Center for Mapping

Test Configuration

In order to make the performance test complete, the receivers were tested first in the static, benign conditions on the short and zero baselines, and subsequently, in kinematic scenario. The test range selected for the experiments is the parking lot on the Ohio State University West Campus. This environment represents rather optimal observability conditions, suitable for receiver testing, offering open sky with no obstructions within about 50 meters. The test range consists of six 10-meter baselines with 10-meter separation between the baselines (Figure 1).

The field tests presented here were performed on: August 27, September 3 and 17, and October 1, 2000, under comparable field/atmospheric conditions. The antennas were mounted on the fixed-height 2-meter tripods over the well-marked points with precisely known coordinates determined earlier from several hours of GPS observations. One 4-way antenna splitter was used in zero baseline tests. Elevation mask of 10 degrees and a 1-second sampling interval were used. Receivers were tracking 7-9 satellites above the 10-degree elevation mask. Several receiver pairs were tested, as listed in Table 1, but due to the limited access to some of the hardware components not all of the receivers were tested each day.

Figure 1. Test Configuration

Hardware Type	Quantity	Antenna type	Hardware Type	Quantity	Antenna/splitter type
Trimble 4000 SSI	3	L1/L2 with ground plane	Leica 9500	2	Choke ring AT303
Trimble 4000 SSE	2	L1/L2 with ground plane	Leica 399	2	Internal
Trimble 4700	2	L1/L2 microcentered with ground plane	Ashtech Z12	2	L1/L2 with ground plane
Topcon/JPS Legacy	2	LegAnt	Antenna splitter	1	4-way, GPS Networking Inc.

Table 1. Hardware Inventory

Test Configuration| Data Processing Technique| Zero Baseline Test Results| Short Baseline Test Results| Analysis of Stochastic Properties of GPS Observable