diff --git a/data/orbits/starlink.csv b/data/orbits/starlink.csv
deleted file mode 100644
index 6c1641e..0000000
--- a/data/orbits/starlink.csv
+++ /dev/null
@@ -1,5 +0,0 @@
-1150.0:53.0:32:50
-1110.0:53.8:32:50
-1130.0:74.0:8:50
-1275.0:81.0:5:75
-1325.0:70.0:6:75
diff --git a/data/orbits/telesat.csv b/data/orbits/telesat.csv
deleted file mode 100644
index 54faaac..0000000
--- a/data/orbits/telesat.csv
+++ /dev/null
@@ -1,2 +0,0 @@
-1000.0:99.5:6:12
-1248.0:37.4:5:9
diff --git a/examples/leo-bulk-send-example.cc b/examples/leo-bulk-send-example.cc
index b8de4b1..2ddf625 100644
--- a/examples/leo-bulk-send-example.cc
+++ b/examples/leo-bulk-send-example.cc
@@ -84,7 +84,7 @@ int main (int argc, char *argv[])
 
   LeoOrbitNodeHelper orbit;
   NodeContainer satellites;
-  if (!orbitFile.empty())
+  if (orbitFile.empty())
     {
       satellites = orbit.Install (orbitFile);
     }
diff --git a/examples/leo-circular-orbit-tracing-example.cc b/examples/leo-circular-orbit-tracing-example.cc
index d8718e9..980b74a 100644
--- a/examples/leo-circular-orbit-tracing-example.cc
+++ b/examples/leo-circular-orbit-tracing-example.cc
@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
   CommandLine cmd;
   std::string orbitFile;
   std::string traceFile;
-  std::string duration = "60s";
+  double duration = 60;
   cmd.AddValue("orbitFile", "CSV file with orbit parameters", orbitFile);
   cmd.AddValue("traceFile", "CSV file to store mobility trace in", traceFile);
   cmd.AddValue("precision", "ns3::LeoCircularOrbitMobilityModel::Precision");
@@ -47,7 +47,7 @@ int main(int argc, char *argv[])
 
   LeoOrbitNodeHelper orbit;
   NodeContainer satellites;
-  if (!orbitFile.empty())
+  if (orbitFile.empty())
     {
       satellites = orbit.Install (orbitFile);
     }
@@ -71,7 +71,7 @@ int main(int argc, char *argv[])
 
   std::cout << "Time,Satellite,x,y,z,Speed" << std::endl;
 
-  Simulator::Stop (Time (duration));
+  Simulator::Stop (Seconds (duration));
   Simulator::Run ();
   Simulator::Destroy ();
 
diff --git a/examples/leo-delay-tracing-example.cc b/examples/leo-delay-tracing-example.cc
index 04555b8..97ea133 100644
--- a/examples/leo-delay-tracing-example.cc
+++ b/examples/leo-delay-tracing-example.cc
@@ -136,7 +136,7 @@ int main (int argc, char *argv[])
 
   LeoOrbitNodeHelper orbit;
   NodeContainer satellites;
-  if (!orbitFile.empty())
+  if (orbitFile.empty())
     {
       satellites = orbit.Install (orbitFile);
     }
diff --git a/model/leo-circular-orbit-mobility-model.cc b/model/leo-circular-orbit-mobility-model.cc
index 43e7ed7..9b2e512 100644
--- a/model/leo-circular-orbit-mobility-model.cc
+++ b/model/leo-circular-orbit-mobility-model.cc
@@ -123,8 +123,7 @@ LeoCircularOrbitMobilityModel::GetProgress (Time t) const
     {
       sign = -1;
     }
-  // 2pi * (distance travelled / circumference of earth) + offset
-  return sign * (((GetSpeed () * t.GetSeconds ()) / (LEO_EARTH_RAD_KM * 1000))) + m_offset;
+  return sign * (2 * M_PI * ((GetSpeed () * t.GetSeconds ()) / LEO_EARTH_RAD_KM)) + m_offset;
 }
 
 Vector3D