Emlid Reach RS4

01

Reach RS4 is a full base-and-rover receiver, and the RS4 Pro is the only version with cameras

Emlid builds the Reach RS4 as a survey-grade GNSS receiver. Under RTK, real-time kinematic correction, it is rated to 7 mm plus 1 ppm horizontal precision. It runs as a base station, a rover, or both. Emlid also sells the Reach RS4 Pro, which shares the RS4's entire GNSS core: same positioning figures, same 672 channels, same radio hardware. Two confirmed differences separate them. One is weight, 927 g for the RS4 against 943 g for the Pro. The other is the Pro's two cameras, built for augmented-reality stakeout and photo-based point capture, which the RS4 does not carry. If that is what your workflow needs, call and we will help you find the right receiver.

02

RTK precision is 7 mm plus 1 ppm horizontal, and a fix typically locks in about 5 seconds

RTK, real-time kinematic, is Emlid's highest-accuracy live correction mode. Emlid's own datasheet rates it at 7 mm plus 1 ppm horizontal and 14 mm plus 1 ppm vertical. The ppm term scales with distance from your correction source, so accuracy loosens the farther the rover sits from its base. Static observation tightens that to 4 mm plus 0.5 ppm horizontal. PPK, post-processed kinematic, sits between the two at 5 mm plus 0.5 ppm horizontal. It logs raw data in the field and corrects it against a base log afterward. Convergence, the time RS4 takes to lock a fixed solution once corrections arrive, runs to about 5 seconds typically. Tilt compensation adds 2 mm plus 0.3 mm per degree of tilt to the base figure. Emlid's own worked example puts a 30-degree tilt over a 1 km baseline at about 18 mm total. RS4 tracks 672 channels across GPS, GLONASS, Galileo, BeiDou, QZSS and NavIC, updating at up to 10 Hz.

04

RS4 weighs 927 g today, but an older 920 g figure still circulates, and which one ships here is unconfirmed

Reach RS4 measures 128.6 by 128.6 by 99.3 mm and weighs 927 g, per Emlid's current datasheet, product page and store specification table, all independently. An older 920 g figure still appears on another listing of this product, alongside the older flat 0.1 W LoRa figure noted above. The two numbers travel together, pointing to an older hardware or documentation revision rather than two unrelated errors. Which hardware revision MYSD currently ships against this SKU has not been confirmed. Call before you order if the exact figure matters to your project. The body is magnesium alloy, rated IP68, and runs from -40 to +65 degrees Celsius, -40 to +149 degrees Fahrenheit. Emlid does not publish a submersion depth or duration beyond the IP68 rating itself. Mounting is a standard 5/8 inch UNC thread. The integrated Li-Ion battery, 5000 mAh at 7.2 V, runs 16 hours as an RTK rover with tilt on, or 22 hours logging data. It charges over USB-C at up to 15 V and 3 A.

06

RS4 needs a clear 30-degree view of the sky, and its status LEDs tell you the fix quality at a glance

Emlid's own guidance calls for a clear view of the sky to at least 30 degrees above the horizon in every direction. Buildings, trees, vehicles and even people standing nearby can block enough signal for a reliable fix. Keep other electronics as far away as practical, since they can generate RF noise that interferes with GNSS reception. The status LED reads the fix directly. Solid white means a SINGLE, uncorrected position, solid orange means a FLOAT solution, and solid green means a FIX, the locked state RS4's accuracy figures assume. Five battery LEDs step from one red LED at 1 to 10 percent through five white LEDs at 81 to 100 percent, blinking in sequence while charging. The 8-pin external connector can supply constant power, relay RTK corrections to a third-party radio over RS-232, or stream position output elsewhere. Its power input is rated 6 to 36 V recommended, against an absolute maximum of -36 to +42 V, and exceeding that maximum may cause permanent damage.

07 FOR UNIVERSITIES, COLLEGES AND GOVERNMENT AGENCIES

We are an Authorized Emlid Dealer, and RS4 ships direct from the manufacturer

My Surveying Direct is an Authorized Emlid Dealer. We accept purchase orders from universities, colleges and government agencies, and every RS4 ships direct from the manufacturer. Two figures on this page, the weight and the LoRa radio power, depend on which hardware revision your unit actually is. Emlid's own manufacturer surfaces do not agree on the exact packing list either. Call before you order: +1 888 850 6533, Monday to Friday, 9 to 5 Mountain Time. We will confirm the hardware revision, the exact contents of your box, and whether the RS4 or another Reach receiver is right for your survey.