expand data format description

man/load_and_tidy_up_GPS.Rd

@@ -26,13 +26,24 @@
 }
 \details{
   The code ignores letter case when reading column names. The GPS csv file is 
-  expected to have the following column names: latitude or lat; longitude or lon;
-  nat(used/view) or nat (used/view) where the value format can be
-  3 (2), 3(2), 3/2, 3 / 2; a column with at least the character string "sat info " 
+  expected to have the following column names: latitude; longitude;
+  a column name height(m); a column named speed(km/h); 
+  a column local data or just date, and; a column local time or just time.
+
+  A column with at least the character string "sat info " 
   where the valueformat can be "(1-1-1-10);(1-1-1-10)" or "#1-1-1-10;#1-1-1-10" where
   the number values per substring does not have to be 4 but the last value is always assumed
-  to reflect SNR; a column name height(m); a column named speed(km/h); 
-  a column local data or just date, and; a column local time or just time.
+  to reflect SNR. If sat info is not available then the code assumes that there is a sid and snr,
+  which when values are fused pairwise reflect the sat info value.
+
+  Satiliate information is either provided with column nsat(used/view) or 
+  nsat (used/view) where the value format can be
+  3 (2), 3(2), 3/2, 3 / 2. If nsat(used/view) column is not available the code will
+  look for column nsat and extracts from the sid column the number of satilites in view.
+
+  Timestamps are expected to be available as either: "datetime" column in local timezone,
+  "time" and "date" columns in local timezone, "local time" and "local date"
+  column, or "utc time" and "utc date" column.
 }
 \value{
   List with a data.frame df that holds the GPS time series