BOREAS Level-0 ER-2 Navigation Data Summary The BOREAS Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of aircraft navigation/attitude data to complement the digital image data. The level-0 ER-2 navigation data files contain aircraft attitude and position information acquired during the digital image and photographic data collection missions. Temporally, the data were acquired from April to September 1994. Data were recorded at intervals of 5 seconds. The data are stored in tabular ASCII files. Note that the level-0 ER-2 navigation data are not contained on the BOREAS CD-ROM set. An inventory listing file is supplied on the CD-ROM to inform users of the data that were collected. See Section 15 for information about how to acquire actual level-0 ER-2 navigation data. Table of Contents * 1 Data Set Overview * 2 Investigator(s) * 3 Theory of Measurements * 4 Equipment * 5 Data Acquisition Methods * 6 Observations * 7 Data Description * 8 Data Organization * 9 Data Manipulations * 10 Errors * 11 Notes * 12 Application of the Data Set * 13 Future Modifications and Plans * 14 Software * 15 Data Access * 16 Output Products and Availability * 17 References * 18 Glossary of Terms * 19 List of Acronyms * 20 Document Information 1. Data Set Overview 1.1 Data Set Identification BOREAS Level-0 ER-2 Navigation Data 1.2 Data Set Introduction The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of aircraft navigation/attitude data to complement the digital image data. 1.3 Objective/Purpose The ER-2 navigation data set consists of navigation parameters gathered by the aircraft's onboard systems in support of the payload instruments. The purpose of the data is to provide general aircraft positioning information and aircraft attitude information during data collection activities. 1.4 Summary of Parameters The data include times and georeferencing information that can be used to determine temporal and spatial coordinates associated with each measurement collected from the onboard instruments. 1.5 Discussion The ER-2 navigation data set consists of navigation parameters gathered by the aircraft's onboard systems in support of the payload instruments. It includes times and georeferencing information that can be used to determine temporal and spatial coordinates associated with each measurement collected from the above instruments. 1.6 Related Data Sets BOREAS Level-0 ER-2 Aerial Photography BOREAS Level-0 AOCI Imagery: Digital Counts in BIL Format BOREAS Level-0 Daedalus TMS Imagery: Digital Counts in BIL Format BOREAS RSS-18 Level-1B AVIRIS Imagery: At-sensor Radiance in BIL Format 2. Investigator(s) 2.1 Investigator(s) Name and Title BOREAS Staff Science 2.2 Title of Investigation BOREAS Staff Science Aircraft Data Acquisition Program 2.3 Contact Information Contact 1 ------------------- Jeffrey S. Myers Aircraft Data and Sensor Facilities NASA/Ames Research Center Moffett Field, CA (415) 604-6253 (415) 604-4987 (fax) jmyers@arc.nasa.gov Contact 2 ------------------- Jeffrey A. Newcomer Raytheon STX Corporation NASA/GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) Jeffrey.Newcomer@.gsfc.nasa.gov 3. Theory of Measurements The National Aeronautics and Space Administration (NASA) at Ames Research Center (ARC) maintains a variety of aircraft and sensor systems dedicated to support of remote sensing research. Among these is the Lockheed ER-2 (U-2R). The ER-2 has carried the Moderate-Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS), the Multispectral Atmospheric Mapping Sensor (MAMS), the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS), the Thematic Mapper Simulator (TMS), the Airborne Ocean Color Imager (AOCI), and the Thermal Infrared Multispectral Scanner (TIMS). For the BOREAS project, the TMS, AOCI, and AVIRIS sensors flew aboard the ER-2. Navigation parameters provided by the Litton LTN-92 Inertial Navigation System (INS) includes latitude/longitude, altitude, air speed, pitch, roll, heading, wind speed and direction and static air temperature. The data were recorded in five-second intervals. 