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The National Aeronautics and Space Administration (NASA) Space Communications and Navigation (SCaN) Program is responsible for providing communications and navigation services to space flight missions throughout the solar system. Astronauts, mission controllers, and scientists depend upon the reliable transmission of information between Earth and spacecraft, from low-Earth orbit to deep space. The SCaN Testbed is an advanced integrated communications system and laboratory facility to be installed on the International Space Station (ISS). Using a new generation of Software Defined Radio (SDR) technologies, this ISS facility will allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. The SCaN Testbed will thus advance space communication technologies in support of future NASA missions and other U.S. space endeavors.
During its development at NASA Glenn Research Center, the SCaN Testbed was also known as the Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) project.
SCaN Testbed Value for Space Missions
The growth of Software Defined Radios (SDRs) offers NASA the opportunity to improve the way space missions develop and operate space transceivers for communications, networking, and navigation. Reconfigurable SDRs with communications and navigation functions implemented in software provide the capability to change the functionality of the radio during a mission and optimize the data capabilities (e.g. video, telemetry, voice, etc.). The ability to change the operating characteristics of a radio through software once deployed to space offers the flexibility to adapt to new science opportunities, recover from anomalies within the science payload or communication system, and potentially reduce development cost and risk through reuse of common space platforms to meet specific mission requirements. SDRs can be used on space-based missions to almost any destination.
SCaN Testbed Project Mission Objectives
The SCaN Testbed Project will provide NASA, industry, other Government agencies, and academic partners the opportunity to develop and field communications, navigation, and networking technologies in the laboratory and space environment based on reconfigurable, software defined radio platforms and the STRS Architecture. The SCaN Testbed Project Experiments Program will devise, solicit, and conduct on-orbit experiments to validate and advance the open architecture standard for SDRs; advance communication, navigation, and network technologies to mitigate specific NASA mission risks and to enable future mission capabilities.
Identified below are several research and technology areas the SCAN Testbed was designed to support.
Software Defined Radios operating at S, L, and Ka-band.
On-board data management function and payload networking.
Radio Science experiments using the unique capabilities of the SDRs
Precise Navigation and Timing
NASA’s Space Communication and Navigation (SCaN) Office has developed an architecture standard for SDRs used in space and ground-based platforms to provide commonality among radio developments to provide enhanced capability and services while reducing mission and programmatic risk. The Space Telecommunications Radio System (STRS) architecture standard defines common waveform software interfaces, methods of instantiation, operation, and testing among different compliant hardware and software products. These common interfaces within the architecture abstract, or remove, the application software from the underlying hardware to enable technology insertion independently at either the software or hardware layer.
SCaN Testbed Location on ISS
The SCaN Testbed will launch to the ISS on a Japanese H-II Transfer Vehicle (JAXA HTV3), and be transferred and installed via Extravehicular Robotics (EVR) to the ExPRESS Logistics Carrier-3 (ELC3) in the inboard, Ram-facing, Zenith-facing payload location on an exterior truss of the ISS. Figure 1 illustrates the location of the SCaN Testbed on the ISS.
Figure 1. SCaN Testbed Location on ISS
SCaN Testbed News
SCaN Testbed Successfully Validated in Space as a Multi-frequency Global Navigation Satellite System Receiver
SCaN Testbed onboard the International Space Station
NASA’s Space Communications and Navigation (SCaN) Testbed now is the world’s first flight-validated, in-space U.S. GPS-European Galileo Global Navigation Satellite System (GNSS) receiver. This achievement and flight validation of GNSS signal reception in the space environment enhances GNSS interoperability while enabling more precise and robust orbital predictions, more diverse multi-frequency GNSS capabilities and improved applications such as on-board autonomous spacecraft operations and scientific measurements.
