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TECHNO-CHAMP 2011
TEAM NAME :: INNO_MATES
HALLENGE :: A mobile phone based solution that helps in farm
management,
ricultural yield improvement, care/maintenance of farm
equipment, producestribution.
HEME :: To find out the moisture content of soil in an
agricultural field
using the GPS system on a mobile device using Android
Application.
HEORETICAL DESCRIPTION AND FUNCTIONALITY::
For precise applications of GPS, reflected signals are
considered as a source of
error rather than a useful signal. Because of the complexity of
the reflecting environment
at most GPS sites (e.g. topography, buildings), there are no
standardized modeling
approaches for removing these effects. Instead, quantification
of multipath levels is
only used as a quality check on GPS sites.
The Block Diagram in fig. 1 shows the flow of signal. Firstly,
the Android based
application on Mobile device (acting as our receiver) sends
signal to the GPS satelliteunder the coverage reach. Then the
Satellite searches for the transmitter having same
frequency as that of the receiver. Once located, the Satellite
sends Radio waves signals
to the transmitter which is located/ placed in the field. Now
the transmitter receives the
signals via Multipath and the signals which are obtained via
reflections from the soil
surface (which mainly constitutes of different moisture content
every time other than
the usual constraints which remain fixed) create Multipath noise
distortions. The
Fig. 1:: Block Diagram showing flow of signals
MOBILE
DEVICE
TRANSMITTER
GPS
SATELLITE
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transmitted GPS signal arrives by both direct and reflected
paths, with the receiver
measuring the sum of these signals. The amplitude of the
composite signal depends on a
combination of ground surface qualities (dielectric constant;
roughness) and the GPS
antenna gain pattern. The phase relationship between the direct
and reflected signals
changes over time, modulating the observed signal amplitude.
Signals for thesesatellites reflect off the ground south of the
antenna . For a known distance above the
ground h and GPS wavelength , the frequency f for multipath
reflections is 4h/.
The Mobile phone device receives the signals in the same form
and shows the output to
the User who is the farmer/owner of the field in this case on
his mobile phone
application.
HARDWARE AND SOFTWARE REQUIREMENTS::y GPS enabled Mobile Phone
with Android as OSy Receiver-Mobile Phone itself acts as the
receivery Transmittery Android SDKy Android Emulator
APPLICATIONS ::y Considering different moisture requirement for
different crops,
estimation of moisture content would help the farm/field owner
tooptimally decide which crop to be cultivated in which part of
the
field.y This technology effectively helps in irrigation in
regular practice.y The owner/farmer could actually monitor the soil
moisture content
without actually being physically present on every part of the
fieldwhich is very crucial if the field is widespread in large
area.
LIMITATIONS ::y In case of extreme weather and cloudy sky, the
efficiency of the
technology decreases as the clouds further increases the
obstructions and increases the multi-path noise and hence is to
beavoided in such conditions.
y This technology can not give 100% accurate estimation as
Idealsituation is not available.
REFERENCE ::www.google.com
www.howstuffworks.comwww.wikipedia.com
