GNSS module integration: how to add RTK positioning to your product
Key takeaways
- Choose between chipset, module, OEM board and smart antenna based on volume, engineering resources and time to market.
- Multi-band, multi-constellation RTK modules fix faster and cope better with multipath than single-band parts.
- The antenna, cable and ground plane often limit accuracy more than the GNSS module itself.
- Plan the correction source early: local base, NTRIP network RTK or PPP each changes the product design.
- Test in real environments, not just open-sky benches, before freezing the hardware.
What is a GNSS module?
A GNSS module is a self-contained satellite positioning receiver designed to be built into another product. It takes signals from an antenna, tracks satellites from constellations such as GPS, GLONASS, Galileo and BeiDou, and outputs position, velocity and time over a digital interface.
The term covers several levels of integration. A chipset, such as an RTK chipset, is the bare silicon, which needs full RF and board design. A GNSS receiver module packages the chipset with RF front end, clock and memory on a small solder-down part. An OEM board is a complete receiver on a circuit board with connectors, ready to mount inside an enclosure. A smart antenna puts the receiver and antenna in one weatherproof housing.
All of them compute position the same way. For the background on constellations and signals, see our explainer on GNSS vs GPS.
GNSS module vs RTK module vs OEM board vs smart antenna
The right form factor depends on how many units you will build, how much RF engineering you can do, and how fast you need to reach market.
| Option | Integration effort | Typical accuracy | Best fit |
|---|---|---|---|
| Standard GPS receiver module (single band) | Low to moderate | Metre level | Trackers, consumer devices, telematics |
| RTK GPS module (multi-band) | Moderate; needs RF and correction design | Centimetre level with RTK | Robots, drones, mowers, high-volume products |
| OEM GNSS board | Lower; connectors and firmware ready | Centimetre level with RTK | Machine control, survey devices, medium volumes |
| Smart antenna (receiver + antenna) | Lowest; connect power, data and corrections | Centimetre level with RTK | Vehicles, agriculture, retrofits, low volumes |
A low-cost single-band GPS board is fine for navigation, but it will not deliver reliable centimetre positioning. If your product must hold a fixed RTK solution near trees or buildings, plan for multi-band hardware.
Key specifications of an RTK GPS module
When comparing an accurate GPS module for RTK work, focus on the specifications that affect real performance and integration, not only headline accuracy.
- Constellations and frequencies: multi-band tracking (for example GPS L1/L2/L5, Galileo E1/E5a/E5b, BeiDou B1/B2/B3) speeds up RTK initialisation and improves resistance to multipath.
- Channels: enough channels to track all visible satellites on all signals.
- RTK performance: time to fix, fix reliability, and accuracy specified as a fixed value plus parts per million of baseline length.
- Update rate and latency: typically from 1 Hz to 20 Hz or more; fast-moving drones and machines need higher rates and low latency.
- Interfaces: UART, USB, SPI, I²C, CAN or Ethernet, plus a pulse-per-second (PPS) output for timing.
- Protocols: NMEA 0183 for position output and RTCM 3.x for corrections in and out.
- Power and size: consumption, supply range and footprint for battery-powered or compact designs.
- Heading and IMU: dual-antenna heading or integrated inertial sensors for orientation and dead reckoning.
Correction options: RTK, network RTK and PPP GNSS
An RTK module only reaches centimetre accuracy when it receives corrections, so the correction method is a core design decision.
Local base RTK uses your own base receiver and a radio or cellular link; it works anywhere but needs a second unit. Network RTK receives corrections from a CORS network over the internet using NTRIP, which needs a mobile data connection and a subscription. Our guide to NTRIP and CORS network RTK explains the setup.
PPP GNSS (precise point positioning) uses precise satellite orbit and clock data rather than a nearby base. A precise point positioning device works globally, often via satellite L-band or internet delivery, but typically needs a convergence period, from minutes to tens of minutes depending on the service, before reaching its best accuracy. PPP-RTK services combine elements of both approaches to shorten convergence.
Match the method to the use: remote agriculture may favour a local base or PPP, while urban robots usually rely on network RTK.