The SCaN Testbed is an advanced, integrated communications laboratory facility that uses a new generation of software-defined radio (SDR) technology to allow researchers to develop, test and demonstrate advanced communications, networking and navigation technologies in space. This SDR technology is based on a new NASA standard – the space telecommunications radio standard (STRS) – that enables radio applications to be changed simply by altering the software. NASA’s SCaN Program has developed the STRS architecture standard for SDR use in space- and ground-based platforms. This architecture standard provides commonality among radio developers to provide enhanced capability and services while reducing mission and programmatic risk. The cost savings and efficiency of this new technology will improve NASA’s data communications in the future. The SCaN Testbed also will help programs, technology developers and mission planners understand how SDRs will be used in future missions.
The ability to track signals from multiple GNSS receivers will enable NASA to improve both space operations and science missions that benefit society as a whole, ranging from better observation of Earth for more precise weather forecasting, sea level height measurements and climate change monitoring. It also will assist in improving our understanding of Earth’s crustal movements and allow advanced tsunami warnings.
This achievement resulted from a “science-of-opportunity” effort, supported by multiple NASA centers, to use the Testbed’s ability to process space-based navigation signals in addition to those of the U.S. GPS system. The SCaN Testbed aboard the International Space Station successfully recorded a navigation signal from the European Galileo satellite constellation and the U.S. GPS constellation at the same time. Signal reception then was successfully correlated to both a Galileo satellite and GPS signal by post-processing data recorded by the SCaN Testbed. The Testbed now is helping pave the way for greater use of international GNSS signals, validate the new modernized GPS signals and support future public and private sector users around the world and beyond Earth.
This reconfigurable laboratory in orbit provides broad participation to NASA, industry, academia and other government agencies to develop and execute experiments on the SCaN Testbed. These experiments will contribute data to the STRS repository and will enable future hardware platforms to use common, reusable software modules to reduce development time and costs. NASA continues to solicit proposals to participate in the development, integration and execution in orbit of research and technology experiments and demonstrations using the Testbed. The first users outside NASA are preparing to validate experiments on the SCaN Testbed, with two announcements of opportunity being prepared for release. The SCaN Testbed Experiment Opportunity invites industry and other government agencies to enter into Space Act Agreements with NASA to use the space station’s SCaN platform. The SCaN Testbed Cooperative Agreement Notice invites academia to develop proposals to use the orbiting laboratory’s SCaN Testbed research capabilities.
NASA’s Glenn Research Center in Cleveland leads the SCaN Testbed multi-center team, which includes the agency’s Goddard Space Flight Center in Greenbelt, Md.; the Jet Propulsion Laboratory in Pasadena, Calif.; and the Johnson Space Center in Houston. General Dynamics of Scottsdale, Ariz., and Harris Corp. of Melbourne, Fla., developed SDRs under cooperative agreements with NASA. The SCaN Program Office in the Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington manages, oversees and funds the Testbed.
For more information about the SCaN Testbed, including opportunities for academia, government agencies and industry to participate, please visit: http://go.nasa.gov/QLp37U
For more information about SCaN, please visit: http://www.nasa.gov/SCaN
SCaN Testbed News Archive
Recent Awards for the SCaN Testbed Team
Richard Reinhart, SCAN Testbed Principal Investigator, was honored at the second annual ISS Research and Development Conference in recognition of outstanding results from the Space Communications and Navigation (SCAN) Testbed – named a top Exploration Technology Application from the International Space Station in 2012. The plenary panel, moderated by NASA’s International Space Station Technology Demonstration Manager George Nelson, showcased key contributions in technology research and development that will enable and advance space exploration goals.
