Why you should be using the Trimble SPS855 series GNSS receivers
Over the last decade receiving RTK corrections through the internet has become a popular and cost effective way for land surveyors to deploy several rovers over multiple projects and jobsites.
Additionally, the SPS85x series GNSS receivers are easily configured to provide independent RTK corrections simultaneously to a wide range of GPS equipment, such as a GCS900 grade control systems and any survey receiver capable of receiving CMR, CMRx or RTCM corrections, which makes it an excellent option for jobsites where both survey and machine control technology is deployed.
The Trimble SPS85x (SPS850, SPS851, SPS852 and SPS855) receiver is a modular GNSS receiver with internal UHF or 900 Mhz radio. Designed for harsh conditions, the SPS85x circuit boards are totally sealed inside its IP67 rated metal housing. Configurable as either a base or rover (depending on options), it includes an internal battery (10 to 12 hour), Bluetooth communications, easy to use front panel interface, and internal serial to Ethernet converter for a simplified internet setup.
Since the receiver is modular, it requires a separate GPS or GNSS antenna to receive satellite signals, preferably Trimble's Zephyr Geodetic Model II or III. Being a modular receiver, the 85x can be installed inside a jobsite trailer or vehicle, keeping it safe from the elements and road-side thieves.
The internal 2 watt UHF radio options range from: 410 to 430 Mhz, 430 to 450 Mhz, 450 to 470 Mhz. There's also a 900 Mhz version for Trimble construction hardware. The distance a radio will transmit is always dependent on terrain, obstructions and radio antenna, and antenna height – but on average we received corrections around 1.5 miles away with either radio type. For longer distances – you can always add a high power external radio, like the TDL450. For dual radio situations (900 and UHF) the SPS85x can transmit out of its internal radio – while also transmitting to an external one. This works great for sites where survey and construction crews are running different radio types e.g. Trimble survey (UHF) and Trimble Grade Control Systems (900 MHz).
The SPS85x front panel user interface makes base station setup easy, removing the need for a data collector. There's also an Auto-base feature that works great for machine control operators. The Auto-base feature will remember its position parameters from the previous setup. It allows for 1 button operation the next day, but be careful with this feature and only use a permanent mount set up for the Zephyr antenna so it's in the exact same position everyday.
The SPS85x was designed with the internet in mind and it's one of the easiest devices to set up on a network. Seriously, this thing was easier to set up than our wireless printer! Within 15 minutes we had it transmitting RTK corrections through our wireless router and over the internet. Trimble's web application provides access to additional advanced futures like remote set up and remote troubleshooting. That’s right, you can access your base station from anywhere in the world – just open your browser and type in the IP address.
Another advantage of the SPS85x is that it can simultaneously transmit corrections over multiple ports, using multiple protocols. For example – you can send CMR+ corrections through the internet while sending RTCM corrections through the internal UHF radio – while also sending CMRx corrections through an external radio – or any combination of the sort. You can even have a 4th port sending via Bluetooth. This is multitasking in 4 different languages! Not only does it support the latest Trimble rovers like the R12 and SPS986, but offers support for Leica, Topcon, Sokkia, JAVAD and of course just about every Trimble RTK receiver made since the late 90's.
Two jobsites – One base station:
Think about this scenario: You have multiple jobs that are close to each other, but out of radio range. The SPS85x can be located on one site, providing corrections locally – while sending corrections to the second site through the internet.
Note:Sending corrections through the internet enables your rover to receive those network corrections over nearly unlimited distances. This is not the same as a VRS solution. Keep in mind that the laws of physics which control RTK accuracy are still in play here and we don’t recommend using corrections when you are more than 20 miles from your base station.
In a pinch, the SPS85x works as a rover too. It can be mounted to a survey pole, tucked away in a backpack like the old 5700, or mounted in a vehicle, making it perfect for daily quantity topos. The SPS receivers are optimized to work with Trimble’s SCS900 software, but it can also be used with Survey Controller software and some versions of Access ** Survey Controller requires and upgrade code – this code is usually free, but we are aware some dealerships will charge up to $250 for it.
SPS85x series receivers can range in price depending on the features installed. Here is what you need to know when buying one of these receivers:SPS850 Extreme:
These were the original from back in 2005. They are 72 channel receivers that included GLONASS tracking and can be used as either a base or rover. They were offered multiple radio options: 900 Mhz, 410-430 Mhz, 430-450 Mhz, 450-470 Mhz There is also a non radio version. Optional upgrades include: L5 and data logging.SPS851:
The SPS851 is the same receiver as the SPS850, except GLONASS tracking was optional (the SPS850 included the GLONASS option standard).SPS852:
This is a 220 channel receiver that gets confusing because everything is an option – including the accuracy. From the factory this is a “dumb” or “blank” receiver. Depending on the options purchased - the receiver can either be a base or a rover – or both. GLONASS and Galileo are also options, along with L5 and data logging. To ensure you are buying a RTK accuracy unit – make sure the RTK Precise option (base or rover) is installed. This option can also be purchased at anytime, but upgrades are not cheap.SPS855:
This is the most current version, released in 2011 with an amazing 440 channels! Trimbles datasheet shows that this receiver will also track BeDiou and Galileo. The SPS855 also has a 900 Mhz option with one UHF option that covers the full 410 to 470 Mhz spectrum. Just like the SPS852, everything is an option with this receiver – so be cautious when purchasing and make sure you know what your getting.
Trimble SPS850 / SPS855 GNSS
Trimble SPS850 through SPS855 look the same on the outside. IP67 rated sealed receivers with internal batteries, yellow paint. Internal radio options and Bluetooth.
The Trimble NetR9 GNSS is grey and color and otherwise looks like the SPS85x, but does not offer an internal radio. The NetR9 was designed for office installations and is compatible with Access 2017, though we have not tested it as of yet.
The Trimble NetRs receiver was the first to go online, but was difficult to set up and was a GPS receiver only. Additionally the NetRS is not a field receiver and does not have an internal radio. This receiver has a Linux operating system. Unless you are already familiar with these, our recommendation is to stay clear of the NetRS because of how difficult it is to get set up.
This article was originally written in 2016 and updated in April, 2020. We put forth our best efforts to ensure accuracy of information listed. Please use this information as an additional guide to help you make a decision.