public void Add(MotionEvaluator <Cartesian> evaluator, JulianDate epoch)
{
Cartesian position = evaluator.Evaluate(epoch);
m_noAccessPositions.Add(position);
m_satellites.Add(evaluator);
}
private void OnTimeChanged(object sender, TimeChangedEventArgs e)
{
if (m_temeToFixedEvaluator == null)
{
return;
}
JulianDate date = e.Time;
Matrix3By3 temeToFixed = new Matrix3By3(m_temeToFixedEvaluator.Evaluate(date));
KinematicTransformation transformation = m_fixedToFacilityTopoEvaluator.Evaluate(date, 0);
List <int> satellitesToRemove = null;
m_satellites.ClearPositions();
for (int i = 0; i < m_satellites.Count; ++i)
{
MotionEvaluator <Cartesian> satellite = m_satellites.GetSatellite(i);
try
{
// Update position of marker representing this satellite
Cartesian position = satellite.Evaluate(date).Rotate(temeToFixed);
// Compute access from satellite to facility
if (m_showAccess)
{
Cartesian positionInTopo = transformation.Transform(position);
AzimuthElevationRange azimuthElevationRange = new AzimuthElevationRange(positionInTopo);
m_satellites.AppendPosition(position, azimuthElevationRange.Elevation > 0.0);
}
else
{
m_satellites.AppendPosition(position, false);
}
}
catch (Exception)
{
if (satellitesToRemove == null)
{
satellitesToRemove = new List <int>();
}
satellitesToRemove.Add(i);
}
}
// Remove satellites that could not be evaluated
if (satellitesToRemove != null)
{
m_satellites.RemoveUsingIndexList(satellitesToRemove);
SetText(m_satellites.Count);
}
m_satellites.SetMarkerBatches();
}
/// <summary>
/// Method to calculate all the data required for the graphs.
/// </summary>
private void OnAddReceiverClick(object sender, EventArgs e)
{
#region CreateAndConfigureReceiver
// Let's create the GPSReceiver. The receiver stores many properties and has a defined location. This location
// is the point of reference for visibility calculations.
receiver = new GpsReceiver();
// add receiver to the tree
TreeNode newNode = new TreeNode(Localization.Receiver);
rootNode.Nodes.Add(newNode);
// Easy reference to Earth Central body used to initialize the ElevationAngleAccessConstraint and
// to calculate the Az/El/Range Data.
EarthCentralBody earth = CentralBodiesFacet.GetFromContext().Earth;
// set the receiver properties based on user selections
// The receiver has a receiver FrontEnd that contains the visibility and tracking constraints
// Be sure to convert your angles to Radians!
double minimumAngle = Trig.DegreesToRadians(Double.Parse(MaskAngle.Text));
receiver.ReceiverConstraints.Clear();
receiver.ReceiverConstraints.Add(new ElevationAngleConstraint(earth, minimumAngle));
receiver.NumberOfChannels = (int)NumberOfChannels.Value;
receiver.NoiseModel = new ConstantGpsReceiverNoiseModel(0.8);
// The receiver's methods of reducing the number of visible satellites to the limit imposed by the number of channels
if (BestNSolType.Checked)
{
receiver.ReceiverSolutionType = GpsReceiverSolutionType.BestN;
}
else
{
receiver.ReceiverSolutionType = GpsReceiverSolutionType.AllInView;
}
// create a new location for the receiver by using the Cartographic type from AGI.Foundation.Coordinates
// again, remember to convert from degrees to Radians! (except the height of course)
Cartographic position = new Cartographic(Trig.DegreesToRadians(double.Parse(Longitude.Text)),
Trig.DegreesToRadians(double.Parse(Latitude.Text)),
double.Parse(ReceiverHeight.Text));
// Now create an antenna for the GPS receiver. We specify the location of the antenna by assigning a
// PointCartographic instance to the LocationPoint property. We specify that the antenna should be oriented
// according to the typically-used East-North-Up axes by assigning an instance of AxesEastNorthUp to
// the OrientationAxes property. While the orientation of the antenna won't affect which satellites are visible
// or tracked in this case, it will affect the DOP values. For example, the EDOP value can be found in
// DilutionOfPrecision.X, but only if we've configured the antenna to use East-North-Up axes.
