Bench Mark US - Surveying equipment

(1.5) Used Hemisphere S321+ RTK GNSS (6th Gen.) Smart Antenna

(7 customer reviews)


See What Matters to Our Customers

The S321+™ is still one of Hemisphere’s best smart antennas. Durable and compact, The S321+™ provides the quality of big-GNSS brands: Centimeter-level accuracy, instantaneous initialization, and performance even in harsh environments.


  • GPS, GLONASS and BeiDou
  • SMS Communication from Base to Rover & Cell Phone
  • L-Band DGPS Support
  • Internal UHF Radio & Cellular Modem
  • Surveyor Tough Magnesium Housing
  • SureFix & aRTK Intelligence for RTK
  • 4GB Internal Memory, with Expandable SD Memory Slot
  • Dual Bluetooth
  • Long Life Batteries


  • S321+ Smart Antenna with 400MHz radio
  • S321+ Battery (2)
  • S321+ Battery Charger
  • Eclipse L-Band Activation
  • Eclipse 10 Hz Activation
  • Raw Data Activation
  • 400 MHz Radio Antenna
  • Free Bench-Mark Approved Technical Support
  • Best Hemisphere Pricing Guarantee


The Hemsiphere S321+ GNSS Receiver

The Hemisphere S321+ was Bench-Mark’s best-selling surveying receiver for years. The S321+ was made to quickly pay itself back, keep you ahead of the competition, and last for years to come.


Multi Constellation GNSS and Triple Frequency

The S321+ is Hemisphere’s multi-GNSS, multi-frequency smart antenna. With the Hemisphere S321+ you receive corrections from; GPS, GLONASS, Galileo, BeiDou, and SBAS constellations without a setup fee. To add to this, the S321+ is also triple frequency, meaning you have access to the most powerful GNSS signal yet, L5. The L5 signal is powerful enough to get through tree canopies, allowing you to get shots that you would otherwise not have been able to get.


Surveyor Tough

The S321+ provides robust performance and high precision in a compact and rugged package. With a surveyor tough aluminum body, the S321+ is built to withstand whatever conditions you throw at it. The S321+ is built to survive a 2 M pole drop. This is the receiver that is built with accidents in mind, and is built to survive them. The IP67 environmental rating means that Hemisphere’s S321+ can withstand whatever conditions you face on site. This is the receiver that is built to last for years to come, and has the technology to compete that long as well.


Athena RTK Engine

The S321+ receiver is powered by Athena RTK technology. With Athena, S321+ provides state-of-the-art RTK performance: centimeter- level accuracy, near-instantaneous initialization times and functionality in the worst environments. With multiple connectivity options, the S321+ allows for RTK corrections to be received over radio, cell modem, Wi-Fi, Bluetooth, or serial connection. 

The S321+ also boasts the impressive SureFix technology. With SureFix, you can always be assured that the solution you are seeing is the repeatable true solution.

With a subscription, the S321+ receiver also enables users to work with Atlas. Atlas is Hemisphere’s industry-leading global correction service, ensuring sub-decimeter positioning performance anywhere on earth.

Atlas L-band has the following benefits:

  • Positioning accuracy – Competitive positioning accuracies down to 2 cm
    RMS in certain applications.
  • Positioning sustainability – Advanced position quality maintenance in the
    absence of correction signals, using Hemisphere’s patented technology.


Powerful Communication

The S321+ features the industry-leading 1 W internal Satel radio that can send and receive corrections over both cell and UHF modems, even up to 3.5 km with no line of sight. The receiver fixes instantly almost every time we step out of the truck.


The internal 4G cell modem also allows you to send and receive corrections over cell, enabling our StormCaster internet RTK service. With StormCaster and an internal cellular modem, you can run an unlimited number of rovers of the same base at multiple different job sites.


In addition, the S321+ also broadcasts a Wifi signal over which setup and updates can be applied. The built-in Web-UI allows you to quickly set up static data, and base and a rover with little to no hassle. 


Key S321+ Features

  • Multi-Frequency, Multi-GNSS Base Station/Rover
  • GPS, GLONASS, BeiDou, Galileo, and QZSS
  • Athena™ RTK, Atlas® L-Band, and SBAS-Capable
  • Hot Swappable Batteries with 12 Hours of Combined Life
  • Wifi, UHF, Cellular and Bluetooth Communication
  • 8 GB of Internal Memory for Data Logging, Downloading, and Uploading
  • 572 Channels
  • 1, 2, 4, 5, or 10 Hz Update Rate (20 Hz Optional)
  • Internal Radio (410 – 470 MHz)


7 reviews for (1.5) Used Hemisphere S321+ RTK GNSS (6th Gen.) Smart Antenna

  1. David Sawatzky

    I can tell you everything works flawlessly and we would be in a very tight spot if you hasn’t been able to ship the gear that you did in such short notice! Thanks a ton!! I love the s321 and I like the 15 min aRTK drift option on the 321, it helps us in a lot of situations.

  2. James Kenny – Pasquini & Associates Consulting

    Just an update, well Rene it’s the best built GPS I’ve ever used, I’m completely impressed with the design, the radio is way better now, and since the S321 firmware update it’s repeatability and accuracy has been dead on!

    Also this Mesa2 works awesome in every aspect daylight, it’s viewability is like nothing else on the market and in wet conditions the screen works flawlessly.

  3. Todd Kuntz – City of Saskatoon

    The guys that are using the S321 are very happy with them. They fix quickly and seem to be very accurate.

  4. Peter Llewellyn – DGH Engineering Ltd.

    A great unit. Did even better near trees compared to other GNSS Equipment I’ve used in the past. I will definitely recommend it to others.

  5. David M. Brubacher O.L.S. – Strata Surveys

    I really like the S321. Battery life is great, positioning is very repeatable and I’m liking Carlson SurvCE more and more. I’m very happy with it. Performance in and around trees is excellent.

  6. Osama Saadeldin – Bosys Technologies

    Just wanted to thank you for the great support we got from both of you. S321 is working out pretty good. We went out to the site and the equipment performed nicely. We had a SureFix and it stuck throughout the whole survey, and even after dumping it, it picked it up so quickly. It was a beautiful thing…

  7. John Lohnes, ALS – Vista Geomatics

    Brian and I took the system out on Sunday and we got radio at 10km. I was really surprised. Brian really likes the system. I will have no problem recommending this to people.

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