.NET Compact Framework下的GPS NMEA data数据分析（二）转

public class NmeaParser
    {
        public struct Coordinate
        {
            public int Hours;
            public int Minutes;
            public double Seconds;
        }
        public enum FixStatus
        {
            NotSet,
            Obtained, //A
            Lost //V
        }
        public enum FixMode
        {
            Auto,   //A
            Manual
        }
        public enum FixMethod
        {
            NotSet,
            Fix2D,
            Fix3D
        }
        public enum DifferentialGpsType
        {
            NotSet, 
            SPS,    
            DSPS,   
            PPS,    
            RTK     
        }
        public class GpsSatellite
        {
            public int PRC { get; set; }
            public int Elevation { get; set; }
            public int Azimuth { get; set; }
            public int SNR { get; set; }
            public bool InUsed { get; set; }
            public bool InView { get; set; }
            public bool NotTracking { get; set; }
        }
        private static readonly CultureInfo NmeaCultureInfo = new CultureInfo("en-US");
        private static readonly decimal KMpHPerKnot = decimal.Parse("1.852", NmeaCultureInfo);
        private Coordinate latitude;
        private Coordinate longitude;
        private decimal altitude = 0;
        private DateTime utcDateTime;
        private decimal velocity = 0;
        private decimal azimuth = 0;
        private FixStatus fixStatus;
        private DifferentialGpsType differentialGpsType;
        private FixMode fixMode;
        private FixMethod fixMethod;
        private int satellitesInView;
        private int satellitesInUsed;
        private readonly Dictionary<int, GpsSatellite> satellites;
        private decimal horizontalDilutionOfPrecision = 50;
        private decimal positionDilutionOfPrecision = 50;
        private decimal verticalDilutionOfPrecision = 50;
        public NmeaParser()
        {
            satellites = new Dictionary<int, GpsSatellite>();
        }
        public bool Parse(string sentence)
        {
            string rawData = sentence;
            try
            {
                if (!IsValid(sentence))
                {
                    return false;
                }
                sentence = sentence.Substring(1, sentence.IndexOf('*') - 1);
                string[] Words = Getwords(sentence);
                switch (Words[0])
                {
                    case "GPRMC":
                        return ParseGPRMC(Words);
                    case "GPGGA":
                        return ParseGPGGA(Words);
                    case "GPGSA":
                        return ParseGPGSA(Words);
                    case "GPGSV":
                        return ParseGPGSV(Words);
                    default:
                        return false;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message + rawData);
                return false;
            }
        }
        private bool IsValid(string sentence)
        {
            // GPS data can't be zero length
            if (sentence.Length == 0)
            {
                return false;
            }
            // first character must be a $
            if (sentence[0] != '$')
            {
                return false;
            }
            // GPS data can't be longer than 82 character
            if (sentence.Length > 82)
            {
                return false;
            }
            try
            {
                string checksum = sentence.Substring(sentence.IndexOf('*') + 1);
                return Checksum(sentence, checksum);
            }
            catch (Exception e)
            {
                Console.WriteLine("Checksum failure. " + e.Message);
                return false;
            }
        }
        private bool Checksum(string sentence, string checksumStr)
        {
            int checksum = 0;
            int length = sentence.IndexOf('*') - 1;
            // go from first character upto last *
            for (int i = 1; i <= length; ++i)
            {
                checksum = checksum ^ Convert.ToByte(sentence[i]);
            }
            return (checksum.ToString("X2") == checksumStr);
        }
        // Divides a sentence into individual Words
        private static string[] Getwords(string sentence)
        {
            return sentence.Split(',');
        }
        private bool ParseGPRMC(string[] Words)
        {
            if (Words[1].Length > 0 & Words[9].Length > 0)
            {
                int UtcHours = Convert.ToInt32(Words[1].Substring(0, 2));
                int UtcMinutes = Convert.ToInt32(Words[1].Substring(2, 2));
                int UtcSeconds = Convert.ToInt32(Words[1].Substring(4, 2));
                int UtcMilliseconds = 0;
                // Extract milliseconds if it is available
                if (Words[1].Length > 7)
                {
                    UtcMilliseconds = Convert.ToInt32(Words[1].Substring(7));
                }
                int UtcDay = Convert.ToInt32(Words[9].Substring(0, 2));
                int UtcMonth = Convert.ToInt32(Words[9].Substring(2, 2));
                // available for this century
                int UtcYear = Convert.ToInt32(Words[9].Substring(4, 2)) + 2000;
                utcDateTime = new DateTime(UtcYear, UtcMonth, UtcDay, UtcHours, UtcMinutes, UtcSeconds, UtcMilliseconds);
            }
            fixStatus = (Words[2][0] == 'A') ? FixStatus.Obtained : FixStatus.Lost;
            if (Words[3].Length > 0 & Words[4].Length == 1 & Words[5].Length > 0 & Words[6].Length == 1)
            {
                latitude.Hours = int.Parse(Words[3].Substring(0, 2));
                latitude.Minutes = int.Parse(Words[3].Substring(2, 2));
                latitude.Seconds = Math.Round(double.Parse(Words[3].Substring(5, 4)) * 6 / 1000.0, 3);
                if ("S" == Words[4])
                {
                    latitude.Hours = -latitude.Hours;
