在 WM 平台上开发 GPS 导航系统

核心提示：75 ' Notify of the new time, adjusted to the local time zone76 RaiseEvent DateTimeChanged(SatelliteTime.ToLocalTime)77 End If78 ' Do we have enough info

75 ' Notify of the new time, adjusted to the local time zone

76 RaiseEvent DateTimeChanged(SatelliteTime.ToLocalTime)

77 End If

78 ' Do we have enough information to extract the current speed?

79 If Words(7) <> "" Then

80 ' Yes. Convert it into MPH

81 Dim Speed As Double = CType(Words(7), Double) * 1.150779

82 ' If we're over 55MPH then trigger a speed alarm!

83 If Speed > 55 Then RaiseEvent SpeedLimitReached()

84 ' Notify of the new speed

85 RaiseEvent SpeedReceived(Speed)

86 End If

87 ' Do we have enough information to extract bearing?

88 If Words(8) <> "" Then

89 ' Indicate that the sentence was recognized

90 Dim Bearing As Double = CType(Words(8), Double)

91 RaiseEvent BearingReceived(Bearing)

92 End If

93 ' Does the device currently have a satellite fix?

94 If Words(2) <> "" Then

95 Select Case Words(2)

96 Case "A"

97 RaiseEvent FixObtained()

98 Case "V"

99 RaiseEvent FixLost()

100 End Select

101 End If

102 ' Indicate that the sentence was recognized

103 Return True

104 End Function

105 ' Interprets a "Satellites in View" NMEA sentence

106 Public Function ParseGPGSV(ByVal sentence As String) As Boolean

107 Dim PseudoRandomCode As Integer

108 Dim Azimuth As Integer

109 Dim Elevation As Integer

110 Dim SignalToNoiseRatio As Integer

111 ' Divide the sentence into words

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

113 ' Each sentence contains four blocks of satellite information.

114 ' Read each block and report each satellite's information

115 Dim Count As Integer