4. Equipment 4.1 Sensor/Instrument Description 4.1.1 Collection Environment The INS on the ER-2 is a Litton LTN-92. The LTN-92 comprises three separate units: the Inertial Navigation Unit (INU), the Control/Display Unit (CDU), and the Mode Select Unit (MSU). Three 28-cm ring laser gyros and a triad of force rebalanced accelerometers make us the LTN-92's instrument cluster. The system accepts Area Navigation (RNAV), Global Positioning System (GPS) or manual position updates, plus INS mixing for improved performance. The Litton Web site (http://www.littoncorp.com/html/newsflash/06_14_97.htm) can be referenced for more information. The system operates by sensing accelerations from a gyro-stabilized, all-attitude platform. This information is integrated by a digital computer to provide an indication of present position (latitude and longitude), attitude data (pitch and roll) and course line computation referenced to great circle routes. The ER-2 has no room for auxiliary personnel; the LTN-92 INU, the instrument control panel, and the temperature and pressure units are directly connected to the data recorder in the payload area. 4.1.2 Source/Platform The NASA ER-2 is a high-altitude, single-pilot aircraft based at ARC in Moffett Field, Moffett Field,CA, and is deployed globally in support of a variety of atmospheric research projects. It has a maximum altitude of 70,000 feet (21 km), a range of 3,000 nautical miles, maximum flight duration of 8 hours (nominal 6.5 hours), and a top speed of 410 knots true air speed. The aircraft accommodates about 2,700 pounds of payload and offers the following science support systems: Inertial navigation Satellite NBS Time Code receiver Navigation data recording system Real-time telemetry data link 4.1.3 Source/Platform Mission Objectives For BOREAS, the primary ER-2 mission objective was to collect various Earth surface data in coordination with satellite overpasses for data verification and integration studies. A secondary objective was to collect data at key times when the satellites were not within range of specific sites. The ER-2 was based in Spokane, WA and could be deployed from there to take advantage of anticipated good data collection conditions. The navigation data provide in-flight geographic location and attitude information for the onboard sensors. 4.1.4 Key Variables The key parameters used by BOREAS Information System (BORIS) staff and investigators are geographic location, time, platform attitude, altitude, aircraft pitch and roll, and temperature in proximity to the aircraft. 4.1.5 Principles of Operation The INS on the ER-2 operates by sensing accelerations from a gyro-stabilized, all-attitude platform. This information is integrated by a digital computer to provide an indication of present position (latitude and longitude), attitude data (pitch and roll), and course line computation referenced to great circle routes. 4.1.6 Sensor/Instrument Measurement Geometry Aboard the ER-2, navigation parameters are recorded at 5-second intervals. The data buffer servicing the navigation recorder samples the particular parameter between records, but is precisely correct only at some point between records. Each parametric measurement is recorded as a count in a 16-bit word; consequently, the conversion of that count to an engineering unit defines the precision. The precision of each measurement is tabulated below. Parameter Precision Julian Date One Day Time One second Latitude 0.33 minutes of angle (2002.6 feet) Longitude 0.33 minutes of angle (2002.6 feet) N-S Velocity 0.1 knot E-W Velocity 0.1 knot True Heading 0.0054932 degrees of an angle Ground Speed 0.1 knot Vertical Velocity 0.025 feet/second Altitude 2.92749 feet (pressure altitude) True Air Speed 0.0152588 knot Pitch 0.0054932 degrees of an angle Roll 0.0054932 degrees of an angle Computed: Ground Speed 1.0 nautical mile per hour Wind Speed 1.0 nautical mile per hour Wind Direction 1.0 degree Vertical Velocity 1.0 foot per second Climb Angle 1.0 degree Air Temperature 0.1 degree centigrade The accuracy of the X-Y-Z position as recorded by the navigation system is limited by the frequency and accuracy of the Tactical Air Navigation (TACAN) - based updates to the inertial system and the accuracy of the recorded altitude. In the conterminous United States, updates occur frequently and are based on strong relative geometry because of the density of TACAN stations, resulting in errors of less than 0.1 nautical mile in X and Y (less error than the precision of the recording system). Altitude is based on barometric pressure with standard pressure defined as 29.92 inches of mercury. Consequently, the actual altitude above mean sea level will vary with current atmospheric conditions and the actual altitude above terrain with the terrain elevation. 