cleaned up code and expanded Passes and EpochTime

Author: reed

OneSGP4_Example/Program.cs

@@ -10,8 +10,8 @@ static void Main(string[] args)
         {
             //Parse three line element
             Tle tleISS = ParserTLE.parseTle(
-                "1 25544U 98067A   19097.23063721 -.00000469  00000-0  00000+0 0  9999",
-                "2 25544  51.6449 353.9503 0002279 151.1697 290.4275 15.52495932164239",
+                "1 25544U 98067A   19132.30925117  .00001081  00000-0  24694-4 0  9993",
+                "2 25544  51.6426 179.4820 0001363 344.4861  92.2261 15.52657683169680",
                 "ISS 1");
 
             //Parse tle from file
@@ -32,9 +32,21 @@ static void Main(string[] args)
 
             //Create Time points
             EpochTime startTime = new EpochTime(DateTime.UtcNow);
-            EpochTime anotherTime = new EpochTime(2018, 100.5); //(Year 2017, 100 day at 12:00 HH)
+            EpochTime anotherTime = new EpochTime(2018, 100.5); //(Year 2018, 100 day at 12:00 HH)
             EpochTime stopTime = new EpochTime(DateTime.UtcNow.AddHours(1));
 
+            //get time difference
+            double daysSince = startTime - anotherTime;
+            //throws exception if first time > second time
+            //double daysSince = anotherTime - startTime;
+
+            //compare Time points
+            EpochTime compareTime = new EpochTime(2018, 100.5); //(Year 2018, 100 day at 12:00 HH)
+            bool equals = anotherTime == compareTime;
+            bool notequals = startTime != anotherTime;
+            bool greater = startTime > anotherTime;
+            bool smaler = anotherTime < startTime;
+
             //Add 15 Seconds to EpochTime
             anotherTime.addTick(15);
             //Add 20 Min to EpochTime
@@ -54,7 +66,7 @@ static void Main(string[] args)
             resultDataList = sgp4Propagator.getRestults();
 
             //Coordinate of an observer on Ground lat, long, height(in meters)
-            One_Sgp4.Coordinate observer = new Coordinate(35.554595, 18.888574, 0);
+            One_Sgp4.Coordinate observer = new Coordinate(35.00, 18.0, 0);
             //Convert to ECI coordinate system
             One_Sgp4.Point3d eci = observer.toECI(startTime.getLocalSiderealTime());
             //Get Local SiderealTime for Observer
@@ -75,6 +87,7 @@ static void Main(string[] args)
             {
                 Console.Out.WriteLine(p.ToString());
             }
+            Console.Out.WriteLine("Done");
         }
     }
 }

One_Sgp4/Pass.cs

@@ -39,9 +39,6 @@ public class SatFunctions
         public const double twoPi = pi * 2.0; //!< double constant two Pi
         public const double toDegrees = 180.0 / pi; //!< double constant conversion to degree
         public const double toRadians = pi / 180.0; //!< double constant converstion to radians
-
-        private const double a_Wgs72 = 6378.135; //!< double WGS72 const in Km
-        private const double a_Wgs84 = 6378.137; //!< double WGS84 const in Km
 
 
         //! Ground constructor.
@@ -124,7 +121,6 @@ public static bool isSatVisible(Coordinate coordinate,
         public static Point3d calcSphericalCoordinate(Coordinate coordinate,
             EpochTime time, Sgp4Data satPosData)
         {
-
             double lsr = time.getLocalSiderealTime(coordinate.getLongitude());
 
             Point3d groundLocation = coordinate.toECI(lsr);
@@ -146,21 +142,11 @@ public static Point3d calcSphericalCoordinate(Coordinate coordinate,
             double re = -sin_theta * r.x + cos_theta * r.y;
             double rz = cos_lat * cos_theta * r.x + cos_lat * sin_theta * r.y + sin_lat * r.z;
 
-            result.x = Math.Sqrt(rs * rs + re * re + rz * rz);
-            result.y = Math.Atan2(-re , rs);
+            result.x = Math.Sqrt((rs * rs) + (re * re) + (rz * rz));
+            result.y = AcTan(-re , rs);
             result.z = Math.Asin(rz / result.x);
 
-            /*
-            if (rs > 0.0)
-            {
-                result.y += pi/2;
-            }
-            if (result.y < 0.0)
-            {
-                result.y += pi;
-            }*/
-            result.y += pi;
-            result.y = result.y * toDegrees;
+            result.y = (result.y + pi) * toDegrees;
             result.z = result.z * toDegrees;
 
             return result;
@@ -261,39 +247,63 @@ public static Coordinate calcSatSubPoint(EpochTime time, Sgp4Data satPosData,
             return new Coordinate(latitude, longitude, height);
         }
 
