gps.cpp

GPS的串口读取数据过程,并且进行了坐标转换,转化为通用的坐标系

#include "StdAfx.h"
#include "GPS.h"

const string GPS::m_sPrefix = "GPGGA";

GPS::GPS(void)
{
	m_sInputBuffer.reserve(GPS_STRINIG_BUFFER_SIZE);
	m_bNewLine = false;
	m_bValid = false;
	m_nFlag = -1;
}

GPS::~GPS(void)
{
}

void GPS::OnReceiveChar(const char ch)
{
	switch (ch)
	{
	case '$':
		m_bNewLine = true;
		m_nFlag = 0;
		break;
	case '*':
		if (m_bValid)
		{
			AnalyseGPGGA(m_sInputBuffer);
			m_bValid = false;
		}
		m_sInputBuffer = "";
		break;
	case 13:	//cr
		break;
	case 10:	//lf
		break;
	default:
		if (m_bNewLine)
		{
			if (m_bValid)
			{
				m_sInputBuffer += ch;
			}
			else
			{
				if (m_nFlag != -1)
				{
					m_sInputBuffer += ch;
					++m_nFlag;

					if (m_nFlag == m_sPrefix.size())
					{
						if (m_sPrefix == m_sInputBuffer)
						{
							m_bValid = true;
						}
						else
						{
							m_nFlag = -1;
						}
					}
				}
			}
		}
		break;
	}
}

void GPS::AnalyseGPGGA(const string& str)
{
	
	assert(!str.empty());

	GPGGADATA data = {0};
	const char comma = ',';
	size_t start = 0, end = 0;

	
//＄GPGGA，(1)Time (UTC),(2)Latitude，(3)N or S，(4)Longitude，(5)E or W，(6)GPS Quality Indicator，
//(7)Number of satellites in view,0-12,(8)Horizontal Dilution of precision，(9)Altitude，M，
//(10)，M，(11)，(12)＊hh(CR)(LF) 
//解析的帧格式 


	//GPGGA
	end = str.find_first_of(comma, start);
	start =  end + 1;

    //Time  int nHours   	int nMinutes	int nSeconds
	end = str.find_first_of(comma, start);
	long temp = atoi(str.substr(start, end - start).c_str());
	data.nHours = (temp / 10000 + 8) % 24;
	data.nMinutes = (temp / 100) % 100;
	data.nSeconds = temp % 100;
	start =  end + 1;


	//float fLatitude
	end = str.find_first_of(comma, start);
	data.fLatitude = (float)atof(str.substr(start, end - start).c_str());
	start =  end + 1;


	

    //N  or  S
    end = str.find_first_of(comma, start);
	assert((end - start) == 1);
	start = end + 1;




	//float fLongitude
	end = str.find_first_of(comma, start);
	data.fLongitude = (float)atof(str.substr(start, end - start).c_str());
	start =  end + 1;



    //E  or  W
    end = str.find_first_of(comma, start);
	assert((end - start) == 1);
	start = end + 1;




	//int nGPSQual;
	end = str.find_first_of(comma, start);
	assert((end - start) == 1);
    data.nGPSQual = atoi(str.substr(start, end - start).c_str());
	start =  end + 1;



	//int nNumofSate;
	end = str.find_first_of(comma, start);
	data.nNumofSate = atoi(str.substr(start, end - start).c_str());
	start =  end + 1;


	//	float fHdop
	end = str.find_first_of(comma, start);
	data.fHdop = (float)atof(str.substr(start, end - start).c_str());
	start =  end + 1;



	//float fAltitude
	end = str.find_first_of(comma, start);
	data.fAltitude = (float)atof(str.substr(start, end - start).c_str());
	start =  end + 1;	
	
	
	
	
	//float fUndulation;
	
	UpdateDataBuffer(data);
	
	
	
	
	/*assert(!str.empty());
	//14 ',' total

	GPGGADATA data = {0};
	const char comma = ',';
	size_t start = 0, end = 0;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	end = str.find_first_of(comma, start);
	cout << str.substr(start, end - start) << endl;
	start =  end + 1;

	UpdateDataBuffer(data);*/
	
}