Lexington/Bluegrass
GPS Community Base Station
Information
The Lexington/Bluegrass Community Base Station (LBCBS) automatically collects base files which users can utilize to differentially correct rover files. The LBCBS is a Trimble Navigation GPS Pathfinder Community Base Station. This GPS Pathfinder Community Base Station consists of an antenna and ground plane placed on a surveyed location (tower on the roof of BGADD building), a 12-channel receiver (capable of tracking 12 satellites) connected directly to a computer, and GPS Pathfinder Community Base Station software (PFCBS).
The PFCBS software tracks satellites and saves all raw data from the radio signals into data files (base files). PFCBS is designed to automatically start and stop logging for a user-determined length of time each day. The following are the operating parameters of the Lexington/Bluegrass Community Base Station:
PFCBS software version: 2.33
Dynamics Code: Static
Elevation Mask: 5º
SNR Mask: 6
PDOP: 6
Filter Constant: 0.005
SV Health Action: Heed Health
Base Logging Rate: 5 sec
- To ensure the best possible accuracy the logging interval for synchronized measurement data at the base and the rover (Trimble Pathfinder Pro XR and Pro XL) should be the same value.
- If the base and rover logging intervals are different, you can improve the accuracy of the rover positions by making the position logging interval at the rover a direct integer multiple of the synchronized measurement interval at the base. Example: Base Logging Rate = 5 sec, Rover Point Logging Rate = 1 sec and Lines and Areas Logging Rate = 5 sec.
Type of Recorded Measurements: Synchronized (Synced) Measurements
- 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.
- The GPS Pathfinder 12-channel Community Base Station uses Maxwell based technology and synchronized measurements in the base file to allow the GPS Pathfinder Pro XL and Pro XR rover systems to achieve maximum positional accuracy. Submeter positions are not possible without Synced Measurements.
- Users will need to use PFINDER version 2.50 or later for differential correction. If you are using an earlier version of PFINDER software you must use the SYNC2RAW standalone utility program to convert synchronized measurements to raw measurements before performing differential correction. The other possible option is to upgrade your PFINDER software to the current version. The current software is a windows based program called Pathfinder Office version 1.10.
- The other type of measurements that some base stations log is called Raw Measurements. Raw Measurements contain code phase data which is not on the GPS integer second (not synchronized). GPS Pathfinder Pro XL and Pro XR rover systems cannot achieve submeter accuracies with that base data (Raw Measurements)
File Naming Convention: XYMMDDHH.SSF
Example file: L7022814.ssf
This file was logged at the "L" LBCBS base station in 1997 on February 28, from 14:00:00 to 14:59:59 GMT. The time of this file in Eastern Standard Time (EST) would be 9:00:00 AM to 9:59:59 AM. Eastern Standard Time is a minus five (-5) hour offset from GMT. The time of this file in Central Day Time would be 11:00:00 AM to 11:59:59 AM. Central Day Time is a minus three (-3) hour offset from GMT. Time offset from GMT depends on your time zone and whether it is standard or daylight savings time.
Operation Hours: 24 hours a day/365 days a year
The intention is for the LBCBS to operate 365 days a year and 24 hours per day. No guarantee is made to the availability or the accuracy of this base station data. This service is provided free to the ever growing world of GPS users in the state of Kentucky and surrounding areas. We will make every reasonable effort to keep the station on line and operating properly.
Station Location:
Further Information: