Independent review by The 3rd Dimension. We have no affiliation with the channel.

Emlid for professional surveyors

Flagship accuracy. A fraction of the flagship price.

You have run $20,000 rovers for someone else. For your own firm, you don't need to. In The 3rd Dimension's independent test, the Emlid RS4 Pro held the same accuracy as receivers that cost several times more. Watch the review, then see the numbers.

About 6 mm horizontal, 12–13 mm vertical on network RTK in his test
All-band GNSS, 200 Hz IMU tilt, IP68, UHF and LoRa radios, built-in LTE modem
FieldGenius perpetual: your rover and total station in one app
Prices posted in the open, not by dealer quote

See the test results Surveyor kits

What the independent test found

ACCURACY

About 6 mm H, 12–13 mm V

Standard deviation of residuals on network RTK, level with the CHC i89 tested beside it. Off a Trimble R780 base, the RS4 Pro came in at about 5 mm and 9 mm.

THE TEST

13 control points, 9 full runs

Rovers swapped point for point with 15-second shots, on a network built to be hard: overhead wires, buildings, utility poles and tree canopy.

VS. THE BIG THREE

No meaningful gap

The i89 had already matched a Trimble R12i in his earlier test. His conclusion: no significant accuracy difference between the latest receivers, Emlid included, obstructions or not.

TILT

200 Hz IMU, within 3–4 cm

In almost every case, even leaned past 80 degrees. For control he still shoots plumb with a calibrated bubble and tilt off, and so do we.

Side by side

Emlid RS4 Pro vs. a big-three flagship rover

The same job done for a quarter of the money, or less. Here is what changes and what doesn't.

What matters	TestedEmlid RS4 ProThe receiver he tested$4,599View	Big-three flagshipTrimble, Leica or TopconOver $20,000
Accuracy, from The 3rd Dimension's test
Network RTK, horizontal / vertical	About 6 mm / 12–13 mm	No significant difference found
Tilt compensation	200 Hz IMU, within 3–4 cm	Yes
Owning it
Price	Posted on our site	Usually by quote from a dealer
Field software	Emlid Flow on your own phone or tablet, or FieldGenius	Their own software, often on their own data collector
Running your own base	Free Emlid Caster feeds any brand's rover, drone or machine control	Their base service stays inside their own brand
Corrections in the rover	Built-in LTE modem, Wi-Fi, UHF and LoRa radios	Depends on the model

Test figures: The 3rd Dimension, "Emlid RS4 Pro GPS Receiver Review: Worth the Hype?" Standard deviation of residuals, 13 control points, 9 runs.

Emlid's RTK specification for the RS4 and RS4 Pro: 7 mm + 1 ppm horizontal, 14 mm + 1 ppm vertical.

The flagship price is the reviewer's figure. Trimble, Leica and Topcon are trademarks of their owners.

What the reviewer liked most

FLOW 360

Field data in the office, live

Points sync to the web as they are shot, with photos attached and named by point. Push new DXF, CSV or XML design files to the crew without driving to site.

EMLID CASTER

Your base, for every brand

Put an RS4 on your control and stream corrections over the internet to any rover, drone or machine control, Trimble and Topcon included. Free.

ANY DATA COLLECTOR

Use the phone you own

Emlid Flow runs on iPhone and Android. Change devices and your projects come with you, with no license keys to move.

BUILT FOR THE FIELD

Light, sealed, USB-C

Magnesium body, IP68, about 943 g with the battery, USB-C charging from almost any charger, and a quick release he calls a must-have.

Where Emlid Flow falls short

Miss the tools you had in Trimble Access? Run FieldGenius.

The reviewer's honest gaps were all in Emlid Flow Pro, Emlid's easy-to-learn field app: no snap tools, no averaging of repeat shots, no road alignments, no point groups. Emlid adds to Flow Pro constantly, and the gap gets smaller with every release. If you need those tools today, FieldGenius is MicroSurvey's full surveying field software. It runs your Emlid rover and your total station from one map screen, on a license you buy once.

Your Emlid rover and your total station in one app
Average a base point, resect a total station
COGO in the field: intersections, offsets, traverses
Grid-to-ground and local transformations
Surface staking with cut and fill from the design
Perpetual license: buy it once, keep it

RS4 Pro + RS4 kit with FieldGenius About FieldGenius

FieldGenius map screen showing a survey over aerial imagery

Surveyor kits

A complete base and rover, ready for work.

Both receivers updated to the latest firmware before they ship, with free setup support by phone.

Emlid + MicroSurvey

GNSS Bundle + FieldGenius

Best for surveyors

FieldGenius survey app included, perpetual license

RS4 Pro rover, RS4 base, carbon fiber poles, bipod and tripod, a quick release adapter and FieldGenius, MicroSurvey's full surveying field software.

FieldGenius perpetual license included: buy once, no subscription
Run your total station and GNSS rover in the same app
COGO, resection and local transformations in the field

$10,174

View the kit

Emlid

GNSS Bundle + Emlid Flow Pro

Emlid Flow Pro survey app included, 1-year license

The same RS4 Pro rover, RS4 base, poles, bipod, tripod and quick release, with Emlid's own Flow Pro survey app instead of FieldGenius.

Emlid Flow Pro included: collect, stake out, CAD and surfaces
Flow 360: field data synced to the office as it is shot
The easiest app to learn, with AR stakeout on the RS4 Pro

$8,790

View the kit

Questions about switching from Trimble or Topcon? Call (901) 444-0804.

Questions surveyors ask us

Is Emlid accurate enough for professional survey work?

In The 3rd Dimension's test, the RS4 Pro held about 6 mm horizontal and 12–13 mm vertical on network RTK, level with a CHC i89 that had already matched a Trimble R12i. Emlid's own specification is 7 mm + 1 ppm horizontal and 14 mm + 1 ppm vertical. As with any rover, your procedures decide the result: redundant shots, checks to control and a calibrated pole.

Will it work with my Trimble or Topcon equipment?

Over NTRIP, yes. The RS4 takes corrections from any NTRIP source, and an RS4 base can feed any brand's rover, drone or machine control through the free Emlid Caster. Over UHF radio the RS4 uses the TrimTalk protocol, so radios on a different protocol won't talk to it, and the reviewer lost BeiDou and Galileo from one third-party base over TrimTalk. When in doubt, use NTRIP.

Emlid Flow or FieldGenius?

Emlid Flow is the fastest to learn, and Flow 360 puts field data in the office as it is shot. Emlid keeps adding to Flow Pro: recent releases brought DWG import, drawings up to 100 MB and live cut and fill to a design height. FieldGenius is full surveying software: total station and GNSS in one app, COGO in the field, and a perpetual license. If you run a total station too, FieldGenius is the one.

Who do I call when something goes wrong?

Us. Free setup support by phone from Memphis, TN, Monday to Saturday, 7 am to 7 pm Central, at (901) 444-0804. Every receiver ships on the latest firmware, and FieldGenius includes MicroSurvey's technical support.