+        //! Calculate satellite position at a single point in time
+        /*!
+            \param tle of satellite
+            \param EpochTime to calculate position
+            \param int WGS-Data to use 0 = WGS_72; 1 = WGS_84
+            \return SGP4Data containing satellite position data
+        */
         public static Sgp4Data getSatPositionAtTime(Tle satellite, EpochTime atTime, Sgp4.wgsConstant wgs)
         {
             Sgp4 sgp4Propagator = new Sgp4(satellite, wgs);
             sgp4Propagator.runSgp4Cal(atTime, atTime, 1 / 60.0);
             return sgp4Propagator.getRestults()[0];
         }
 
-
+        //! Calculate Passes of a satellite for ceratin number of days from a starting time
+        /*!
+            \param Coordinate position of observer
+            \param Tle satellite data
+            \param EpochTime of startpoint
+            \param int accuracy time between calculations default 15 seconds
+            \param int number of days to calculate default 5 days
+            \param int WGS-Data to use 0 = WGS_72; 1 = WGS_84 default WGS 84
+            \return List<Pass> List of passes satellite is visible
+        */
         public static List<Pass> CalculatePasses(Coordinate position, Tle satellite, EpochTime startTime, int accuracy = 15,
             int maxNumberOfDays = 5, Sgp4.wgsConstant wgs = Sgp4.wgsConstant.WGS_84)
         {
             List<Pass> results = new List<Pass>();
             EpochTime epoch = new EpochTime(startTime);
             EpochTime end = new EpochTime(startTime);
             end.addDays(maxNumberOfDays);
+
             while (epoch < end)
             {
                 Sgp4Data satPos = getSatPositionAtTime(satellite, epoch, wgs);
                 if (SatFunctions.isSatVisible(position, 0.0, epoch, satPos))
                 {
-                    EpochTime passStart = new EpochTime(epoch);
                     Point3d spherical = SatFunctions.calcSphericalCoordinate(position, epoch, satPos);
-                    double maxElevation = spherical.z;
+                    PassDetail startDetails = new PassDetail(new EpochTime(epoch), spherical.z, spherical.y, spherical.x);
+                    PassDetail maxEleDetails = new PassDetail(new EpochTime(epoch), spherical.z, spherical.y, spherical.x);
+                    //double maxElevation = spherical.z;
                     epoch.addTick(accuracy);
                     satPos = getSatPositionAtTime(satellite, epoch, wgs);
-                    while (SatFunctions.isSatVisible(position, 0.0, epoch, satPos))
+                    while(spherical.z >= 0)
+                    //while (SatFunctions.isSatVisible(position, 0.0, epoch, satPos))
                     {
+                        
                         spherical = SatFunctions.calcSphericalCoordinate(position, epoch, satPos);
-                        if (maxElevation < spherical.z)
-                            maxElevation = spherical.z;
+                        if (maxEleDetails.elevation < spherical.z)
+                        {
+                            maxEleDetails = new PassDetail(new EpochTime(epoch), spherical.z, spherical.y, spherical.x);
+                        }
                         epoch.addTick(accuracy);
+                        satPos = getSatPositionAtTime(satellite, epoch, wgs);
                     }
-                    results.Add(new One_Sgp4.Pass(position, passStart, new EpochTime(epoch), maxElevation * 180.0 / pi));
+                    PassDetail endDetails = new PassDetail(new EpochTime(epoch), spherical.z, spherical.y, spherical.x);
+                    results.Add(new One_Sgp4.Pass(position, startDetails, maxEleDetails, endDetails));
                 }
                 epoch.addTick(accuracy);
             }

One_Sgp4/SatFunctions.cs

@@ -37,10 +37,6 @@ public class Coordinate
         private double longitude; //!< double longitude in degree
         private double height; //!< double height in meters
 
-        private const double a_Wgs72 = 6378.135; //!< double WGS72 const in Km
-        private const double a_Wgs84 = 6378.137; //!< double WGS84 const in Km
-        private const double f = 1.0 / 298.26;
-
         //! GeoCoordinate constructor.
         /*!
         \param double latetude
@@ -97,21 +93,29 @@ public double getHeight()
         //! Convert to ECI
         /*!
         \param double SidrealTime
+        \param WGSconstant default WGS_84
         \return point3D ECI-Position vector of the Coordinate
         */
-        public Point3d toECI(double siderealTime)
+        public Point3d toECI(double siderealTime, Sgp4.wgsConstant wgs = Sgp4.wgsConstant.WGS_84)
         {
+            double f = WGS_72.f;
+            double a = WGS_72.radiusEarthKM;
+            if (wgs == Sgp4.wgsConstant.WGS_84)
+            {
+                f = WGS_84.f;
+                a = WGS_84.radiusEarthKM;
+            }
             double srt = siderealTime + (toRadians * longitude);
             double lat_rad = toRadians * latetude;
             Point3d eciPos = new Point3d();
-
+            //oblate earth
             double c = 1.0 / (Math.Sqrt(1.0 + f * (f - 2.0) *
                        (Math.Sin(lat_rad) * Math.Sin(lat_rad))));
 