4.1.7 Manufacturer of Sensor/Instrument ARC personnel built the navigation data recorder specifically for NASA’s ER-2 fleet. LTN-92 INU Litton Industries, Inc. Woodland Hills, CA 91367-6675 4.2 Calibration 4.2.1 Specifications None given. 4.2.1.1 Tolerance None given. 4.2.2 Frequency of Calibration None given. 4.2.3 Other Calibration Information None. 5. Data Acquisition Methods The ER-2 has no room for auxiliary personnel; the LTN-92 INV, the GPS, the instrument control panel, and the temperature and pressure units are connected to the payload area by RS232 and Aeronautical Radio Inc. (ARINC) 429 data buses. Data are recorded serially as a flux change on both track 1 and track 2, with a flux change on track 1 representing a logic one and a flux change on track 2 representing a logic zero. Data words are grouped with 16 bits per word and are separated by a three-step gap in which no flux changes occur on either track. After 1316-bit words (or up to 21 words, depending upon how many analog channels have been recorded), a 12-bit end-of-file gap is recorded (no flux changes). The order of words is as follows: WORD DESCRIPTION Serial Number, Flags, Julian Date Clock Latitude Longitude N-S Velocity E-W Velocity True Heading Ground Speed (valid data only with standard INS) Vertical Velocity (valid data only with high-resolution INS) Altitude True Air Speed Pitch Roll 14-21 Analog Inputs (optional) For more detailed information on the Cassette Data Format see Guillot, 1985. 6. Observations 6.1 Data Notes None. Pertinent in-flight comments are recorded in the digital data records. 6.2 Field Notes Flight summary reports and verbal records on videotapes are available from the ER-2 flights. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The BOREAS level-0 ER-2 navigation data were collected primarily as the ER-2 flew over portions of the Northern Study Area (NSA) and the Southern Study Area (SSA) during its image data acquisition missions. The SSA and the NSA are located in the southwest and northeast portions of the overall BOREAS region. Some navigation data exist in the data set that cover the BOREAS transect area between the NSA and SSA and areas outside the BOREAS region. The North American Datum 1983 (NAD83) corner coordinates of the SSA are: Latitude Longitude -------- --------- Northwest 54.321 N 106.228 W Northeast 54.225 N 104.237 W Southwest 53.515 N 106.321 W Southeast 53.420 N 104.368 W The NAD83 corner coordinates of the NSA are: Latitude Longitude -------- --------- Northwest 56.249 N 98.825 W Northeast 56.083 N 97.234 W Southwest 55.542 N 99.045 W Southeast 55.379 N 97.489 W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution Spatial resolution is not strictly applicable to ER-2 navigational data. The sampling rate for each portion of the navigation data can be combined with aircraft position, speed, and altitude to derive a spatial component for each data sample. However, because of the 5-second duration between each navigation parameter, interpolating the navigation data to specific lines in the image data may have limited usefulness. 7.1.4 Projection The BOREAS level-0 ER-2 navigation data contain latitude and longitude coordinates in the parameter set. Although the latitude and longitude coordinates could be used to calculate coordinates for any map projection, BORIS staff did not assess their accuracy and therefore cannot make any statements about their validity. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The data were collected during BOREAS' Focused Field Campaign (FFC) and three Intensive Field Campaigns (IFCs), covering the period from 19-Apr-1994 through 17-Sep-1994. The ER-2 collected various image data sets over the BOREAS sites in 1996, but no navigation data were delivered to BORIS. 