diff --git a/qaup-collision/src/main/java/com/qaup/collision/websocket/broadcaster/WebSocketMessageBroadcaster.java b/qaup-collision/src/main/java/com/qaup/collision/websocket/broadcaster/WebSocketMessageBroadcaster.java
index 80ec6ba..1f1c593 100644
--- a/qaup-collision/src/main/java/com/qaup/collision/websocket/broadcaster/WebSocketMessageBroadcaster.java
+++ b/qaup-collision/src/main/java/com/qaup/collision/websocket/broadcaster/WebSocketMessageBroadcaster.java
@@ -157,12 +157,19 @@ public class WebSocketMessageBroadcaster {
     public void handlePositionUpdate(PositionUpdateEvent event) {
         try {
             if (event == null || event.getPayload() == null) {
+                log.warn("[TMP-POS-DROP] reason=event_or_payload_null objectId=<blank> rawLatitude=null rawLongitude=null");
                 return;
             }
             if (!(event.getPayload() instanceof PositionUpdatePayload payload)) {
+                log.warn("[TMP-POS-DROP] reason=payload_not_position_update objectId=<blank> rawLatitude=null rawLongitude=null payloadType={}",
+                        event.getPayload().getClass().getName());
                 return;
             }
             if (payload.getObjectId() == null || payload.getObjectId().isBlank()) {
+                Double rawLatitude = payload.getPosition() != null ? payload.getPosition().getLatitude() : null;
+                Double rawLongitude = payload.getPosition() != null ? payload.getPosition().getLongitude() : null;
+                log.warn("[TMP-POS-DROP] reason=blank_object_id objectId=<blank> rawLatitude={} rawLongitude={}",
+                        rawLatitude, rawLongitude);
                 return;
             }
 
@@ -381,13 +388,27 @@ public class WebSocketMessageBroadcaster {
         if (payload.getPosition() == null
                 || payload.getPosition().getLatitude() == null
                 || payload.getPosition().getLongitude() == null) {
+            logDroppedPosition("missing_position_or_coordinate", payload, null, null, null);
             return null;
         }
 
-        double latitude = payload.getPosition().getLatitude();
-        double longitude = payload.getPosition().getLongitude();
+        double rawLatitude = payload.getPosition().getLatitude();
+        double rawLongitude = payload.getPosition().getLongitude();
+        double latitude = rawLatitude;
+        double longitude = rawLongitude;
         if (!isValidCoordinate(latitude, longitude)) {
-            return null;
+            // Optimization: tolerate upstream lat/lon swap and keep the track continuous.
+            if (isPotentiallySwappedCoordinate(latitude, longitude)) {
+                double swappedLatitude = longitude;
+                double swappedLongitude = latitude;
+                log.warn("[TMP-POS-FIX] reason=swap_lat_lon objectId={} rawLatitude={} rawLongitude={} fixedLatitude={} fixedLongitude={}",
+                        safeObjectId(payload), rawLatitude, rawLongitude, swappedLatitude, swappedLongitude);
+                latitude = swappedLatitude;
+                longitude = swappedLongitude;
+            } else {
+                logDroppedPosition("invalid_coordinate_range", payload, rawLatitude, rawLongitude, null);
+                return null;
+            }
         }
 
         long payloadTimestamp = payload.getTimestamp() != null ? payload.getTimestamp() : System.currentTimeMillis();
@@ -425,6 +446,13 @@ public class WebSocketMessageBroadcaster {
                 boolean isOutlierJump = rawDistance > maxAllowedJump;
                 if (isOutlierJump && !aircraft && state.rejectedCount < REACQUIRE_AFTER_REJECTS - 1) {
                     state.rejectedCount++;
+                    logDroppedPosition(
+                            "outlier_jump_rejected",
+                            payload,
+                            rawLatitude,
+                            rawLongitude,
+                            String.format("jumpMeter=%.3f,allowedMeter=%.3f,rejectedCount=%d", rawDistance, maxAllowedJump, state.rejectedCount)
+                    );
                     log.debug("Drop outlier position update: objectId={}, jumpMeter={}, allowedMeter={}",
                             payload.getObjectId(), rawDistance, maxAllowedJump);
                     return null;
@@ -514,6 +542,29 @@ public class WebSocketMessageBroadcaster {
         return latitude >= -90.0 && latitude <= 90.0 && longitude >= -180.0 && longitude <= 180.0;
     }
 
+    private boolean isPotentiallySwappedCoordinate(double latitude, double longitude) {
+        return latitude >= -180.0 && latitude <= 180.0
+                && longitude >= -90.0 && longitude <= 90.0
+                && !isValidCoordinate(latitude, longitude);
+    }
+
+    private String safeObjectId(PositionUpdatePayload payload) {
+        if (payload == null || payload.getObjectId() == null || payload.getObjectId().isBlank()) {
+            return "<blank>";
+        }
+        return payload.getObjectId();
+    }
+
+    private void logDroppedPosition(String reason, PositionUpdatePayload payload, Double rawLatitude, Double rawLongitude, String extra) {
+        if (extra == null || extra.isBlank()) {
+            log.warn("[TMP-POS-DROP] reason={} objectId={} rawLatitude={} rawLongitude={}",
+                    reason, safeObjectId(payload), rawLatitude, rawLongitude);
+        } else {
+            log.warn("[TMP-POS-DROP] reason={} objectId={} rawLatitude={} rawLongitude={} {}",
+                    reason, safeObjectId(payload), rawLatitude, rawLongitude, extra);
+        }
+    }
+
     private double resolveMaxAllowedJumpMeters(double speedMps, double jumpMarginMeter, double dtSec) {
         double safeDtSec = Math.max(dtSec, MIN_DT_SECONDS);
         return speedMps * safeDtSec + Math.max(jumpMarginMeter, 0.0);