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IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data, Version 1
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.
|Sensor(s):||GPS/IMU, UAF GPS/IMU|
|Data Contributor(s):||Chris Larsen|
|Metadata XML:||View Metadata Record|
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.Larsen, C. 2011. IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: http://dx.doi.org/10.5067/LXDUDGNFZXHV. [Date Accessed].
Detailed Data Description
The data files are in ASCII format.
Data files are organized on the HTTPS site,
The data files are named according to the following convention and as described in Table 1:
||Short name for IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data|
||Indicates ASCII data file|
||DeHavilland Otter aircraft|
||Four-digit year of data collection|
||Two-digit month of data collection|
||Two-digit day of data collection|
||Hour, minute and second of start time of collection|
||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
Varies, measured in decimal degrees longitude and latitude, eight decimal places.
Projection and Grid Description
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.
Sample Data Record
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.
Software and Tools
The data files may be opened by any ASCII text reader.
Data Acquisition and Processing
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.
- All GPS processing of the aircraft position uses L1 frequency 1575.42 MHz and L2 frequency 1227.6 MHz data recorded at 5 Hz, processed with the TRACK GPS differential phase kinematic positioning program, a module of the GAMIT/GLOBK software programs from the Department of Earth Atmospheric and Planetary Sciences, MIT. For further information on TRACK, see http://geoweb.mit.edu/~tah/track_example.
- GPS base station coordinates are found using Online Positioning User Service (OPUS). For further information on OPUS, see http://www.ngs.noaa.gov/OPUS/. The kinematic processing and the laser shot point coordinates are referenced to these base station coordinates.
- The IMU raw data are post processed and blended with the GPS post processed solution using OxTS program "RTpostprocess". The results are output from this program in the .pos format provided.
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.
References and Related Publications
Contacts and Acknowledgments
University of Alaska Fairbanks
903 Koyukuk Drive
Fairbanks, Alaska 99775 USA
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.
DOCUMENT CREATION DATE
08 March 2013