2016 IEEE Aerospace Conference最新文献

{"title":"Development of effective and efficient operations for NASA's Soil Moisture Active Passive mission","authors":"R. Tung","doi":"10.1109/AERO.2016.7500588","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500588","url":null,"abstract":"NASA's Soil Moisture Active Passive (SMAP) is an earth orbiting mission which launched 1/31/2015, successfully completed an aggressive Commissioning plan, and is currently collecting Science data. A 90-day, activity-rich Launch and Commissioning Phase required 7 days per week operations with heavy staffing. It was followed by a steep ramp down to a very small operations team performing mostly unattended (“lights out”) operations. Completing Commissioning ahead of schedule despite major inflight anomalies was made possible by transitioning development experts into operations, preparing sequences for all baseline activities and selected contingency scenarios prior to Launch, and developing tools to streamline routine activities (sequence generation/validation, data management, telemetry query and reporting, long term trending). Powerful operations analysis tools coupled with development experience allowed the team to quickly troubleshoot, work around, and recover from a variety of significant anomalies (including several safemode entries) and still maintain schedule. To enable lights out operation, SMAP developed a reliable infrastructure relying heavily on automation. Orbit determination was successfully automated to simplify Navigation. Automatic command generation and radiation was implemented for benign routine commanding. This capability was phased in during Commissioning, and now accounts for 95-100% of SMAP commanding during the week. SMAP also developed reliable autonomous monitoring and notification systems for non-receipt of data, detection of anomalous data, and auto-commanding failures. Upon detection of problems, SMAP uses a role-based email/text notification tool to disposition anomalies. These capabilities allow the SMAP mission operations center to be largely unattended. System engineers are cross-trained to perform numerous tasks including command radiation, scheduling, and sequence integration and testing. Choosing simplification over optimization allows most tasks to be performed by a handful of people. These are some of the efficiencies that have enabled successful small team operations in the Science Phase.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132122506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asteroid search operations with the space surveillance telescope","authors":"G. Ushomirsky, J. Ruprecht, J. Varey, D. Woods, M. Cornell, G. Stokes","doi":"10.1109/AERO.2016.7500569","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500569","url":null,"abstract":"Over the past two years, the Lincoln Near Earth Asteroid Research (LINEAR) program, funded by the National Aeronautics and Space Administration (NASA), has transitioned to asteroid search operations using the new 3.5-meter wide-field-of-view Space Surveillance Telescope (SST) located at the Atom Site on White Sands Missile Range, N.M. The SST was developed for the Defense Advanced Research Projects Agency (DARPA) by MIT Lincoln Laboratory to help advance the nation's capabilities in space situational awareness. The goals of LINEAR using SST are to continue discovering Near-Earth objects (NEOs) especially focusing on improving knowledge of asteroids 140 meters in diameter and larger. In this paper, we will review results of the first two years of asteroid search operations, during which the SST has delivered over 9.4 million observations to the Minor Planet Center. Recent and planned system improvements will also be discussed.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134510541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of SATCOM link in the presence of radio frequency interference","authors":"G. Wang, Zhihui Shu, Genshe Chen, X. Tian, Dan Shen, T. Nguyen, K. Pham, Erik Blasch","doi":"10.1109/AERO.2016.7500741","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500741","url":null,"abstract":"Digital Video Broadcasting - Satellite - Second Generation (DVB-S2) and Digital Video Broadcasting - Return Channel via Satellite (DVB-RCS) are two important commercial satellite communications (SATCOM) standards, for forward link and return link information transmission via satellites, correspondingly. Advanced channel coding schemes have been designed in DVB-S2 and DVB-RCS to mitigate the information transmission uncertainties and unintentional interferences effects. However, the intentional interferences have been shown to increase dramatically in SATCOM application scenarios. Therefore, performance evaluation of a SATCOM link in the presence of both unintentional radio frequency interference (RFI) and intentional RFI are critical. The evaluation could provide guidance for next-generation SATCOM upgrades. In this paper, we leverage the Intelligent Fusion Technology, Inc. (IFT) communication data link simulator (ICDLS) to evaluate the performances of SATCOM links in the presence of various RFI conditions. The comprehensive RFIs are categorized into three types, which are wideband RFI, narrowband RFI, and radar RFI. Specifically, the carrier and phase synchronization errors caused by RFI are evaluated. Various waveforms including modulation and coding (MODCOD) schemes set in DVB-S2 and DVB-RCS standards are then evaluated considering the synchronization errors due to the existence of various RFI. Valuable observations are obtained based on ICDLS, which can be provided for next-generation SATCOM standards development.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134521447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of different uplink and downlink range mod indices on PRN range accuracy","authors":"S. Raghavan, J. Kreng, M. Ardeshiri","doi":"10.1109/AERO.2016.7500509","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500509","url":null,"abstract":"Pseudorandom noise (PRN) sequences are used to provide a means to measure the ranging distance between a ground station and a satellite. Satellite Ground Link System (SGLS), Global Positioning System (GPS), and some radars are some of the examples that make use of PRN sequences. PRN ranging also provides a certain level of immunity to narrowband interference. The basic procedure involves transmitting a long binary PRN sequence, and measuring the time between its transmission and reception. A PRN ranging system will typically measure the propagation time by performing correlation of the received sequence with the locally generated sequence. A simple equation is used to convert that propagation time value to an accurate range. The length of the PRN sequence determines