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At least 19 records

Flight Test Performance of a High Precision Navigation Doppler Lidar

A navigation Doppler Lidar (DL) was developed at NASA Langley Research Center (LaRC) for high precision velocity measurements from a lunar or planetary landing vehicle in support of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. A unique feature of this DL is that it has the capability to provide a precision velocity vector which can be easily separated into horizontal and vertical velocity components and high accuracy line of sight (LOS) range measurements. This dual mode of operation can provide useful information, such as vehicle orientation relative to the direction of travel, and vehicle attitude relative to the sensor footprint on the ground. System performance was evaluated in a series of helicopter flight tests over the California desert. This paper provides a description of the DL system and presents results obtained from these flight tests.

Pierrottet, Diego↗

Navigation Doppler Lidar Signal Processing Architecture and Algorithms

A coherent Doppler lidar has been developed to address the need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard landing vehicles. One of the core subsystems within NDL is its signal processing architecture. The primary function of this subsystem is to digitize the analog output of the homodyned signal received from the photo-diode associated with each telescope, process this signal in the frequency domain, and then turn this information into velocity and range measurements. A secondary function of this subsystem is to setup and control the internal components within NDL and to enable the instrument to interface with external systems by receiving commands, sending telemetry, and synchronizing its measurements with external clocks and pulses. This paper will give an overview of the signal processing architecture within NDL. This will include a discussion on its fundamental processing components and the core signal processing algorithms. Command, telemetry and internal component controls will also be discussed as will how the signal processing architecture has also evolved over the years of development. We will discuss provisions for robust operation including Triple-Mode Redundancy (TMR) within NDL’s Field Programmable Gate Array (FPGA) and storage elements, a fault-tolerant boot process, and Error Detection and Correction (EDAC) on the Static Random-Access Memories (SRAMs). Finally, we conclude this paper with how this architecture could continue to evolve.

Doppler Lidar↗

First Demonstration of Simultaneous Ranging and Velocimetry With Coherent Lidar on the Moon With NASA'S Navigation Doppler Lidar

A coherent Doppler lidar, referred to as Navigation Doppler Lidar (NDL), has been developed at NASA Langley Research Center for providing simultaneous but independent precision velocity and altitude measurements to a spacecraft’s navigation system during the final stages of landing, starting at approximately 5 km altitude. Onboard the Intuitive Machines NOVA-C lunar lander (also known as Odysseus), NDL provided fully reliable measurements within its intended operational range without any false alarms and demonstrated the sensitivity of coherent lidar by measuring velocity and range to the ground from up to 10 km altitude. The data collected during this mission illustrates the capability of NDL for future lunar and interplanetary missions, enhancing navigation accuracy and safety.

FMCW lidar↗

Navigation Doppler Lidar for Lunar Landers

The new generation of Navigation Doppler Lidar has been designed, developed, and tested for lunar missions. Comprehensive environmental testing is performed to assess the performance of the instrument for upcoming lunar missions and future missions to the Moon and other planetary bodies.

Lidar↗

Navigation Doppler Lidar for Lunar Landers

The new generation of Navigation Doppler Lidar has been designed, developed, and tested for lunar missions. Comprehensive environmental testing is performed to assess the performance of the instrument for upcoming lunar missions and future missions to the Moon and other planetary bodies.

Lidar↗

Development of Navigation Doppler Lidar for Future Landing Mission

A coherent Navigation Doppler Lidar (NDL) sensor has been developed under the Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) project to support future NASA missions to planetary bodies. This lidar sensor provides accurate surface-relative altitude and vector velocity data during the descent phase that can be used by an autonomous Guidance, Navigation, and Control (GN&C) system to precisely navigate the vehicle from a few kilometers above the ground to a designated location and execute a controlled soft touchdown. The operation and performance of the NDL was demonstrated through closed-loop flights onboard the rocket-propelled Morpheus vehicle in 2014. In Morpheus flights, conducted at the NASA Kennedy Space Center, the NDL data was used by an autonomous GN&C system to navigate and land the vehicle precisely at the selected location surrounded by hazardous rocks and craters. Since then, development efforts for the NDL have shifted toward enhancing performance, optimizing design, and addressing spaceflight size and mass constraints and environmental and reliability requirements. The next generation NDL, with expanded operational envelope and significantly reduced size, will be demonstrated in 2017 through a new flight test campaign onboard a commercial rocketpropelled test vehicle.

Amzajerdian, Farzin↗

Navigation Doppler Lidar

A Doppler lidar has been developed by NASA as an alternative to radars for providing velocity and altitude data to landing vehicles. Future robotic and manned missions to planetary bodies demand precise ground-relative velocity vector and altitude data to execute complex descent maneuvers for safe, soft and pinpoint landing at a pre-designated site. This lidar sensor, referred to as Navigation Doppler Lidar (NDL), provides velocity and altitude data from over five kilometers altitude to within a few cm/sec and tens of centimeters precision, respectively. NDL technology will be demonstrated on two lunar landing missions this year that will serve as precursors for large robotic and manned landing missions to the Moon, Mars, and other solar system destinations. NDL can also benefit terrestrial aerial vehicles that cannot rely on the GPS for position and velocity data or require precision data relative to local ground.

