D.I.Y. & CLS

position processing compared


Major advantages

Immediate access to processed data and position tracks any time. Potentially lower ARGOS cost for GEO and 3D

Predictable flat-rate ARGOS delivery and processing fee. Likely lower cost for SAM and 3D with extensive time series data. No charge for data delivery for ST-GOLD replaced tags. Delivery of presentation ready graphs and estimated position tracks. More sophisticated estimated position track generation with regions of probability.


ARGOS Date Delivery cost for pre-deployment tests and one month post pop-up use

Estimated US $150

30% of the cost of the total cost of the tag (i.e. including ST-GOLD extended warranty if ordered).

ARGOS data delivery cost beyond first month post pop-up. (For extensive time series data etc)

Estimated US $100 per month of additional use

$150 for unlimited use beyond first month

ARGOS data delivery cost for opportunistic transmissions

Estimated US $18 for each month during which a transmission occurs, plus about $2 for each 6h time slot. Limited to about $100 per month

Included in basic price

ARGOS data delivery cost for a tag replaced under ST-GOLD

Same costs as original tag, depending on use.

No additional charge if ST-GOLD has been ordered

Data Delivery

ARGOS position track and raw data delivery

Auto retrieved once per hour by SeaWatch on your machine

Access of ARGOS website. Complete ARGOS track delivered with processed data post pop-up.*

ARGOS position track length

Unlimited. SeaWatch auto-appends new data as it becomes available.

Prior 20 days on ARGOS web site. Unlimited for track delivered with processed data*

Decoded data delivery

Decode the SeaWatch collected data any time using SeaConvert.

Delivered to customer 30 days after pop-up or as specified.*

Estimated (light & magnetic) position track delivery

Process any time using SeaTrack software

Delivered by customer 30 days after pop-up or as specified.*

Estimated Position Track

Processing Method

Intersection of two measurements: magnetic field intensity (latitude) and light observation (longitude)

'Random walk' biased by observations (light,magnetic field intensity, temperature, depth) interpreted in the context of models (SST, bathymetry, coast line avoidance, magnetic model, known tagging and pop-up locations)

Track Characteristics

A transparent track based directly on two intersecting measurements with basic filtering of your choice. Measurement errors will immediately manifest as track errors and track may violate coastlines etc. A smooth track implies precision of the underlying, independent daily position estimates.

A smooth track that is constrained to always start at the known tagging and end at the known pop-up location. The track reflects the 'most probable' path to connect the tagging with the pop-up location, avoiding coast lines, regions of SST or bathymetry mismatch etc. The constraints including end points at known tagging and pop-up locations, and compliance with animal migratory capabilities means that errors in the track may be obscured or difficult to identify.

Manifestation of Measurement Errors in Track

Unless smoothed, manifestation is immediate as a large position jump or displacement, reverting immediately if the error subsides.

Errors will appear as a bias or excursion of the track, diverging slowly from the true path and returning once the error subsides or time proximity to the pop-up date forces the track towards the known end point. Short lived measurement of model errors cause only small divergences. Track excursion caused by measurement or model errors may not be readily apparent.

Work required to obtain graphs and filtered position estimation track?

Yes. Some position filtering in SeaTrack required. Graphs must be generated from decoded .csv data

No. Data ready for presentation use is delivered.

Factors considered in estimated position track computation

Light and magnetic observations, basic outlier filtering, position averaging

Light and magnetic observations, sea surface temperature, bathymetry, shore lines, plausible animal behavior (Kalman filtering)

Produces regions of probability

No. Track only. Track consistency serves as track precision indicator because daily positions are independently measured.

Yes. 50% and 90% probability regions stated. However, actual animal position may be outside probability region due to model limitations. For example, when relying on SST measurements, tag measurements of diurnal layer temperature variations or local temperature anomalies that are not captured by the model may cause significant track displacement.

Suitability for tag models

Good for GEO and 3D because magnetic sensing provides tight latitude error bounds and light sensing provides tight longitude error bounds. Limited use for SAM, because light-only position estimation can produce large latitude errors requiring other inputs to control.

Suitable for all tags

  * Self processing is always available to the customer. (i.e. You may choose to process your data using Desert Star software at any time, even if you are using the CLS Track&Loc Processing method)