The technology of the SCAN Testbed demonstrates software defined radios (SDRs) that can reconfigure their functions via ground commands while the SDRs are in orbit. This unprecedented operational flexibility enables adaptability for new science capabilities and increased data return, while potentially reducing development costs and providing a flexible platform to address anomalies and risks both in orbit and during production. The new SDR technology also provides demonstrations for the development and operation of Earth-based applications with remote reconfigure systems, such as distributed telephony networks and other power resource constrained platforms such as small handheld radios. “It is a sincere honor to have one’s work both recognized and acknowledged for its potential to advance space exploration by selection as one of the Top ISS Technology Applications Enabling Exploration,” said Reinhart. “The SCAN Testbed project is the culmination of 10 years of research and development by a dedicated group of individuals to develop a software defined radio architecture standard, infuse the standard into space products and advance the understanding of software defined radio both within NASA and the software radio community.” Reinhart continued, “Few technologies make the leap from laboratory to space, and our team was fortunate enough to have the opportunity to demonstrate and experiment using the technology in space, on the International Space Station. I hope that the recognition and awareness of the ISS award encourages mission developers to assess, consider and adopt this new technology to enable or advance their mission capability and ultimately enable greater science return from their mission.”
The R&D 100 Awards are given annually to the top 100 most significant innovations and are widely recognized as the Oscars of Invention. The awards salute the 100 most technologically significant products from around the world. Winners are selected by an independent judging panel and the editors of R&D Magazine.
One team at NASA Glenn Research Center receiving the award in 2013 developed the NASA/Harris Ka-Band Software-Defined Radio. This is the first fully reprogrammable space-qualified radio of its kind operating in the Ka-Band frequency range. By providing the ability to upload new software applications once deployed to space, this radio offers future space missions flexibility to recover from problems during development, while on orbit and even adapt to new science opportunities. This technology will allow reuse of software waveform applications on new radios as hardware components become obsolete or as new radio technologies become available, providing flight proven software for future use. This will enable greater scientific return from future NASA missions and reduce the cost to develop and use new radio platforms.
The radio was integrated into the Space Communications and Navigation Testbed on the International Space Station on July 20, 2012, and is now fully operational. Experiments are currently underway, leveraging reprogrammability and the high data rate Ka-Band link from the space station through the Tracking and Data Relay Satellite System. New proposals from academia or industry for experiments are currently being accepted.
Members of this team include Glenn’s Thomas Kacpura, Sandra Johnson, Richard Reinhart and Joseph Downey; and Kevin Moran and Jeffery Anderson of Harris Corporation-Government Communication Systems Division, Melbourne, Fla.
September 11, 2013
Since our last corner, we’ve celebrated being on Station for a year. And here’s a neat way to further celebrate that milestone: check out these 3 screenshots from a very recent video survey of SCaN Testbed. This includes images of the APS Gimbal, and all the antennas (esp. closeups of Ka-band and S-band MGA).
Since the last Corner, here’s a recap of what we’ve achieved:
• We successfully updated our avionics software for the second time. This update included enhancements to enable the next cycle of the JPL GPS Experiment; various Spacewire improvements; various bug fixes and file system improvements; and, additional scripting capabilities to further enhance the productivity of our operations. Thanks to our software and QA teams for their efforts and for realizing further efficiencies in V&V and in planning.
• We upgraded and evaluated a new waveform on-orbit for the GD SDR. This waveform has an improved Bit Error Rate (BER) checker.
• Continued on-orbit tests with the Network Services WSC User Services Subsystems – Component Replacement (USS-CR) SGLT 5. The Space Network (SN) Project has implemented the USS-CR Project to free up legacy equipment from two Space-to-Ground Link Terminals (SGLTs) for use as spares. The primary objective of the testing is to provide checkout of configurations supported by the SCaN Testbed project with the USS-CR equipment using the GD radio. SCaN Testbed is supporting the Pre-Level 5 Testing on SGLT 5 SA1 by emulating S-band user (coherent (DG1M1), non-coherent (DG2M2), and transition back-and-forth to test forward, return, and tracking services. This is yet another instance (now 6+) of us providing value to SCaN Network Services.
• Continued on-orbit tests of all our launch waveforms, including experimenting with Harris’ low-end data rate of 300 Kbps.
