diff --git a/src/algorithms/libs/rtklib/rtklib_sbas.cc b/src/algorithms/libs/rtklib/rtklib_sbas.cc
index 1cd36a1c5..b115e9821 100644
--- a/src/algorithms/libs/rtklib/rtklib_sbas.cc
+++ b/src/algorithms/libs/rtklib/rtklib_sbas.cc
@@ -221,7 +221,7 @@ int decode_sbstype6(const sbsmsg_t *msg, sbssat_t *sbssat)
         }
     for (i = 0; i < sbssat->nsat && i < MAXSAT; i++)
         {
-            if (sbssat->sat[i].fcorr.iodf != iodf[i / 32])
+            if (sbssat->sat[i].fcorr.iodf != iodf[i / 39])
                 {
                     continue;
                 }