diff --git a/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs b/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs
index def5886a..edb41678 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs
@@ -8,43 +8,41 @@ namespace AsbCloudInfrastructure.Services.Subsystems.Utils
     internal class DepthInterpolation
     {
         private IEnumerator<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)> enumerator;
-        (DateTimeOffset x, float? y) lastValue = default;
+        (DateTimeOffset x, float y) lastValue = default;        
 
         private DateTimeOffset dateMin;
         public DepthInterpolation(IOrderedEnumerable<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)> collection)
         {
             enumerator = collection.GetEnumerator();
             enumerator.MoveNext();
-            dateMin = enumerator.Current.dateMin;
+            dateMin = enumerator.Current.dateMin;            
         }
 
         public float GetDepth(DateTimeOffset date)
-        {            
+        {
+            var isNotEnd = true;
+            while (isOnInterval(date) && isNotEnd)
             {
-                while (isLess(date))
-                {                    
-                   lastValue.x = date;
-                   lastValue.y = CalcValue(enumerator.Current, (date - dateMin).TotalSeconds);
-                   enumerator.MoveNext();
-                }
+                lastValue.x = date;
+                lastValue.y = CalcValue(enumerator.Current, (date- enumerator.Current.dateMin).TotalSeconds);
+                isNotEnd = enumerator.MoveNext();
             }
-            return (float)lastValue.y;
+            return lastValue.y;
+
         }
         
-        private bool isLess(DateTimeOffset date)
-        {
-           if (date >= enumerator.Current.dateMin)
-                return true;
-           return false;
-        }
+        private bool isOnInterval(DateTimeOffset date)
+        => date >= enumerator.Current.dateMin && date <= enumerator.Current.dateMax;
         private float CalcValue((DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax) item, double timestamp)
         {
-            var a = (item.depthMax - item.depthMin) / (item.dateMax - item.dateMin).TotalSeconds;
-            var b = item.depthMin * (item.dateMax.Second - (item.depthMax - item.depthMin) / (item.dateMax.Second - item.dateMin.Second));
-            var resultDepth = a * timestamp + b;
-            return (float)resultDepth;
+            if (item.depthMin == item.depthMax)
+            {
+                return item.depthMin;
+            }            
+            var w = timestamp / (item.dateMax - item.dateMin).TotalSeconds;
+            var d = ((item.depthMax - item.depthMin) * w)+ item.depthMin;
+            return (float)d;
         }
-
     }
 #nullable disable
 }
diff --git a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
index def85fa4..62e9e927 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
@@ -298,7 +298,7 @@ namespace AsbCloudInfrastructure.Services.Subsystems
                 );
                 dataDepthFromSaub.Add(dateRowItem);
             }
-            var interp = new DepthInterpolation(dataDepthFromSaub.OrderBy(t => t.depthMin));
+            var interp = new DepthInterpolation(dataDepthFromSaub.OrderBy(t => t.dateMin));
             if (dataSpinList.Any())
             {
                 var mode = dataSpinList[0].Mode;