Autonomous Landing and Hazard Avoidance Technology (ALHAT)

Epp, Chirold; Robertson, Edward A.; Brady, Tye

doi:10.1109/aero.2008.4526297

Cited by 79 publications

(41 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Only that comparable to the Lunar Reconnaissance Orbiter (LRO) data, advertised as 1+ meter resolution in the best circumstances, is assumed available for a Sortie location. 4 That being the case, higher resolution data of the landing site, be it from a sensor or just the human eye, would not be available until the Approach and Terminal Descent portion of the descent trajectory when the landing zone is reasonably in view, which then defines when hazard detection and avoidance could begin to occur. Prior to this point in the trajectory, the target is either over the horizon, blocked by the vehicle, or subtends too narrow of an angle of view for any terrain details to be discernable.…”

Section: Figure 1 Altair Descent and Landing Profilementioning

confidence: 99%

“…The ALHAT project has been exploring ideas along this line of reasoning, including a focus beyond passive optics, almost since its inception. 4 Furthermore the Altair Project, though not ruling out the possibility of passive optics including just the use of human vision, has generally acknowledged the difficulties posed with a lunar polar Sortie mission and, as such, has included in its baseline a hazard detection system and has been looking to the ALHAT Project to assist with its definition.…”

Section: Hazard Detection Sensor Conceptsmentioning

confidence: 99%

“…Finally Hazard Relative Navigation is a function that uses a subset of hazards or other surface features identified during final approach as navigation references, allowing the lander to steer to a safe target relative to the features identified in the HDA map. 4 Of these functions, the Altair Project is presently looking to ALHAT only as the source for the HDA function. While the Altair Project is interested in how ALHAT is pursuing the TRN and HRN functions, Altair has other strategies in its baseline for accomplishing these functions.…”

Section: Alhat Integrated Systemmentioning

confidence: 99%

“…While autonomous was in the title, the Project requirements call on the system to support either robotic or crewed missions, where for the latter the system would provide situational awareness at a minimum while also allowing for crew interaction ranging from just a flight manager approving a target to an active pilot using the ALHAT information as a reference. 4 In supporting this charter, the ALHAT system evolved into three basic functions supported by a handful of candidate sensors and software algorithms. Some of these candidate components have now supported flight test while others are in the planning stages.…”

Section: Alhat Integrated Systemmentioning

confidence: 99%

See 3 more Smart Citations

Terrain Hazard Detection and Avoidance during the Descent and Landing Phase of the Altair Mission

Strhan

Johnson

2010

AIAA Guidance, Navigation, and Control Conference

View full text Add to dashboard Cite

This paper describes some of the environmental challenges associated with landing a crewed or robotic vehicle at any certified location on the lunar surface (i.e. not a mountain peak, permanently dark crater floor or overly steep terrain), with a specific focus on how hazard detection technology may be incorporated to mitigate these challenges. For this discussion, the vehicle of interest is the Altair Lunar Lander, being the vehicle element of the NASA Constellation Program aimed at returning humans to t he moon. Lunar environmental challenges for such global lunar access primarily involve terrain and lighting. These would include sizable rocks and slopes, which are more concentrated in highland areas; small craters, which are essentially everywhere independent of terrain type; and for polar regions, low-angle sunlight, which leaves significant terrain in shadow. To address these issues, as well as to provide for precision landing, the Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project was charted by NASA Headquarters, and has since been making significant progress. The ALHAT team considered several sensors for real-time hazard detection, settling on the use of a Flash Lidar mounted to a high-speed gimbal, with computationally intense image processing and elevation interpretation software. The Altair Project has been working with the ALHAT team to understand the capabilities and limitations of their concept, and has incorporated much of the ALHAT hazard detection system into the Altair baseline design. This integration, along with open issues relating to computational performance, the need for system redundancy, and potential pilot interaction, will be explored further in this paper.

show abstract

Section: Figure 1 Altair Descent and Landing Profilementioning

confidence: 99%

Section: Hazard Detection Sensor Conceptsmentioning

confidence: 99%

Section: Alhat Integrated Systemmentioning

confidence: 99%

Section: Alhat Integrated Systemmentioning

confidence: 99%

See 2 more Smart Citations

Terrain Hazard Detection and Avoidance during the Descent and Landing Phase of the Altair Mission

Strhan

Johnson

2010

AIAA Guidance, Navigation, and Control Conference

View full text Add to dashboard Cite

show abstract

“…NASA's autonomous landing and hazard avoidance technology (ALHAT) program is currently developing a guidance, navigation, and control (GNC) system as well as hazard detection and avoidance algorithms for precision lunar landing [20]. As part of this project, studies have been conducted analyzing the trade space of potential lunar landing trajectories [5,6].…”

Section: Alhat Lunar Landing Trajectoriesmentioning

confidence: 99%