Intelligent Containers Based on a Low-Power Sensor Network and a Non-Invasive Acquisition System for Management and Tracking of Goods

Abstract

This paper presents a prototype of a system for intermodal freight transport with electronics management of goods. The system is based on low-power wireless networks connecting intelligent containers. The proposed intelligent container can be configured with different type of sensors inside. With the objective to preserve the sealing of the container, data collected inside the container are transmitted through a metal communication channel based on ultrasonic techniques. Outside the container, the implemented system is composed by a long range and low power scalable wireless network. Finally, a management subsystem has been designed for tracking, monitoring and alarm reporting.

Low-Power Ultrasonic Front End for Cargo Container Monitoring

“…However, the establishment of a robust communication becomes a challenging task in this latter case: the insufficient and irregular transducer-wall pressure as well as the deficient support due to the surface roughness, are typical harmful effects associated to a reversible fixing approach. A system based on magnetic enclosures was used in [25] for containing the whole communication system (PT transmitter/receiver modules) and protecting it from adverse environmental conditions, but the coupling quality between the transducer and the container wall was not a major concern.…”

“…Electromagnetic-acoustic transducers (EMATs) [9,14] and piezoelectric transducers (PTs) [15][16][17][18][19][20][21][22][23][24][25][26] are the most popular devices for this approach. The strength of EMATs lies in their capability of non-contact operation.…”

“…Orthogonal Frequency Division Multiplexing (OFDM) is by far the most common choice [17][18][19][20], usually including empirical equalization schemes based on feedback algorithms. However, previous works addressing in depth low-power through-wall ultrasonic communication in general [22] and regarding cargo container monitoring in particular, are only marginally covered in the literature [24,25].…”

“…In this context, a versatile non-invasive ultrasonic front-end for data transmission through the container wall is presented in this work. It follows a low-cost, low-rate and low-power approach, clearly improving the transmission power requirements of any of the related proposals [22,24,25].…”

“…A pseudo-differential charge amplifier [28] providing sensitivity programmability is employed for signal conditioning. A final architecture based on the previous contributions is implemented under simplicity and low-power criteria in Section VII, since a low data rate (of one or few kbps) clearly fulfills the requirements for container monitoring [25]. Finally, a brief conclusion is drawn in Section VIII.…”