PointCartographic antennaLocationPoint = new PointCartographic(earth, position);
Platform antenna = new Platform
{
LocationPoint = antennaLocationPoint,
OrientationAxes = new AxesEastNorthUp(earth, antennaLocationPoint)
};
receiver.Antenna = antenna;
#endregion
// update the tree to reflect the correct receiver info
newNode.Nodes.Add(new TreeNode(string.Format(Localization.FixedMaskAngle + "= {0:0.00} " + Localization.degrees, MaskAngle.Text)));
newNode.Nodes.Add(new TreeNode(string.Format(Localization.NumberOfChannels + "= {0}", NumberOfChannels.Value)));
newNode.Nodes.Add(new TreeNode(string.Format(Localization.SolutionType + "= {0}", receiver.ReceiverSolutionType == GpsReceiverSolutionType.AllInView ? Localization.AllInView : Localization.BestN)));
newNode.Nodes.Add(new TreeNode(string.Format(Localization.Latitude + "= {0:0.000000} " + Localization.degrees, Latitude.Text)));
newNode.Nodes.Add(new TreeNode(string.Format(Localization.Longitude + "= {0:0.000000} " + Localization.degrees, Longitude.Text)));
newNode.Nodes.Add(new TreeNode(string.Format(Localization.Height + "= {0:0.000} " + Localization.meters, ReceiverHeight.Text)));
rootNode.Expand();
newNode.Expand();
#region CalculateDataForGraphs
// Now, we'll open the almanac
SemAlmanac almanac;
using (Stream stream = openAlmanacDialog.OpenFile())
using (StreamReader reader = new StreamReader(stream))
{
// Read the SEM almanac from an almanac stream reader.
almanac = SemAlmanac.ReadFrom(reader, 1);
}
// Now create a PlatformCollection to hold GpsSatellite object instances. The SemAlmanac method CreateSatellitesFromRecords returns
// just such a collection. We'll use this set of satellites as the set from which we'll try and track. There is a
// GpsSatellite object for each satellite specified in the almanac.
PlatformCollection gpsSatellites = almanac.CreateSatelliteCollection();
// We provide the receiver with the complete set of gpsSatellites to consider for visibility calculations.
// This is usually all SVs defined in the almanac - however you may want to remove SVs that aren't healthy. This can
// be done by creating the gpsSatellites collection above using another version of the CreateSatellitesFromRecords method that
// takes a SatelliteOutageFileReader.
receiver.NavigationSatellites = gpsSatellites;
// Optimization opportunity: Add the following code in a thread. This will help for long duration analyses.
// Now that we have the receiver and location setup, we need to evaluate all the pertinent data.
// using a SatelliteTrackingEvaluator, we can track satellites and using a DOP Evaluator,
// we can calculate DOP at a specified time.
// The receiver's GetSatelliteTrackingEvaluator method will provide a SatelliteTrackingEvaluator for you.
// Similarly, the GetDilutionOfPrecisionEvaluator provides the DOP evaluator.
// We create all evaluators in the same EvaluatorGroup for the best performance.
EvaluatorGroup group = new EvaluatorGroup();
Evaluator <int[]> satTrackingEvaluator = receiver.GetSatelliteTrackingIndexEvaluator(group);
Evaluator <DilutionOfPrecision> dopEvaluator = receiver.GetDilutionOfPrecisionEvaluator(group);
// We also need to create an evaluator to compute Azimuth/Elevation for each of the SVs
MotionEvaluator <AzimuthElevationRange>[] aerEvaluators = new MotionEvaluator <AzimuthElevationRange> [gpsSatellites.Count];
for (int i = 0; i < gpsSatellites.Count; ++i)
{
Platform satellite = receiver.NavigationSatellites[i];
VectorTrueDisplacement vector = new VectorTrueDisplacement(antenna.LocationPoint, satellite.LocationPoint);
aerEvaluators[i] = earth.GetAzimuthElevationRangeEvaluator(vector, group);
}
// First we'll initialize the data structures used to plot the data
for (int i = 0; i < DOPData.Length; i++)
{
// PointPairList is defined in the ZedGraph reference
DOPData[i] = new PointPairList();
}
// We need to know which time standard to use here. If the user has specified that GPS time is to be used
// we need to create the JulianDates with the GlobalPositioningSystemTime standard.
if (GPSTimeRadio.Checked)
{
startjd = new JulianDate(StartTime.Value, TimeStandard.GlobalPositioningSystemTime);
stopjd = new JulianDate(StopTime.Value, TimeStandard.GlobalPositioningSystemTime);
}
else
{
// otherwise, the default time standard is UTC
startjd = new JulianDate(StartTime.Value);
stopjd = new JulianDate(StopTime.Value);
}
// Now we''ll create the variables we'll need for iterating through time.
