CAMEX-4 ER-2 NAVIGATION DATA

Table of Contents

1. Introduction
2. Content and Structure of the NAV files
  2a. 01-fff.ASC
  2b. 01.fff.F13
  2c. 01-fff.RPT
  2d. 01-fff.PS
3. Contact Information

1. Introduction

This README file contains information about the content and structure of the ER-2 navigation files for flights in support of CAMEX-4. These data files were generated on board the ER-2, saved to disk, and downloaded post flight.

2. Content and structure of the NAV files

Each NAV filename has the structure: c4enav_2001.ddd_010fff.tar. In its own way, the filename is a metadata tag for the data file itself, where c4enav announces that this is navigation data from the NASA ER-2 aircraft. The year (2001) and day of year (ddd) give the start date (UTC) of the mission. The mission number (010fff) is also included in the tar file name where fff is the flight sequence number. The data for each mission is combined in a tape archive format (.tar) file so that the data may be easily disseminated.

Once 'untarred', the .tar file yields five files each named in the following manner:

Where fff is the flight number assigned to the mission. Each of these files are detailed below.

2a. 01-fff.ASC

This text file contains raw information recorded by on board navigation and data collection systems. In addition to typical navigation data (e.g. date, time, lat/lon and altitude) it contains outside meteorological parameters such as wind speed and direction and temperature. Data is collected in one second increments. While easily readable using almost any text viewer (in notepad set the font to courier and size to 8, for example) there is a better, more formatted form of flight data available.

2b. 01-fff.F13

This is that better format shown below.
  

NASA        809 Flight #01-135 09/07/01/250 (GMT) RECORDER 5 HARD DISK 5 
                                                                                       INS   INS   . . . . . based on MMS pressure sensors . . . . .  
DAY   TIME   T    INU     INU     INU PRESS SAT  PITCH  ROLL TRUE AIR  N/S  E/W   GND Wind   Wind  mach                static    SAT  wind   wind 
DDD HH:MM:SS S LATITUDE LONGITUDE ALT                        HEAD SPD  VEL  VEL   SPD  Dir  Speed number TAS altitude   press   temp   dir  speed TIME 
                 deg       deg    ft  mbar  degC  deg    deg  deg knts knts knts knts  deg  knots       knots  feet       mb   deg C   deg  knots HH:MM:SS
250 16:03:00   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 272.9  49.2 0.045   29     -148 1018.69   -0.1 272.7   28.7 16:03:00 
250 16:03:01   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 272.9  49.2 0.047   30     -132 1018.09   -0.1 272.7   30.4 16:03:01 
250 16:03:02   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 272.9  49.2 0.047   30     -164 1019.27   -0.1 272.7   30.1 16:03:02 
250 16:03:03   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 272.9  49.2 0.045   29     -145 1018.57   -0.1 272.7   28.7 16:03:03 
250 16:03:04   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 273.5  49.2 0.042   27     -142 1018.47   -0.1 272.7   27.2 16:03:04 
250 16:03:05   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 273.5  49.2 0.045   29     -150 1018.74   -0.1 272.7   29.3 16:03:05 
250 16:03:06   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 273.2  49.7 0.044   28     -166 1019.33   -0.1 272.7   28.5 16:03:06 
250 16:03:07   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 273.2  49.8 0.046   30     -149 1018.72   -0.1 272.7   29.6 16:03:07 
250 16:03:08   N30.231  W 81.674 -78 1016.1 -0.1 + 4.4 - 0.6 272.7     N 0  E 0     0 273.2  49.8 0.046   30     -165 1019.30   -0.1 272.7   29.6 16:03:08 
.
.
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The first line of data decodes as follows:

          NASA 809 - ER-2 tail number 809 belonging to NASA
          Flight #01-135 09/07/01/250 (GMT)-  01-135 is the NASA flight number
          09/07/01- DD/MM/YY , 250is the numeric day of the year, GMT-UTC on which the flight took off
          RECORDER 5HARD DISK 5- the recorder and disk the data was originally saved upon.

Lines 3 and 4 provide column headers (when properly aligned) for the data, while line 5 provides the units in which the data are reported. INU means Inertial Navigation Unit. The other abbreviations are self-explanatory. Time is in UTC.

As these data are extensive in nature and difficult to extract to fit on one page as text. Here are two methods that work. Import these data into a spreadsheet: once there you can format the cells so that the data fit to columns, then realign the column headers to reflect the pattern above. Or, open in a window, format with a small font (6 or 8 point) and put in courier style as it is a constant width font.

2c. 01-fff.RPT

Commonly called 'switchology', this file describes information about the mission, pilot, date and time as well as on/off times for each of the switches which control the separate scientific instruments. If for example you knew that your instrument was in the q-bay and was powered through switch Q6, you would could easily find the times that the pilot powered up/down your instrument.
 

2d. 01-fff.PS

This is a post-script file. It contains three images two parameter graphs, and the flight track map. We have extracted these images and they are named:

3. Contact Information

Data can be ordered and questions addressed at http://ghrc.nsstc.nasa.gov/.

To order this data or for further information, please contact:
Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: ghrc@eos.nasa.gov

[NASA logo] NASA Information Contact: Michael Goodman, Global Hydrology and Climate Center
GHRC Web Curator: GHRC Web Team
Last update: Tuesday, 12-Jun-2007 16:53:57 CDT
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