the maximum unambiguous distance that can be measured, while the code rate and code signal-to-noise ratio (SNR) or sometimes ranging code power-to-noise density ratio (C/No) determine the ranging accuracy. Typically a delay lock loop is used to measure the propagation delay. The SNR in the correlation receiver tracking loop bandwidth determines the phase error variance which is the range measurement accuracy. The SNR is a function of both the signal and noise power at the receiver, and the range signal power is a function of range modulation index. Normally the range mod indices are related through the turnaround ratio for the uplink and the downlink when the range signal is a coherent signal in SGLS. Range mod indices on the up- and downlinks can be different. This is more frequently found on new satellites with the need to have different uplink and downlink range mod indices to improve the link margin and the ranging accuracy, and also to reduce the interference such as from the command echo and intermodulation (IM) signals. In this paper the effect of different uplink and downlink range modulation indices on the achievable range accuracy is presented along with the details of the equations developed.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114392861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commercializing low-Earth orbit and the role of the International Space Station","authors":"Robyn L. Gatens","doi":"10.1109/AERO.2016.7500763","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500763","url":null,"abstract":"With the extension of the International Space Station (ISS) operations until at least 2024, NASA and its partners have the opportunity to leverage the orbiting laboratory to conduct research and validate systems in microgravity that will better prepare humans and systems for future missions, farther into deep space. Beyond 2024, it is vitally important to ensure that the infrastructure and capabilities that have been developed over the past three decades in low Earth orbit (LEO) do not languish, and in fact are used to enable sustainable commercial activity in LEO beyond the ISS. This paper will explore the opportunities and challenges in developing the commercial market in LEO through the ISS program while at the same time continuing to use the ISS as a testbed to enable human missions into deep space. System and technology capability gaps requiring demonstrations on the ISS will be discussed in detail. NASA's strategic plan for leveraging the ISS to enable commercial markets and stimulate commercial supply of LEO services will be summarized, along with initial steps and progress. The intersection between NASA's needs beyond LEO and commercial LEO platforms will be explored. Finally, the paper will discuss preliminary measures that will indicate when a transition from ISS to the Proving Ground is appropriate.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124797029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical ARQ link analysis and planning for dynamic links","authors":"K. Cheung, Thomas Choi","doi":"10.1109/AERO.2016.7500547","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500547","url":null,"abstract":"In [1] and [2], we discussed automatic Repeat-reQuest (ARQ) link analysis and planning in terms of effective data rate, effective throughput, latency, and frame-error-rate (FER), under the standard assumption that the signal-to-noise ratio (SNR) remains the same throughout the ARQ communication session. In [3], we argued that the concept of constant SNR might not be valid when considering events over a long time horizon, as many link parameters are inherently statistical. This is particularly true for long-haul ARQ links because the channel SNR changes during subsequent retransmissions of un-received or non-decodable frames. As shown in [3], this inaccurate assumption of constant SNR might be non-consequential for static links such as S-band and X-band, but can lead to large discrepancies in the analysis and planning of the more dynamic communication links such as Ka-band and optical communication frequencies. In this paper, using similar techniques developed in [3], we incorporate the effect of changing SNR, or link uncertainty, into the analysis of ARQ links. SNR is no longer considered as a fixed value, but a random variable whose long-term statistics can be characterized with a probability distribution function. We consider two limiting cases: 1. “Fast-varying” SNR: when SNRs in subsequent retransmissions of a code-block can assume different values, and they are independent. One example is the deep space link when the ARQ acknowledgement time is much larger than the coherency time of the channel. For communications between Earth's ground stations and spacecraft at Mars, the round trip light time is 20-40 minutes, and this is much more than the typical atmospheric coherency time of Ka-band. 2. “Slow-varying” SNR: when SNR values in subsequent retransmissions of a code-block remain the same. One example is the proximity link between a low-Mars-orbit orbiter and a surface asset at Mars. In this case, the ARQ acknowledgement time is of the order of milliseconds and we can assume identical channel environment in subsequent re-transmissions. We expect the ARQ behavior of real-world dynamic channels would fall in between the “fast-varying” and “slow-varying” cases, thus providing interesting insights on the ARQ data return performance and latency performance. We illustrate the aforementioned analysis using the NASA (1024, ½) low-density-parity check (LDPC) code.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125429799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tiny houses: Planetary protection-focused materials selection for spaceflight hardware surfaces","authors":"D. Pugel, J. Rummel, C. Conley","doi":"10.1109/AERO.2016.7500727","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500727","url":null,"abstract":"When developing spaceflight hardware, an engineering team is faced with a broad range of materials selections for design trade studies. Typical trade studies hone in on materials selection with thermal or mechanical environmental requirements as design selection drivers. With the growing interest in spaceflight hardware development for life-detection and restricted sample return missions, materials selection processes during the design phase will need to factor in the impact that materials selection will have on the growth of terrestrial microbes in the pre- and post-launch environment. From a planetary protection point of view, during the design and pre-fabrication processes, materials choices (composition, termination, finish) can result in surfaces that have the potential to support, sustain, or senesce microbes. We evaluate known surface properties of common spaceflight materials choices in the context of planetary protection considerations for future sample return and life-detection missions.