Receiver connection guides

Step-by-step setup for each kind of GNSS receiver OpenSurvey3D connects to. Every receiver is connected from the same place: hold the accuracy pill on the map (or tap it, then ⋯) to open Precision, then Source.

The same guides are in the app, word for word: open Precision (hold the accuracy pill, or tap ⋯ in the expanded toolbar), tap Source, then Connection guides. Each section of the Positioning source screen also ends with a How to connect: … link straight to the guide for that kind of receiver.

A good connection looks like

• Precision shows the receiver as the source, and the status reads Connected.
• Receiver status lists satellites, HDOP and a horizontal and vertical σ. A missing σ means the receiver isn't sending GST.
• Messages lists each NMEA sentence the receiver sends and how often. GGA should arrive at the rate set on the receiver, usually once a second.
• With RTK corrections running, Correction age stays under a few seconds and the fix reads fixed.

Emlid Reach RX2, RX, RS4

Bluetooth. The receiver pairs over Bluetooth inside OpenSurvey3D. The app runs NTRIP and sends the corrections to the receiver over the same link, so the receiver needs no internet of its own.

Tested with a Reach RX2. The RX and RS4 use the same connection.

Before you go out

1. Charge the receiver and update its firmware in Emlid Flow.
2. Make sure it isn't connected to another phone or tablet. Close Emlid Flow on this phone if it is holding the connection.

Connect

1. Power the receiver on and keep it near the phone.
2. Precision → Source → Bluetooth receiver → Search for receivers.
3. Pick the receiver. Emlid receivers appear by model, such as "RX2". Enter PIN 123456 if iOS asks.
4. The app connects as soon as pairing finishes. Next time, the receiver is already in the list: tap it.

Corrections

• Precision → NTRIP corrections. Enter the caster address, port, user name and password, and pick a mountpoint.
• Set what frame the corrections are in (for example NAD83(2011) for a state network), so heights and coordinates land in the right datum.

Antenna height

Precision → Antenna height: enter the pole height and pick the Reach RX2 preset (+147 mm to the antenna phase centre). If "Stream compensated position" is on in Emlid Flow, the pole is already included in every fix: set the pole height to 0 here instead.

If something's wrong

• The receiver isn't in the search list. Check it's powered on and not connected to another device. Turn off "Only show GNSS receivers" and search again; it lists every nearby Bluetooth device.
• It was connected before but now shows "Waiting for…". The receiver is off or out of range. Power it on; the app reconnects by itself.
• The fix stays float. Look at Correction age in Receiver status. If it's missing or growing, check the NTRIP login and mountpoint. If it's steady, give the receiver open sky and a minute.

Emlid Reach RS2, RS2+

Wi-Fi. iOS can't use these receivers over Bluetooth, so the app reads their NMEA over Wi-Fi: on the receiver's own hotspot or a network both share.

Tested.

Before you go out

1. In Emlid Flow, open Position output, turn on an output set to TCP, server role, NMEA format, and note its port (for example 9001).

Connect

1. On the phone, join the receiver's Wi-Fi hotspot in Settings → Wi-Fi (its name starts with "Reach"), or put the receiver and phone on the same network.
2. Precision → Source → NMEA over TCP/IP. Enter 192.168.42.1 on the hotspot, or the receiver's address on a shared network, and the port from Emlid Flow.
3. Tap Connect. If iOS asks to find devices on your local network, allow it.

Corrections

• Either in Emlid Flow under Correction input, if the receiver has its own internet connection,
• or in OpenSurvey3D under Precision → NTRIP corrections, which sends them to the receiver over the same Wi-Fi connection. The phone then needs cellular data, because the receiver's hotspot has no internet.

Antenna height

Precision → Antenna height: enter the pole height and pick the Reach RS2/RS2+ preset (+134 mm to the antenna phase centre).

If something's wrong

• "Local network access denied". Settings → OpenSurvey3D → turn on Local Network, then connect again.
• "Connection refused". The TCP output isn't on in Emlid Flow, or the port doesn't match. Check Position output.
• It connects but nothing arrives. Check the output format is NMEA, not LLH or ERB.

