galmon/glonass.cc

36 lines
894 B
C++

#include "glonass.hh"
#include <math.h>
#include <string.h>
// this strips out spare bits + parity, and leaves 10 clean 24 bit words
std::basic_string<uint8_t> getGlonassMessage(std::basic_string_view<uint8_t> payload)
{
uint8_t buffer[4*4];
for(int w = 0 ; w < 4; ++w) {
setbitu(buffer, 32*w, 32, getbitu(&payload[0], w*32, 32));
}
return std::basic_string<uint8_t>(buffer, 16);
}
uint32_t GlonassMessage::getGloTime() const
{
struct tm tm;
memset(&tm, 0, sizeof(tm));
tm.tm_year = 96+4*(n4 -1);
tm.tm_mon = 0;
tm.tm_mday = 1;
tm.tm_hour = -3;
tm.tm_min = 0;
tm.tm_sec = 0;
time_t t = timegm(&tm);
// cout<<" n4 "<<(int)gm.n4<<" start-of-4y "<< humanTime(t) <<" NT "<<(int)gm.NT;
t += 86400 * (NT-1);
t += 3600 * (hour) + 60 * minute + seconds;
return t - 820368000; // this starts GLONASS time at 31st of december 1995, 00:00 UTC
}