diff --git a/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/executor/D341LocationMessageExecutor.java b/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/executor/D341LocationMessageExecutor.java
index a72c5a97..de61ffc5 100644
--- a/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/executor/D341LocationMessageExecutor.java
+++ b/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/executor/D341LocationMessageExecutor.java
@@ -74,7 +74,7 @@ public class D341LocationMessageExecutor implements Executor<D341LocationMessage
 
         // update trx
         device.updateRx(message.getHeader(), message.getLen(), 1);
-        if(device.getCalcVer()!=3) {
+        if(device.getCalcVer()==null || device.getCalcVer()!=3) {
             double[] pos = message.getB562_loc();
             device.updateB562Quality((int) pos[3]);
         }
@@ -87,7 +87,7 @@ public class D341LocationMessageExecutor implements Executor<D341LocationMessage
                 device.setLongitude(gga.getLongitude());
                 device.setAltitude(gga.getAltitude());
             }
-            if(device.getCalcVer()==3){
+            if(device.getCalcVer()!=null && device.getCalcVer()==3){
                 device.updateB562Quality(gga.getQuality());
             }
         }