The Emlid Reach RS4 is an all-band, all-constellation RTK GNSS receiver with built-in tilt compensation, a magnesium alloy body, and a dual-band UHF and LoRa radio system that transmits and receives on both frequencies. Designed for surveyors, drone-mapping operators, GIS crews, and construction teams who need centimeter-level positioning under tree canopy, in urban canyons, and at the edges of correction-network coverage, the RS4 tracks 672 channels across GPS, GLONASS, Galileo, BeiDou, QZSS, and NavIC — including the lower L5 and L6 bands that resist multipath and jamming. Pair it with a DJI, Autel, or Skydio RTK drone as a project-local base station, mount it on a survey pole for stake-out and topo, or set it up as a permanent CORS-style reference. Backed by Emlid Flow software and lifetime support from the manufacturer.

All-band RTK GNSS receiver. 672 channels, L1/L2/L5/L6 across every major constellation, 7 mm + 1 ppm RTK accuracy, no-angle-limit tilt compensation, IP68 magnesium body, 16-hour battery, and dual-band UHF + LoRa radios that transmit and receive.

Features

• All-band, all-constellation tracking: GPS L1C/A, L2C, L5; GLONASS L1OF, L2OF; Galileo E1-B/C, E5a, E6; BeiDou B1I, B1C, B2a, B3I; QZSS L1C/A, L1C/B, L2C, L5; NavIC L1-SPS and L5-SPS
• 672 channels — tracks 40+ satellites simultaneously for steadier fixes under canopy and in urban environments
• RTK positioning accuracy of 7 mm + 1 ppm horizontal, 14 mm + 1 ppm vertical, with typical convergence in under 5 seconds
• Next-generation tilt compensation with no angle limit, factory calibration, and a few-second initialization (no walking pattern required) — immune to magnetic interference because it's IMU-only
• Dual-band radio that transmits and receives on both UHF (410–470 MHz, up to 2 W, TRIMTALK 450S protocol) and LoRa (868/915 MHz, up to 1 W, license-free in most of North America)
• Built-in global LTE modem with nano-SIM slot for NTRIP corrections from the Emlid NTRIP Caster or third-party caster networks
• Magnesium alloy body — the same material class used in aerospace housings — for a lighter, stronger receiver than a polycarbonate-shell equivalent
• IP68 ingress protection, rated for dust, immersion, and continuous rain
• Operating temperature from -40 °C to +65 °C (-40 °F to +149 °F) for cold-weather survey work and hot-climate operations
• 16 hours of continuous battery life as an RTK rover with tilt enabled, from the internal 5000 mAh / 36 Wh Li-ion pack
• USB-C Power Delivery charging at 5/9/12/15 V — recharge from a laptop, USB-C wall brick, or field power bank
• Emlid Quick Release adapter mount (sold separately) eliminates pole backlash for accurate tilt measurements; standard 5/8"-UNC thread also accepts any survey pole or tripod
• 16 GB internal storage for RINEX, NMEA, LLH/XYZ, and UBX log files
• Wi-Fi 802.11 a/b/g/n and Bluetooth 5.1 for connection to Emlid Flow on iOS or Android
• Compatible with the Emlid Flow and Flow 360 ecosystem for project management, stake-out, layouts, line surveys, cut-and-fill, and as-built verification
• Lifetime expert support from Emlid included with every receiver

What it does

• RTK rover: Receives corrections over NTRIP (cellular or Wi-Fi), UHF radio, or LoRa radio and delivers centimeter-level position to Emlid Flow or any compatible data collector
• RTK base station: Logs a known point, computes corrections, and broadcasts them to a rover, a drone, a tractor autopilot, or a GPR system via Emlid NTRIP Caster, UHF, or LoRa
• PPK base: Records raw RINEX observations alongside drone-collected geotags for post-processed kinematic workflows in Emlid Studio or third-party photogrammetry tools
• Drone RTK base: Streams RTCM3 corrections to DJI, Autel, and Skydio RTK aircraft over Emlid NTRIP Caster or Local NTRIP for sub-2 cm geotag accuracy in the field
• Permanent base / CORS-style reference: External power input through the bottom connector lets the receiver run indefinitely on a 6–36 V supply for fixed installations

