Geography Reference
In-Depth Information
4.4.2. Transformation of the linear offset distances,
y
D
, in circular arcs
corresponding to the angular coordinate segments:
and respectively
and
D
x
V
min.
360
60
D
2
R
cos
meters
(5)
x
-
for the distances on the longitude
λ
direction ;
min.
360
60
D
2
R
meters
(6)
y
V
-
for the distances on the latitude
direction.
It is also adopted the notation:
z
Dh
.
(7)
On this basis, the geographical coordinates,
λ
L
,
L
,
h
L
,
of the reference point L which is
constituted from the video camera objective centre, are obtained as follows:
;
;
L
hhh
.
(8)
where
λ,
, h,
represent the geographical coordinates supplied by the IMU for the point in
which this is situated.
5. The computing relations group with which it is achieved the
determination of the target T geographic position in the horizontal
plane of the referential ellipsoid
At the computing of the linear distances, on the longitude and, respectively, on the latitude
direction, between the video camera successive positions and, respectively, between the
camera positions and the sighted target, it, also, takes account from the fact that this mono-
cameral stereo-fotogrammetric system, permits the sighting of some objectives which are
situated at distances of up to 200 - 300 meters from the lab vehicles. This way, it is possible
to adopt the hypothesis consisting in the approximation of the terrestrial globe with an
equivalent sphere with a radius R = 6.367.472 km., as it is presented in the Fig. 20.
The geographic position of the target T in the horizontal plane of the referential ellipsoid is
achieved, by combining the determinations of the absolute angular coordinates,
, of the sighted target, for two different
positions,
L
and, respectively,
L
, of the video camera, positions which are obtained as a
result of the lab vehicle displacement with a distance in limits of which the target T is
maintained in the video camera viewing field.
and respectively,
, ,
TTT
, ,
TTT
1
1
1
2
2
2
In the positioning scheme presented in Figure 20, the following notations were introduced:
