Adding topography to ImpulseRadar data

[Janthony20]

UPDATE: Issue fixed. The interpolate function had identified duplicate values in the topographic data and deleted them, so there was a mismatch between the number of traces in the GPR data and the number of topographic data points. I removed the duplicate value from the FID file and then applied the interpolate function again. This plot worked after this.

Dear RGPR community,
Has anyone added topography to Impulse Radar formatted GPR data files (iprb)?
I have followed the instructions for adding topographic data, interpolating with mySurvey <- interpPos(mySurvey, FIDs) code. There are total of 3917 traces, but I have topographic data for only 207 data points.
When plotting data with plot(mySurvey[[1]], addTopo=TRUE)

I get an error:
Error in checkArgStop(msg) : Check arg
arg 'ts': must be a numeric vector of length 1 or 3917

Does anyone know how I can resolve this? I cannot see how to edit the "ts" value.

Many thanks,
Josh