Bad Elf Flex, Flex Mini

Bluetooth. The receiver pairs over Bluetooth. Corrections run either in the Bad Elf Flex app in the background, which Bad Elf recommends, or in OpenSurvey3D on the Extreme models.

Supported; not yet tested on our own hardware. Tell us how it goes from Settings → Report a problem.

Before you go out

1. Install the Bad Elf Flex app and update the receiver's firmware.
2. The default output (GGA, RMC and GST) is all OpenSurvey3D needs.

Connect

1. Precision → Source → Bluetooth receiver → Search for receivers, and pick the Flex. Or pair it in Settings → Bluetooth; it then appears in the list.
2. Tap it to connect.

Corrections

• Recommended: set up NTRIP in the Bad Elf Flex app and leave it running in the background. Nothing to set up in OpenSurvey3D; the fix type and correction age still show.
• Or, on a Flex or Flex Mini Extreme: Precision → NTRIP corrections in OpenSurvey3D. If the fix never gets better than float, switch to the Flex app.
• Use one or the other, not both.

Antenna height

Precision → Antenna height: enter the pole height to the antenna's reference point.

If something's wrong

• The Flex isn't in the search list. Make sure it isn't connected to another phone, then turn off "Only show GNSS receivers" and search again.
• The source shows "External accessory via iOS Location Services". iOS is relaying the Flex's position without its fix type or accuracy. Connect to the Flex in Positioning source to get the full stream.

Leica Zeno GG04 plus, FLX100 plus

Zeno Connect. Leica's Zeno Connect app owns the antenna's Bluetooth link and its corrections, and shares the antenna's NMEA with OpenSurvey3D on the phone itself. No internet or pairing in OpenSurvey3D is needed.

Tested with Zeno Connect 4.3.

Before you go out

1. Install Zeno Connect (4.0 or later) and connect the antenna in it.
2. In Zeno Connect's NMEA settings, turn on GGA, GST and GSA. GGA carries the position, GST its accuracy and GSA the DOP.

Connect

1. Leave Zeno Connect running, and switch to OpenSurvey3D.
2. Precision → Source → Leica Zeno → Connect to Zeno Connect.
3. Keep Zeno Connect running in the background while you work. If it's closed, the position stops until it's open again; OpenSurvey3D reconnects by itself.

Corrections

• Set up NTRIP in Zeno Connect. OpenSurvey3D can't send corrections to a Zeno antenna; it shows the fix type and correction age Zeno Connect reports.

Antenna height

Set the antenna height in one place only. Set it to 0 in Zeno Connect and enter the pole height in OpenSurvey3D under Precision → Antenna height.

If something's wrong

• "Zeno Connect isn't running, or no antenna is connected in it". Open Zeno Connect, check the antenna shows as connected, then switch back.
• Horizontal σ or PDOP is missing. Turn on GST and GSA in Zeno Connect's NMEA settings.

Other receivers (NMEA over Wi-Fi)

Wi-Fi. Many receivers and Bluetooth-to-Wi-Fi bridges can serve their NMEA stream on a TCP port. OpenSurvey3D reads it like any other receiver.

Works with any receiver or bridge that serves NMEA on a TCP port.

Before you go out

1. Turn on NMEA output over TCP on the receiver or bridge, as a server, and note its IP address and port.
2. Include GGA, and GST and GSA if the receiver offers them.

Connect

1. Put the phone on the same network, or on the receiver's hotspot.
2. Precision → Source → NMEA over TCP/IP: enter the address and port and tap Connect. Allow local network access if iOS asks.

Corrections

• Either on the receiver itself, or in OpenSurvey3D under Precision → NTRIP corrections, which sends them back over the same connection.

Antenna height

Precision → Antenna height: enter the pole height to the antenna's reference point.

If something's wrong

• "Connection refused". The output isn't on, or the port is wrong.
• Horizontal σ is missing. The receiver isn't sending GST. The app falls back to an estimate from HDOP.

Related

• Connect a Bluetooth receiver
• Connect a Wi-Fi receiver
• Connect a Leica Zeno antenna
• Get RTK corrections over NTRIP
• Set the antenna height
• Report a problem