Garmin GPS 18 5Hz, Technical Specifications

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GPS 18 Technical Specifications (190-00307-00) Rev. D
Page 26
The USB Packet for the Satellite Record looks like:
- 0x72
(Record ID – single byte)
- 0x54 (Number of data bytes – single byte)
- cpo_all_sat_data
Position Record
The Position Record has a record identifier of
typedef struct
{
float
alt;
float epe;
float eph;
float epv;
int fix;
double gps_tow;
double lat;
double lon;
float lon_vel;
float lat_vel;
float alt_vel;
float msl_hght;
int leap_sec;
long grmn_days;
} cpo_pvt_data;
alt Ellipsoid altitude (meters)
epe Est pos error (meters)
eph Pos err, horizontal (meters)
epv Pos err, vertical (meters)
fix 0 = no fix; 1 = no fix; 2 = 2D; 3 = 3D; 4 = 2D differential; 5 = 3D differential;
6 and greater = not defined
gps_tow GPS time of week (sec)
lat Latitude (radians)
lon Longitude (radians)
lon_vel Longitude velocity (meters/second)
lat_vel Latitude velocity (meters/second)
alt_vel Altitude velocity (meters/second)
msl_hght Mean sea level height (meters)
leap_sec UTC leap seconds
grmn_days Garmin days (days since December 31, 1989)