At the 1995 UNAVCO Users Meeting (May 2 and 3), Working Group 3 (WG3) asked the facility to conduct tests to determine the effect of different antenna mounts on GPS baseline results. Especially the effect of mounting antennas low above the ground... Read More

An Improved GPS Geodetic Antenna F. Solheim, C. Alber, M. Exner, C. Rocken, C. Meertens, J. Johnson UNAVCO, POB 3000, Boulder, CO 80307 Signal reflected from the antenna environment mixes with the direct sky signal to induce error in GPS... Read More

Ashtech and Trimble Choke Ring SNR Analysis Mike Jackson Ph.D. UNAVCO Network Operations Manager 3340 Mitchell Lane, Boulder CO 80301   Introduction The Trimble 4000 receiver is obsolete and the Ashtech Z12 is nearing the end of its product... Read More

Assessing the Impact of the SCIGN Radome on Geodetic Parameter Estimates John J. Braun UCAR/COSMIC Program P.O. Box 3000, Boulder, CO Introduction The SCIGN radome is widely used within the geodetic community to protect GPS antennas at... Read More

The Iridium satellite communication system uses the 1616-1626.5 MHz band to uplink with orbiting communication satellites. UNAVCO Inc. uses iridium communication links to download GPS data from remote GPS stations located at high latitudes. The L1... Read More

GNSS Antenna Phase Center Stablity Test - TPSPG_A1+GP Background Topcon TPSPG_A1+GP Campaign Height Measurement Bias Problems were reported by Bob King, Adrian Borsa and other investigators regarding height estimate biases introduced when using... Read More

This article presents a comparison of measured signal to noise ratio (SNR) values observed from several  GNSS antenna types. The results presented below were collected using a monument located on the UNAVCO Facility Roof in Boulder, CO. Each... Read More

Update: GPS/GNSS Interference From Iridium Data TransmissionsThe Iridium satellite communication system broadcasts in the 1610 to 1626.5 MHz band. UNAVCO Inc. uses iridium communication links to download GPS data from remote GPS stations. The L1 freq... Read More

Preliminary report on data quality with a Trimble 5700 GPS receiver and an Ashtech Choke Ring Antenna Date: May 22, 2002 Author: Mike Jackson A critical issue with the use of the Trimble 5700 GPS receiver for use as a geodetic base station system is... Read More

The Effect of Antenna Covers On GPS Baseline Solutions J. Braun, B. Stephens, O. Ruud and C. Meertens University NAVSTAR Consortium, Boulder, CO Abstract With the increasing number of permanent GPS monuments being deployed, many investigators are... Read More