Summit Camp GPS Survey System - Base Station

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Base Station SMM1

A geodetic quality GPS base station is located in the Green House at Summit Camp. The system consists of a Trimble NetR8 GPS receiver with Zephyr Geodetic antenna, a Trimble HPB450 radio transmitter, and a computer for data downloading and processing. Data can be logged for post processing, and a real-time kinematic (RTK) broadcast allows local real-time surveys and stakeouts. The base will support RTK surveys up to 5 km from Summit Camp, and post-processed surveys over 100 km away. The system is considered to be a permanent base station, and is not intended to be moved or disconnected.

• Base Station Inventory
• Trimble NetR8 user guide  [pdf]

Coordinates

The Green House facility was moved between June 30 and July 2 2009. At this time the base station location changed by ~80 meters, therefore the station name was changed from SUMM to SMM1 and a new coordinate was generated for use in the RTK broadcast. As of July 2 2009 the RTK base station coordinate (0m to bottom of antenna mount) is:

Coordinate	Value	Ref. Frame
Latitude	72° 34' 46.50309" N	ITRF-00
Longitude	38° 27' 33.06611" W	ITRF-00
Height Above Ellipsoid (HAE)	3260.293m	ITRF-00
Elevation Above MSL	3216.350m	EGM96

ITRF: For precise geodesy, the International Terrestrial Reference Frame (ITRF) is used. Unlike NAD-83, WGS-84, and other datums, ITRF also incorporates tectonic plate velocities. Therefore, when referring to ITRF coordinates, one must also provide the date that the coordinates refer to. See the on-line NGS calculator for reference frame transformations.

Data Download

Users at Summit camp can download base station data from Trimble NetR8 web interface:

• Online access to NetR8 base receiver  (rtkgps.summitcamp.org or summitcamp.org:34080)

This will bring up the receiver's web interface. The receiver is programmed to allow anonymous access for data download, however if prompted, the username and password are:

Username: smm1
Password: gps

The web interface also allows you to see how many satellites the receiver is tracking, what data files are being logged, and other configuration information. However, you can only download data using this user account and cannot change any of these parameters. Configuration changes are done remotely by UNAVCO using a separate account; contact UNAVCO for any changes or requests.

To download data, next click on the Data Logging tab, then Data Files. Click on the Internal directory then navigate to the directory where the desired files are stored. When you locate the file(s) you want, click on the filename to download. Note that you cannot download any files that are currently being written to. The NetR8 is configured to log files in the following locations:

24-hour 15-second datafiles
/Internal/YYYYMM/24hr15sc/SMM1YYYYMMDD0000A.T01

60-minute 2-Hz datafiles
/Internal/YYYYMM/DD/1hr2hz/SMM1YYYYMMDDHH00B.T01

60-minute 5-Hz datafiles
/Internal/YYYYMM/DD/1hr5hz/SMM1YYYYMMDDHH00C.T01

Each of these file types is allocated a certain portion of the NetR8 memory. When this section of memory is full, the oldest files are deleted. The NetR8 stores approximately 800 days of 15-second data, 40 days of 2Hz data, and 16 days of 5Hz data.

The 15-second data are also available from the UNAVCO data archive (site SMM1). Upon request, high-rate data files can be downloaded and made available by UNAVCO, however in general the higher sample rate data are recorded on the receiver only and are not archived. Due to the limited storage space for high-rate data on the receiver, request for archiving high-rate data should be made as soon as possible by emailing archive-gpsunavco.org.

Last modified: 2019-12-24  02:12:45  America/Denver