diff --git a/src/algorithms/libs/rtklib/rtklib_pntpos.cc b/src/algorithms/libs/rtklib/rtklib_pntpos.cc
index c5eea1526..e07489a09 100644
--- a/src/algorithms/libs/rtklib/rtklib_pntpos.cc
+++ b/src/algorithms/libs/rtklib/rtklib_pntpos.cc
@@ -58,8 +58,13 @@ double varerr(const prcopt_t *opt, double el, int sys)
 
 
 /* get tgd parameter (m) -----------------------------------------------------*/
-double gettgd(int sat, const nav_t *nav)
+double gettgd(int sat, const nav_t *nav, int tgd_index)
 {
+    if (tgd_index < 0 || tgd_index >= 4)
+        {
+            return 0.0;
+        }
+
     int i;
     for (i = 0; i < nav->n; i++)
         {
@@ -67,11 +72,17 @@ double gettgd(int sat, const nav_t *nav)
                 {
                     continue;
                 }
-            return SPEED_OF_LIGHT_M_S * nav->eph[i].tgd[0];
+            return SPEED_OF_LIGHT_M_S * nav->eph[i].tgd[tgd_index];
         }
     return 0.0;
 }
 
+
+double gettgd(int sat, const nav_t *nav)
+{
+    return gettgd(sat, nav, 0);
+}
+
 /* get isc parameter (m) -----------------------------------------------------*/
 double getiscl1(int sat, const nav_t *nav)
 {
@@ -209,7 +220,10 @@ double prange(const obsd_t *obs, const nav_t *nav, const double *azel,
     /* if no P1-P2 DCB, use TGD instead */
     if (P1_P2 == 0.0)
         {
-            P1_P2 = gettgd(obs->sat, nav);
+            // Galileo I/NAV clocks are referenced to E1/E5b. For an E1
+            // pseudorange, use BGD(E1,E5b), stored in tgd[1].
+            const int tgd_index = (sys == SYS_GAL && obs->code[i] != CODE_NONE) ? 1 : 0;
+            P1_P2 = gettgd(obs->sat, nav, tgd_index);
         }
 
     if (sys == SYS_GPS || sys == SYS_QZS)
diff --git a/src/algorithms/libs/rtklib/rtklib_pntpos.h b/src/algorithms/libs/rtklib/rtklib_pntpos.h
index 735df2905..55c2a881a 100644
--- a/src/algorithms/libs/rtklib/rtklib_pntpos.h
+++ b/src/algorithms/libs/rtklib/rtklib_pntpos.h
@@ -48,6 +48,7 @@ double varerr(const prcopt_t *opt, double el, int sys);
 
 /* get tgd parameter (m) -----------------------------------------------------*/
 double gettgd(int sat, const nav_t *nav);
+double gettgd(int sat, const nav_t *nav, int tgd_index);
 
 /* get isc parameter (m) -----------------------------------------------------*/
 double getiscl1(int sat, const nav_t *nav);
diff --git a/src/algorithms/libs/rtklib/rtklib_ppp.cc b/src/algorithms/libs/rtklib/rtklib_ppp.cc
index 21b501623..5e0c3f11f 100644
--- a/src/algorithms/libs/rtklib/rtklib_ppp.cc
+++ b/src/algorithms/libs/rtklib/rtklib_ppp.cc
@@ -1040,8 +1040,13 @@ int ifmeas(const obsd_t *obs, const nav_t *nav, const double *azel,
 
 
 /* get tgd parameter (m) -----------------------------------------------------*/
-double gettgd_ppp(int sat, const nav_t *nav)
+double gettgd_ppp(int sat, const nav_t *nav, int tgd_index)
 {
+    if (tgd_index < 0 || tgd_index >= 4)
+        {
+            return 0.0;
+        }
+
     int i;
     for (i = 0; i < nav->n; i++)
         {
@@ -1049,12 +1054,18 @@ double gettgd_ppp(int sat, const nav_t *nav)
                 {
                     continue;
                 }
-            return SPEED_OF_LIGHT_M_S * nav->eph[i].tgd[0];
+            return SPEED_OF_LIGHT_M_S * nav->eph[i].tgd[tgd_index];
         }
     return 0.0;
 }
 
 
+double gettgd_ppp(int sat, const nav_t *nav)
+{
+    return gettgd_ppp(sat, nav, 0);
+}
+
+
 /* slant ionospheric delay ---------------------------------------------------*/
 int corr_ion(gtime_t time, const nav_t *nav, int sat __attribute__((unused)), const double *pos,
     const double *azel, int ionoopt, double *ion, double *var,
@@ -1137,9 +1148,13 @@ int corrmeas(const obsd_t *obs, const nav_t *nav, const double *pos,
     gamma = std::pow(lam[1] / lam[0], 2.0); /* f1^2/f2^2 */
     P1_P2 = nav->cbias[obs->sat - 1][0];
     P1_C1 = nav->cbias[obs->sat - 1][1];
-    if (P1_P2 == 0.0 && (satsys(obs->sat, nullptr) & (SYS_GPS | SYS_GAL | SYS_QZS)))
+    const int sys = satsys(obs->sat, nullptr);
+    if (P1_P2 == 0.0 && (sys & (SYS_GPS | SYS_GAL | SYS_QZS)))
         {
-            P1_P2 = (1.0 - gamma) * gettgd_ppp(obs->sat, nav);
+            // Galileo I/NAV clocks are referenced to E1/E5b. PPP reaches
+            // this path for E1, whose BGD is stored in tgd[1].
+            const int tgd_index = sys == SYS_GAL ? 1 : 0;
+            P1_P2 = (1.0 - gamma) * gettgd_ppp(obs->sat, nav, tgd_index);
         }
     if (obs->code[0] == CODE_L1C)
         {
diff --git a/src/algorithms/libs/rtklib/rtklib_ppp.h b/src/algorithms/libs/rtklib/rtklib_ppp.h
index cdaedfea9..3d7d9e4a8 100644
--- a/src/algorithms/libs/rtklib/rtklib_ppp.h
+++ b/src/algorithms/libs/rtklib/rtklib_ppp.h
@@ -120,6 +120,7 @@ int ifmeas(const obsd_t *obs, const nav_t *nav, const double *azel,
     double phw, double *meas, double *var);
 
 double gettgd_ppp(int sat, const nav_t *nav);
+double gettgd_ppp(int sat, const nav_t *nav, int tgd_index);
 
 int corr_ion(gtime_t time, const nav_t *nav, int sat, const double *pos,
     const double *azel, int ionoopt, double *ion, double *var,