Specifications

FASTER Engineering Model
64
Missing GPS data prevent magnetic declination determination so the computed
heading coming from magnetometers is relative to the magnetic north direction instead of
the true north direction; true heading is thus provided by the Garmin GPS receiver.
NAV420 accuracy is reported in the following table.
NAV420 Accuracy
Specification
GPS disabled
GPS enabled
X,Y Velocity [m/s rms]
N.S
< 0.4
Z velocity [m/s rms]
N.S
< 0.5
Attitude angles [° rms]
< 2.5
< 0.75
Bias: R,P,Y (EKF stabilized) [°/sec]
< ±0.1
< ±0.1
Table 7: Crossbow NAV420 measurement accuracy
Figure 54: Crossbow NAV420 and its mechanical drawing [Ref. (35)]
6.1.2 Visualization and data storage
The second PC based board is a mini-itx (170 x 170 mm) VIA EPIA EN15000,
powered by a VIA C7 cpu running at 1.5 GHz and provided with a 1 Gbyte of DDR2
RAM memory, a Gigabit Ethernet interface and an integrated VIA UniChrome Pro AGP
graphics card with up to 64 Mbyte of shared memory [Ref (36)]. The EPIA EN15000 has
two Sata II ports, one of which is occupied by a 3.5” 80 Gbyte hard disk used to store the
images coming from the Canon EOS camera; RS232 and VGA ports are available too.
This kind of embedded PC solution has been selected because of the need to guarantee a
sufficient graphical performance in 3D graphic, although another PC/104 board should
represents a better choice in term of reliability.