diff --git a/dump1090.h b/dump1090.h
index dbc3383..fb36a9c 100644
--- a/dump1090.h
+++ b/dump1090.h
@@ -435,7 +435,7 @@ void decodeModesMessage (struct modesMessage *mm, unsigned char *msg);
 void displayModesMessage(struct modesMessage *mm);
 void useModesMessage    (struct modesMessage *mm);
 void computeMagnitudeVector(uint16_t *pData);
-void decodeCPR          (struct aircraft *a, int fflag, int surface);
+int  decodeCPR          (struct aircraft *a, int fflag, int surface);
 int  decodeCPRrelative  (struct aircraft *a, int fflag, int surface);
 void modesInitErrorInfo ();
 //
diff --git a/interactive.c b/interactive.c
index 579144c..95af551 100644
--- a/interactive.c
+++ b/interactive.c
@@ -343,6 +343,7 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
 
     // If we've got a new cprlat or cprlon
     if (mm->bFlags & MODES_ACFLAGS_LLEITHER_VALID) {
+        int location_ok = 0;
 
         if (mm->bFlags & MODES_ACFLAGS_LLODD_VALID) {
             a->odd_cprlat  = mm->raw_latitude;
@@ -354,23 +355,23 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
             a->even_cprtime = mstime();
         }
 
-        if (((mm->bFlags | a->bFlags) & MODES_ACFLAGS_LLEITHER_VALID) == MODES_ACFLAGS_LLBOTH_VALID) {
-        // If we now have both even and odd, decode the CPR
-
-            // Try relative CPR first
-            if (decodeCPRrelative(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG))) {
-                // If relative CPR fails then try global if the two data are less than 10 seconds apart
-                if (abs((int)(a->even_cprtime - a->odd_cprtime)) <= 10000) {
-                    decodeCPR(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG));
-                }
+        // If we have enough recent data, try global CPR
+        if (((mm->bFlags | a->bFlags) & MODES_ACFLAGS_LLEITHER_VALID) == MODES_ACFLAGS_LLBOTH_VALID && abs((int)(a->even_cprtime - a->odd_cprtime)) <= 10000) {
+            if (decodeCPR(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG)) == 0) {
+                location_ok = 1;
             }
+        }
 
-            //If we sucessfully decoded, back copy the results to mm so that we can print them in list output
-            if (a->bFlags & MODES_ACFLAGS_LATLON_VALID) {
-                mm->bFlags |= MODES_ACFLAGS_LATLON_VALID;
-                mm->fLat    = a->lat;
-                mm->fLon    = a->lon;
-            }
+        // Otherwise try relative CPR.
+        if (!location_ok && decodeCPRrelative(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG)) == 0) {
+            location_ok = 1;
+        }
+
+        //If we sucessfully decoded, back copy the results to mm so that we can print them in list output
+        if (location_ok) {
+            mm->bFlags |= MODES_ACFLAGS_LATLON_VALID;
+            mm->fLat    = a->lat;
+            mm->fLon    = a->lon;
         }
     }
 
diff --git a/mode_s.c b/mode_s.c
index 5c4b26e..25943a5 100644
--- a/mode_s.c
+++ b/mode_s.c
@@ -2062,11 +2062,8 @@ double cprDlonFunction(double lat, int fflag, int surface) {
 //
 // A few remarks:
 // 1) 131072 is 2^17 since CPR latitude and longitude are encoded in 17 bits.
-// 2) We assume that we always received the odd packet as last packet for
-//    simplicity. This may provide a position that is less fresh of a few
-//    seconds.
 //
-void decodeCPR(struct aircraft *a, int fflag, int surface) {
+int decodeCPR(struct aircraft *a, int fflag, int surface) {
     double AirDlat0 = (surface ? 90.0 : 360.0) / 60.0;
     double AirDlat1 = (surface ? 90.0 : 360.0) / 59.0;
     double lat0 = a->even_cprlat;
@@ -2092,7 +2089,8 @@ void decodeCPR(struct aircraft *a, int fflag, int surface) {
             surface_rlat = Modes.fUserLat;
             surface_rlon = Modes.fUserLon;
         } else {
-            return;
+            // No local reference, give up
+            return (-1);
         }
         rlat0 += floor(surface_rlat / 90.0) * 90.0;  // Move from 1st quadrant to our quadrant
         rlat1 += floor(surface_rlat / 90.0) * 90.0;
@@ -2105,7 +2103,8 @@ void decodeCPR(struct aircraft *a, int fflag, int surface) {
     if (rlat0 < -90 || rlat0 > 90 || rlat1 < -90 || rlat1 > 90) return;
 
     // Check that both are in the same latitude zone, or abort.
-    if (cprNLFunction(rlat0) != cprNLFunction(rlat1)) return;
+    if (cprNLFunction(rlat0) != cprNLFunction(rlat1))
+        return (-1);
 
     // Compute ni and the Longitude Index "m"
     if (fflag) { // Use odd packet.
@@ -2131,6 +2130,8 @@ void decodeCPR(struct aircraft *a, int fflag, int surface) {
     a->seenLatLon      = a->seen;
     a->timestampLatLon = a->timestamp;
     a->bFlags         |= (MODES_ACFLAGS_LATLON_VALID | MODES_ACFLAGS_LATLON_REL_OK);
+
+    return 0;
 }
 //
 //=========================================================================