Filter duplicates in track_sensor

[lucas-johnson]

Potential fix for this kind of problem: #392 (comment)

It might be nice to filter out duplicates in the track_sensor() function. Filtering these duplicates will not change the underlying data but will only be used to compute the sensor positions so it seems pretty safe.

track_sensor.LAScluster <- function(las, algorithm, extra_check = TRUE, thin_pulse_with_time = 0.001, multi_pulse = FALSE)
{
  x <- readLAS(las)
  if (is.empty(x)) return(NULL)
  x <- filter_duplicates(x)
  pos  <- track_sensor(x, algorithm, extra_check, thin_pulse_with_time, multi_pulse)
  return(pos)
}

[Jean-Romain]

Do agree

[Jean-Romain]

Done