1998 - Draper Laboratory

More documents

Recommendations

Info

Software EngineeringLinda AlgerAdvanced Fault-TolerantComputing for FutureManned Space MissionsJaynarayan H. LalaAndrew L. BenjaminRobert L. ShulerAutomated Station-Keeping for SatelliteConstellationsRonald J. ProulxPaul CefolaNaresh H. ShahBrian KantsiperJohn Draim
As real-time systems evolve into the tolerant computer with inputs and outputs. We havenext millennium, the role of developed techniques for sensor redundancysoftware becomes increasingly management — the detection and resolution of dataimportant. Innovative software conflicts among sensors — and network fault detection,engineering will simultaneously isolation, and reconfiguration.lower the cost and increase such systems’ capability. TheDraper Software Engineers are in the forefront of thesetrends, with special expertise in the complex controlsystems designed for high-priority exploration and defensetasks that have been Draper’s historical specialty.Astrodynamics Software: Another specialty of DraperSoftware Engineering and the subject of the papers by R.Proulx, P. Cefola, N. H. Shah, B. Kantsiper, and J. Draim issoftware supporting the management of multiple man-madeobjects in space.Software for embedded systems, especially systems thatAstrodynamics functions include determining andoperate land, sea, air, and space vehicles, is thepredicting orbits based on observed data and thequintessential competency of the Directorate. We havemanagement of spacecraft constellations. We are developingprovided real-time software for the Polaris, Poseidon, andnew methods for including the effects of atmospheric drag,Trident strategic missiles; the Unmanned Undersea Vehiclesolar perturbations, and tesseral harmonic geopotential(UUV), the Deep Sea Rescue Vehicle (DSRV), and Seawolf;effects. We are applying these techniques to multiplethe F-8, A-10, and Cobra aircraft; and all NASA mannedsatellites in low Earth orbits, geosynchronous orbits, andspacecraft from Apollo to the International Space Stationhighly-elliptic 12-h resonant orbits.(ISS).Software for real-time embedded systems is very differentfrom that for mainframe or workstation applications.Dynamic vehicle control requires sensor inputs andeffector outputs that are subject to stringent timeconstraints. Software must be cognizant of the underlyinghardware and of the mission being implemented. Thesoftware must be highly reliable and must function in thefield for long periods. When the system has a pilot,additional human-interface requirements and still greaterreliability are implied.Software Architectures: High-level software architecture isdriven by the need to optimally use the computationalresources, to provide a software environment that facilitatesthe development of applications, to segment the software sothat changes can be made in one area without unnecessaryimpacts on other functions, and to set the stage for real-timeadaptivity.Real-time embedded systems have traditionally beendedicated to and optimized for particular missions.Software for such systems has been expensive to build andFault-Tolerance and Reliability: The paper by J. Lala, A. maintain. The future direction of real-time systems isBenjamin, and R. Shuler discusses the future of faulttolerantcomputing. Following the Apollo project, Draperbegan to explore fault-tolerant computer architectures,toward generic platforms designed for particularenvironments, but not for particular missions—the ISS is aprominent example of this trend.leading in 1980 to the ground-breaking Draper Fault-The practicality of such systems depends on a softwareTolerant Multiprocessor. Such systems offer a more costeffectivemeans of achieving reliability than the slow, ultra-architecture that facilitates the design of new missionsthroughout an operational life that may be measured inreliable, single-string computer used by the Apollodecades. The Directorate has been a pathfinder in this area.spacecraft.Our Timeliner sequencing system allows operationalDraper has pioneered software error-detection andreconfiguration techniques, multiversion programming,and automated software generation. Current thinking inthis area is driven by the requirements of a mannedmission to the planet Mars.Fault tolerance can be extended to the sensors, actuators,and communications networks that provide the faultpersonnelto program, execute, and monitor new missionoperations at any time. Carrying this method to its nextlevel, an onboard library of hierarchical, operational scriptsoffers the potential to achieve significant gains in the totalsystem’s capability to adapt itself autonomously to achieve asuccessful result despite subsystem failures, damage, andaltered circumstances requiring mission changes.Introduction
Page 2 and 3:
Letter from thePresident and CEO,Vi
Page 4 and 5:
Information TechnologyMilton AdamsE
Page 6 and 7:
