b'Environmental geophysics be optimised for e\x1cciency. A commontelco infrastructure/software. The goodGlobal Navigation Satellite Systems protocol packaged in a LoRaWANnews is that both NB IoT and LTE Cat(GNSS)system is SDI12, which is a simple textM1 are well supported in Australia. And protocol in which one master deviceboth are suited to sending the requisiteAnother area in geophysics where can manage and systematically pollsmall packets of information. Unlikemicrowave communication is important communication with several sensors.conventional cellular connections, theseis in GNSS, i.e. satellite-based timing and This is a relatively simple protocol totechnologies are not restricted to alocational services. Receivers connected learn and is becoming dominant in30 km range (by e.g., timing electronicsto geophysical systems are commonly sensor communications. in mobile phone towers), so coverage isused to absolutely locate and time-Another approach is to go direct frommore extensive. synchronise geophysical equipment. If sensors in the bush to the internet viaprecision positioning (10 cm) is needed, In order to \x1dt information intothen di\x1eerential corrections are required cellular networks or good old-fashionedsmall packets that can be e\x1cciently WiFi. This is typically handled by extraalong with dual-frequency receivers. It transmitted by low power devices,wasnt that long ago that these systems low-power Remote Terminal Unitsoverheads of data sending/receiving (RTU), which are e\x1eectively a modemcost around $200 000 per pair. In protocol have to be modest and wellcontrast, recent advances in electronics board, a processor and physical sensorthought out. Common HTTP/HTTPS, FTP connections. When instrument designhave allowed the development of, for and other protocols that we are mostlyexample, the uBlox F9 dual frequency is optimised, the RTU is integratedmore familiar with are overhead-heavy, directly into geophysical sensors. Thischipset and Point Perfect corrections that so the MQTT protocol was developed,use the open-source, compact SPARTN is common already in telemeteredand most new low-power telemetry seismic nodes. For remote operation,correction format transmitted using the now uses this protocol. MQTT, a legacyMQTT protocol. This information is either cellular type low earth orbit (LEO)acronym of no real meaning, adds satellite communication (Figure 1sourced via satellite using the UBlox a clever, broker-managed, means ofNeoD9S chipset, or by cellular network. shows a typical LEO satellite) is in itshandling periods when communication infancy, and we expect to see dramaticCost of these systems is now below links are broken so that sending devices$1000 and becoming cheaper. The uBlox new opportunities and drastic costcan operate with very low power drain. reductions in this space soon. chipsets are now readily available on More data intensive applications arechipset evaluation boards popular with In order to keep remote monitoringnow more likely to send data using anelectronics enthusiasts and are starting costs and power consumption down,alternative Application Programmingto \x1dlter into mainstream GNSS devices. cellular communication from remoteInterface (API) type called RESTFor the geophysicist they will be a really sensors is (again) best limited to small(Representational State Transfer) whichgood opportunity to improve positioning, messages, sent relatively infrequently,typically operates over HTTP/HTTPS. although, at \x1drst, they will require a high in small packets. Conventional cellulardegree of understanding to properly communication hardware and protocolNot only do protocols need to becon\x1dgure the system to get the di\x1eerential do not work well for this; two newe\x1ccient for low-power microwavecorrections right, and then will need to systems have been developedNBcommunication, but the data sentbe integrated with existing applications. IoT (short for Narrow Band Internetneeds to be compactly and sensiblySimpler options, available now, include the of Things) and LTE Cat M1. This one ismanaged. Until recently this was donefree CORSnet corrections. Unfortunately, a cellular LTE (Long Term Evolution using compact, highly speci\x1dc binaryto use these corrections, operators will i.e., basically cell phone technologydata formats. Unfortunately, theseneed to be using fully RTK-equipped after 3G) technology speci\x1dcallyrequire both specialised knowledge asGNSS systems. Both Geoscience Australia designed for the Internet of Thingswell as management skills. Software(https://gnss.ga.gov.au/stream) and the (IoT) and machine-to-machine (M2M)that reads and manages data todayNew South Wales government (https://communications. Access to theseexpects standardised formats that havecorsnet.nsw.gov.au/), among others, communication methods requireintermediate to high organisationalo\x1eer this service. Positional corrections specialised SIM cards, modems andoverheads. Files using standard ASCIIare applied either in real time via cellular text and comma-separated variablessignal, where coverage exists continuously, have been used to transfer informationor in post processing using open-source but are not suitable for complex generictools such as RTKLib (https://www.data management systems. XML andrtklib.com/) or in commercial surveying JSON formats are improvements on textpackages. These advances in GNSS \x1dles, as they add nesting and hierarchypositioning are likely to usher in uptake of to information so that machine andmicrowave-frequency communication that human readers can e\x1cciently searchwill dramatically improve the quality of and allocate data as it is read. Of the two,geophysics data collected.JSON is more compact and therefore Figure 1.A low Earth orbiting satellite typicalis becoming the format of choice forGeophysicists understanding of of new microwave and VHF communicationsdata sent via low-power microwavefundamental geophysical technology is technology that change object dimensions andcommunication. Python Dictionaryof great value, yet its value can be greatly data transmission rates by orders of magnitudeis increasingly being used as a dataextended when uptake of modern compared to old technology (image source - SWARMstructuring tool competing with JSONmicrowave communication technology is technologies). and XML. integrated.37 PREVIEW DECEMBER 2023'