King Air
2086
King Air
1039
Citation
1715
Citation
1503
Citation
873
Citation
748
2 Sec
15
5 sec
58
2 sec
4
2 sec
5
5 sec
33
5 sec
34

0.002/0.270
0.004
/0.412

0.007/0.409
0.000/0.031 0.000/0.063

0.001/0.055
0.000/0.032 0.001/0.084 0.000/0.063
0.000/0.292

0.002/0.261
0.002
/0.281
0.001
/0.286
0.000/0.274

0.002/0.261
Aircraft
Sample
Sample
% of
Mean/Std Dev
Type
Size
Rate
sample
of Sample (m)
> 20 cm
X,Y, and Z
Table 1 Evaluation of 2 and 5Second Sample Rates for GPS Phase Information During a Photo Mission
____________________________________________________________ 0.000/0.055

0.001/0.122
0.001
/0.114
INTERPOLATION ALGORITHM
The objective of the interpolation is to compute, using a limited portion of the navigation file, a position for the antenna phase center at the time of exposure which is within a half epoch of the central time of the limited data set i.e., less than 0.5 second for a 1Hertz sample.
The interpolation algorithm uses a secondorder polynomial whose three coefficients are solved for by least squares method.
The polynomial represents a curve which fits the aircraft
trajectory over a 5epoch to each coordinate axis.
period.
A different curve is fit
The
coefficients
of
this
polynomial
can and
be used to compute the aircraft position offset, acceleration in each coordinate direction.
velocity
The following models are used for interpolating the antenna
phase center coordinates:
.
.
.
.
.
.
.
.
(1)
X_{1 }
where t_{i }
(2)
(3)
=
= time_{i }
X_{i }= a_{x }+ b_{x}t_{i }+ c_{x}t_{i } time_{3}; when i = 1,2,...5; 2
2
a X x 2
+ b x t =a 1 x + c x t + b_{x}t 1 2 2 + c_{x}t_{2 }