Obed Sands - Academia.edu (original) (raw)

Papers by Obed Sands

This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 2.0 subsystem for the Advanced Extravehicular Mobile Unit (AEMU). The following systems are described in detail: Caution Warn- ing and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS project at Glenn Research Center (GRC).

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This paper summarizes recent advances in antenna and power systems technology to enable a high da... more This paper summarizes recent advances in antenna and power systems technology to enable a high data rate Ka-band Mars-to-Earth telecommunications system. Promising antenna technologies are lightweight, deployable space qualified structures at least 12-m in diameter (potentially up to 25-m). These technologies include deployable mesh reflectors, inflatable reflectarray and folded thermosetting composite. Advances in 1kW-class RF power amplifiers include both TWTA and SSPA technologies.

The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Althoug... more The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. Since these regions have poor Earth visibility, a navigation system comprised solely of Earth-based tracking stations will not provide adequate navigation solutions in these areas. In this report, a dilution-of-precision (DoP)-based analysis of the performance of a network of Moon orbiting satellites is provided. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associated with a variety of ass...

This work investigates acoustic impedance matching materials for coupling 200 kHz ultrasonic sign... more This work investigates acoustic impedance matching materials for coupling 200 kHz ultrasonic signals from air to materials with similar acoustic properties to that of water, flesh, rubber and plastics. Porous filter membranes as well as a new class of cross-linked polyimide aerogels are evaluated. The results indicate that a single impedance matching layer consisting of these new aerogel materials will recover nearly half of the loss in the incident-to-transmitted ultrasound intensity associated with an air/water, air/flesh or air/gelatin boundary. Furthermore, the experimental results are obtained where other uncertainties of the "real world" are present such that the observed impedance matching gains are representative of real-world applications. Performance of the matching layer devices is assessed using the idealized 3-layer model of infinite half spaces, yet the experiments conducted use a finite gelatin block as the destination medium.

The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Althoug... more The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. These regions are known to have poor Earth visibility, but unknown is the extent to which a navigation system comprised solely of Earth-based tracking stations will provide adequate navigation solutions in these areas. This report presents a dilution-of-precision (DoP)-based analysis of the performance of a network of Earth-based assets. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associa...

The SCaN Testbed is an advanced integrated communications system and laboratory facility installe... more The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the ...

Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Oct 11, 2019

is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in ... more is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in Darmstadt, Germany. Previously, he worked at the European GNSS Authority (GSA) as the Head of System Evolutions for Galileo and EGNOS and he also worked for the European Commission in the Galileo Unit. For over 25 years, he has worked on activities related to the use of GPS/GNSS for space applications. He holds a master and doctoral degree in aerospace engineering from the Technical University of Berlin, Germany. Erik Schönemann has joint the Navigation Support Office at ESA/ESOC in 2006 as a contractor and became permanent staff in 2015. He is involved in Galileo studies since the launch of the first Galileo validation satellite GIOVE-A and is the technical manager of the Galileo Reference Service Provider (GRSP). He is involved in the coordination of ESA's reference frame activities and contribution to International Services like ILRS, IGS and UTC. Erik Schönemann holds a master and a doctoral degree in Geodesy from the Technical University of Darmstadt, Germany. Francesco Gini is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Center (ESOC) of ESA. He is responsible for the Space Service Volume (SSV) and Precise Orbit Determination (POD) related activities. He received his PhD in Astronautics and Satellite Sciences at the University of Padova, Italy in 2014 and since then he has been working in ESOC. Michiel Otten is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Center (ESOC) of ESA. He is responsible for the LEO POD activities and the International Doris Service (IDS) Analysis Centre activities. He received his Master degree in Aerospace Engineering at the Delft University of Technology in 2001 and since then he has been working at ESOC. Pietro Giordano holds a Master in Telecommunication Engineering from University of Padua (Italy) and a Second Level specializing Master in Navigation and Related Application from University of Torino (Italy). He worked in Thales Alenia Space (Italy) as GNSS receiver Engineer before joining ESA in 2009, where he worked first as GNSS receiver support to Galileo project and later as GNSS Security Engineer in the Galileo project. Currently he is in charge of multiple activities related with space GNSS receivers and R&D in space GNSS receiver technology such as Technical Officer for POD receiver in Sentinel, Proba3 missions, development of GNSS space borne receivers for real time on-board POD in CubeSats, development of LEO PNT payloads, support for definition of new AGGA chip and development of GNSS space borne receivers for lunar missions.

