--- title: "Instruments: Sensors & instruments | Nexus Observatory" description: "Instruments, inside Sensors & instruments: water level, discharge by velocity-area and rating curves, acoustic Doppler current profilers (river)…" url: https://observatory.global/sensors/instruments/ publisher: Nexus Observatory Inc. updated: 2026-10-27 --- [Nexus Observatory](https://observatory.global/) / [Sensors & instruments](https://observatory.global/sensors/) / **Instruments** # Atmosphere, water, ground and sky. Instruments, inside Sensors & instruments: water level, discharge by velocity-area and rating curves, acoustic Doppler current profilers (river), water quality sondes and more. Every item is traced to its specification, from ISO 4373 (water level measuring devices) to WMO-No. 1044 Manual on Stream Gauging, and runs on the open Observatory Protocol. [Plan with us](https://observatory.global/contact/) Architecture [The protocol](https://observatory.global/protocol/specification/) **Technologies**: 9 **At the frontier**: 0 **Protocol functions**: 3 of 8 **Industries served**: 21 Reference design, drawn to scale · drag to turn · hover a part **01** What it is ## Hydrology and water. Instruments placed in the air, water, ground and spectrum, from weather stations to seismometers, radars and cameras, with the calibration, metadata and quality control that make their readings evidence. Each technology below carries what it is, what we do with it, and the standard it is drawn against. In situ sensors and instruments ### Water level Pressure, radar, bubbler and float sensors at gauging stations and reservoirs. We design, integrate, deploy, operate, maintain and support. ISO 4373 (water level measuring devices) · WMO-No. 1044 Manual on Stream Gauging In situ sensors and instruments ### Discharge by velocity-area and rating curves Current-meter gaugings and stage-discharge relations that turn level into flow. We design, integrate, deploy, operate and maintain. ISO 748 (velocity-area methods) · WMO-No. 1044 Manual on Stream Gauging In situ sensors and instruments ### Acoustic Doppler current profilers (river) Boat-mounted and fixed profilers for discharge, velocity fields and bathymetry. We design, integrate, deploy, operate and maintain. ISO 24578:2021 (acoustic Doppler profiler) · ISO 15769 (acoustic Doppler and echo correlation meters) In situ sensors and instruments ### Water quality sondes Multiparameter probes for temperature, conductivity, dissolved oxygen, pH, turbidity and fluorescence. We design, integrate, deploy, operate, maintain and support. ISO 7027-1 (turbidity) · ISO 5814 (dissolved oxygen, electrochemical) · ISO 7888 (electrical conductivity) In situ sensors and instruments ### Groundwater monitoring Piezometers and loggers for groundwater level, temperature and quality. We design, integrate, deploy, operate and maintain. WMO-No. 168 Guide to Hydrological Practices In situ sensors and instruments ### Soil moisture and soil temperature Profile probes for drought, irrigation, landslide and flood antecedent conditions. We design, integrate, deploy, operate and maintain. WMO-No. 8 Volume I (soil moisture) · International Soil Moisture Network practices In situ sensors and instruments ### Hydrological data exchange Standard time-series encodings for water observations shared between agencies. We design and integrate. OGC WaterML 2.0 Part 1 (time series) · WMO WHOS In situ sensors and instruments ### Spectrum monitoring receivers Measured occupancy, interference and emissions across bands at a site. We design, integrate, deploy, operate, maintain and support. ITU-R Handbook on Spectrum Monitoring · ITU-R SM.1880 (spectrum occupancy measurement) In situ sensors and instruments ### Direction finding and emitter geolocation Locating interference and unknown emitters by angle and time difference of arrival. We design, integrate, deploy and operate. ITU-R SM.854 (direction finding) · ITU-R Handbook on Spectrum Monitoring **02** Architecture ## Where it sits, and what it speaks. Instruments draws on 1 domain and 8 layers of the spectrum; the highlighted layers carry this area. It speaks 3 of the protocol's 8 core functions. Meteorology (WMO No. 8 classes) 10 Air quality and atmospheric composition 7 Hydrology and water 7 Ocean and coastal 7 Seismic, geodetic, geomagnetic and radiation 8 RF, acoustics, cameras and radar 9 Calibration, metadata and quality control 7 Frontier and research 6 01**Join** Identity, attestation quote, signed policy. 02**Admit** Admitted for a stated scope, nothing wider. 03**Describe** What, where, how and by whom, with calibration. 04**Time** One clock across the grid, with its error bound. 05**Observe** Every value with quality and provenance. 06**Qualify** Tested against the specification, state on record. 07**Federate** Signed exchange across grids and trust domains. 