Configure an Emlid Reach RS3 or RS4

An Emlid Reach RS3 or RS4 can do any of the three GPS jobs in a Ditch Assist® system:

• the base on the tripod, sending corrections;
• the rover on the implement, plugged into the control module or DIG™ module with the GPS cable;
• the Ditch Assist Lite rover on the implement, which the tablet reads over Wi-Fi.

The Ditch Assist app knows all three setups (it calls them presets) and can set up a Reach for you in a minute or two. This page explains what each one sets and why. Check and program a Reach with Emlid Diagnostics shows every tap.

Which job do you need?

Before you start

Time: about 5 minutes per receiver, from the app.

• A Reach RS3 or RS4, charged. The app was checked on firmware 33.1 (RS3) and 34.8 (RS4) and newer; older firmware still works, but update it in Emlid Flow if the app tells you to.
• The tablet with the Ditch Assist app, able to join the receiver's Wi-Fi hotspot (Reach:XX:XX, password emlidreach unless it was changed).
• If you use your own base: your LoRa radio frequency (902–928 MHz), the same on the base and every rover.
• Automatic grading stopped. The app won't change a receiver while it's grading.

What each setup changes on the receiver

When the app sets up a Reach, it writes only the settings below, one part at a time, and reads each part back to check it took. Anything else on the receiver stays as you had it. NTRIP logins are never read or changed.

All three: satellite (GNSS) settings

• GPS, GLONASS and Galileo satellites on; BeiDou and QZSS off.
• Update rate 5 Hz, elevation mask 15°, SNR mask 35.
• Tilt compensation (IMU) off: the receiver rides on the machine, so it reports the antenna position.
• A few solver settings Emlid Flow no longer shows (kinematic positioning mode, fix-and-hold, GLONASS ambiguity resolution off, acceleration limits) are put back to Emlid's defaults, in case someone left the receiver in a survey or static setup.

In the lists below, "Position output" is what Emlid Diagnostics calls an output. Emlid Flow calls the same thing "Position streaming".

Base

• Both position outputs off, correction input off (the base makes corrections, it doesn't take them).
• Base position averaged for 2 minutes every time it starts (Average SINGLE, 2:00), antenna height 1.0 m (it doesn't affect Ditch Assist).
• RTCM3 messages (the standard correction format): 1006 at 0.1 Hz; 1074 (GPS), 1084 (GLONASS) and 1094 (Galileo) at 1 Hz; every other message off.
• Base output 1: LoRa radio on your frequency, 18.23 kb/s. RS4 at the 500 or 1000 mW you pick; RS3 at 20 dBm, its maximum. Base output 2 off.
• If the radio can't carry all three satellite systems once a second (1 Hz), the app slows GLONASS, then Galileo, then GPS to 0.5 Hz until it fits, and tells you the rates it used.

Setting up the base itself (site, mount, power): Set up an RTK base.

Rover (control module or DIG)

• Position output 1: serial, RS-232, 38,400 baud, NMEA, GGA at 5 Hz and VTG at 1 Hz, every other message off, talker ID GP, no tilt compensation. This is what the control module and DIG need (see What your receiver must send).
• Position output 2: Bluetooth, NMEA, GGA and VTG at 1 Hz.
• Both base outputs off, which frees the LoRa radio.
• Correction input: LoRa radio on your base's frequency, 18.23 kb/s.
• Turn on automatically when powered via EXT port on: the receiver switches on and off with the control module, which powers it through the cable.

Lite Rover (Ditch Assist Lite)

• Position output 1: TCP server on port 9001, NMEA (the receiver's Wi-Fi position output), GGA at 5 Hz and VTG at 1 Hz, every other message off, talker ID GP, no tilt compensation. The tablet reads this over the receiver's Wi-Fi.
• Position output 2, base outputs and correction input: the same as the Rover.
• EXT power switch left as it is: the receiver runs on its own battery.
• Leave the receiver's Wi-Fi in Hotspot mode; the tablet joins it.

Set it up

From the app (quickest)

The app's Emlid Diagnostics button, at the very bottom of Settings, reads the receiver, tells you which setup it matches, and sets it up for you (the whole run took about 15 seconds on an RS3). Follow Check and program a Reach with Emlid Diagnostics: every tap has a close-up picture there.

By hand in Emlid Flow

The same settings, screen by screen with pictures, are in the receiver setup guide: GNSS settings, RTK base, Ditch Assist rover and Ditch Assist Lite rover. The key settings for the two rovers:

A receiver set up by hand can still show a difference or two in Emlid Diagnostics (base antenna height, or settings Emlid Flow doesn't show). It runs the same. Set it up from the app if you want the green tick.

On the machine

• Rover: mount the Reach on a mast on the implement, on the part that moves up and down with the cutting edge, and connect the RTK GPS cable to the control module or DIG harness. The module powers it. See Mount the GPS antenna.
• Lite Rover: mount it where it rises and falls with the cutting edge and won't get hit. It runs about a working day on its internal battery; a USB power bank on the mount extends it. See Power the receiver. Then connect from the app: Connect to the Reach.

If it doesn't work

• Not connected to a Reach in Emlid Diagnostics: the tablet isn't on the receiver's Wi-Fi. Join it and tap Retry.
• Setting up stops part-way: set that part in Emlid Flow, then come back and check. Programming stopped.
• Rover cabled to the module, Status 2 not blinking: nothing is arriving. The receiver's serial output may be off (no Rover setup yet), or the cable isn't plugged in all the way. Status 2 not blinking.
• Rover cabled to the module, Status 2 blinks but the app has no GPS: the baud rate or messages are wrong. Program it as Rover again in Emlid Diagnostics. Status 2 blinks, but no GPS.
• Rover stuck on Float or GPS: Stuck on Float.
• Ditch Assist Lite won't connect: Fix Ditch Assist Lite problems.