# Send NMEA as prime GPS
## PX4 parameter setting
1. set main gps listen to TELEM3
2. GPS_1_PROTOCOL to NMEA
3. SER_TEL3_BAUD to prefer baudrate
4. SENS_GPS_PRIME to -1

## NMEA packeting

pip install nmeasim

from datetime import datetime, timedelta, timezone
from nmeasim.models import GpsReceiver
import serial
import time


gps = GpsReceiver(
    date_time=datetime.fromtimestamp(time.time()),
    output=("GGA", "GLL", "GSA", "GSV", "RMC", "VTG", "ZDA"),
    manual_2d=False,
    horizontal_dp=3,
    vertical_dp=1,
    speed_dp=1,
    time_dp=3,
    angle_dp=1,
    lat=20.0,
    lon=120.0,
    altitude=10.0,
    geoid_sep=None,
    kph=0.0,
    heading=0.0,
    mag_heading=None,
    mag_var=None,
    num_sats=12,
    hdop=1.0,
    vdop=0.5,
    pdop=0.5,
    last_dgps=None,
    dgps_station=None,
    has_rtc=False
)
for i in range(30):
    gps.date_time += timedelta(seconds=0.1)
    print(str(gps.get_output()))
    # choose baudrate and serial COM
    ser = serial.Serial('COM8', 57600, timeout=1.5)
    ser.write(str(gps.get_output()).encode())
    time.sleep(0.1)
    ser.close()