We can carry out acceleration compensation with help of board digital computer
(BDC)
0
)
cos(
2
)
cos(
2
)
sin(
2
)
sin(
2
,
0
)
sin(
)
cos(
)
sin(
)
cos(
2
3
3
3
=
−
−
+
=
−
−
C
C
C
C
C
C
C
C
r
r
r
r
r
r
Disregarding second order of infinitesimals components in the (2) and putting θ=0
we'll receive:
)
cos(
,
C
y
C
x
r
f
r
f
−
=
−
=
(3)
If every of signals f
x
and f
y
getting from accelerometers HSP will be multi plied
by r
-1
, integrated and multiplied by -1 then it can be received
and λcos(φ) at the output
of corresponding channels. Signal φ can be used to control stabilized platform
relatively axis X, signal λcos(φ)- to control HSP relatively axis Y. Constructed by such
way HSP will be similar to Schuler pendulum of 84.4 min period.
It's pointed out that accuracy requirements of modern international navigation
systems (INS), which ensure measurements of aviation
gravimetric
altogether.
That's why, we'll use INS in the capacity of navigation information source of AGS
later on. Sensing elements of INS unit force are placed on the HSP which operation
has been described above. We can see that measured output signals of accelerometers
are magnitudes of angular velocities relatively north and east axis after division by r
-1
,
integration, account of initial conditions and sign change:
)
cos(
=
=
y
X
(4)
We'll receive longitude λ after multiplication ω
y
by sec(φ) and result integration
(taking into consideration given initial longitude value ). It will be received φ after
integration of ω
x
and taking given initial value of latitude into account. The product of
ω
x
, ω
y
into r will give magnitudes of north and east components of airplane speed.
Above mentioned operations results can be set to the BCD. Described functional
diagram is navigation self - adjusting system scheme with feedback.
Following equation to define gravimetry abnormalities with help of AGS was
received
,
0
−
−
+
+
=
h
A
E
f
g
z
(5)
where f
z
- gravimeter output signal (of third accelerometer placed on the HSP,
which sensivity axis Z is coincided with inquiry vertical); E - Etweshe correction; A -
correction for height; γ
0
- inquiry magnitude of gravity acceleration; h-airplane position
height over ellipsoid;
);
2
sin
0000059
.
0
sin
0052884
.
0
1
(
78049
.
9
;
2
sin
cos
2
cos
sin
2
)
sin
2
1
(
cos
2
1
2
1
;
cos
2
2
2
0
1
3
2
1
2
1
2
2
2
3
1
0
−
+
=
−
+
−
−
−
=
+
=
−
−
−
−
K
her
K
V
k
e
r
V
E
h
hr
A
- 1580 -