Sensor Data Acquisition

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Overview

Traditionally, environmental sensor data from remote field sites were manually acquired during infrequent site visits. However, with today's technology, these data can now be acquired in real-time. Indeed, there are several methods of automating data acquisition from remote sites, but there is insufficient knowledge among the environmental sensor community about their availability and functionality. Moreover, there are several factors that should be taken into consideration when choosing a remote data acquisition method, including how immediately the data are needed, bandwidth, hardware and network protocols, line-of-sight, power consumption, security, reliability and redundancy, and budget. Here, we provide an overview of these methods and recommend best practices for their implementation.

Introduction

Considerations

Here, we provide an overview of important considerations when choosing a remote data acquisition method.. also see site & platform selection...

Bandwidth

can be an important consideration, particularly when high frequency data are being collected. Will cameras be utilized at the site? Where is broadband point of presence (POP) located? Does equipment work with required bandwidth? collection/access interval

Protocols

IP: private vs public networks Serial: Many field instrumentation only comes with serial ports, therefore a Serial-to-Ethernet (e.g. Campbell Scientific NLxxx series) converter is required to interface with transmission instrumentation, which often comes with ethernet port.

Line-of-sight

Evaluation of environment, topography, and vegetation. Can be initially determined using LOS calculators, which use DEM models, but must be ground truthed. Often requires a repeater infrastructure. Choosing repeater locations involves many of the same considerations for choosing site selection. Distance to repeater is a factor.

Power

How important is real-time accessibility? (e.g., what is desired collection frequency?). What are the transmission type power requirements, onsite buffer size. Redundancy is preferred, especially in very remote sites. If power is disrupted, will system resume operations?

Security

Physical Security

see Sensor, Site, and Platform Selection

Network Security

Encryption keys, VPN

Reliability and Redundancy

of transmission mode and of equipment

Budget

Costs of implementing a data acquisition and transmission method depend on existing infrastructure, initial setup costs including personnel, personnel costs, specifically technician maintenance, and recurring costs, such as monthly recurring costs with cellular transmission.