please provide a link to the reference document you are talking about.
From doc 9905 RNP procedure design manual
2.1.1 RNP APCH versus RNP AR APCH
2.1.1.1 RNP APCH is defined as an RNP approach procedure that requires a lateral TSE of +/-1 NM in the initial, intermediate and missed approach segments and a lateral TSE of +/- 0.3 NM in thefinal approach segment. Guidance on implementing RNP APCH operations can be found in the PBN
Manual, Volume II, Chapter 5, Implementing RNP APCH.
2.1.1.2 RNP AR APCH is defined as an RNP approach procedure that requires a lateral TSE as low as +/- 0.1 NM on any segment of the approach procedure. RNP AR APCH procedures also require that a specific vertical accuracy be maintained as detailed in the PBN Manual, Volume II, Chapter 6.
