The NSIDC Web site and data services are currently having intermittent problems and may be unavailable. We are working to restore these services as soon as possible and apologize for any inconvenience this may cause. Please contact NSIDC User Services for assistance.
This data set contains Global Positioning System (GPS) and Inertial Measurement Unit (IMU) positioning and orientation measurements for the University of Alaska Fairbanks Glacier LIDAR system campaigns. The data were collected as part of Operation IceBridge funded aircraft survey campaigns.
Operation IceBridge products may include test flight data that are not useful for research and scientific analysis. Test flights usually occur at the beginning of campaigns. Users should read flight reports for the flights that collected any of the data they intend to use. Check IceBridge campaign Flight Reports for dates and information about test flights.
We kindly request that you cite the use of this data set in a publication using the following citation example. For more information, see our Use and Copyright Web page.
Larsen, Chris. 2011. IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data, [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center. http://nsidc.org/data/ipuaf1b.html.
DeHavilland Otter DHC-3
Oxford Technical Solutions Inertial+2 Inertial Measurement Unit
Decimal degrees latitude and longitude
19 August 2009 to present
University of Alaska Fairbanks
903 Koyukuk Drive
Fairbanks, Alaska 99775 USA
NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
This program has been supported by grants from NASA, NOAA and NSF. Current support comes from NSF Arctic Natural Sciences grant ARC-0612537 and from NASA's Operation Ice Bridge, Earth Science Project Office, Grant NNX09AP54G.
The data files are in ASCII format.
Data files are organized on the FTP site, ftp://n4ftl01u.ecs.nasa.gov/SAN2/ICEBRIDGE_FTP/, as described in Figure 1.
Figure 1. Directory Structure
The data files are named according to the following convention and as described in Table 1:
|IPUAF1B||Short name for IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data|
|ascii||Indicates ASCII data file|
|DHC-3||DeHavilland Otter aircraft|
|YYYY||Four-digit year of data collection|
|MM||Two-digit month of data collection|
|DD||Two-digit day of data collection|
|xxxxxx_x||Hour, minute and second of start time of collection|
|.pos||Indicates positional data|
Data files range from approximately 45 MB to 251 MB.
The total data set volume is approximately 3.6 GB.
Spatial coverage for the UAF GPS/IMU L1B Corrected Position and Attitude data:
Southernmost Latitude: 55° N
Northernmost Latitude: 72° N
Westernmost Longitude: 156° W
Easternmost Longitude: 130° W
Decimal degrees longitude and latitude, eight decimal places.
These data were collected as part of NASA Operation IceBridge funded campaigns from 19 August 2009 to the present.
IceBridge campaigns are conducted on an annual repeating basis. Alaska campaigns are conducted during May, June, July, August, and September.
Parameters contained in UAF GPS/IMU L1B Corrected Position and Attitude data files are described in Table 2. Columns 1 to 7 in Table 2 represent columns left-to-right in the data. Columns are not numbered in the data files.
Below is an excerpt of the data file IPUAF1B_ascii_DHC-3_20110530_022658_1.pos. The seven fields in each record correspond to the columns described in Table 2.
Data are available via FTP.
The data files may be opened by any ASCII text reader.
These data are position and attitude of the inertial platform. They are recorded at 100 Hz by an Oxford Technical Solutions (OxTS) Inertial+2 IMU coupled with a Trimble R7 GPS.
The IMU data are recorded on the IMU at 100 Hz. The GPS data are recorded on the GPS at 5 Hz. The two datasets are merged in post processing to provide the .pos files with 100 Hz resolution.
The following processing steps are performed by the data provider.
Typical errors sources include the normal GPS post processing kinematic solution concerns, including loss of lock from aircraft maneuvers, and ionosphere noise.
The main components of the GPS/IMU are an Oxford Technical Solutions Inertial+2 inertial measurement unit, and a Trimble R7 geodetic GPS receiver.
Johnson, A. J. 2012. Estimating the Mass Balance of Glaciers in the Glacier Bay Area of Alaska and British Columbia. M.S. Thesis, Geology and Geophys. Dept., Univ. Alaska, Fairbanks, AK. http://glaciers.gi.alaska.edu/theses.
GAMIT-GLOBK, MIT Department of Earth Atmospheric and Planetary Sciences (http://www-gpsg.mit.edu/~simon/gtgk/).
IceBridge Data Web site at NSIDC (http://nsidc.org/data/icebridge/index.html).
IceBridge Web site at NASA (http://www.nasa.gov/mission_pages/icebridge/index.html).
ICESat/GLAS Web site at NASA Wallops Flight Facility (http://glas.wff.nasa.gov/).
ICESat/GLAS Web site at NSIDC (http://nsidc.org/daac/projects/lidar/glas.html).
NOAA OPUS: Online Positioning User Service (http://www.ngs.noaa.gov/OPUS/).
UAF Glacier Lidar System Web page (http://www.gps.alaska.edu/chris/images/Geophysical_Institute_LiDAR/index.html).
The acronyms used in this document are listed in Table 3.
|ASCII||American Standard Code for Information Interchange|
|ASPRS||American Society for Photogrammetry and Remote Sensing|
|CIRES||Cooperative Institute for Research in Environmental Science|
|FTP||File Transfer Protocol|
|GPS||Global Positioning System|
|IMU||Inertial Measurement Unit|
|ITRF||International Terrestrial Reference Frame|
|L1||L1 is a civilian-use GPS signal broadcast on the 1575.42 MHz frequency, that currently contains the course acquisition signal used by all current GPS users. Also known as L1C.|
|L2||L2 is a civilian-use GPS signal broadcast on the 1227.6 MHz frequency. Also known as L2C.|
|NASA||National Aeronautics and Space Administration||NOAA||National Oceanic and Atmospheric Administration|
|NSF||National Science Foundation|
|NSIDC||National Snow and Ice Data Center|
|OPUS||Online Positioning User Service|
|OxTS||Oxford Technical Solutions|
|UAF||University of Alaska Fairbanks|
|URL||Uniform Resource Locator|
|UTM||Universal Transverse Mercator|
|WGS-84||World Geodetic System 1984|
08 March 2013