Community GPS Base Station
The Environmental Resources Engineering Faculty of SUNY-ESF operates a Trimble GPS Pathfinder Community Base Station (PFCBS). This 12-channel receiver collects raw data at 5-second intervals into hourly data files 24 hours a day.
These files are available through an electronic bulletin board system located at 315-470-6930; modem settings are 8 bits, no parity and 1 stop bit (8N1). The BBS will ask for your name and a password, and thereupon you may download files via the Xmodem protocol.
For those full internet access the data can be retrieved from: “ftp://feg-gps.esf.edu”, or 220.127.116.11.
The PFCBS software is currently at version 2.68i. The static operating parameters are set as follows: Elevation Mask = 10º, SNR = 6, PDOP Switch and Mask = 6, GPS Fix Mode = Auto 2D/3D, Filter Constant = 0.005 and Sync Measurements are on (This flag was set on March 29, 1996). The antenna, a compact L1/L2 with ground plane, is located on the roof of Bray Hall, Syracuse, NY. A first order survey established the antenna location at Latitude 43º 02' 03.9376" N, Longitude 76º 08' 05.0514 W and Altitude 162.131 M (HAE). This is an unobstructed view of the sky in all quadrants.
Note: The Synchronized Measurements contain full pseudorange data and carrier phase data. Synchronized Measurements occur when measurements from all satellites tracked by the base and rover receivers are made at the same logging interval and are synchronized to the start of the GPS week. These data in the base file allow the GPS Pathfinder Pro XL rover system to achieve maximum positional accuracy. However, you must have PFINDER version 2.50 or later to properly differentially correct against a base file that contains synchronized measurement data. If you are using PFINDER version 2.40 or earlier, you must use the SYNC2RAW.EXE standalone utility program to convert the synchronized measurements to raw measurements before performing differential correction with the base file. This utility is available to you in the same subdirectory as the data files.
Note: For those persons using non-Trimble software, these data sets may be converted to the Receiver Independent Exchange Format (RINEX) by using the SSFRNX.EXE file. The current version is also available in the same subdirectory as the data, but you will need the proper “dongle” to execute. If RINEX data is required, please contact Paul Szemkow for the conversion process.
Files are collected and stored on the computer hard drive for the current month. At the beginning of each month, the previous month's data are archived onto backup tape and removed. These backups are stored for 6 months. To obtain archived data please contact Paul Szemkow at 315-470-6635, or FAX at 315-470-4768 or 6958. His email address is firstname.lastname@example.org.