Spotter Data Subscription and Storage

This page outlines the remote data subscription service currently provided by Sofar Ocean Technologies. We continue to refine and improve our offerings, and we will update this page accordingly. In the following sections we outline how the various Spotter operation modes, data packages, and pricing work, as well as how all of this relates to what you see on your Dashboard. Sofar makes an effort to keep data transmission affordable and simple. Any savings we can accommodate due to future price breaks with our satellite provider we intend to pass on to our users. Also, we will continue to refine and update data subscription features and options to accommodate user needs. Please contact with any questions, suggestions, or feature requests.

Data Subscription

With a data subscription, your Spotter will send selected data via satellite transmission to be stored in our database and made accessible to you via the dashboard and API. Without a subscription your Spotter continues to operate normally and will store all collected data on the on-board SD card. For real-time satellite updates of wave data, status, and position, you will need a current data subscription. Subscription status information and renewal is accessible via the detailed view of your Spotter on your Dashboard.

Your data subscription includes unlimited access to the Spotter Dashboard and:

- Continuous real-time wave data and position updates on interactive Dashboard map.
- Rich interface for visualizing historical wave and position data.
- Simple file download of historical wave and position data.
- Comprehensive API and WebHook for seamless integration of Spotter data into your custom applications and websites.
- Two-way over-the-air communication for on-the-fly configuration changes to your Spotter(s).
- Geofence notifications to alert when a Spotter leaves the user-set perimeter.
- Real-time system health monitoring.
- Firmware update notifications.
- Access to guides, user manuals, post-processing scripts and other support documentation.

Spotter Data Modes

Your Spotter has three (3) remotely configurable modes (Waves: Standard, Waves: Spectrum, and Track). For each mode you can set a range of update rates so you can tailor your Spotter’s behavior to your specific application needs. These changes are achieved via your Spotter’s 2-way satellite communications interface, and can be changed at any time from your Dashboard regardless of where your Spotter is in the world.

Waves: Standard

In this mode your Spotter calculates wave statistics based on a 30-minute sample period, and transmits bulk wave statistics through the satellite network (see the technical manual for more specifics on the on-board calculations of wave bulk statistics). You can select a satellite update rate of 30 minutes or 60 minutes (default). In the default setting, Spotter will include two 30-minute samples in its hourly update. The 30-minute update option can be selected if more real-time updates are required for your application, but will incur higher data usage costs

Figure 1 The Waves: Standard mode uses 30-minute sampling periods to calculate wave statistics. You can select either 30-minute or 60-minute (default) update intervals. If the 60-minute update rate is selected, two sample periods are included in a single update to the Dashboard, which saves data transfer costs. If data updates are required faster, you can set your Spotter to send updates every 30 minutes.

Waves: Spectrum

If Waves: Spectrum mode is activated, your Spotter transmits the variance density spectrum and directional moments (a­1, b1, a2, b2) as a function of frequency (for further details, see the technical manual). In this mode, the system uses a 60-minute sample period to improve the statistical estimate of spectrum and directional moments. The user can select an update rate of between 1 and 6 hours. Update rates faster than 6 hours will incur higher data usage costs than Waves:Standard mode due to the increase in amount of data transmitted.

Figure 2 In Waves: Spectrum mode, Spotter uses a 60-minute sampling period to compute wave statistics. The user can select update intervals between 1 and 6 hours. Example for 1-hour (top), 2-hour (middle), and 3-hour (bottom) update intervals shown in figure.


In this mode, Spotter transmits five samples of its position (lat/lon) separated by 3 minutes, every 15 minutes. Measurement resolution is 1/100,000th minute of arc. This mode is designed to provide high-resolution location track data for retrieval or surface current tracking. Based on the location data, the Dashboard continuously calculates and provides a 15-minute forecast of Spotter position (to aid retrieval) and estimates surface drift rates based on differential position.

Renewal and Pricing

At any time you can purchase a 1 to 24-month renewal for your Spotter data subscription. To keep things simple, each month of subscription allocates a fixed amount of satellite transmission budget. This amount is the equivalent of continuous operation in Waves:Standard mode using the default update rate (1 hour). The subscription expires at the end of the number of months purchased (use-by-date) or when the transmission budget is exceeded, whichever comes first. When your current subscription expires, any pending renewal will automatically activate. All data services are subject to Sofar's Terms of Sale and Terms of Use.

Continuous operation in data modes and/or update rates other than 1-hour Waves:Standard may reduce the effective duration of the subscription (see Table 1). For instance, if you switch your system to Waves:Spectrum with 3 hour updates, the Data Usage Multiplier (Table 1) is equal to 2, which means that the rate of transmissions is effectively doubled, and if the system is used continuously in this month, your subscription will expire in half the time than the number of months purchased. However, if you switch to 3-hourly Waves:Spectrum and only use your system half the time, your effective subscription remains unchanged. This may sound complicated, but the Dashboard will automatically update available transmission budget in real-time whenever you make a change. So you can always check your current subscription usage in the Spotter view on your Dashboard. In this view you will always find the up-to-date subscription use-by date, as well as the continuous days of operation in the current configuration before the data transmission budget is exhausted for your Spotter. When changing modes on the Dashboard, any resultant changes to the subscription are displayed before confirming the mode change so you can decide whether you want to make the change or not. For reference, Table 1 shows the Data Usage Multipliers for the various mode options.


Renewals can be purchased through the dashboard in durations between 1 and 24 months. Renewals will automatically activate upon expiry of your current subscription, or on purchase if your subscription is currently expired. The Dashboard will indicate if you have any pending renewals on your Spotter.

Renewal Prices:

1-5 months – $100/month
months – $92/month
months – $84/month

SD Logging

Regardless of the Spotter mode, Spotter always stores its geographical location (lat/lon) at 1-minute time intervals, and saves 3D (east, north, up) 2.5Hz relative displacement time series to the SD card.

In either of the Waves modes (Standard or Spectrum), Spotter stores the ensemble-averaged spectrum and cross-spectra for each sample period. Note that in Track mode, wave spectra and wave statistics are not stored on the SD card (they are not calculated in this mode).

To help you with the analysis of displacement and spectra data on the SD card, Sofar provides an open-source Python script you can use to collate all raw SD data files for position and displacement, and calculate directional moments from the cross-spectra, which are saved in easy-to-read formats.

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