• Completed TDRS 5 & TDRS 6 antenna characterizations
• Tested large file downlinks with a 650 Mb Harris file. The HRDL rate for SCAN Testbed was set to 6 MBps. The download was successful and took approximately 24 minutes. Thanks again to ops for working with ISS to bump the HRDL rates.
• Ran additional test events for the NEN-LGA Pattern Characterization that we originally ran in March and July, and will continue to run periodically. For those tests, the JPL SDR captured an S-Band ground beacon from the JPL campus.
• Continued on-orbit tests of Sun Tracking Experiment, which characterized the noise temperature of the JPL SDR. The team collected noise power data from the JPL SDR as it pointed towards the sun and as it pointed to dark sky.
• Conducted new set of S-band, GPS, and Glenn, Goddard, TDRSS (GGT) waveform tests. First, we conducted additional GGT testing to obtain power profile for combinations of TDRS Tx power and antennas. Second, the team repeated the open sky sun capture test with MGA at its zenith. Third, the team performed 90 minute GPS captures and provided data to Navsys as input into future decision point for whether to proceed with Phase 2 SBIR.
As for near-term, upcoming events:
• Another SDR reconfiguration, this time by Harris Ka-band capture waveforms, which will include a signal strength (APQM) indicator and sampling waveform to enable closed loop pointing. These waveforms will also help as utilities in the development of our spectral-efficient Ka-band waveforms (Expt #6).
What’s also really cool about this upcoming experiment is that all three of our SDRs will have been reconfigured, and this marks the seventh theme/type of reconfiguration (5 waveforms, 2 PAS updates), with dozens of actual reconfigurations (switching between launch / new waveforms, etc.).
• TDRS-K (now TDRS-11) Level 5 user operations testing. As part of that, while we have a very short two-month (no longer three month) window for user testing, we will be shooting for 60-80 events with TDRS-11 to get a dense sample set for a novel, in-situ/non-invasive method of calibrating TDRS antennas.
• Completing USS-CR testing
• Another round of GD launch waveform and GGT waveform tests
June 10, 2013
Since the last update, a lot of great events, tests, and experiments have taken place.
We’ve successfully performed our first on-orbit Payload Avionics Software (PAS) update. Various checks on the subsystems and radios were performed, with all checks and activities running nominally. The PAS update included necessary heartbeat telemetry support to enable the JPL GPS experiment, gaining operational efficiencies (scripting capability for operators), and corrective actions to various other bugs and issues.
The very next day, SCaN Testbed executed the JPL GPS experiment to operate the JPL SDR as a GPS receiver. The software (waveform) successfully tracked civil pseudo-range and phase GPS signals at L1, L2, and L5, and this is the first known civilian GPS receiver to track L5 from space. Kudos to the ops and experiment teams for their efforts in this important experiment!
This past weekend, we executed the first in-orbit test of the Ka-band autotrack feature of TDRS-K. The SCaN Testbed Autotrack test demonstrated that TDRS-K can acquire and autotrack a Ka-band user in low Earth orbit. Kudos to the investigators for their diligence and to the Ops team for executing this important experiment!
We are currently in the middle of a 48-hour JPL GPS test, straight away after the TDRS-K test.
Coming up: a series of tests with the Air Force GPS Directorate’s Civilian Navigation (CNAV) test campaign. A large part of CNAV Test Program’s success is performance evaluation and utility assessment of L2C and L5 navigation signals, and SCaN Testbed is front-and-center in that evaluation and assessment.
May 1, 2013
Checkout and Commissioning is complete. The flight and ground systems are healthy and robust. The Antenna Pointing System’s two-axis, closed-loop control gimbal is robust (a big unknown during development).