BiographyMilton Adams has been at D
Page 9 and 10:
Figure 1 represents a functional de
Page 11 and 12:
Programs. In effect, these controll
Page 13 and 14:
Although the terminal area traffic
Page 15 and 16:
Table 2. ATFM performance evaluatio
Page 17 and 18:
In the experiments, a nominal capac
Page 19 and 20:
[3] Wambsganss, Michael C. “Colla
Page 21 and 22:
Guidance, Navigation, and Control A
Page 23 and 24:
A Control Lyapunov FunctionApproach
Page 25 and 26:
x( 0) ∈ X and w(t) ∈Wfor all t
Page 27 and 28: (b) Select a quadratic RCLF V i (x)
Page 29 and 30: at each grid point. In the case w 1
Page 31 and 32: References[1] Ball, J.A. and A.J. v
Page 33 and 34: Guidance, Navigation, and Control A
Page 35 and 36: Relative and Differential GPSData T
Page 37 and 38: The first term on the right in the
Page 39 and 40: H R# δρ R,GPS -H A# δρ A,GPSThi
Page 41 and 42: selection; and (3) shown that the a
Page 43 and 44: Guidance, Navigation, and Control A
Page 45 and 46: Segmentation of MR ImagesUsing Curv
Page 47 and 48: (3)where ν now represents a contin
Page 49 and 50: Experimental ResultsThe results of
Page 51 and 52: Table 1. A summary of segmentation
Page 53 and 54: Guidance, Navigation,and ControlJim
Page 55 and 56: BiographyGeorge SchmidtGeorge Schmi
Page 57 and 58: clock and ephemeris errors, as well
Page 59 and 60: maintained in a rigid structure, wh
Page 61 and 62: Table 5. “Typical” absolute GPS
Page 63 and 64: performed, then the target location
Page 65 and 66: tightly-coupled system, however, ca
Page 67 and 68: Concluding RemarksRecent progress i
Page 69 and 70: As real-time systems evolve into th
Page 71 and 72: Advanced Fault-TolerantComputing fo
Page 73 and 74: The Viking and Voyager were both in
Page 75 and 76: Containment Regions (FCRs). There a
Page 77: well as reversing the whole process
Page 81 and 82: Automated Station-Keepingfor Satell
Page 83 and 84: Figure 2. Minimum elevation angles
Page 85 and 86: anomaly M and/or the ascending node
Page 87 and 88: However, since optimization and rec
Page 89 and 90: is maintained in the Northern Hemis
Page 91 and 92: autonomy. It must have the ability
Page 93 and 94: [31] Neelon, Joseph G., Jr., Paul J
Page 95 and 96: Draper’s primary goal is to Drape
Page 97 and 98: )Rotordynamic Modelingof an Activel
Page 99 and 100: Eq. (9) becomes:λ[ R ] { Φ } = [
Page 101 and 102: chosen to be 24, for a total of 48
Page 103 and 104: InertialInstruments/MechanicalDesig
Page 105 and 106: BiographyJeffrey Borenstein is curr
Page 107 and 108: process step. Process information i
Page 109 and 110: Figure 4. Control chart for boron d
Page 111 and 112: References[1] Barbour, N., J. Conne
Page 113 and 114: Draper Laboratory continues to engi
Page 115 and 116: Validating the Validating Tool:Defi
Page 117 and 118: calculates miscellaneous terms, suc
Page 119 and 120: Table 1. Suggested specification sh
Page 121 and 122: User Accuracy as aFunction of Simul
Page 123 and 124: 20-min averaging, this clock lockin
Page 125 and 126: Table 2. Sample high-level summary
Page 127 and 128: AcknowledgmentR.L. Greenspan, J.A.
Page 129 and 130:
Systems IntegrationRich MartoranaPe
Page 131 and 132:
BiographyAnthony Kourepenis is an A
Page 133 and 134:
control is employed to maintain the
Page 135 and 136:
Table 1. Summary of automotive yaw
Page 137 and 138:
Resolution (60 Hz) deg/h10000000100
Page 139 and 140:
References[1] Greiff, P., B. Boxenh
Page 141 and 142:
Page 143 and 144:
An Integrated Safety AnalysisMethod
Page 145 and 146:
Infrastructure ModelsSystemRequirem
Page 147 and 148:
Figures 6 and 7 illustrate the bloc
Page 149 and 150:
Notice that each flight track descr
Page 151 and 152:
Table 7. Safety statistics at 1700-
Page 153 and 154:
Page 155 and 156:
An Optimal Guidance Law forPlanetar
Page 157 and 158:
Note that the states in the three d
Page 159 and 160:
Crossrange (Kft)10090807060504030Cl
Page 161 and 162:
The 1997 Charles StarkDraper PrizeT
Page 163 and 164:
The 1997 Charles StarkDraper Prize1
Page 165 and 166:
“Draper encourages its personnel
Page 167 and 168:
Gimballed Vibrating GyroscopeHaving
Page 169 and 170:
Page 171 and 172:
Optical Source Isolator withPolariz
Page 173 and 174:
Page 175 and 176:
Hunting Suppressor forPolyphase Ele
Page 177 and 178:
Page 179 and 180:
Sensor Having an Off-Frequency Driv
Page 181 and 182:
proof mass from transients and enha
Page 183 and 184:
1997 Published PapersThe following
Page 185 and 186:
monitoring of space structures and
Page 187 and 188:
measured by kinematic degrees of fr
Page 189 and 190:
i.e., what percent of the earth’s
Page 191 and 192:
McConley, M. W.; Dahleh, M. A.; Fer
Page 193 and 194:
unaffordable, or even misguided. Bu
Page 195 and 196:
The Draper DistinguishedPerformance
Page 197:
Educational Activitiesat Draper Lab
show all

1998 - Draper Laboratory

Create successful ePaper yourself

Delete template?

Save as template?