AIDJEX Bulletin #40 - Polar Science Center - University of Washington

TABLE 1
STAND-ALONE ACCURACY
68th Percent Point
Latitude Lonzitude Radial
Camp 1 (Caribou) 30 m 55 m 67 m
Camp 3 (Snow Bird) 28 m 62 m 69 m
- Trans1 ocati on Accuracy
The fixes from two receivers were scanned to find pairs of fixes from
the same satellite with closest approach times in the same two-minute interval.
This guarantees that the truncated fixes use data from exactly the same time
interval.
Table 2 and Figures 8b and 8c show the accuracy of translocation
between camp 3 (Snow Bird) and camp 1 (Caribou) and between receivers A and
B at camp 1 (Caribou).
TABLE 2
TRANSLOCATION ACCURACY
Number
Radial Error
Receivers of Fixes Separation (68th % Point)
1 - 3 199 98 km 20 m
1A - 1B 241 94 m 5 m
The translocation effect reduces the radial errors of about 70 m stand-
alone at each camp to translocation errors of 20 m over about 100 km, and 5m
over about 100 m.
The improvement occurs because refraction errors and orbit
prediction errors in the two fixes are highly correlated.
coefficient p can be estimated as
translocation error = 0.86 for 98 km
= 2(stand-alone error) 0.96 for 94 m.
The correlation
The increase in radial error from 5 m to 20 m is probably due to ice motion
and uncorrelated refraction at the 98 km separation.
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