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Point One Smart Antenna
on macOS

Ntrip-example reads GGA from the antenna over USB serial, sends it to the NTRIP caster, and forwards the RTCM corrections back to the antenna.

You need:

  • A Mac with internet access

  • The Point One Smart Antenna 

  • Point One credentials (NTRIP username and password)

  • A clear view of the sky for testing

  1. Create a Free Point One account

You'll get a free six month extended trial of our highest accuracy service so you have plenty of time to get building. Sign up before starting the tutorials below.

Use the same email address you used to register for FUSE.

Get Your Point One Account

Get Your Point One Account

2. Build the client

Install Apple's Command Line Tools:

xcode-select --install

Clone the repo and build it:

git clone https://github.com/PointOneNav/ntrip-example.git
cd ntrip-example
make

When the build finishes, you'll have an ntrip_client binary in the folder.

3. Find the antenna's serial port

Plug in the antenna over USB, then list the serial devices:

ls /dev/tty.usb

Copy the path the command prints, such as /dev/tty.usbserial-XXXX or /dev/tty.usbmodemXXXX. To check you have the right one, unplug the antenna and run the command again; the port that disappears is the antenna.

4. Edit config.json

Open config.json in the repo folder and fill in your values:

{
  "ntrip_host": "truertk.pointonenav.com",
  "ntrip_port": 2101,
  "ntrip_mountpoint": "AUTO",
  "ntrip_user": "<your ntrip username>",
  "ntrip_password": "<your ntrip password>",
  "serial_port": "/dev/tty.usbserial-XXXX",
  "serial_baud": 115200,
  "tcp_port": 5000,
  "gga_interval_sec": 10
}

4. Run and verify

Start the client from the repo folder:

./ntrip_client config.json

To read the NMEA stream in another app while the client runs, connect to localhost:5000 instead of the serial port.

Troubleshooting

Symptom

Fix

fatal error: 'iostream' file not found during make

Reinstall the Command Line Tools: sudo rm -rf /Library/Developer/CommandLineTools, then xcode-select --install. If it still fails, run export SDKROOT=$(xcrun --show-sdk-path) && make.

No serial port in ls /dev/tty.usb*

Try a different cable (it must carry data) and a different USB port

"Resource busy" on the serial port

Another app has the port open. Close it, or have that app connect to localhost:5000 instead.

No GGA, or garbled text

serial_baud doesn't match the antenna's baud rate (115200)

HTTP 401 from the caster / Unauthorized

Your username, password or mountpoint is wrong

Sample Smart Antenna output

Example GGA sentence

$GNGGA

Key

Value

Field

Meaning

$GNGGA

Sentence ID

GPS/GNSS fix data

212418.000

Time (UTC)

21:24:18.000

3745.250501 N

Latitude

3745.250501 N → 37.45251°

12224.942773 W

Longitude

12224.942773 W → 122.24943°

5

Fix Quality

Fix Quality Codes: 0 = No Fix 1 = GPS/autonomous 2 = DGPS 4 = RTK Fixed 5 = RTK Float

21

Satellites

Satellites in use

0.83

HDOP

Horizontal precision indicator

23.157 M

Geoid Separation

Height above sea-level (mean), in meters.

1.0

Age of Corrections

Seconds since last RTCM correction

1056*51

Checksum

Integrity check, not data.