1、(网络查询关键词)Preflight and Vicarious Calibration of ArtemisARTEMIS Hyperspectral SensorAchieving Multipurpose Space Imaging with the ARTEMIS Reconfigurable Payload ProcessorThe ARTEMIS, a hyperspectral imaging sensor from Raytheon, is being tasked for the Air Force Space Commands tactical military role,
2、 which is the first of its kind.Raytheon ARTEMIS Hyperspectral Imaging Sensor for Tactical Military RoleIs there a best hyperspectral detection algorithm?（SPIE ）Infrared Technology and Applications XXXVI (Proceedings Volume)IEEE ARTEMIS Hyperspectral SensorHyperspectral Sensor ARTEMISARTEMIS Hypersp
3、ectral PayloadTacSat 3 ARTEMISTACSAT 3- Information | Home | Passes (visible) | Passes (all) | Orbit | Identification USSPACECOM Catalog No.: 35001International Designation Code: 2009-028-A Satellite Details Orbit: 416 x 446 km, 40.5Country/Org. of Origin: USAIntrinsic brightness (Mag): 5.2 (at 1000
4、km distance, 50% illuminated)Maximum brightness (Mag): 1.4 (at perigee, 100% illuminated)Launch Date (UTC): May 18, 2009Sensor complement: (ARTEMIS, ODTML, SAE) Building on the experiences with TacSat-1 and -2, TacSat-3 is the first spacecraft of the series to have gone through a formal payload sele
5、ction process with AFSPC (Air Force Space Command) and Coordinating Commands (COCOMs) and Services. ARTEMIS (Advanced Responsive Tactically Effective Military Imaging Spectrometer): ARTEMIS is a hyperspectral imager (HSI), funded by AFRL with additional funding by the US Army, designed and developed
6、 at Raytheon Space and Airborne Systems of El Segundo, CA, using COTS components extensively (ARTEMIS contract award in 2005). There is also a collaboration on the imaging spectrometer from NASA/JPL. The main objectives are: To demonstrate tactically significant hyperspectral imagery collection and
7、processing sufficient to meet militarily relevant detection thresholds For a single-pass opportunity, the time period from a specified target collect to delivery of a processed product to the warfighter level must occur within 10 minutes (threshold: 30 min). The instrument consists of a telescope, a
8、n imaging spectrometer, a high resolution imager and a real-time processor referred to as HSIP (Hyperspectral Imaging Processor). ARTEMIS provides HSI observations in the visible and SWIR (Short Wave Infrared) region as well as panchromatic data. The spectral range coverage is from 0.4 -2.5 m. The t
9、elescope is a standard Ritchey-Chrtien form and is telecentric as is required to meet the spectral and spatial uniformity goals of the imaging spectrometer (heritage of TacSat-2). Additionally the secondary mirror has a built-in focus mechanism for on-orbit optimization. 12) 13) 14) 15) 16) Figure 6
10、: Illustration of the ARTEMIS telescope (image credit: AFRL) The imaging spectrometer is of the basic Offner form consisting of two powered reflecting surfaces comprising the primary and tertiary elements. The secondary mirror is replaced by a curved grating for dispersion and is the limiting stop o
11、f the system. This form has the merit of being simple, compact, and both spatially and spectrally uniform. Spatial and spectral uniformity is critical to the operational performance of imaging spectrometers as it enables robust exploitation of data products. Spectral sampling is at 5 nm intervals. A
12、dditionally the design has 50 kbit per node per day - 0.1 Joule per bit transmitted. The ODTML network system consists of the following elements: 1) “Smart sensor nodes,” each containing an RF terminal, which collect the sensor data and communicate with the satellite payload. These smart sensor node
13、s are mounted on the sensor platforms, e.g., free-floating buoys or UGS (Unattended Ground Sensors). 2) Spacecraft Communications Payload (SCP), a microsatellite-mounted payload serving as a “router in the sky.” 3) Portable ground stations, acting as gateways to transfer the sensor data from the RF
14、link to the Internet. 4) The Internet, as the communication conduit between the users and the ocean and ground-based observing platforms. Figure 11: Overview of the ODTML system elements (image credit: NRL) Figure 12: Conceptual overview of ODTML elements (image credit: Praxis Inc.) The ODTML demons
15、tration will collect data from sea-based buoys and then will transmit the information back to a ground station. SAE (Space Avionics Experiment): The collection of concepts developed by AFRL to realize PnP (Plug-and-Play) space systems is collectively termed SPA (Space Plug-and-Play Avionics). These
16、concepts include self-forming networks, machine-negotiated interfaces, encapsulation of complexity, and test bypass. The objective is to validate plug-n-play avionics capability, which involves the use of reprogrammable components to integrate the SPA experiment and the spacecraft structure. 23) 24)
17、 25) 26) 1) Encapsulation: The most fundamental concept in the SPA paradigm is that of encapsulationhiding complexity within modular building blocks in order to simplify design. In SPA, this concept manifests itself both in the design of hardware and software. In hardware, the complex inner workings