Specifications

Who this is for

• Land surveyors needing a single all-band receiver that handles base, rover, tilt, and NTRIP duty without juggling separate radios or correction services
• Drone mapping operators flying DJI Phantom 4 RTK, Mavic 3 Enterprise, Matrice 30/30T, Matrice 300/350 RTK, Matrice 4 Series, Autel EVO II RTK, or Skydio X10 platforms who want a project-local base for centimeter geotags instead of relying on public CORS
• Construction crews running stake-out, layouts, cut-and-fill, and as-built verification daily, where the tilt compensation removes the need to plumb the pole over every point
• GIS and asset-mapping teams collecting points and lines under tree canopy or near buildings, where the all-band L5/L6 tracking and improved antenna keep fixes stable
• Archaeology, environmental, and research crews working in cold or hot climates where IP68 rating and the -40 to +65 °C range matter
• Precision agriculture operators integrating an RTK base with tractor autopilots, where the external power input keeps the receiver running on a 12 V or 24 V supply indefinitely
• Public-safety and emergency-mapping programs that need a portable, rugged base station for incident-area surveys without dependence on cellular coverage
• Existing Reach RS2+ or RS3 owners upgrading for transmit-and-receive on both UHF and LoRa (the RS3 only received on UHF), faster tilt initialization, and the magnesium body

What's included

• 1 × Emlid Reach RS4 receiver
• 1 × Carrying case
• 1 × USB-C cable

Please note: Survey pole, tripod, Emlid Quick Release adapter, UHF antenna whip, LoRa antenna whip, nano-SIM card, NTRIP service subscription, and data collector (tablet or phone running Emlid Flow) are sold separately. The receiver ships with a built-in modem but no SIM card — supply your own or use Wi-Fi tethering for cellular NTRIP. For tilt-compensation work, the Emlid Quick Release adapter is strongly recommended to eliminate pole backlash.

Reach RS4 vs. Reach RS3 vs. Reach RS2+

Emlid's current field-ready RTK lineup gives surveyors three tiers:

• Reach RS2+: Multi-band RTK receiver with LoRa radio (transmit and receive) but no UHF, no tilt compensation, and a polycarbonate body. The value option for crews that mostly work over LoRa or NTRIP and don't need tilt.
• Reach RS3: Multi-band RTK receiver with tilt compensation, LoRa transmit-and-receive, and UHF receive-only. Discontinued or de-emphasized as the RS4 takes over, but still in inventory at some dealers.
• Reach RS4 (this product): All-band (adds L5/L6 to the L1/L2 stack), 672 channels, magnesium body, faster tilt initialization with no angle limit, and transmit-and-receive on both UHF and LoRa. The flagship single-IMU receiver in the lineup.
• Reach RS4 Pro (sold separately): Adds a dual-camera AR system for visual stake-out and point capture; same GNSS engine, IMU, and radio system as the RS4. Pick the Pro if the workflow benefits from camera-aided positioning in confined, obstructed, or visually marked areas.

DJI RTK drone integration

The Reach RS4 acts as a base station for DJI Enterprise aircraft that support NTRIP corrections, including the Phantom 4 RTK, Mavic 3 Enterprise / Mavic 3 Multispectral / Mavic 3 Thermal, Matrice 30 / 30T, Matrice 300 RTK / 350 RTK, and Matrice 4 Series. The workflow:

• Set up the RS4 over a known point or run an averaged single-point base
• Stream RTCM3 corrections out over Emlid NTRIP Caster (internet) or Local NTRIP (Wi-Fi to the drone controller)
• Connect the DJI remote controller to the same Emlid Caster mount point or local Wi-Fi NTRIP source
• Fly the mission — the drone applies corrections in real time for centimeter-accurate geotags
• Process the geotagged images in any photogrammetry pipeline (Pix4D, Metashape, DJI Terra, etc.) for survey-grade orthomosaics, point clouds, and DEMs

The Reach RS4 also supports PPK workflows: log raw RINEX on the receiver during the flight, sync against the drone's onboard log file in Emlid Studio after landing, and produce corrected positions even if real-time RTK was unstable.

FAQ