Doppler Lidar↗

Navigation Doppler Lidar Performance at High Speed and Long Range

NASA is developing a Navigational Doppler LiDAR (NDL) for use in missions involving robotic and human landing scenarios on solar system bodies. The NDL provides unprecedented accuracy in position and velocity measurement for the guidance, navigation and control (GNC) subsystem of a spacecraft. NDL performance has been characterized over different phases of its development through ground tests, helicopter flight tests, and onboard rocket-powered test vehicles, however, none of these tests provided measurements over its full performance envelope. For this reason, a high speed rocket sled test was recently conducted to resolve both range and velocity up to the maximum limits of the NDL. This test campaign was performed at the Supersonic Naval Ordnance Research Tracks (SNORT) facility, Naval Air Weapons Station China Lake, as part of the Safe & Precise Landing and Integrated Capabilities Evolution (SPLICE) project.

Aram Gragossian↗

Navigation Doppler Lidar Sensor for Precision Altitude and Vector Velocity Measurements Flight Test Results

An all fiber Navigation Doppler Lidar (NDL) system is under development at NASA Langley Research Center (LaRC) for precision descent and landing applications on planetary bodies. The sensor produces high resolution line of sight range, altitude above ground, ground relative attitude, and high precision velocity vector measurements. Previous helicopter flight test results demonstrated the NDL measurement concepts, including measurement precision, accuracies, and operational range. This paper discusses the results obtained from a recent campaign to test the improved sensor hardware, and various signal processing algorithms applicable to real-time processing. The NDL was mounted in an instrumentation pod aboard an Erickson Air-Crane helicopter and flown over vegetation free terrain. The sensor was one of several sensors tested in this field test by NASA?s Autonomous Landing and Hazard Avoidance Technology (ALHAT) project.

Pierrottet, Diego F.↗

Non-Mechanical Beam Steering for NASA's Navigation Doppler LiDAR

Transparent electro-optic (EO) devices can potentially be used for efficient, high speed, and low mass non-mechanical beam steering. Transmission through EO devices will affect the wavefront quality and aberration of both the transmitted and received laser light. The consequences of wavefront distortions on coherent detection are not fully understood. Therefore, we have tested the performance of coherent detection lidar using liquid crystal polarization grating (LCPG) beam steering device. We will discuss the impact of LCPG beam steering devices on the performance of NASA’s Navigation Doppler Lidar, built for providing altitude and vector velocity data to aerial and space vehicles.

Lidar↗

Demonstration of Navigation Doppler Lidar Capabilities Onboard the First Commercial Lunar Lander

Landing on the Moon safely, softly, and precisely is still an extremely difficult task to achieve. Navigation Doppler Lidar (NDL) was designed to provide a solution to spaceflight landing vehicles in achieving this task. NDL is a high-performance, compact, and cost-effective velocity and altitude measurement instrument that has been developed, tested and improved over many years. Testing has now culminated with NDL’s successful operation on two spaceflight vehicles this year: Astrobotic’s Peregrine lunar lander and Intuitive Machines’ Odysseus lunar lander. Odysseus became the first U.S. vehicle to land successfully on the Moon since Apollo 17. The performance data obtained by NDL during the Intuitive Machines mission is exceptional, and this mission fully demonstrated NDL’s ability to produce critical velocity and altitude data for future robotic and human exploration missions to the Moon and other planetary bodies. This paper will give an overview of NDL briefly describing its history, architecture, and theory of operation. NDL’s system checkout on Astrobotic’s Peregrine lunar lander is then discussed followed by NDL’s performance during the Intuitive Machines Odysseus lunar lander mission. A description of how the data acquired by NDL is then used to perform trajectory reconstruction and animation is then provided. Finally, this paper concludes with potential uses of NDL’s acquired mission data to future applications.

Lunar Landing↗

Demonstration of Navigation Doppler Lidar Capabilities Onboard the First Commercial Lunar Lander

Landing on the Moon safely, softly, and precisely is still an extremely difficult task to achieve. Navigation Doppler Lidar (NDL) was designed to provide a solution to spaceflight landing vehicles in achieving this task. NDL is a high-performance, compact, and cost-effective velocity and altitude measurement instrument that has been developed, tested and improved over many years. Testing has now culminated with NDL’s successful operation on two spaceflight vehicles this year: Astrobotic’s Peregrine lunar lander and Intuitive Machines’ Odysseus lunar lander. Odysseus became the first U.S. vehicle to land successfully on the Moon since Apollo 17. The performance data obtained by NDL during the Intuitive Machines mission is exceptional, and this mission fully demonstrated NDL’s ability to produce critical velocity and altitude data for future robotic and human exploration missions to the Moon and other planetary bodies. This paper will give an overview of NDL briefly describing its history, architecture, and theory of operation. NDL’s system checkout on Astrobotic’s Peregrine lunar lander is then discussed followed by NDL’s performance during the Intuitive Machines Odysseus lunar lander mission. A description of how the data acquired by NDL is then used to perform trajectory reconstruction and animation is then provided. Finally, this paper concludes with potential uses of NDL’s acquired mission data to future applications.

Lunar Landing↗

Cobalt: Terrestrial Flight Test of Landing Navigation Using Lander Vision System with Navigation Doppler Lidar

COBALT (CoOperative Blending of Autonomous Landing Technologies) is a NASA technology development and test program to advance precision landing capabilities for future soft landers. The COBALT payload demonstrated terrain relative navigation utilizing the Lander Vision System and Navigation Doppler Lidar sensors on the Masten Space Systems Xodiac rocket. In spring 2017, the program culminated in two open-loop free flights to 500 m altitude with downrange diverts of 300 m. The COBALT system performed well, navigating within meters of the Xodiac vehicle’s GPS-based solution. This paper outlines details of the navigation filter and its performance during the test campaign.

Carson, John M. III↗