7.2.2 Temporal Coverage Map IFC# Dates ----- -------------------------- FFC-T 16-Apr-1994 -- 20-Apr-1994 IFC-1 23-May-1994 -- 08-Jun-1994 IFC-2 21-Jul-1994 -- 08-Aug-1994 IFC-3 08-Sep-1994 -- 17-Sep-1994 7.2.3 Temporal Resolution All of the parameters in the navigation data were collected at intervals of 5 seconds. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (er2nav0.def). 7.3.1 Parameter/Variable A listing of the navigation data file parameter is given in Section 8.2. 7.3.2 Variable Description/Definition A detailed description of the navigation data parameters is given in Section 8.2. 7.3.3 Unit of Measurement A detailed description of the navigation data parameter units is given in Section 8.2. 7.3.4 Data Source A detailed description of the navigation data files and their content is given in Section 8.2. 7.3.5 Data Range The range of values for the parameters in the actual navigation data files was not tabulated. 7.4 Sample Data Record A sample data record for the level-0 ER-2 navigation data is not available here. Sample data format shown in the companion data definition file (er2nav0.def). 8. Data Organization 8.1 Data Granularity The smallest unit of level-0 ER-2 navigation data is all the ER-2 navigation information collected during the ER-2 flights over the BOREAS areas. All nine of the data files are in a single tar file on a single tape for distribution. 8.2 Data Format(s) The image inventory files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (er2nav0.def). The data are contained in a single tar file and after extraction (tar –xvf) can be seen correctly if unblocked using a block size of 150. (dd if=in_fn ibs=150 cbs=150 obs=150 conv=unblock of=out_fn). FLIGHT 94-079 DATE 19-APR-94:16:30 FLIGHT 94-080 DATE 20-APR-94:15:55 FLIGHT 94-082 DATE 28-APR-94:14:45 FLIGHT 94-102 DATE 08-JUN-94:13:45 FLIGHT 94-120 DATE 21-JUL-94:15:00 FLIGHT 94-123 DATE 04-AUG-94:13:10 FLIGHT 94-124 DATE 08-AUG-94:13:14 FLIGHT 94-142 DATE 16-SEP-94:15:00 FLIGHT 94-143 DATE 17-SEP-94:13:55 Each data file contains a header record that is formatted as described in the following table: U2/USER PLUS DIGITIZED ANALOG VALUES HEADER INFORMATION CHARACTERS CONTENTS ---------- -------- RECORD 1 2 - 7 "FLIGHT" 9 - 14 The flight identifier, which consists of the last two digits of the fiscal year, a dash, and a three-digit unique number that identifies the flight within the fiscal year (e.g., 92-001) 17 - 20 "DATE" 22 - 29 The date of the flight at liftoff, in the form MM/DD/YY, where MM gives the number of the month DD gives the day YY gives the last two digits of the current year 32 - 34 "A/C" 36 - 38 Tail number of the aircraft (706, 708, or 709) 41 - 47 "TAKEOFF" 49 - 56 The takeoff time, in the form HH:MM/DD, where HH gives the hour (24-hour clock) MM gives the minute DD gives the day of the month at takeoff 59 - 62 "LAND" 64 - 71 The landing time, in the same form as "TAKEOFF," except that DD gives the day of the month at landing 82 - 101 "RECORDER UNIT NUMBER" 103 ID number of the navigation data recorder 104 - 200 Blank RECORDS 2 - 5 Title that serves to label the contents of the data records. NOTE: Characters not explicitly mentioned here are filled with blanks; i.e., the American Standard Code for Information Interchange (ASCII) code for "space." (END of Table E-6A) The data part of each file is formatted as described in the following table: U2/USER PLUS DIGITIZED ANALOG VALUES DATA RECORD FORMAT (English Units) CHARACTER CONTENTS --------- -------- 02 - 12 The time and day in the form HH:MM:SS/DD, where HH gives the hour (24-hour clock) MM gives the minute SS gives the second DD gives the day of the month 15 Time source indicator "G" -- from Geostationary Operational Environmental Satellite (GOES) "I" -- Internal time source 18 - 25 Latitude, hHH:MM.t, as follows: 18 h -- hemisphere, "N" for northern, or "S" for southern 19 - 20 DD -- Degrees of latitude 21 : -- separator between degrees and minutes 22 - 25 MM.t -- Minutes and tenths of minutes of latitude (with