Phase Data Output; Phase Output Data Binary Format - Garmin GPS 35 LP Technical Specification

Two records are transmitted once per second by the GPS 35LP. One record contains primarily post-
process information such as position and velocity information. The second record contains receiver
measurement information. The records are sent at a default baud rate of 9600 baud, 8 bits, no parity.
Records begin with a delimiter byte (10 hex). The second byte identifies the record type (28 hex for a
position record, 29 hex for a receiver measurement). The third byte indicates the size of the data. The
fourth byte is the first byte of data. The data is then followed by a chksum byte, a delimiter byte (10
hex), and an end-of-transmission character (03 hex).
Note - If RTCM-104 differential data is sent to the GPS 35LP the board will reset the Phase Output Data
baud rate to the same baud rate used for RTCM-104 data. If the differential inputs are used on the GPS
35LP then the RTCM-104 data must be sent to the GPS 35LP at 9600 baud(preferred) or 4800 baud.
RTCM-104, baud rates less than 4800 baud are not supported by the GPS 35LP since it would limit bus
bandwidth past the point where a once per second phase output data rate could be maintained.
Position Record
- 0x10
- 0x28
- 0x36
- cpo_pvt_type
- one byte chksum
- 0x10
- 0x03
typedef struct
{
float
float
float
float
int
double
double
double
float
float
float
} cpo_pvt_type;
alt ellipsoid altitude (mt)
epe est pos error (mt)
eph pos err, horizontal (mt)
epv pos err, vertical (mt)
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)
Appendix C

Phase Output Data Binary Format

(dle is first byte)
(position record identifier)
(size of data)
(see description below)
(the addition of bytes between the delimiters should equal 0)
(dle)
(etx is last byte)
alt;
epe;
eph;
epv;
fix;
gps_tow;
lat;
lon;
lon_vel;
lat_vel;
alt_vel;
29