/// <summary>
/// 读取头部信息
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public static Sp3Header Read(string path)
{
Sp3Header header = new Sp3Header();
header.SourceName = Path.GetFileName(path);
using (TextReader r = new StreamReader(path))
{
string line = null;
string symbol = null;
line = r.ReadLine();
symbol = line.Substring(0, 1);
if (symbol != LineSymbols[0])
{
throw new Exception("SP3文件不合法");
}
header.VersionId = line.Substring(1, 1);
header.P_V_ModeFlag = line.Substring(2, 1);
header.StartTime = Time.Parse(line.Substring(3, 28));
header.NumberOfEpochs = int.Parse(line.Substring(32, 7));
header.DataUsed = line.Substring(40, 5);
header.CoordinateSystem = line.Substring(46, 5);
header.OrbitType = line.Substring(52, 3);
header.AgencyName = line.Substring(56, 4);
int lineIndex = 0;
int sartLineIndexOfSat = 0;
int sartLineIndexOfSatAccuracy = 0;
do
{
line = r.ReadLine();
lineIndex++;
switch (FirstTwoCharToMarker(line))
{
case Sp3HeaderLineMarker.Time:
header.GPSWeek = int.Parse(line.Substring(3, 4));
header.SecondsOfWeek = double.Parse(line.Substring(9, 15));
header.EpochInterval = double.Parse(line.Substring(24, 14));
header.ModJulianDayStart = int.Parse(line.Substring(39, 5));
header.FractionalDay = double.Parse(line.Substring(45, 15));
break;
case Sp3HeaderLineMarker.SatelliteCount:
sartLineIndexOfSat = lineIndex;
header.NumberOfSatellites = int.Parse(line.Substring(3, 3));
int len = header.NumberOfSatellites >= 17 ? 17 : header.NumberOfSatellites;
header.PRNs = SatelliteNumber.ParsePRNs(line.Substring(9, len * 3));
break;
//都用于存储卫星号。
case Sp3HeaderLineMarker.SatelliteNumber:
int prevSatCount = 17 * (lineIndex - sartLineIndexOfSat);
int satLen = header.NumberOfSatellites >= prevSatCount + 17 ? 17 : header.NumberOfSatellites - prevSatCount;
if (satLen > 0)
{
header.PRNs.AddRange(SatelliteNumber.ParsePRNs(line.Substring(9, satLen * 3)));
}
break;
//用于表示卫星的精度，1表示极佳， 99表示不要用，0表示未知。
case Sp3HeaderLineMarker.Accuracy:
if (sartLineIndexOfSatAccuracy == 0)
{
sartLineIndexOfSatAccuracy = lineIndex;
}
if (header.SatAccuraces == null)
{
header.SatAccuraces = new Dictionary <SatelliteNumber, int>();
}
int prevSatAccuCount = 17 * (lineIndex - sartLineIndexOfSatAccuracy);
int satAccLen = header.NumberOfSatellites >= prevSatAccuCount + 17 ? 17 : header.NumberOfSatellites - prevSatAccuCount;
if (satAccLen > 0)
{
List <string> sts = Utils.StringUtil.Split(line.Substring(9, satAccLen * 3), 3);
for (int i = prevSatAccuCount, j = 0; j < satAccLen; i++, j++)
{
header.SatAccuraces.Add(header.PRNs[i], int.Parse(sts[j]));
}
}
break;
case Sp3HeaderLineMarker.Char:
if (header.Characters == null)
{
header.Characters = new List <string>();
}
header.Characters.AddRange(new List <String>(line.Substring(3, 57).Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)));
break;
case Sp3HeaderLineMarker.Float:
if (header.Floats == null)
{
header.Floats = new List <double>();
}
List <String> list = new List <String>(line.Substring(3, 57).Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries));
foreach (string Str in list)
{
header.Floats.Add(double.Parse(Str));
}
break;
case Sp3HeaderLineMarker.Int:
if (header.Ints == null)
{
header.Ints = new List <int>();
}
List <String> listINts = new List <String>(line.Substring(3, 57).Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries));
foreach (string Str in listINts)
{
header.Ints.Add(int.Parse(Str));
}
break;
case Sp3HeaderLineMarker.Comment:
if (header.Comments == null)
{
header.Comments = new List <string>();
}
if (line.Length > 3)
{
header.Comments.Add(line.Substring(3));
}
break;
case Sp3HeaderLineMarker.End:
header.LineNumber = lineIndex;
return(header);
// break;
default:
throw new ApplicationException("天啊！你是不可能看到我的！除非出错了，难道是版本变了？");
}
} while (String.Compare(line.Substring(0, 2), "* ", true) != 0);
header.LineNumber = lineIndex + 1;
}
return(header);
}