Proceedings of the 31st International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2018), Oct 26, 2018

is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in ... more is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in Darmstadt, Germany. Previously, he worked at the European GNSS Authority (GSA) as the Head of System Evolutions for Galileo and EGNOS and he also worked for the European Commission in the Galileo Unit. Since more than 20 years, he is involved in activities related to the use of GPS/GNSS for space applications. He holds a doctoral degree in aerospace engineering from the Technical University of Berlin, Germany. Francesco Gini is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Centre (ESOC) of ESA. He is responsible for the Space Service Volume (SSV) and Precise Orbit Determination (POD) related activities. He received his PhD in Astronautics and Satellite Sciences at the University of Padova in 2014 and since then he has been working in ESOC. Henno Boomkamp has worked on precise orbit determination and satellite tracking data analysis for more than two decades. He chaired the Low Earth Orbiter Working Group of the International GNSS Service for seven years, as well as a Working Group on precise orbit determination of the International Association of Geodesy (IAG).

34th AIAA International Communications Satellite Systems Conference, 2016

Free space optical communication is of interest to NASA as a complement to existing radio frequen... more Free space optical communication is of interest to NASA as a complement to existing radio frequency communication methods. The potential for an increase in science data return capability over current radio-frequency communications is the primary objective. Deep space optical communication requires laser beam pointing accuracy on the order of a few microradians. The laser beam pointing approach discussed here operates without the aid of a terrestrial uplink beacon. Precision pointing is obtained from an on-board star tracker in combination with inertial rate sensors and an outgoing beam reference vector. The beaconless optical pointing system presented in this work is the current approach for the Integrated Radio and Optical Communication (iROC) project.

perform research in systems analysis, communications architecture, and signal processing within t... more perform research in systems analysis, communications architecture, and signal processing within the Communications Technology Division at NASA's Glenn Research Center. J. Russell Carpenter has a long history of accomplishments in navigation while working in NASA Goddard's Flight Dynamics Analysis with Kevin Berry. Todd Ely is with the NASA JPL's Guidance, Navigation, and Control section and has worked on Mars and lunar navigation architectures; he developed a class of inclined elliptical frozen orbits for the Moon.

20th AIAA International Communication Satellite Systems Conference and Exhibit, 2002

Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rat... more Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflectorbased systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2π phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.

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This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 2.0 subsystem for the Advanced Extravehicular Mobile Unit (AEMU). The following systems are described in detail: Caution Warn- ing and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS project at Glenn Research Center (GRC).

20th AIAA International Communication Satellite Systems Conference and Exhibit, 2002

Phased Array Antennas (PAAs), using patch -radiating elements, are projected to transmit data at ... more Phased Array Antennas (PAAs), using patch -radiating elements, are projected to transmit data at rates several orders of magnitu de higher than currently offered with reflector -based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA -based links. Short spacing of radiatin g elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2� phase errors can add to Inter - Symbol Interference (ISI), and phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased - array antennas when used in a high data rate modulation link. The system effects created by small increments in the scan angle, as would be experienced during a LEO system passing over a fixed point on the ground, have been simulated in the far field environment and analyzed. Computer simulation of the system under test has also been conducted by creating models using Matlab/Simulink. Variations of the test configuration, including a lower carrier frequency to data rate ratio and various modulation schemes, have been analyzed with these models. The results from the experimentation and simulation will be discussed and the impact for future implementations will be examined.

13th International Conference on Space Operations 2014, 2014

This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 1.0 subsystem for the Advanced Extravehicular Mobility Unit (AEMU). The following systems are described in detail: Caution Warning and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS subsystem being developed at Glenn Research Center (GRC).

SAE Technical Paper Series, 2014

This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 2.0 subsystem for the Advanced Extravehicular Mobile Unit (AEMU). The following systems are described in detail: Caution Warn- ing and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS project at Glenn Research Center (GRC).