a decimal point) 27 - 35 Longitude, hDDD:MM.t, as follows: 27 h -- hemisphere, "W" for western, or "E" for eastern 28 - 30 DDD -- Degrees of longitude 31 : -- separator between degrees and minutes 32 - 35 MM.t -- Minutes and tenths of minutes of longitude (with a decimal point) 37 - 41 Altitude, in feet (from 0 - 70000) 42 "space" if below 70,000 feet, or "+" if over 70,000 feet, (if over 70,000 feet, the altitude (37-41) will contain 70000) 45 - 47 True air speed, in nautical miles per hour 49 - 53 Aircraft pitch, in degrees, given to tenths (with a decimal point); positive indicates nose up 55 - 59 Aircraft roll, in degrees, given to tenths (with a decimal point; positive indicates right roll; (i.e., right wing down) 61 - 66 True heading, in degrees, given to tenths (with a decimal Point); zero degrees indicates north, positive to the east of north (90 indicates due east; 180 indicates south; and 270 indicates west) 67 - 72 North-South velocity, in nautical miles per hour 74 - 77 East-West velocity, in nautical miles per hour 79 - 82 Vertical velocity, in feet per second 85 - 87 Ground speed, in nautical miles per hour 94 - 96 Computed ground speed, in nautical miles per hour (square root of the sum of the squares of the north-south and east-west velocities) 100 - 103 Computed wind speed, in nautical miles per second (the vector difference of the true air speed and true heading and north-south and east-west velocities 107 - 109 Computed wind direction, in degrees from north (clockwise is positive) 113 - 116 Computed vertical velocity (in feet per second) computed from the altitude difference and time difference between consecutive records 122 - 124 Computed angle of attack (degrees); i.e., arcsine (vertical velocity divided by ground speed) 134 - 138 Static air temperature in degrees C, computed from the first digitized analog value, if recorded 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms None. 9.2 Data Processing Sequence 9.2.1 Processing Steps BORIS staff processed the level-0 ER-2 navigation data by extracting pertinent header information from the navigation file and loading the online database with needed information. 9.2.2 Processing Changes ARC applied no special or additional processing to the ER-2 navigation data from BOREAS. 9.3 Calculations 9.3.1 Special Corrections/Adjustments ARC made no special adjustments or offsets to the data. 9.3.2 Calculated Variables ARC made no special adjustments or offsets to the data. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error The data buffer servicing the navigation recorder samples the particular parameter between records, but is precisely correct only at some point between records. Each parametric measurement is recorded as a count in a 16-bit word; consequently the conversion of that count to an engineering unit defines the precision. 10.2 Quality Assessment 10.2.1 Data Validation by Source Data distribution to NASA/ARC occurs at the conclusion of the deployment. Data tapes are presented in total for documentation and archive. Data evaluation consists primarily of identifying component failure (i.e., radar altitude, GPS values, and pressure measurements). 10.2.2 Confidence Level/Accuracy Judgment The quality of the data is judged to be good. 10.2.3 Measurement Error for Parameters See Sections 4.1.6 and 8.2. 10.2.4 Additional Quality Assessments BORIS staff imported selected navigation files into a spreadsheet and graphed the values to check for reasonableness. 10.2.5 Data Verification by Data Center BORIS Staff reviewed the contents of the data files for consistency and used portions of the information to inventory and describe the data in the relational data base. 11. Notes 11.1 Limitations of the Data None. 11.2 Known Problems with the Data None. 11.3 Usage Guidance The tar file should be copied from tape to disk. All nine ASCII files are contained in a single tar file and should be extracted (tar –xvf filename). Each file should then be placed into 150-byte records. This can be accomplished by the UNIX command dd. dd if=nav.94-123 of=filename ibs=150 cbs=150 obs=150 conv=unblock. The files will then appear as 19 ASCII columns with a 5-line header. 