Wireless Soil Scout prototype radio signal reception compared to the attenuation model

Abstract

Wireless underground Soil Scout prototypes, introduced here for the first time, were used for remote soil monitoring during 5 months in real conditions. Every Soil Scout transmitted moisture and temperature data once every 10 min. The prototype system works well. A signal attenuation model is able to predict long periods of lost signals when soil moisture and on-soil vegetation conditions change. The model attenuation -98 dB is the threshold level for distinguishing probable failure from success, even if the system hardware design would suggest -110 dB. Individual transmission failures do not always correlate to changes of condition. Further work should focus on increasing transmission power and improving knowledge of the effect of vegetation.

Communication with Aboveground Devices in Wireless Underground Sensor Networks: An Empirical Study

“…The results show an adequate radiation efficiency (>90%) of this antenna in different soil textures and moisture levels. A model exclusively for UG2AG communication is proposed in [14] and experimental results are provided using the ultra wideband elliptical antenna in [13] and a high-gain antenna for an aboveground receiver. Communication ranges of 30 and 150m are reported for the burial depths of 40cm and 25cm, respectively.…”

Connectivity in Wireless Underground Sensor Networks

“…Because of the unique channel characteristics and the heterogeneous network architecture of the WUSNs, the connectivity analysis is much more complicated than in the terrestrial wireless sensor networks and ad hoc networks. In particular, since WUSNs consist of underground (UG) sensor nodes and aboveground (AG) data sinks [1], [3], [4], three different communication channels exist in WUSNs based on the locations of the transmitter and the receiver, including: underground-tounderground (UG-UG) channel, underground-to-aboveground (UG-AG) channel, and aboveground-to-underground (AG-UG) channel. The transmission range in these three different channels is different from each other.…”

“…For the UG-UG channel, the transmission range is very limited compared to the terrestrial air channel [5], [6] due to the material absorption of the soil medium. For the UG-AG channel, the transmission range is much longer than the UG-UG channel [3], [4], [6]. This is because a large portion of the radiation energy can penetrate the air-ground interface from the soil to the air, and the path loss in the air is much smaller than that in the soil.…”

Testing the use of an analytical and mechanistic C3 - biomass accumulation model for precision fertilization

“…The crop itself can be measured directly by means of leaf area, light reflectance in field (Scmidhalter et al 2008) or indirectly by means of soil water (Tiusanen 2009) or nutrient content (Schmidhalter et al 2008) in the soil. When information from large areas is needed, the soil surface or crop canopy can be measured directly by remote sensing (Shanahan et al 2008, Laurila et al 2010, Hu and Mo 2012 before the field is actually entered with a machine.…”

“…The soil moisture can be measured from large areas with Soil Scouts that are entirely embedded in soil and send information about soil moisture status wirelessly (Tiusanen 2009). However, there are also challenges in the measurements.…”