Probabilistic surface characterization for safe landing hazard detection and avoidance (HDA)

• US 9,141,113 B1
• Filed: 04/26/2012
• Issued: 09/22/2015
• Est. Priority Date: 04/26/2012
• Status: Active Grant

• Current Assignee: United states of america as represented by the administration of the national aeronauties and space admiinistration (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Ivanov, Tonislav I., Huertas, Andres, Johnson, Andrew E.
• Primary Examiner(s): O'Hara, Brian M
• Application Number:
  US13/456,451
• Time in Patent Office: 1,244 Days
• US Class Current: 1/1
• CPC Class Codes: B64G 1/00 Cosmonautic vehicles
• CPC Class Codes: B64G 1/62 Systems for re-entry into the earth's atmosphere; Retarding or landing devices
• CPC Class Codes: G01S 13/935 for terrain-avoidance
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G05D 1/0676 specially adapted for landing

Abstract

Apparatuses, systems, computer programs and methods for performing hazard detection and avoidance for landing vehicles are provided. Hazard assessment takes into consideration the geometry of the lander. Safety probabilities are computed for a plurality of pixels in a digital elevation map. The safety probabilities are combined for pixels associated with one or more aim points and orientations. A worst case probability value is assigned to each of the one or more aim points and orientations.

Claims

1. An apparatus configured to implement probabilistic hazard detection and avoidance for landing a craft, comprising:

a processor and memory for storing digital elevation map data for one or more potential landing sites and computer program instructions, wherein the computer program instructions are configured to cause the processor to;

assign one or more of a plurality of pixels of said digital elevation map to be one or more landing aim points for the landing craft,

compute a probability of safe touchdown for one or more of said landing aim points and one or more orientation of the landing craft, said probability of safe touchdown based on measured roughness of pixels surrounding the landing aim point and the orientation of the landing craft; and

assign a worst case probability value to each of the one or more landing aim points, the worst case probability value being the smallest value of said probability of safe touchdown.

2. The apparatus of claim 1, wherein the computer program instructions are further configured to cause the processor to:

assign the probability of safe touchdown to one or more landing sites comprising multitude adjacent landing aim points.

3. The apparatus of claim 2, wherein the probability of safe touchdown are computed using a two-dimensional Gaussian kernel and recorded in a probability of safety map.

4. The apparatus of claim 1, wherein landing craft geometry and mechanical hazard tolerances are taken into account in computing the probability of safe touchdown.

5. The apparatus of claim 1, wherein the probability of safe touchdown around the one or more landing aim points are weighted by a probability of deviation due to navigation error to produce a final safety score for a current trajectory.

6. The apparatus of claim 1, wherein the computer program instructions are further configured to cause the processor to:

output one or more safe landing sites based on the worst case probability values assigned to the one or more landing aim points to a visual display device for review by a pilot or controller.

7. The apparatus of claim 6, wherein the one or more safe landing sites are displayed in ascending or descending order based on relative safety.

8. The apparatus of claim 1, wherein the computer program instructions are further configured to cause the processor to:

engage flight control systems to direct a vehicle comprising the apparatus to one or more safe landing sites based on the worst case probability values assigned to the one or more landing aim points.

9. The apparatus of claim 8, wherein the computer program instructions are further configured to cause the processor to engage the flight control systems to direct the vehicle to the safest landing site.

10. The apparatus of claim 1, wherein the probability of safe touchdown are computed for every possible orientation, and a smallest probability is taken and used as the worst case probability value for each respective landing aim point.