of point B, based on the estimated orientation and on data from the sensor equipment, said velocity vector being hereinafter referred to as “sensor-based velocity vector”; and
based on the at least two coordinates of the sensor-based velocity vector and the NSS signals observed during said motion, at least one of:
generating information usable to estimate the heading of the at least one axis of interest; and
estimating the heading of the at least one axis of interest.

2. Method of claim 1 , wherein estimating the heading of the at least one axis of interest comprises:
computing at least two coordinates of a second velocity vector, in the reference frame or in a further reference frame, of point B, with non-zero horizontal projection of said second velocity vector, based on the NSS signals observed during said motion, said second velocity vector being hereinafter referred to as “NSS-based velocity vector”; and
generating an estimate of the heading of the at least one axis of interest based on the at least two coordinates of the sensor-based velocity vector and the at least two coordinates of the NSS-based velocity vector.

3. Method of claim 1 , wherein estimating the heading of the at least one axis of interest comprises:
computing, for each of at least one of the NSS satellites, a projection of the sensor-based velocity vector in direction of line of sight to the NSS satellite; and
generating an estimate of the heading of the at least one axis of interest based on the at least one computed projection, and the NSS signals observed during said motion.

4. Method according to claim 1 , wherein
the motion causing point B's horizontal position to change while keeping point A's position fixed relative to the Earth comprises a rotation about an Earth-fixed axis passing through point A;
a distance between point B and said Earth-fixed axis is larger than zero and constant; and
the sensor equipment comprises:
two accelerometers arranged for measuring a specific force in direction of two linearly independent axes; and
at least one of:
a gyroscope arranged for measuring an angular rate about said Earth-fixed axis; and
an angle sensor arranged for measuring orientation about said Earth-fixed axis.

5. Method according to claim 1 , wherein:
the motion causing point B's horizontal position to change while keeping point A's position fixed relative to the Earth comprises a rotation about an Earth-fixed axis passing through point A;
a distance between point B and said Earth-fixed axis is larger than zero and constant; and
the sensor equipment comprises an angle sensor arranged for measuring orientation about said Earth-fixed axis.

6. Method according to claim 1 , wherein:
the motion causing point B's horizontal position to change while keeping point A's position fixed relative to the Earth comprises a rotation about a vertical or substantially vertical Earth-fixed axis passing through point A;
a distance between point B and said vertical or substantially vertical Earth-fixed axis is larger than zero and constant; and
the sensor equipment comprises at least one of:
a gyroscope arranged for measuring an angular rate about said vertical or substantially vertical Earth-fixed axis; and
an angle sensor arranged for measuring orientation about said vertical or substantially vertical Earth-fixed axis.

7. Computer program, computer program product, or computer-readable medium comprising computer-readable instructions configured, when executed on a computer, to cause the computer to carry out at least one of the following sets of operations comprising:
estimating the orientation of the body frame, computing at least two coordinates of the sensor-based velocity vector, and generating information usable to estimate the heading, as defined in claim 1 ;
estimating the orientation of the body frame, computing at least two coordinates of the sensor-based velocity vector, and estimating the heading, as defined in claim 1 ;
estimating the orientation of the body frame, computing at least two coordinates of the sensor-based delta-position vector, and generating information usable to estimate the heading;
estimating the orientation of the body frame, computing at least two coordinates of the sensor-based delta-position vector, and estimating the heading;
computing an initial position estimate, and generating information usable to estimate the heading; and
computing an initial position estimate, and estimating the heading.

8. Method according to claim 1 , wherein the sensor equipment comprises:
three gyroscopes arranged for measuring angular rate about three linearly independent axes of the rigid body; and
two accelerometers arranged for measuring a specific force in direction of two linearly independent axes of the rigid body.

9. Method of claim 8 , wherein the sensor equipment comprises:
three gyroscopes arranged for measuring the angular rate about three linearly independent axes of the rigid body; and
three accelerometers arranged for measuring the specific force in direction of three linearly independent axes of the rigid body.

10. Method for estimating, or at least for generating information usable to estimate, a heading of at least one axis of interest of a rigid body, wherein the rigid body is equipped with an antenna of a navigation satellite system receiver, hereinafter abbreviated as “NSS receiver”, wherein a phase center of the antenna is located at a point, hereinafter referred to as “point B”, which is away from another point, hereinafter referred to as “point A”, wherein point A is either a point of the rigid body or a point being at a fixed position with respect to the rigid body, and wherein the rigid body is further equipped with sensor equipment comprising at least one of:
a gyroscope,
an angle sensor, and
two accelerometers,
the method comprising:
subjecting the rigid body to a motion causing point B's horizontal position to change while keeping point A's position fixed relative to the Earth; and
observing, by the NSS receiver, a NSS signal from each of a plurality of NSS satellites during said motion;
wherein the method further comprises the following operations, carried out by at least one of: the NSS receiver,

Assignees

• Trimble Inc

Inventors

• Görcke Lorenz

Classifications

• G01C21/165

  combined with non-inertial navigation instruments · CPC title

• G01S19/49 Primary

  whereby the further system is an inertial position system, e.g. loosely-coupled · CPC title

• G01C19/34

  for indicating a direction in the horizontal plane, e.g. directional gyroscopes · CPC title

• G01C15/06 Primary

  Surveyors' staffs; Movable markers · CPC title