rrlp-ephemeris: Add a note about extracting RefPos from AID_INI

Yeah we could do it if anyone is willing to implement conversion
from ecef to WGS84.

See http://en.wikipedia.org/wiki/Geodetic_system

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/rrlp-ephemeris/ubx-parse.c b/rrlp-ephemeris/ubx-parse.c
index 60bc057..1dbb279 100644
--- a/rrlp-ephemeris/ubx-parse.c
+++ b/rrlp-ephemeris/ubx-parse.c
@@ -85,6 +85,10 @@
 	//printf("[.] AID_INI\n");
 
 	// FIXME: Extract info for "Reference Time"
+	
+	// FIXME: We could extract ref position as well but we need it in
+	//        WGS84 geodetic coordinates and it's provided as ecef, so
+	//        we need a lot of math ...
 }
 
 static void