Method for resolving ground level errors in simulations

• US 20080234936A1
• Filed: 09/21/2007
• Published: 09/25/2008
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Appareo Systems LLC (AGCO Corporation)
• Original Assignee: Appareo Systems LLC (AGCO Corporation)
• Inventors: Ohlsen, Tyler Chris, Weinmann, Robert Vincent
• Granted Patent: US 8,116,922 B2
• Time in Patent Office: Days
• US Class Current: 701/217
• CPC Class Codes: G01C 5/00 Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels G01C3/20, G01C3/30 take precedence
• CPC Class Codes: G01C 7/00 Tracing profiles by photogrammetry or videogrammetry G01C11/00
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G09B 25/06 for surveying; for geography, e.g. relief models globes G09B27/00; maps G09B29/00
• CPC Class Codes: G09B 29/12 Relief maps relief models G09B25/06
• CPC Class Codes: G09B 9/02 for teaching control of vehicles or other craft

Abstract

A method for reconciling ground-level discrepancies between the displayed path of a moving body and a terrain model in a graphical simulation, including the steps of (1) examining the individual data points describing a recorded trip by a vehicle, (2) determining which of the data points correspond to points when the vehicle was actually on the ground, (3) determining the altitude difference between the recorded altitude data and the terrain model at each of the determined “on-ground” points, and (4) using the altitude difference to create a correction signal which can be applied either to the recorded altitude data or the terrain model.

Claims

1. A method for resolving errors in a virtual recreation of ground-level activities caused by inaccurate altitude data, comprising the steps of:

acquiring a first set of data points representing a recorded trip of a moving body, wherein each point in said first set of data points comprises information describing an altitude of said moving body at a given point in said recorded trip,

applying an on-ground algorithm to said first set of data points to produce a second set of data points, wherein said second set of data points is a subset of said first set of data points, and wherein all points in said second set of data points correspond to known points in said recorded trip when said moving body was operating on the ground,

determining an altitude difference between said each point in said second set of data points and an altitude of a corresponding elevation point on the surface of a virtual terrain model,

using said altitude difference to generate an altitude correction signal for said each point in said first set of data points, and

applying said altitude correction signal to said altitude of said moving body contained in said each point of said first set of data points.

2. The method of claim 1, wherein said moving body is selected from the group consisting of a fixed-wing aircraft, a rotary-wing aircraft, a glider, a ground vehicle, and a human performer.

3. The method of claim 1, wherein said each point in said first set of data points further comprises the ground speed and vertical speed of said moving body at a given point in said recorded trip.

4. The method of claim 3, wherein said each point in said first set of data points further comprises oscillation frequency, wherein said oscillation frequency describes the frequency of oscillations recorded on said moving body at a given point in said recorded trip.

5. The method of claim 3, wherein said applying said on-ground algorithm step comprises:

eliminating points in said first set of data points wherein said ground speed exceeds a pre-defined ground speed threshold to create a first intermediate set of data points, and

eliminating points in said first intermediate set of data points wherein the absolute value of said vertical speed exceeds a pre-defined vertical speed threshold to create said second set of data points.

6. The method of claim 4, wherein said applying said on-ground algorithm step comprises:

eliminating points in said first set of data points wherein said ground speed exceeds a pre-defined ground speed threshold to create a first intermediate set of data points,

eliminating points in said first intermediate set of data points wherein the absolute value of said vertical speed exceeds a pre-defined vertical speed threshold to create a second intermediate set of data points, and

eliminating points in said second intermediate set of data points wherein said oscillation frequency falls below a pre-defined frequency threshold to create said second set of data points.

7. A method for resolving errors in a virtual recreation of ground-level activities caused by an inaccurate terrain model, comprising the steps of:

acquiring a first set of data points representing a recorded trip of a moving body, wherein each point in said first set of data points comprises information describing an altitude of said moving body at a given point in said recorded trip,

applying an on-ground algorithm to said first set of data points to produce a second set of data points, wherein said second set of data points is a subset of said first set of data points, and wherein all points in said second set of data points correspond to known points in said recorded trip when said moving body was operating on the ground,

determining an altitude difference between said each point in said second set of data points and an altitude of a corresponding elevation point on the surface of a virtual terrain model,

using said altitude difference to generate a terrain correction signal for said each point in said first set of data points, and

applying said terrain correction signal to said surface of said virtual terrain model, wherein said surface of said virtual terrain model is modified accordingly.

8. The method of claim 7, wherein said moving body is selected from the group consisting of a fixed-wing aircraft, a rotary-wing aircraft, a glider, a ground vehicle, and a human performer.

9. The method of claim 7, wherein said each point in said first set of data points further comprises the ground speed and vertical speed of said moving body at a given point in said recorded trip.

10. The method of claim 9, wherein said each point in said first set of data points further comprises oscillation frequency, wherein said oscillation frequency describes the frequency of oscillations recorded on said moving body at a given point in said recorded trip.

11. The method of claim 9, wherein said applying said on-ground algorithm step comprises:

eliminating points in said first set of data points wherein said ground speed exceeds a pre-defined ground speed threshold to create a first intermediate set of data points, and

eliminating points in said first intermediate set of data points wherein the absolute value of said vertical speed exceeds a pre-defined vertical speed threshold to create said second set of data points.

12. The method of claim 10, wherein said applying said on-ground algorithm step comprises:

eliminating points in said first set of data points wherein said ground speed exceeds a pre-defined ground speed threshold to create a first intermediate set of data points,

eliminating points in said first intermediate set of data points wherein the absolute value of said vertical speed exceeds a pre-defined vertical speed threshold to create a second intermediate set of data points, and

eliminating points in said second intermediate set of data points wherein said oscillation frequency falls below a pre-defined frequency threshold to create said second set of data points.