11.4 Other Relevant Information Not applicable. 12. Application of the Data Set To date, BORIS staff has extracted, blocked, and examined the data but has not used them for any particular purpose. 13. Future Modifications and Plans No modification is planned for the ER-2 navigation data currently logged in the BORIS data base. 14. Software 14.1 Software Description The UNIX dd command is useful in placing the new-line characters in the correct place so that the ASCII file appears correctly. See Section 11.3. BORIS developed software to extract needed information from the data files and inventory the ER-2 navigation data in the relational data base. 14.2 Software Access The software developed by BORIS is available by contacting BORIS personnel or the ORNL DAAC. 15. Data Access 15.1 Contact for Data Center/Data Access Information These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 15.2 Procedures for Obtaining Data BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. 15.3 Output Products and Availability Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. 16. Output Products and Availability 16.1 Tape Products The BOREAS level-0 ER-2 navigation data can be made available on 8-mm, Digital Archive Tape (DAT), or 9-track tapes at 6250 or 1600 Bytes Per Inch (BPI). 16.2 Film Products Color aerial photographs and video records were made during data collection. The video record includes aircraft crew cabin intercom conversations and an audible tone that was initiated each time the sensors were triggered. The BOREAS data base contains an inventory of available BOREAS aircraft flight documentation, such as flight logs, videotapes, and photographs. 16.3 Other Products None. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Ekstrand, R. E. and D. Wolf. 6 May 1992. INSPLOT. Guillot, D. 1 April 1985. Cassette Data Format for the U-2 navigation recorder. 17.2 Journal Articles and Study Reports Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P. and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue. Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms A/D - Analog-digital AOCI - Airborne Ocean Color Imager ARC - Ames Research Center ARINC - Aeronautical Radio Inc. ASAS - Advanced Solid-State Array Spectroradiometer ASCII - American Standard Coding for Information Interchange AVIRIS - Airborne Visible and Infrared Imaging Spectrometer BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BPI - Bytes Per Inch CCT - Computer Compatible Tape CD-ROM - Compact Disk-Read-Only Memory CDU - Control/Display Unit DAAC - Distributed Active Archive Center DAT - Digital Archive Tape EOS - Earth Observing System EOSDIS - EOS Data and Information System FFC - Focused Field Campaign GPS - Global Positioning System GSFC - Goddard Space Flight Center INS - Inertial Navigation System INU - Inertial Navigation Unit MAMS - Multispectral Atmospheric Mapping Sensor MAS - MODS Airborne Simulator MODIS - Moderate-Resolution Imaging Spectrometer MSU - Mode Select Unit NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NBS - National Bureau of Standards NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PRT-5 - Precision Radiation Thermometer RNAV - Area Navigation SCSI - Small Computer Serial Interface S/D - synchro-digital SGI - Silicon Graphics IRIX SSA - Southern Study Area TACAN - Tactical Air Navigation TAS - True Air Speed TIMS - Thermal Infrared Multispectral Scanner TMS - Thematic Mapper Simulator URL - Uniform Resource Locator 20. Document Information 20.1 Document Revision Date(s) Written: 10-Mar-1998 Last Updated: 08-May-1998 20.2 Document Review Date(s) BORIS Review: 17-Mar-1998 Science Review: 20.3 Document ID 20.4 Citation The BOREAS level-0 ER-2 navigation data were collected and processed from the original aircraft tapes by personnel of the Medium Altitude Aircraft Branch at NASA/ARC. BORIS staff reviewed, repackaged, and documented the data received from ARC into the current product. The contributions of ARC and BORIS staff to enhancing and checking this data set are greatly appreciated. 20.5 Document Curator 20.6 Document URL Keywords ER-2 Navigation INS ER2_Nav_L0.doc 05/26/98