The Trimble R8 GPS receiver to GNSS capable R8 Model 2, Model 3, Model 4 and the latest R8s. Trimble R8 build on the 5800 “smart receiver” platform, Trimble R8 Model 1 came out in 2002 before Trimble even supported GLONASS, the hardware inside was a GPS only that could track L2C to make it different from the Trimble 5800.
The R8 was the first introduction of Trimble’s R-Track technology, which was capable of tracking the L2C civil signal, a stronger satellite signal that assisted maintaining fixed RTK solutions around tree canopy and other obstacles that obstruct clear view of the sky. Another feature that separated the R8 from the 5800 was the newly added ability to transmit RTK corrections from its internal UHF radio. With integrated Bluetooth, the TX radio option offered a clean and cable-free base station and rover setup.
There’s a big difference between the R8 model 1, 2, 3, or 4. Something along the lines of: Model 1 was GPS only, Model 2 was GPS/GLONASS
Trimble R8 Model 1
- 24 channels L1/L2/L2C/WAAS/EGNOS/SBAS GPS (only)
- Base and rover operation
- Internal radio transmit
The R8 Model 2 tracks GPS and GLONASS constellations. Along with L2C and L5 tracking, it provides better performance around obstructions compared to the R8 (model 1) but still struggles to maintain a fixed RTK solution around medium-height trees. Slower re-initialization times when signals are lost due to obstructions
Trimble R8 Model 2 GNSS (rev 1) RTK surveying receiver
The R8 GNSS Model 2 (R8-M2) was released around 2004 and continued to build on the same board form of the 5800 and R8 – with a noticeable bulge on the top cover (radome), as if it were flexing its new GNSS muscles. Expanding beyond tracking the L2C civil signal, the R8-M2 added additional capability of tracking L5 and the Russian satellite constellation GLONASS. A second iteration of the R8-M2 came around 2006 to meet the European Union’s ban on electronic devices containing lead solder. The new R8 Model 2 – version 2 adopted a grey trim instead of the yellow and blue of the previous version. Possibly a byproduct of the lead free solder – the second version seems to hold up better to vibrations and drops and offers extended Bluetooth range (up to 30 feet).
Trimble R8 GNSS Model 2 Rev 2
Compared to the R8, the R8-M2 is a better choice if you’re surveying in areas that have moderate sky obstructions – e.g. intermittent tree coverage and multilevel buildings.
R8 GNSS Model 2 Highlights:
- 72 Channels L1/L2/L2C/L5/WAAS/EGNOS/SBAS
- GPS + GLONASS
- 11 MB internal memory
- Base and rover operation
- Internal radio transmit (paid upgrade optional)
Trimble R8 Model 3 GNSS RTK receiver
Other than the new flat-top radome design, the R8-M3 didn’t look much different compared to the R8-M2. But looks can be deceiving. Released around 2008, the R8-3 was now loaded with 220 channels and the ability to track the Galileo constellation (optional upgrade). It featured “R-Track Signal Prediction” which greatly improved the receiver’s performance around canopy and other sky obstructions (for short bursts of time). Where the R8-M2 would maintain a fixed solution at the outer extents of a tree’s foliage, the R8-M3 enabled you to take shots under light to medium canopy. CMRx was a new protocol that was necessary for the receiver to compress and transmit the data that was now being tracked on those 220 channels. 57 MB of internal memory was upgraded for storing GNSS observations (post processing). Finally – the internal UHF radio transmit option was now a standard feature.
R8 GNSS Model 3 Highlights:
- 220 Channels L1/L2/L2C/L5/WAAS/EGNOS/SBAS
- GPS + GLONASS + Galileo*
- 57 MB internal memory
- Base and rover operation
- Internal radio transmit
Simply the best receiver for mid-range budgets. The R8 Model 3 is a great performer in challenging environments. R-Track with Signal Prediction™ (prelude to Xfill) offers roughly 20 to 30 seconds of precision after the RTK signal has been interrupted. 220 channels offer faster initializations – which reduces downtime. *Galileo tracking was an optional upgrade.
Trimble R8 Model 4 GNSS RTK receiver
440 Channels, GLONASS, Galileo and BeiDou tracking included…what’s not to love? And if the R10 is out of your price range, the R8-M4 is the best alternative.
Identical in appearance and similar in performance to the R8 Model 3, the Model 4 is an excellent surveying receiver that performs very well in traditionally challenging areas – enabling RTK shots around, and in some cases, under light to medium tree canopy. Released around 2013, the primary difference between the R8 Model 4 versus the Model 3 is Galileo (European Union) tracking was now included as a standard feature – as well as the addition of BeiDou (China) constellation tracking (also standard feature). The additional channels not only tack more satellites, which can help when GPS and GLONASS satellites are in a bad position (PDOP), they help with faster initialization times when signal is interrupted due to obstructions of the sky.
Trimble R8 GNSS Model 4 Highlights:
- 440 Channels L1/L2/L2C/L5/WAAS/EGNOS/SBAS/QZSS/GAGAN
- GPS + GLONASS + Galileo + BeiDou
- 56 MB internal memory
- Base and rover operation
- Internal radio transmit (TX)
The R8 Model 4 is a great performer in challenging environments. R-Track with Signal Prediction™ (prelude to Xfill) offers 20 to 30 seconds of extended precision after the RTK signal has been interrupted. 440 channels offer fast initializations – which reduces downtime. Galileo and Beidou tracking can help when GPS and Glonass satellites are not enough
Trimble R8s
Trimble R8s comparison, vs R8-M4
Released in 2017 the R8s is the latest in the R8 series. Think of the R8s as a deconstructed R8 Model 4. It has identical capabilities as the R8 Model 4, but, like the not so popular R6, you only pay for the features that you need. Starting from the bottom, the R8s can be enabled for post processing GPS L1 signal. From there, you can purchase upgrade codes to enable the R8s to track each individual constellation and signal (L1, L2, L2C, L5). RTK is also a paid option – as is Base station or Rover functionality.
If you’re buying a used R8s receiver, it’s very important to know which features have been enabled, otherwise by the time you pay for every option, you’ve got yourself an R8 Model 4 but paid for an R10!
It’s worth mentioning that the R8s has a more current cellular modem option (compared to the R8-M4) and a single wide-band UHF radio (403MHz to 473Mhz). Also – if you’re running Trimble’s Field Link software (M.E.P.) this is currently the only survey receiver that is fully supported (by Field Link 5.3).
R8s Highlights:
- 440 Channels L1/L2/L2C*/L5*/WAAS/EGNOS/SBAS/QZSS/GAGAN – *L2C / L5 are purchased options
- GPS + *GLONASS + *Galileo + *BeiDou – *purchased options
- 56 MB internal memory *purchased option
- *Base and *Rover capable – *purchased options
- *Internal radio transmit -*purchased option
- Compatible with Trimble Field Link 5.3 and newer
Source: https://positioningsolutions.com/blogs/product-info/trimble-r8-series-gps-gnss-receivers-compared-a-buyers-guide-positioning-solutions