Quick Answer
The RS2+, RS3 and RS4 are three generations of the same Emlid Reach receiver line. Each newer model tracks more satellite signals, gets a fixed position faster, and adds features like built-in tilt compensation. The RS2+ is the oldest and cheapest of the three. The RS4 is the newest, with the most complete feature set. Most surveyors only need to upgrade if their current unit is missing tilt compensation or struggles in tricky sky conditions.
Why Emlid Keeps Releasing New Models
GNSS chips improve every few years. A newer chip can track more signals at once. It can also filter out noisy reflections better. And it can lock onto a fixed position faster in hard spots, like near buildings or under thin tree cover.
Emlid folds these chip gains into a new RS model every so often. It also updates the antenna, the radio hardware, and the outer case each time. That is why the RS2+, RS3 and RS4 look similar on the outside. But they can behave quite differently once you are out in the field.
Satellite Tracking: More Bands, Faster Fixes
Every RS-series unit is a multi-band receiver. That means it listens to more than one frequency from each satellite system. More bands usually mean a faster fix. They also mean a more reliable fix, especially when some sky is blocked by trees, hills or buildings.
Later models track a wider set of signals than earlier ones. In practice, this shows up in two ways. First, you get a shorter wait for a fixed solution when you first power on. Second, you get fewer dropouts back to a floating solution as you walk between points. If your site already has good, open sky, this gap between generations matters less.
What This Looks Like in a Real Field Day
Picture a small survey site with a few trees near one corner. On an older model, you might lose your fixed solution every time you walk under those trees, and have to stand still and wait for it to lock again. On a newer model, that same walk under the trees might barely interrupt your fix at all.
This kind of small, repeated delay adds up over a full day of work. It rarely shows up in a spec sheet, but it is often the real reason a surveyor decides to upgrade.
Tilt Compensation: The Biggest Workflow Change
The single biggest change across these three generations is tilt compensation. Older receivers required you to hold the pole perfectly level (using a bubble level) for every point, which slows you down and invites mistakes.
Newer RS models use an internal sensor system, often called an IMU, that tracks how far the pole is tilted and corrects the recorded position automatically. This lets you collect a point while holding the pole at a slight angle, which is faster and more natural in the field. If your current receiver lacks this, it is one of the strongest reasons to consider an upgrade.
Radio, Connectivity and Battery
All three generations support LoRa radio for base-to-rover links without the internet, plus NTRIP over Wi-Fi or a phone's data connection for network RTK. The exact radio range and Wi-Fi behavior varies by model, so check the current specification sheet for the unit you are considering rather than assuming it matches an older one.
Battery life has generally improved across generations as power use per fix has gone down, but treat any specific hour figure as a best-case number that depends on your settings and the temperature you are working in.
Build Quality and Physical Design
The case shape has changed slightly across generations, along with the port layout and the mounting thread. If you already own a pole, bracket or mount for an older RS unit, check the physical dimensions of the newer model before assuming your existing accessories fit.
Weather sealing has stayed strong across the line, and all three models are built to work outdoors in rain, dust and normal field temperatures.
Should You Upgrade?
Ask yourself these questions before spending money on a newer model:
- Do you often struggle to get a fixed solution under trees or near tall buildings?
- Do you manually level the pole for every point, and want tilt compensation to speed that up?
- Does your current unit still meet your accuracy needs on open sites?
- Would the money be better spent on a network RTK subscription instead of new hardware?
If your current RS unit gets a reliable fixed solution and you do not need tilt compensation, it may still be doing its job well. Surveyors on a tight budget often get more value from a correction network subscription than from a hardware upgrade.
| Generation | Tilt compensation | Best fit |
|---|---|---|
| RS2+ | No | Budget setups, open-sky sites |
| RS3 | Depends on configuration | Mixed conditions, moderate budget |
| RS4 | Yes | Fast fieldwork, tricky sky conditions |
For the full picture of how RS units fit into the wider Reach lineup, including the RX rovers and M-series modules, see our Emlid Reach receiver guide. And once you have a receiver, our base and rover setup guide walks through the actual field steps.