在 WM 平台上开发 GPS 导航系统

核心提示：32 End Function33 ' Interprets a $GPRMC message34 Public Function ParseGPRMC(ByVal sentence As String) As Boolean35 ' Divide the sentence into words36 D

32 End Function

33 ' Interprets a $GPRMC message

34 Public Function ParseGPRMC(ByVal sentence As String) As Boolean

35 ' Divide the sentence into words

36 Dim Words() As String = GetWords(sentence)

37 ' Do we have enough values to describe our location?

38 If Words(3) <> "" And Words(4) <> "" And Words(5) <> "" And _

39 Words(6) <> "" Then

40 ' Yes. Extract latitude and longitude

41 Dim Latitude As String = Words(3).Substring(0, 2) & "°" ' Append hours

42 Latitude = Latitude & Words(3).Substring(2) & """" ' Append minutes

43 Latitude = Latitude & Words(4) ' Append the hemisphere

44 Dim Longitude As String = Words(5).Substring(0, 3) & "°" ' Append hours

45 Longitude = Longitude & Words(5).Substring(3) & """" ' Append minutes

46 Longitude = Longitude & Words(6) ' Append the hemisphere

47 ' Notify the calling application of the change

48 RaiseEvent PositionReceived(Latitude, Longitude)

49 End If

50 ' Do we have enough values to parse satellite-derived time?

51 If Words(1) <> "" Then

52 ' Yes. Extract hours, minutes, seconds and milliseconds

53 Dim UtcHours As Integer = CType(Words(1).Substring(0, 2), Integer)

54 Dim UtcMinutes As Integer = CType(Words(1).Substring(2, 2), Integer)

55 Dim UtcSeconds As Integer = CType(Words(1).Substring(4, 2), Integer)

56 Dim UtcMilliseconds As Integer

57 ' Extract milliseconds if it is available

58 If Words(1).Length > 7 Then UtcMilliseconds = _

59 CType(Single.Parse(Words(1).Substring(6), _

60 CultureInfo.InvariantCulture) * 1000, Integer)

61 ' Now build a DateTime object with all values

62 Dim Today As DateTime = System.DateTime.Now.ToUniversalTime