18、 of the device are hidden from the rest of the system. Only single-point electrical connections consisting of data, power, and time synchronization are used to connect the device to the SPA network. Software encapsulation occurs at many levels, but the greatest example is in the use of XML-based or
19、xTEDs (eXtended Transducer Electronic DataSheets) to precisely define the interfaces between components and even “pieces of software.” The goal of this architecture is the achievement of “pure” or “glueless” hardware and software modularity. “Gluelessness” is a very constrained form of modularity th
20、at allows rapid integration to occur. Instead of requiring custom electronics or software (the glue) to interface one modular block with another, each block contains everything it needs to maintain compatibility with other blocks in the system. 2) Self-forming networks: The second important SPA conc
21、ept is that of self-forming networks. In SPA, every device is considered an endpoint on the network, including both traditional bus components, such as reaction wheels or torque rods, and payload components, such as imaging devices. In fact, even structures are endpoints and can be treated in the sa
22、me manner as other SPA devices on the network. For example, a spacecraft structural panel may contain its own harnessing and internal routers and hubs - essentially an entire SPA sub-network in itself, but the panel is also an endpoint and can be treated as such in the larger SPA network that is the
23、 PnP spacecraft. The result is a collection of endpoints separated by hubs or routers and arranged in any order or configuration. The SPA network is created dynamically as devices are introduced. 3) Machine-negotiated interfaces: Glueless modularity and self-describing networks are achieved in the S
24、PA architecture through the use of the third SPA concept-machine-negotiated interfaces. SPA interfaces are defined by components in their resident xTEDs and managed by the SDM (Satellite Data Model). The xTEDs contains descriptions of all commands accepted, variables produced, and data messages that
25、 can be delivered by the device. It fully describes the services and data provided by the device and represents the protocol for accessing these services and data. SDM is a type of “middleware” that manages the SPA distributed network and makes it possible for applications and components to share da
26、ta and services without needing to know addresses or specific messaging structures. The SDM allows plug-and-play-based hardware communications interfaces to devices. It also allows intelligent devices to describe their controls and data formats to the network using an electronic data sheet. SDM allo
27、ws application software to query a device to discover its requirements and capabilities for both control and data. By facilitating the query of device capabilities and needs, SDM offers the capability of a glueless rapid system integration, which is capable of dynamic device interfacing without a-pr
28、iori knowledge of an expected system configuration. Some background: In 2004, an AFRL study, referred to as RSATS (Responsive Space Advanced Technology Study), revealed that Plug-and-Play technologies similar to those used in the commercial electronics industry could be used to help achieve ORS capa
29、bilities such as the rapid reconstitution and augmentation of existing space assets. The study featured an AFRL proposal to develop the AAE (Adaptive Avionics Experiment), which embraced many of the key principles behind a modern plug-and-play (PnP) approach for aerospace. The AAE focused on avionic
30、s as the area most readily transformed into a PnP system, with the following four elements as crucial: appliqu sensor network, adaptive wiring manifold, high-performance computing on-orbit, and software definable radio. The appliqu sensor network, proving to be the most useful of the four was expand
31、ed and refined to become the current SPA architecture. In late 2004 AFRL received approval for a committee on standards (CoS) by the AIAA (American Institute for Aeronautics and Astronautics), a US national level standards development organization. This CoS included representatives from government,
32、industry, and academia. The working group developed a series of standards, christened “Spacecraft Plug-n-Play Avionics” (SPA) to describe a spacecraft architecture based on standard interfaces to connect modular components or subsystems. These standards are based on commonly used standards in the In
33、formation Technology (IT) industry. Figure 13: Overview of the plug-and-play avionics architecture (image credit: AFRL) Any SPA standard, for example, must support data transport, power delivery, time synchronization, single point ground connection, and minimal “hooks” for self-description. While th
