VIA Technologies EPIA SN-Series Specifications download pdf (Page 51)

FASTER Planning Software

The image scale factor is given by the ratio /. For the purposes of this study flying

height is limited to 500 ft (152.4 m) over the highest obstacle in a 3000 m range, because

of the Italian regulation on Very Light Aircrafts flight. Low altitude makes a

photogrammetric instrument more sensitive to scale factor variations; if the flight is

conducted in a mountainous area there may be percentage variations of the scale factor in

the order of 300/400% as experienced in the last FASTER EM flight campaign presented

in Chapter 7. Once defined , ,  and  the total number of acquired images is a

function of the target area dimensions. The minimum required time interval between two

acquisition is defined as follows:















1 



100



Eq.5

where  is the ground speed velocity measured by the G.P.S receiver which is different

from IAS (Indicated Air Speed) shown by a standard anemometer installed onboard the

aircraft.

Aerial flight can only be made in clear, cloudless weather conditions, carefully taking

into account wind direction in the over flight area. If the photogrammetric system is not

able to apply corrections to remove the crab angle (namely the sideslip angle , as shown

in Figure 34) via electric or pneumatic control systems, wind direction should be known

and its effects must be planned [Ref. (22)].

Figure 34: Crab angle representation [Ref. (22)]

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VIA Technologies EPIA SN-Series Specifications Page 51