Probabilistic Hazard Detection for Autonomous Safe Landing

AIAA SPACE 2015 Conference and Exposition

et al. 2015

Self Cite

A suite of prototype sensors, software, and avionics developed within the NASA Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) project were terrestrially demonstrated onboard the NASA Morpheus rocket-propelled Vertical Testbed (VTB) in 2014. The sensors included a lidar-based Hazard Detection System (HDS), a Navigation Doppler Lidar (NDL) velocimeter, and a long-range Laser Altimeter (LAlt) that enable autonomous and safe precision landing of robotic or human vehicles on solid solar system bodies under varying terrain lighting conditions. The flight test campaign with the Morpheus VTB involved a detailed integration and functional verification process, followed by tether testing and six successful free flights, including one night flight.The ALHAT sensor measurements were combined within a specialized ALHAT Navigation filter that was employed in closed-loop flight testing within the Morpheus Guidance, Navigation and Control (GN&C) subsystem. Flight testing on Morpheus utilized ALHAT for safe landing site identification and ranking, followed by precise surface-relative navigation to the selected landing site. The successful autonomous, closed-loop flight demonstrations of the prototype ALHAT system have laid the foundation for the infusion of safe, precision landing capabilities into future planetary exploration missions.

Section: Iva Hds Performancementioning

confidence: 99%

Flight Testing ALHAT Precision Landing Technologies Integrated Onboard the Morpheus Rocket Vehicle

Carson

Robertson

AIAA SPACE 2015 Conference and Exposition

et al. 2015

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“…4 The HDS was developed as a stand-alone, bolt-on system to detect available safe landing sites within a 100 m × 100 m region of the Lunar surface from 1 km slant range, 500 m altitude, in real-time and under any surface lighting conditions, and to subsequently provide hazard-relative position measurements to the Host Vehicle (HV)'s GN&C subsystem to improve landing accuracy. 5,6 The current generation HDS system was fully integrated with the Morpheus avionics and tested during a helicopter flight test campaign (Field Test #5) at the simulated lunar hazard field at KSC in December 2012. 7 These flight test demonstrated the full range of HDS operations -DEM generation, safe site detection, and hazard relative navigation -and provided rich datasets for performance evaluation and tuning.…”

Section: Introductionmentioning

confidence: 99%

Flight testing a Real-Time Hazard Detection System for Safe Lunar Landing on the Rocket-Powered Morpheus Vehicle

AIAA Guidance, Navigation, and Control Conference

Huertas

Luna

et al. 2015

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The Hazard Detection System (HDS) is a component of the ALHAT (Autonomous Landing and Hazard Avoidance Technology) sensor suite, which together provide a lander Guidance, Navigation and Control (GN&C) system with the relevant measurements necessary to enable safe precision landing under any lighting conditions. The HDS consists of a stand-alone compute element (CE), an Inertial Measurement Unit (IMU), and a gimbaled flash LIDAR sensor that are used, in real-time, to generate a Digital Elevation Map (DEM) of the landing terrain, detect candidate safe landing sites for the vehicle through Hazard Detection (HD), and generate hazard-relative navigation (HRN) measurements used for safe precision landing. Following an extensive ground and helicopter test campaign, ALHAT was integrated onto the Morpheus rocket-powered terrestrial test vehicle in March 2014. Morpheus and ALHAT then performed five successful free flights at the simulated lunar hazard field constructed at the Shuttle Landing Facility (SLF) at Kennedy Space Center, for the first time testing the full system on a lunar-like approach geometry in a relevant dynamic environment. During these flights, the HDS successfully generated DEMs, correctly identified safe landing sites and provided HRN measurements to the vehicle, marking the first autonomous landing of a NASA rocket-powered vehicle in hazardous terrain. This paper provides a brief overview of the HDS architecture and describes its in-flight performance.

“…[1][2][3] The project and teaming has been a highly-successful demonstration of multi-center collaboration within NASA, involving team members from NASA Johnson Space Center (JSC), NASA Jet Propulsion Laboratory (JPL), NASA Langley Research Center (LaRC), and many other supporting contractors and research centers, including the Charles Stark Draper Laboratory (CSDL) and the Johns Hopkins Applied Physics Laboratory (APL). The ALHAT team has developed several generations of prototypes sensors and algorithms that provide precision velocimetry and altimetry, Hazard Detection (HD) 4 and Hazard Relative Navigation (HRN), and Terrain Relative Navigation (TRN).…”

Section: Introductionmentioning

confidence: 99%

“…During the HDA phase, the ALHAT system generates an onboard Digital Elevation Model/Map (DEM) in real time of the local terrain, which is analyzed through sophisticated onboard Hazard Detection (HD) algorithms to determine safe landing sites, along with prominent terrain features. 4 The ILP itself may or may not be a high-probability safe site within the region of the DEM, so the onboard GN&C system assesses the ALHAT-provided safe sites and determines divert maneuvers to the desired safe location (i.e., the hazard avoidance part of HDA) based on a site safety ranking and fuel requirements.…”

mentioning

confidence: 99%

Preparation and Integration of ALHAT Precision Landing Technology for Morpheus Flight Testing

Carson

AIAA SPACE 2014 Conference and Exposition

Robertson

et al. 2014

Self Cite

The Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) project has developed a suite of prototype sensors for enabling autonomous and safe precision landing of robotic or crewed vehicles on solid solar bodies under varying terrain lighting conditions. The sensors include a Lidar-based Hazard Detection System (HDS), a multipurpose Navigation Doppler Lidar (NDL), and a long-range Laser Altimeter (LAlt). Preparation for terrestrial flight testing of ALHAT onboard the Morpheus free-flying, rocket-propelled flight test vehicle has been in progress since 2012, with flight tests over a lunar-like terrain field occurring in Spring 2014. Significant work efforts within both the ALHAT and Morpheus projects has been required in the preparation of the sensors, vehicle, and test facilities for interfacing, integrating and verifying overall system performance to ensure readiness for flight testing. The ALHAT sensors have undergone numerous stand-alone sensor tests, simulations, and calibrations, along with integrated-system tests in specialized gantries, trucks, helicopters and fixed-wing aircraft. A lunar-like terrain environment was constructed for ALHAT system testing during Morpheus flights, and vibration and thermal testing of the ALHAT sensors was performed based on Morpheus flights prior to ALHAT integration. High-fidelity simulations were implemented to gain insight into integrated ALHAT sensors and Morpheus GN&C system performance, and command and telemetry interfacing and functional testing was conducted once the ALHAT sensors and electronics were integrated onto Morpheus. This paper captures some of the details and lessons learned in the planning, preparation and integration of the individual ALHAT sensors, the vehicle, and the test environment that led up to the joint flight tests.