34、ey are excellent standards for data transport, neither USB (Universal Serial Bus) nor SpaceWire provide all of these features. To make them into SPA standards, the CoS focused on minimally-invasive approaches. The CoS tended to overlay features as opposed to modifying the inner workings of proven st
35、andards. Instead, sensible extensions were proposed: Connectors with enhanced robustness The addition of a separate 28V power delivery Use of a distinguished single point ground conductor Addition of a one pulse per second (1PPS) signal for system-wide time synchronization Provision for an electroni
36、c datasheet The optional inclusion of a special test bypass interface to support test/debug and hardware-in-the-loop integration. Ultimately these standards allow a spacecraft avionics architecture with distributed computer processors and sensors connected as shown in Figure 14. Figure 14: Distribut
37、ed avionics architecture based on plug-n-play standards (image credit: AFRL) ASIM (Appliqu Sensor Interface Module). ASIM is a device as well as an enabling technology for SPA systems. One of the challenges faced by the commercial computer electronics industry in designing PnP devices was (and is) t
38、he sheer complexity of the interfaces. The ASIM interface module was defined for existing spacecraft components. This evokes a “peel-and-stick” paradigm; permitting legacy devices to rapidly integrate into a PnP (Plug-n-Play) network. In essence, the ASIM is a smart interface chip (or multi-chip mod
39、ule). They are analogous to a USB interface chip in a personal computer. Just as USB chips permit the rapid integration of a mouse or keyboard into a personal computer, the ASIM permits ordinary legacy spacecraft components (such as a reaction wheel, thermometer, or camera) to be rapidly integrated
40、into a spacecraft vehicle. The ASIM electronically stores specific information about the device (using XML) in a small nonvolatile memory. This information becomes an xTEDs (XML Transducer Electronic Datasheet). The ASIM passes xTEDs information to the spacecraft system upon request as devices are p
41、lugged into the network. The ASIM not only acts as a SPA interface chip, but also includes other SPA-enabling features such as xTEDs, power management, time synchronization and test bypass. Figure 15: Block diagram of a generic ASIM device (image credit: AFRL) The aerospace industry is plagued with
42、a vast array of incompatible interface standards. The integration of numerous components and payloads utilizing many different connection standards into a spacecraft bus is one of the more time-consuming aspects to spacecraft design, often leading to time delays and cost overruns. However, if non-Pn
43、P components are affixed with a SPA interface, the actions of integrating components into a SPA-compliant bus are reduced to simple plugging functions, thereby vastly reducing satellite build time. One of the primary functions of the ASIM is to serve as a bridge between legacy components and a SPA n
44、etwork. On one side, referred to as the host side, the ASIM functions as a SPA device, communicating with the SPA network via the SPA-x protocol. On the other side, referred to as the target side, the ASIM communicates with the legacy device according to its native communications protocol. A certain
45、 amount of time is still required to program the ASIM to communicate with the legacy device, but this overhead is a small price to pay for the time and reduction of human-induced errors saved during integration. This action could even be incorporated into the component design itself, encapsulating b
46、oth the SPA nature of the ASIM and functionality of the component into one single truly SPA-compatible device. All SPA devices and structural panels could be designed in this way and stored until required for a new spacecraft. Spacecraft construction would then consist of connecting panels together
47、to form a bus, selecting whatever components are required for the specific mission, pulling them off the shelf and plugging them into the panels. AFRL has created two prototype versions of an ASIM, referred to as Gen 0 (Generation 0) and Gen 1 (Generation 1). Gen 0 was a “house” version of the ASIM
48、(developed by SAIC, Albuquerque, NM) used predominately in the Responsive Space Testbed (RST) for initial exploration of SPA devices and networks. The most current version of the ASIM (Gen 1) is based on the SPA-U interface and has been made commercially available (Data Design Corp., Gaithersburg, M
49、D). The ASIM is currently a small printed wiring board (PWB), employing an FPGA-based design serving as a “soft testbed” for further refinement. The standards have initially focussed on interface definitions for low-data-rate components, “SPA-U” which is based on the USB 1.1 standard, and high-data-rate components SPA-S (based on the European SpaceWire standard). Figure 16: Simplified architecture of a SPA device (image credit: AFRL) Prototype Hyperspectral Satellite Fast-Tracked to Begin Official Spy Work for MilitaryBy Rebecca Boyle Posted 06.11.2010 at 3:36 pm 6