NASA issued a press release talking about completion of checkout and starting experiments. That is here: http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-116_SCaN_Up_and_Running.html
There’s been a good buzz about the release. SCaN Testbed is also the cover story of the April IEEE Aerospace and Electronic Systems Magazine, a peer reviewed publication. This is a very good article. Also, some good additional press on SCaN Testbed in Signal Magazine: http://www.afcea.org/content/?q=node%2F10979
We are also beginning SCaN experiments, as well as other government agency, university, and industry experiments. There is considerable interest in utilization of STB, as evidenced by approximately 40 NASA, industry, university, and Other Government Agency (OGA) experiment proposals. NASA and OGA programs are recognizing cost and time savings opportunities by using STB to demonstrate new capabilities and reduce risk to their programs.
SCaN Testbed recently supported Network Services over at White Sands, specifically the SN Digital Architecture Testing Project, with a Ka-band test signal for the TDRSS Digital System Distribution (TDSD) effort. This was another ~6 week turnaround from initial discussion to ops. Thanks to the Principal Investigator for leading this test, well done!
We’ve also achieved another major milestone with our first reconfiguration and waveform upgrade. The Glenn/Goddard/TDRS (GGT) waveform was upgraded to include a power estimator and a signal to noise ratio estimator, and the updated GGT was tested using the JPL SDR with the SN-MGA. The GGT adds BER measurement capabilities, and to-date the GGT has improved performance by approximately 6 dB. We’re continuing to characterize the performance of the GGT, and this most recent build also fixes a long-standing, minor performance issue that was around during development.
As far as near-term activities, we’ll become the first NASA Ka-band in-orbit user of TDRS-K, specifically the dual autotrack capability (SCaN Testbed tracking TDRS-K and vice versa). Then it’s on to the first Payload Avionics Software Upgrade, and then the JPL GPS experiment.
Kudos to the team for these huge achievements!
March 13, 2013
We’ve completed this first round of SDR commissioning operations. The overarching objectives of SDR Commissioning are to verify the end-to-end data flow of the SCaN Testbed and ground systems, and to verify that the radio links’ performance is predictable. SDR Commissioning activities are really the beginning stages of the in-house experiments, by virtue of the launch waveforms going through more operating hours. Support from White Sands (WSC) and the Space Network has been excellent, as inline measurements and delogs at WSC are not typical services for Ka-band users. Thanks to the team for supporting the Commissioning here at GRC and WSC. They worked long hours and through the weekend too. Kudos SCaN Testbed team!
While every test didn’t pass, we’re on track to better understanding the system issues, the interactions of SCaN Testbed with SN and NEN, and predicting link performance. We’re going to go through another round of SDR Commissioning operations to start tests that we requested but weren’t granted passes/events; and, to complete tests that were partially complete during this recent first round, including Space Wire tests that were planned during Commissioning but deferred for additional TDRS-K on-orbit dry-runs. We’re working on the timeframe to do this second round of SDR Commissioning operations.
We are continuing along with another round of antenna / TDRS Characterizations this week. This next round of events reflects the need for a 2nd Ka-Band TDRS characterization effort, after learning that they adjusted their power levels since the first round of Antenna Characterization. This includes going through each combination of TDE/TDW vs. SA1/SA2 vs. High Power/Normal Power in order for SCaN Testbed to understand and baseline its TDRS link performance. This makes for a total of 26 events, so the Experiments and Operations team will soon be busy with that.
The Mission ops team is continuing to conduct tests to balance the Ka-band EIRPs across the TDW and TDE birds. SN also formally requested our participation in additional TDRS-K Testing, so we will begin planning for that as well.
Then it’s on to the JPL Mini-Captures (JPL Ground Station to SCaN Testbed signal capture events to further characterize the NEN-LGA), SDR Commissioning Round 2, then TDRS-K testing, and then our first on-orbit Payload Avionics Software (PAS) upload/update. Then we’ll get some more operating hours with the launch waveforms, and then the important TDRS-K autotrack test on 4/16 (the first in-orbit checkout of TDRS’s dual autotrack capability at Ka-band).