// The propagator requires a Duration type be used to specify the timestep.
Duration dur = stopjd - startjd;
double timestep = Double.Parse(TimeStep.Text);
// Initialize the progressbar with appropriate values
progressBar1.Maximum = (int)dur.TotalSeconds;
progressBar1.Step = (int)timestep;
// now we'll iterate through time by adding seconds to the start time JulianDate
// creating a new JulianDate 'evaluateTime' each time step.
for (double t = 0; t <= dur.TotalSeconds; t += timestep)
{
JulianDate evaluateTime = startjd.AddSeconds(t);
// The string 'trackedSVs' is the start of a string we'll continue to build through this time
// iteration. It will contain the info we'll need to put in the DOP graph tooltips for the different
// DOP series (VDOP, HDOP, etc.)
String trackedSVs = Localization.Tracked + ": ";
// The evaluator method GetTrackedSatellites will take the current time and the initial list of satellites and
// determine which satellites can be tracked based on the receiver constraints setup earlier. This method
// returns a PlatformCollection object as well (though we'll cast each member of the Collection to a GPSSatellite type)
int[] trackedSatellites = satTrackingEvaluator.Evaluate(evaluateTime);
foreach (int satelliteIndex in trackedSatellites)
{
Platform satellite = receiver.NavigationSatellites[satelliteIndex];
// Now we have access to a Platform object representing a GPS satellite and calculate the azimuth and elevation
// of each. Note that we're just calculating the azimuth and elevation, but could just as easily get the
// range as well.
AzimuthElevationRange aer = aerEvaluators[satelliteIndex].Evaluate(evaluateTime);
// Get the GpsSatelliteExtension attached to the platform. The extension extends a
// platform with GPS-specific information. In this case, we need the
// satellites PRN.
GpsSatelliteExtension extension = satellite.Extensions.GetByType <GpsSatelliteExtension>();
// Create two separate PointPairLists to hold the data stored by Time and Azimuth
PointPairList thisTimePointList, thisAzPointList;
// Before we can arbitrarily create new PointPair Lists, we have to see if the Data Storage structures already contain a list
// for this PRN.
// The variables AzElData_TimeBased and AzElData_AzimuthBased are dictionaries that hold the PointPairLists using the PRN
// as a key. We use this structure to store a large amount of data for every satellite in a single, easy to access, variable.
// if the satellite we're currently looking at already has a list defined in the dictionary, we'll use that one, otherwise
// we'll create a new list
if (AzElData_TimeBased.ContainsKey(extension.PseudoRandomNumber))
{
thisTimePointList = AzElData_TimeBased[extension.PseudoRandomNumber];
AzElData_TimeBased.Remove(extension.PseudoRandomNumber);
}
else
{
thisTimePointList = new PointPairList();
}
if (AzElData_AzimuthBased.ContainsKey(extension.PseudoRandomNumber))
{
thisAzPointList = AzElData_AzimuthBased[extension.PseudoRandomNumber];
AzElData_AzimuthBased.Remove(extension.PseudoRandomNumber);
}
else
{
thisAzPointList = new PointPairList();
}
// Now to get the actual Azimuth and elevation data
// Converting your Radians to degrees here makes the data appear in a more readable format. We also constrain the azimuth
// to be within the interval [0, 2*pi]
double azimuth = Trig.RadiansToDegrees(Trig.ZeroToTwoPi(aer.Azimuth));
double elevation = Trig.RadiansToDegrees(aer.Elevation);
#endregion
// now create the point for the Azimuth based data
PointPair thisAzPoint = new PointPair(azimuth, elevation);
// and add the tooltip (ZedGraph uses the Tag property on a PointPair for the tooltip on that datapoint )
thisAzPoint.Tag = String.Format("PRN {0}, {1}, " + Localization.Az + ": {2:0.000}, " + Localization.El + ": {3:0.000}", extension.PseudoRandomNumber, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), azimuth, elevation);
// and finally add this point to the list
thisAzPointList.Add(thisAzPoint);
// now we'll do the same for the time-based data, instead of adding the Az and El, we'll add the time and El.
