uere: Estimate UERE from calibration data

Description Usage Arguments Details Value Note Author(s) See Also

View source: R/uere.R

Description

Functions for estimating and assigning the User Equivalent Range Error (UERE) of a GPS device from calibration data.

Usage

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uere(data,override=FALSE,integrate=FALSE,diagnostic=FALSE)

uere(data) <- value

Arguments

data

Telemetry object or list of telemetry objects, preferably with DOP columns.

override

Return a UERE estimate even for data that are calibrated.

integrate

Consider HDOP and VDOP as being specified by the same UERE value.

diagnostic

Return extra details, such as the UERE's 95% confidence interval and a plot.

value

UERE value(s) to assign to telemetry data (see details).

Details

Often times GPS animal tracking devices return HDOP values but do not specifiy the device's UERE necessary to transform the HDOP values into absolute errors. uere() allows users to estimate the UERE from calibration data, where the device was left fixed over a period of time. Otherwise, when error=TRUE in ctmm, ctmm.fit will estimate the UERE simultaneously with the movement model, which is less reliable than using calibration data.

The calibration UERE can then be applied to tracking data during import, with as.telemetry, or after import with the uere()<- assignment method.

Ideally, device HDOP and VDOP values are scaled to the same UERE. However, in many cases not all DOP values are supplied and some must be approximated. In such cases, different UERE values need to be estimated for each set of DOP values, via the axes argument of uere. A c combination of properly named UERE values can then be used in assignment via uere<-. Proper names include "horizontal", "vertical", and "speed".

Value

The UERE estimate.

Note

The GPS device should be fixed during calibraiton.

Author(s)

C. H. Fleming

See Also

as.telemetry.


ctmm-initiative/ctmm documentation built on May 18, 2018, 5:57 a.m.