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"485 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131636190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Teleoperation for on-orbit servicing missions through the ASTRA geostationary satellite","authors":"J. Artigas, R. Balachandran, M. De Stefano, M. Panzirsch, R. Lampariello, A. Albu-Schaeffer, J. Harder, Juergen Letschnik","doi":"10.1109/AERO.2016.7500785","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500785","url":null,"abstract":"Force-feedback teleoperation for on-orbit servicing tasks demands real-time communication requirements, latencies below one second and the presence of a skilled human operator to perform the on-orbit servicing tasks in real-time from an on-ground station. On the other hand, teleoperation is a technology that enjoys high TRLs, has evidenced benefits in other domains as nuclear or medical and has little dependency on optical sensors and image processing algorithms that need to operate in extreme illumination conditions. While all of these factors could be of high value in future on-orbit servicing missions, the following questions remain still to be answered: 1) How is the free floating dynamics and time delay affecting the control structure of the system? 2) Can current space communication infrastructures support real time control requirements established by the bilateral controller (i.e. force-feedback teleoperation)? 3) Can a skilled human operator perform on-orbit servicing tasks through the teleoperation system, probably affected by high latencies and force-feedback distortions? This paper presents initial answers to these questions based on results from a force-feedback teleoperation system that has been implemented using the ASTRA geostationary satellite and the DLR on-orbit servicing facility (OOS-SIM).","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134548308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computer assisted design and integration of FPGA accelerators in aerospace systems","authors":"M. Lattuada, Fabrizio Ferrandi, M. Perrotin","doi":"10.1109/AERO.2016.7500675","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500675","url":null,"abstract":"The integration of Field Programmable Gate Arrays (FPGAs) in an aerospace system allows to improve its efficiency and its flexibility thanks to their programmability. To exploit these devices, the designer has to identify the functionalities that have to be executed on them and provide their implementation by means of Hardware Description Languages. Generating these descriptions for a software developer could be a very difficult task because of the different programming paradigms of software programs and hardware descriptions. To facilitate the developer in this activity, High Level Synthesis techniques have been developed aiming at (semi-)automatically generating hardware implementations of specifications written in high level languages (e.g., C). State of the art tools implementing such methodologies have not been designed for the integration with aerospace systems design flows, so significant adaptations could be required to the designer for integrating the hardware implementations with the rest of the design solution. In this paper the integration of a High Level Synthesis design flow in the TASTE framework (http://taste.tuxfamily.org) is presented. TASTE is a set of freely available tools for the development of real time embedded systems developed by the European Space Agency together with a set of its industrial partners. This framework allows to integrate specifications described in different languages (e.g., C, ADA, Simulink, SDL) by means of formal languages (AADL and ASN.1) and to early verify the correctness of the produced solutions. TASTE has been extended with Bambu (http://panda.dei.polimi.it), a tool for the High Level Synthesis developed at Politecnico di Milano. In this way the TASTE users have the possibility to specify which functionalities, provided by means of high level languages such C, have to be implemented in hardware on the FPGA without having to directly provide the hardware implementations. Thanks to the integration of the High Level Synthesis tool indeed, the framework is able not only to produce the hardware implementations, but also to integrate them in the rest of the aerospace system by automatically generating the whole architecture to be implemented on the FPGA. This architecture contains not only the implementation of the hardware accelerators, but also of the components required to transfer the data from and to the rest of the system and to correctly manage their size and endianness. The application of the extended framework to a real case study shows its effective usability.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134107074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolutionary upgrade for the multi-mission radioisotope thermoelectric generator (MMRTG)","authors":"T. Hammel, R. Bennett, Bob Sievers","doi":"10.1109/AERO.2016.7500748","DOIUrl":"https://doi.org/10.1109/AERO.2016.7500748","url":null,"abstract":"Advanced thermoelectric materials developed over the last 10 years have opened up a number of radioisotope generator design options for deep space and planetary exploration. Publications over the last several years have described options ranging from low risk upgrades to the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) to higher risk game changing designs with efficiency above 10% and power density above 5 W/kg. While the latter are very compelling to the mission planners, the reality is that only the former is within reach of the current NASA budget and near term missions. System design and mission studies have determined that even the former approach will provide significant power system improvements for future missions. A program is therefore in progress to evaluate evolutionary MMRTG upgrades using new skutterudite (SKD) thermoelectric materials. Modest temperature increases to produce higher beginning of life (BOL) power from the SKD materials are expected to be within the capability of the MMRTG system design. The SKD materials are also expected to provide a substantial end of life (EOL) improvement relative to MMRTG materials. This paper examines the evolutionary system design changes for this enhanced (e)MMRTG, provides a risk assessment of each and summarizes the expected performance.","PeriodicalId":150162,"journal":{"name":"2016 IEEE Aerospace Conference","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131752732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}