Viavi 87339, Operation Manual

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Testing
4 -17
4.1.7.E Positional Accuracy
3D position accuracy and repeatability can be determined by creating simulations at
various UTC’s. It is important to test accuracy at various UTC’s, because the available
satellites and their geometries, change substantially even over the course of several
hours. An example of latitude, longitude and altitude information, taken at four different
UTC’s, is shown in Table 4-4.
Table 4-4 Horizontal Accuracy for Various UTC Simulations
Table 4-4 shows that you can calculate horizontal error in meters absolutely based on the
simulated position. The horizontal error is determined from the equation:
The accuracy that a receiver can attain, is highly dependent on the available satellites
that it has to lock to. Whilst a receiver’s accuracy will vary over the course of several
hours (when satellites change), the positional repeatability for a given UTC will usually
result in only a small deviation. With the GPSG-1000, you can perform multiple trials of a
particular simulated 3D position. This also can confirm that the GPSG-1000 does not add
uncertainty to the simulated GPS signal.
Initial UTC Latitude Longitude Alt (MSL) Horizontal
Error (m)
10:14:02m 37.658331 -97.438891 603.000000 0.268341
14:06:18 37.658325 -97.438888 597.000000 0.900046
16:12:01m 37.658320 -97.438887 598.000000 1.457469
18:32:22 37.658310 -97.438891 601.000000 2.559818
Average 34.94 97.438889 599.750000 1.296419
Standard DEV 2.88 0.00000156 2.75378527 .0972312
SIM Position
DEC
2.88 -97.438889 -
SIM Position 2.88 97:96:20 E 600.000000