                }
                longitude.Hours = int.Parse(Words[5].Substring(0, 3));
                longitude.Minutes = int.Parse(Words[5].Substring(3, 2));
                longitude.Seconds = Math.Round(double.Parse(Words[5].Substring(6, 4)) * 6 / 1000.0, 3);
                if ("W" == Words[6])
                {
                    longitude.Hours = -longitude.Hours;
                }
            }
            if (Words[8].Length > 0)
            {
                azimuth = decimal.Parse(Words[8], NmeaCultureInfo);
            }
            if (Words[7].Length > 0)
            {
                velocity = decimal.Parse(Words[7], NmeaCultureInfo) * KMpHPerKnot;
            }
            return true;
        }
        private bool ParseGPGGA(string[] Words)
        {
            if (Words[6].Length > 0)
            {
                switch (Convert.ToInt32(Words[6]))
                {
                    case 0:
                        differentialGpsType = DifferentialGpsType.NotSet;
                        break;
                    case 1:
                        differentialGpsType = DifferentialGpsType.SPS;
                        break;
                    case 2:
                        differentialGpsType = DifferentialGpsType.DSPS;
                        break;
                    case 3:
                        differentialGpsType = DifferentialGpsType.PPS;
                        break;
                    case 4:
                        differentialGpsType = DifferentialGpsType.RTK;
                        break;
                    default:
                        differentialGpsType = DifferentialGpsType.NotSet;
                        break;
                }
            }
            if (Words[7].Length > 0)
            {
                satellitesInUsed = Convert.ToInt32(Words[7]);
            }
            if (Words[8].Length > 0)
            {
                horizontalDilutionOfPrecision = Convert.ToDecimal(Words[8]);
            }
            if (Words[9].Length > 0)
            {
                altitude = Convert.ToDecimal(Words[9]);
            }
            return true;
        }
        private bool ParseGPGSA(string[] Words)
        {
            if (Words[1].Length > 0)
            {
                fixMode = Words[1][0] == 'A' ? FixMode.Auto : FixMode.Manual;
            }
            if (Words[2].Length > 0)
            {
                switch (Convert.ToInt32(Words[2]))
                {
                    case 1:
                        fixMethod = FixMethod.NotSet;
                        break;
                    case 2:
                        fixMethod = FixMethod.Fix2D;
                        break;
                    case 3:
                        fixMethod = FixMethod.Fix3D;
                        break;
                    default:
                        fixMethod = FixMethod.NotSet;
                        break;
                }
            }
            foreach (GpsSatellite s in satellites.Values)
            {
                s.InUsed = false;
            }
            satellitesInUsed = 0;
            for (int i = 0; i < 12; ++i)
            {
                string id = Words[3 + i];
                if (id.Length > 0)
                {
                    int nId = Convert.ToInt32(id);
                    if (!satellites.ContainsKey(nId))
                    {
                        satellites[nId] = new GpsSatellite();
                        satellites[nId].PRC = nId;
                    }
                    satellites[nId].InUsed = true;
                    ++satellitesInUsed;
                }
            }
            if (Words[15].Length > 0)
            {
                positionDilutionOfPrecision = Convert.ToDecimal(Words[15]);
            }
            if (Words[16].Length > 0)
            {
                horizontalDilutionOfPrecision = Convert.ToDecimal(Words[16]);
            }
            if (Words[17].Length > 0)
            {
                verticalDilutionOfPrecision = Convert.ToDecimal(Words[17]);
            }
            return true;
        }
        private bool ParseGPGSV(string[] Words)
        {
            int messageNumber = 0;
            if (Words[2].Length > 0)
            {
                messageNumber = Convert.ToInt32(Words[2]);
            }
            if (Words[3].Length > 0)
            {
                satellitesInView = Convert.ToInt32(Words[3]);
            }
            if (messageNumber == 0 || satellitesInView == 0)
            {
                return false;
            }
            for (int i = 1; i <= 4; ++i)
            {
                if ((Words.Length - 1) >= (i * 4 + 3))
                {
                    int nId = 0;
                    if (Words[i * 4].Length > 0)
                    {
                        string id = Words[i * 4];
                        nId = Convert.ToInt32(id);
                        if (!satellites.ContainsKey(nId))
                        {
                            satellites[nId] = new GpsSatellite();
                            satellites[nId].PRC = nId;
                        }
                        satellites[nId].InView = true;
                    }
                    if (Words[i * 4 + 1].Length > 0)
                    {
                        satellites[nId].Elevation = Convert.ToInt32(Words[i * 4 + 1]);
                    }
                    if (Words[i * 4 + 2].Length > 0)
                    {
                        satellites[nId].Azimuth = Convert.ToInt32(Words[i * 4 + 2]);
                    }
                    if (Words[i * 4 + 3].Length > 0)
                    {
                        satellites[nId].SNR = Convert.ToInt32(Words[i * 4 + 3]);
                        satellites[nId].NotTracking = false;
                    }
                    else
                    {
                        satellites[nId].NotTracking = true;
                    }
                }
            }
            return true;
        }
    }