[

This paper summarizes recent advances in antenna and power systems technology to enable a high da... more This paper summarizes recent advances in antenna and power systems technology to enable a high data rate Ka-band Mars-to-Earth telecommunications system. Promising antenna technologies are lightweight, deployable space qualified structures at least 12-m in diameter (potentially up to 25-m). These technologies include deployable mesh reflectors, inflatable reflectarray and folded thermosetting composite. Advances in 1kW-class RF power amplifiers include both TWTA and SSPA technologies.

The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Althoug... more The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. Since these regions have poor Earth visibility, a navigation system comprised solely of Earth-based tracking stations will not provide adequate navigation solutions in these areas. In this report, a dilution-of-precision (DoP)-based analysis of the performance of a network of Moon orbiting satellites is provided. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associated with a variety of ass...

This work investigates acoustic impedance matching materials for coupling 200 kHz ultrasonic sign... more This work investigates acoustic impedance matching materials for coupling 200 kHz ultrasonic signals from air to materials with similar acoustic properties to that of water, flesh, rubber and plastics. Porous filter membranes as well as a new class of cross-linked polyimide aerogels are evaluated. The results indicate that a single impedance matching layer consisting of these new aerogel materials will recover nearly half of the loss in the incident-to-transmitted ultrasound intensity associated with an air/water, air/flesh or air/gelatin boundary. Furthermore, the experimental results are obtained where other uncertainties of the "real world" are present such that the observed impedance matching gains are representative of real-world applications. Performance of the matching layer devices is assessed using the idealized 3-layer model of infinite half spaces, yet the experiments conducted use a finite gelatin block as the destination medium.

The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Althoug... more The NASA Vision for Space Exploration is focused on the return of astronauts to the Moon. Although navigation systems have already been proven in the Apollo missions to the Moon, the current exploration campaign will involve more extensive and extended missions requiring new concepts for lunar navigation. In contrast to Apollo missions, which were limited to the near-side equatorial region of the Moon, those under the Exploration Systems Initiative will require navigation on the Moon's limb and far side. These regions are known to have poor Earth visibility, but unknown is the extent to which a navigation system comprised solely of Earth-based tracking stations will provide adequate navigation solutions in these areas. This report presents a dilution-of-precision (DoP)-based analysis of the performance of a network of Earth-based assets. This analysis extends a previous analysis of a lunar network (LN) of navigation satellites by providing an assessment of the capability associa...

The SCaN Testbed is an advanced integrated communications system and laboratory facility installe... more The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the ...

Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Oct 11, 2019

is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in ... more is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in Darmstadt, Germany. Previously, he worked at the European GNSS Authority (GSA) as the Head of System Evolutions for Galileo and EGNOS and he also worked for the European Commission in the Galileo Unit. For over 25 years, he has worked on activities related to the use of GPS/GNSS for space applications. He holds a master and doctoral degree in aerospace engineering from the Technical University of Berlin, Germany. Erik Schönemann has joint the Navigation Support Office at ESA/ESOC in 2006 as a contractor and became permanent staff in 2015. He is involved in Galileo studies since the launch of the first Galileo validation satellite GIOVE-A and is the technical manager of the Galileo Reference Service Provider (GRSP). He is involved in the coordination of ESA's reference frame activities and contribution to International Services like ILRS, IGS and UTC. Erik Schönemann holds a master and a doctoral degree in Geodesy from the Technical University of Darmstadt, Germany. Francesco Gini is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Center (ESOC) of ESA. He is responsible for the Space Service Volume (SSV) and Precise Orbit Determination (POD) related activities. He received his PhD in Astronautics and Satellite Sciences at the University of Padova, Italy in 2014 and since then he has been working in ESOC. Michiel Otten is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Center (ESOC) of ESA. He is responsible for the LEO POD activities and the International Doris Service (IDS) Analysis Centre activities. He received his Master degree in Aerospace Engineering at the Delft University of Technology in 2001 and since then he has been working at ESOC. Pietro Giordano holds a Master in Telecommunication Engineering from University of Padua (Italy) and a Second Level specializing Master in Navigation and Related Application from University of Torino (Italy). He worked in Thales Alenia Space (Italy) as GNSS receiver Engineer before joining ESA in 2009, where he worked first as GNSS receiver support to Galileo project and later as GNSS Security Engineer in the Galileo project. Currently he is in charge of multiple activities related with space GNSS receivers and R&D in space GNSS receiver technology such as Technical Officer for POD receiver in Sentinel, Proba3 missions, development of GNSS space borne receivers for real time on-board POD in CubeSats, development of LEO PNT payloads, support for definition of new AGGA chip and development of GNSS space borne receivers for lunar missions.