             double s = (1.0 - f) * (1.0 - f) * c;
-            eciPos.x = a_Wgs72 * c * Math.Cos(lat_rad) * Math.Cos(srt);
-            eciPos.y = a_Wgs72 * c * Math.Cos(lat_rad) * Math.Sin(srt);
-            eciPos.z = a_Wgs72 * s * Math.Sin(lat_rad);
+            eciPos.x = a * c * Math.Cos(lat_rad) * Math.Cos(srt);
+            eciPos.y = a * c * Math.Cos(lat_rad) * Math.Sin(srt);
+            eciPos.z = a * s * Math.Sin(lat_rad);
 
             return eciPos;
         }

One_Sgp4/Coordinate.cs renamed to One_Sgp4/ground/Coordinate.cs

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2018 Nikolai Reed <reed@1manprojects.de>
+ *
+ * Licensed under the The MIT License (MIT)
+ * You may obtain a copy of the License at
+ *
+ * https://tldrlegal.com/license/mit-license#summary
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+namespace One_Sgp4
+{
+    public class Pass
+    {
+        private Coordinate observer; //!< Coordinates of observer
+        private PassDetail start; //!< Pass details at start of pass
+        private PassDetail maxElevation; //!< Pass details at max elevation
+        private PassDetail end; //!< Pass details at end of pass
+
+        //! Constructor
+        /*!
+        \param Coordinate of observer
+        \param PassDetail at start of pass
+        \param PassDetail at max elevation
+        \param PassDetail at end of pass
+        */
+        public Pass(Coordinate Observer, PassDetail passStart, PassDetail maxElevation, PassDetail passEnd)
+        {
+            this.observer = Observer;
+            this.start = passStart;
+            this.end = passEnd;
+            this.maxElevation = maxElevation;
+        }
+
+        //! get Coorindates of observer
+        /*!
+        \return Coordinate
+        */
+        public Coordinate getObserverLocation()
+        {
+            return this.observer;
+        }
+
+        //! get the EpochTime at start of the pass
+        /*!
+        \return EpochTime
+        */
+        public EpochTime getStartEpoch()
+        {
+            return this.start.time;
+        }
+
+        //! get the EpochTime at end
+        /*!
+        \return EpochTime
+        */
+        public EpochTime getEndEpoch()
+        {
+            return this.end.time;
+        }
+
+        //! get PassDetails at start
+        /*!
+        \return PassDetail
+        */
+        public PassDetail getPassDetailsAtStart()
+        {
+            return this.start;
+        }
+
+        //! get PassDetail at end
+        /*!
+        \return PassDetail
+        */
+        public PassDetail getPassDetailsAtEnd()
+        {
+            return this.end;
+        }
+
+        //! get PassDetails at max elevation
+        /*!
+        \return PassDetail
+        */
+        public PassDetail getPassDetailOfMaxElevation()
+        {
+            return this.maxElevation;
+        }
+
+        //! overriden ToString()
+        /*!
+        \return String
+        */
+        public override string ToString()
+        {
+            return string.Format("{0}:\nStart: {1}\nMax Elevation: {2}\nEnd: {3}", start.time.getDateToString(), start.ToString(), maxElevation.ToString(), end.ToString());
+        }
+    }
+}

One_Sgp4/ground/Pass.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace One_Sgp4
+{
+    /**
+   * \brief PassDetail class
+   *
+   * This class holds more detailed information over elevation, azimuth for a satellite pass
+   */
+    public class PassDetail
+    {
+        public EpochTime time;  //!<  EpochTime timepoint
+        public double elevation;//!< double elevation at timepoint in degrees
+        public double azimuth; //!< double azimuth at timepoint in degrees
+        public double range;  //!< double range to satellite in km
+
+        //! Constructor
+        /*!
+        \param EpochTime timepoint
+        \param double elevation at timepoint
+        \param double azimuth at timepoint
+        \pram double range at timepoint
+        */
+        public PassDetail(EpochTime timepoint, double elevation, double azimuth, double range)
+        {
+            this.time = timepoint;
+            this.elevation = elevation;
+            this.azimuth = azimuth;
+            this.range = range;
+        }
+
+        override
+        public String ToString()
+        {
+            return string.Format("{0} : Elevation: {1}°, Azimuth {2}°, Range {3}km ",time.getTimeToString(), elevation, azimuth, range);
+        }
+    }
+}