diff --git a/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs b/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs
new file mode 100644
index 00000000..def5886a
--- /dev/null
+++ b/AsbCloudInfrastructure/Services/Subsystems/DepthInterpolation.cs
@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace AsbCloudInfrastructure.Services.Subsystems.Utils
+{
+#nullable enable
+    internal class DepthInterpolation
+    {
+        private IEnumerator<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)> enumerator;
+        (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;
+        }
+
+        public float GetDepth(DateTimeOffset date)
+        {            
+            {
+                while (isLess(date))
+                {                    
+                   lastValue.x = date;
+                   lastValue.y = CalcValue(enumerator.Current, (date - dateMin).TotalSeconds);
+                   enumerator.MoveNext();
+                }
+            }
+            return (float)lastValue.y;
+        }
+        
+        private bool isLess(DateTimeOffset date)
+        {
+           if (date >= enumerator.Current.dateMin)
+                return true;
+           return false;
+        }
+        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;
+        }
+
+    }
+#nullable disable
+}
diff --git a/AsbCloudInfrastructure/Services/Subsystems/Interpolation.cs b/AsbCloudInfrastructure/Services/Subsystems/Interpolation.cs
deleted file mode 100644
index cf87da98..00000000
--- a/AsbCloudInfrastructure/Services/Subsystems/Interpolation.cs
+++ /dev/null
@@ -1,52 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
-namespace AsbCloudInfrastructure.Services.Subsystems.Utils
-{
-#nullable enable
-    internal class Interpolation
-    {
-        private IEnumerator<(DateTimeOffset dateMin, float? depthMin, DateTimeOffset dateMax, float? depthMax)> enumerator;
-        (DateTimeOffset x, float? y) lastValue = default;
-
-        public Interpolation(IOrderedEnumerable<(DateTimeOffset dateMin, float? depthMin, DateTimeOffset dateMax, float? depthMax)> collection)
-        {
-            enumerator = collection.GetEnumerator();
-            enumerator.MoveNext();
-        }
-
-        public float GetDepth(DateTimeOffset date)
-        {            
-            {
-                while (date >= enumerator.Current.dateMax)
-                {
-                    if (isLess(date))
-                    {
-                        lastValue.x = date;
-                        lastValue.y = CalcValue(enumerator.Current, date.Second);
-                    }
-                    enumerator.MoveNext();
-                }
-            }
-            return (float)lastValue.y;
-        }
-        
-        private bool isLess(DateTimeOffset date)
-        {
-           if (date <= enumerator.Current.dateMax && date >= enumerator.Current.dateMin)
-                return true;
-           return false;
-        }
-        private float CalcValue((DateTimeOffset dateMin, float? depthMin, DateTimeOffset dateMax, float? depthMax) item, int x)
-        {
-            
-            var a = (item.depthMax - item.depthMin) / (item.dateMax.Second - item.dateMin.Second);
-            var b = item.depthMin * (item.dateMax.Second - (item.depthMax - item.depthMin) / (item.dateMax.Second - item.dateMin.Second));
-            var resultDepth = a * x + b;
-            return (float)resultDepth;
-        }
-
-    }
-#nullable disable
-}
diff --git a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
index b2cf39fc..def85fa4 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeBackgroundService.cs
@@ -284,24 +284,21 @@ namespace AsbCloudInfrastructure.Services.Subsystems
                 dataSpinList.Add(dateRowItem);
             }
             await resultSpin.DisposeAsync();
-
-
             using var resultDepthFromSaub = await GetResultFromQueryAsync(queryDepthFromSaub, begin, idTelemetry, db, token);
-
-            var dataDepthFromSaub = new List<(DateTimeOffset dateMin, float? depthMin, DateTimeOffset dateMax, float? depthMax)>();
+            var dataDepthFromSaub = new List<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)>();
             while (resultDepthFromSaub.Read())
             {
                 var dateRowItem =
                 (
                     resultDepthFromSaub.GetFieldValue<DateTimeOffset>(0),
-                    resultDepthFromSaub.GetFieldValue<float?>(1),
+                    resultDepthFromSaub.GetFieldValue<float>(1),
                     resultDepthFromSaub.GetFieldValue<DateTimeOffset>(2),
-                    resultDepthFromSaub.GetFieldValue<float?>(3)
+                    resultDepthFromSaub.GetFieldValue<float>(3)
 
                 );
                 dataDepthFromSaub.Add(dateRowItem);
             }
-            var interp = new Interpolation(dataDepthFromSaub.OrderBy(t => t.depthMin));
+            var interp = new DepthInterpolation(dataDepthFromSaub.OrderBy(t => t.depthMin));
             if (dataSpinList.Any())
             {
                 var mode = dataSpinList[0].Mode;