Proceedings of the 31st International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2018), Oct 26, 2018

is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in ... more is the Head of the Navigation Support Office at ESA's European Space Operations Center (ESOC) in Darmstadt, Germany. Previously, he worked at the European GNSS Authority (GSA) as the Head of System Evolutions for Galileo and EGNOS and he also worked for the European Commission in the Galileo Unit. Since more than 20 years, he is involved in activities related to the use of GPS/GNSS for space applications. He holds a doctoral degree in aerospace engineering from the Technical University of Berlin, Germany. Francesco Gini is a Navigation Engineer at the Navigation Support Office (OPS-GN) at the European Space Operations Centre (ESOC) of ESA. He is responsible for the Space Service Volume (SSV) and Precise Orbit Determination (POD) related activities. He received his PhD in Astronautics and Satellite Sciences at the University of Padova in 2014 and since then he has been working in ESOC. Henno Boomkamp has worked on precise orbit determination and satellite tracking data analysis for more than two decades. He chaired the Low Earth Orbiter Working Group of the International GNSS Service for seven years, as well as a Working Group on precise orbit determination of the International Association of Geodesy (IAG).

34th AIAA International Communications Satellite Systems Conference, 2016

Free space optical communication is of interest to NASA as a complement to existing radio frequen... more Free space optical communication is of interest to NASA as a complement to existing radio frequency communication methods. The potential for an increase in science data return capability over current radio-frequency communications is the primary objective. Deep space optical communication requires laser beam pointing accuracy on the order of a few microradians. The laser beam pointing approach discussed here operates without the aid of a terrestrial uplink beacon. Precision pointing is obtained from an on-board star tracker in combination with inertial rate sensors and an outgoing beam reference vector. The beaconless optical pointing system presented in this work is the current approach for the Integrated Radio and Optical Communication (iROC) project.

perform research in systems analysis, communications architecture, and signal processing within t... more perform research in systems analysis, communications architecture, and signal processing within the Communications Technology Division at NASA's Glenn Research Center. J. Russell Carpenter has a long history of accomplishments in navigation while working in NASA Goddard's Flight Dynamics Analysis with Kevin Berry. Todd Ely is with the NASA JPL's Guidance, Navigation, and Control section and has worked on Mars and lunar navigation architectures; he developed a class of inclined elliptical frozen orbits for the Moon.

20th AIAA International Communication Satellite Systems Conference and Exhibit, 2002

Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rat... more Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflectorbased systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2π phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.

[

This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 2.0 subsystem for the Advanced Extravehicular Mobile Unit (AEMU). The following systems are described in detail: Caution Warn- ing and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS project at Glenn Research Center (GRC).

20th AIAA International Communication Satellite Systems Conference and Exhibit, 2002

Phased Array Antennas (PAAs), using patch -radiating elements, are projected to transmit data at ... more Phased Array Antennas (PAAs), using patch -radiating elements, are projected to transmit data at rates several orders of magnitu de higher than currently offered with reflector -based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA -based links. Short spacing of radiatin g elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2� phase errors can add to Inter - Symbol Interference (ISI), and phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased - array antennas when used in a high data rate modulation link. The system effects created by small increments in the scan angle, as would be experienced during a LEO system passing over a fixed point on the ground, have been simulated in the far field environment and analyzed. Computer simulation of the system under test has also been conducted by creating models using Matlab/Simulink. Variations of the test configuration, including a lower carrier frequency to data rate ratio and various modulation schemes, have been analyzed with these models. The results from the experimentation and simulation will be discussed and the impact for future implementations will be examined.

13th International Conference on Space Operations 2014, 2014

This document describes the communication architecture for the Power, Avionics and Software (PAS)... more This document describes the communication architecture for the Power, Avionics and Software (PAS) 1.0 subsystem for the Advanced Extravehicular Mobility Unit (AEMU). The following systems are described in detail: Caution Warning and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS subsystem being developed at Glenn Research Center (GRC).

SAE Technical Paper Series, 2014