// Create a new XDate object to store the time for this point
double txd = (double)new XDate(evaluateTime.ToDateTime());
// add the time and elevation data to this point
PointPair thisTimePoint = new PointPair(txd, Trig.RadiansToDegrees(aer.Elevation));
// Create the tooltip tag
thisTimePoint.Tag = String.Format("PRN {0}, {1}, " + Localization.Az + ": {2:0.000}, " + Localization.El + ": {3:0.000}", extension.PseudoRandomNumber, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), azimuth, elevation);
// finally add this point to the list
thisTimePointList.Add(thisTimePoint);
//Now that this data is all calculated, we'll add the point lists to the correct data structures for the GpsSatellite we're working with
AzElData_TimeBased.Add(extension.PseudoRandomNumber, thisTimePointList);
AzElData_AzimuthBased.Add(extension.PseudoRandomNumber, thisAzPointList);
// now update the 'trackedSVs' string to be used for the DOP data tooltip
// wee need to do this inside the GpsSatellite loop because we need to get the entire list of tracked SVs for this time step.
// we won't use this string until we're out of the loop however.
trackedSVs += extension.PseudoRandomNumber.ToString() + ", ";
}
// now we're out of the GpsSatellite loop, we'll do some string manipulation to get the tooltip for the DOP data.
// (gets rid of the last inserted comma)
string svs = trackedSVs.Substring(0, trackedSVs.LastIndexOf(' ') - 1);
try
{
// Now we use the evaluator to calculate the DilutionOfPrecision for us for this timestep
DilutionOfPrecision dop = dopEvaluator.Evaluate(evaluateTime);
// if the dop object throws an exception, there aren't enough tracked satellites to form a navigation solution (typically < 4 tracked)
// in that case we leave the data for this time unfilled. The graph will then have empty spots for this time.
// Here we create a new PointPair and a new XDate to add to the X-Axis
PointPair pp;
double txd = (double)new XDate(evaluateTime.ToDateTime());
// add the East DOP value and the time to the PointPair and set the tooltip tag property for this series.
pp = new PointPair(txd, dop.X);
pp.Tag = String.Format("{0}\n{1} " + Localization.EDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.X);
// add the point to the 0th element of the DOPData structure
DOPData[0].Add(pp);
// repeat for North DOP
pp = new PointPair(txd, dop.Y);
pp.Tag = String.Format("{0}\n{1} " + Localization.NDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.Y);
DOPData[1].Add(pp);
// repeat for the Vertical DOP
pp = new PointPair(txd, dop.Z);
pp.Tag = String.Format("{0}\n{1} " + Localization.VDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.Z);
DOPData[2].Add(pp);
// repeat for the Horizontal DOP
pp = new PointPair(txd, dop.XY);
pp.Tag = String.Format("{0}\n{1} " + Localization.HDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.XY);
DOPData[3].Add(pp);
// repeat for the Position DOP
pp = new PointPair(txd, dop.Position);
pp.Tag = String.Format("{0}\n{1} " + Localization.PDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.Position);
DOPData[4].Add(pp);
// repeat for the Time DOP
pp = new PointPair(txd, dop.Time);
pp.Tag = String.Format("{0}\n{1} " + Localization.TDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.Time);
DOPData[5].Add(pp);
// repeat for the Geometric DOP
pp = new PointPair(txd, dop.Geometric);
pp.Tag = String.Format("{0}\n{1} " + Localization.GDOP + ": {2:0.000}", svs, evaluateTime.ToDateTime().ToString("M/d/yyyy, h:mm tt"), dop.Geometric);
DOPData[6].Add(pp);
// Notice here that the different DOP values (East, North, etc) were denoted by the dop.X, dop.Y etc. This is because the
// DOP values could be in any coordinate system. In our case, we're in the ENU coordinate system an X represents East, Y
// represents North, Z represents Vertical, XY represents horizontal. You can change the reference frame the DOP is reported in
// but you will then have to understand that the dop.X value corresponds to your X-defined axis and so on.
}
catch
{
// Do Nothing here - we just won't add the data to the data list
}
// update the progress bar - we're done with this time step!
progressBar1.PerformStep();
}
// finally update the graphs
UpdateDopGraph();
updateAzElGraph();
// reset the progress bar
progressBar1.Value = 0;
// and set the appropriate button states
SetControlStates(true);
}