08**Orchestrate** Software and configuration by signed plan. **03** On the grid ## Every site joins one observing grid. The open networks on the grid today, over real relief and the geodesic cells we count them into, filtered to the air health domain this area serves. A site built here enrols into the same grid. **04** In the field ## Where this runs, sector by sector. 6 deployment scenarios from the sector research that rely on instruments. [Government and public safety National GBON surface and upper-air networkWMO-grade stations reporting through WIS 2.0, funded through the systematic-observations financing pathway.](https://observatory.global/sectors/public-safety/) [Government and public safety Wildfire camera network and fire-weather stationsCamera towers with edge inference and co-located fire-weather stations, utility- or agency-funded.](https://observatory.global/sectors/public-safety/) [Government and public safety Urban street-flood sensor networkOpen-hardware depth sensors with open data and alerts to emergency management.](https://observatory.global/sectors/public-safety/) [Government and public safety Alerting integration with the Common Alerting Protocol and cell broadcastSoftware-heavy: sensor triggers feed an alert origination tool; the alert authority keeps every decision.](https://observatory.global/sectors/public-safety/) [Cities Hybrid air-quality networkReference analysers plus calibrated low-cost nodes; low-cost sensors alone do not meet regulatory requirements.](https://observatory.global/sectors/cities/) [Communities and rural Remote microgrid, sensing and connectivity bundleSolar-plus-storage telemetry with a weather station and a small cell in a diesel-reduction project.](https://observatory.global/sectors/communities/) **05** Open and enterprise ## Open by default. Enterprise by contract. The open counterpart lives on the main site for anyone to read and run. The enterprise service is designed, deployed and operated with you, under contract. Open, on the main site - Metadata and quality rules - Open networks on the grid Enterprise, on this site - Sensing as a Service - Calibration programmes - Qualification **06** The rest of the line ## Sensors & instruments, area by area. [Sensors & instruments Weather and environmentWMO siting practice, WIGOS metadata.](https://observatory.global/sensors/weather-and-environment/) [Sensors & instruments RF sensingOccupancy and interference, measured in the band.](https://observatory.global/sensors/rf-sensing/) [Sensors & instruments CalibrationTraceable to reference, recorded, repeated.](https://observatory.global/sensors/calibration/) [Sensors & instruments Sensing as a ServiceYou take the observations; we run the hardware.](https://observatory.global/sensors/sensing-as-a-service/) ## Bring us the site. Survey, design, deployment and operation for instruments. The form names who receives your details. [Talk to us](https://observatory.global/contact/) [contact@observatory.global](mailto:contact@observatory.global?subject=Sensors%20%26%20instruments%3A%20Instruments) [Nexus Observatory](https://observatory.global/)**Sensors & instruments** . Measurements that carry their own proof.[Talk to us](https://observatory.global/contact/) Sensors & instruments - [Instruments](https://observatory.global/sensors/instruments/) - [Weather and environment](https://observatory.global/sensors/weather-and-environment/) - [RF sensing](https://observatory.global/sensors/rf-sensing/) - [Calibration](https://observatory.global/sensors/calibration/) - [Sensing as a Service](https://observatory.global/sensors/sensing-as-a-service/) Technologies - [Meteorology (WMO No. 8 classes)](https://observatory.global/technologies/sensors/meteorology-wmo-no-8-classes/) - [Air quality and atmospheric composition](https://observatory.global/technologies/sensors/air-quality-and-atmospheric-composition/) Industries - [Public safety](https://observatory.global/sectors/public-safety/) - [Government](https://observatory.global/industries/) - [Cities](https://observatory.global/sectors/cities/) - [Civil resilience](https://observatory.global/industries/) - [Communities](https://observatory.global/sectors/communities/) - [Humanitarian](https://observatory.global/sectors/humanitarian/) - [Climate](https://observatory.global/industries/) Service platforms - [Observatory Protocol](https://observatory.global/protocol/) - [Protocol & Grid](https://observatory.global/grid-services/) - [Software](https://observatory.global/software/) - [Hardware & power](https://observatory.global/hardware/) - [Connectivity](https://observatory.global/connectivity/) - [Edge compute & AI](https://observatory.global/edge-ai/) - [Earth observation & GeoAI](https://observatory.global/earth-observation/) © 2026 Nexus Observatory Inc. 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