In addition to their motion-sensing and positioning capabilities, Spotters are outfitted with onboard sensors that provide further insight into metocean conditions:

• The onboard barometer measures the barometric pressure at the surface without adjustment to mean sea level (i.e., station pressure).
• The onboard sea surface temperature (SST) sensor, which is only present on Spotters without Smart Mooring, measures the water temperature at the surface.

Aggregated sensor data is logged to the onboard SD card and transmitted to the Spotter Dashboard and Spotter & Smart Mooring API at defined intervals.

In this guide, you’ll learn how onboard sensor data is sampled and reported, how to adjust the reporting schedule, and get key onboard sensor specifications.

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Data sampling and reporting

Spotter’s onboard sensors operate on continuous sampling schedules, which means that a powered-on Spotter’s onboard sensors are consistently sampling and processing data.

By default, samples are logged to the onboard SD card every 60 seconds. Each entry is the average of the readings from the previous 60 seconds and the timestamp corresponds to the end of the sample.

Unlike Smart Mooring sensors, Spotter’s onboard sensors do not have a separate reporting schedule. They follow the same reporting schedule as the Spotter, which means that averaged sensor readings are transmitted at the configured update / processing rate (see Spotter Data Modes). Each transmission is the average of the readings from the previous sample interval. For example, in Waves: Standard mode with a 1-hour update rate, an average of the readings from the previous hour is transmitted every hour.

Example of a Spotter in HDR mode with a processing rate of 15 minutes: the SST sensor collects readings every second for 15 minutes, then aggregates those readings into a sample which is transmitted every 15 minutes.

Barometer

Barometer data is read from the sensor at 200-millisecond intervals, and a noise filter creates filtered readings at 10-second intervals.

By default, the BARO.csv file on the SD card contains barometer samples at a 1-minute time resolution, where each timestamped entry represents the average of the previous six 10-second filtered readings (see Spotter 3 SD Card Data Guide).

In the Dashboard and the API, barometer data is reported at the configured update / processing rate. Each data point represents the average of the 10-second filtered readings collected during the preceding sample interval. The timestamp indicates the end of the sample duration.

Example of a barometric pressure chart in the Spotter Dashboard

Snippet of a sample API response including barometer data

SST sensor

SST data is read from the sensor at 1-second intervals.

By default, the SST.csv file on the SD card contains SST samples at a 1-minute time resolution, where each timestamped entry represents the average of the previous sixty 1-second readings (see Spotter 3 SD Card Data Guide).

In the Dashboard and the API, SST data is reported at the configured update / processing rate. Each data point represents the average of the 1-second readings collected during the preceding sample interval. The timestamp indicates the end of the sample duration.

Example of a sea surface temperature chart in the Spotter Dashboard

Snippet of a sample API response including SST data

Adjusting the reporting schedule

To adjust the reporting schedule ****of the onboard sensors, update the Spotter’s data mode and update / processing rate in the Spotter Dashboard (see Spotter Dashboard).

Key sensor specifications