Antenna selection and RF design
The antenna and RF path often decide whether a GNSS module meets its datasheet. A poor antenna or noisy layout can prevent an RTK fix entirely.
- Antenna quality: use a multi-band antenna with a stable phase centre, good multipath rejection and right-hand circular polarisation (RHCP).
- Active antenna and LNA: a low-noise amplifier at the antenna compensates for cable loss; confirm the bias voltage the module supplies.
- Ground plane: patch antennas need a ground plane of suitable size beneath them for their rated performance.
- Cable and connectors: keep runs short, use low-loss 50 Ω cable and quality connectors.
- Interference: separate the antenna from motors, switching regulators, cameras and radio transmitters, and shield noisy electronics.
- Mounting: give the antenna a clear sky view and keep it away from reflective surfaces where possible.
Our GNSS antenna guide covers geodetic and smart antennas in more detail.
How to integrate a GNSS receiver module step by step
A structured integration process avoids costly hardware revisions. A typical sequence is:
- Define requirements: accuracy, update rate, environment, power budget, size, operating temperature and correction method.
- Select the module or board: compare candidates on signals, RTK performance, interfaces and long-term availability.
- Choose the antenna: select a matching multi-band antenna and plan its mounting and cable route.
- Design power and layout: provide clean, filtered power and follow the RF layout guidance for the module.
- Connect interfaces: route serial, USB or CAN to the host processor and bring out PPS if timing matters.
- Configure firmware: set message types, output rate, RTCM input, elevation mask and dynamic model.
- Integrate corrections: implement the radio, NTRIP client or PPP service in the host software.
- Test and certify: test in open sky, near buildings and under trees, then complete the EMC and radio certification required in your markets.
Integrating GNSS into drones, machines and robots
Each platform adds its own demands on the GNSS design.
A drone GPS module must be light and low power and sit well away from motor and video interference. RTK or PPK capability allows accurate camera positions for mapping. Machines and agricultural vehicles face vibration, dust, water and wide temperature ranges, so rugged smart antennas with CAN or serial output are often preferred. Ground robots and mowers work close to trees and buildings, where multi-band tracking and sensor fusion with wheel odometry or an IMU maintain position when the RTK fix drops.
For vehicles that need direction as well as position, dual-antenna heading provides orientation even when stationary.
Build or buy: when a smart antenna or complete receiver is simpler
For low to medium volumes, a finished smart antenna or receiver often costs less overall than designing your own board, once engineering time and certification are counted.
Mars Geosystems’ S20 GNSS smart antenna combines a 1408-channel RTK receiver and antenna in one IP67 housing, tracks GPS, GLONASS, Galileo, BeiDou, QZSS, NavIC and SBAS, outputs over Bluetooth and operates from −45 °C to +75 °C. For your own receiver boards, the SA102 geodetic antenna offers 36 ± 2 dB LNA gain, RHCP, a TNC connector and IP67 sealing. The E1 GNSS RTK receiver can act as a base station for your test fleet.
OEM and ODM branding is available from 10 units; see our OEM and ODM service or send your integration requirements through the quote page.
Frequently asked questions
What is the difference between a GNSS module and a GPS module?
A GPS module tracks only the United States GPS constellation, while a GNSS module tracks several constellations such as GPS, GLONASS, Galileo and BeiDou. More satellites improve availability and accuracy, especially near buildings and trees. Most modern modules are GNSS, even when they are still marketed as GPS modules.
How accurate is an RTK GPS module?
With good corrections, a multi-band RTK module typically achieves around one to two centimetres horizontally and slightly worse vertically, specified as a fixed value plus parts per million of distance to the base. Real accuracy depends on antenna quality, sky view, multipath and the correction source. Without corrections, accuracy is typically metre level.
What is the difference between RTK and PPP GNSS?
RTK uses corrections from a nearby base station or network, giving centimetre accuracy within seconds but needing a base within range. PPP uses precise satellite orbit and clock corrections that work worldwide without a local base, but typically needs a convergence period before reaching its best accuracy. PPP-RTK combines aspects of both.
Which interface should a GNSS receiver module use?
UART serial is the most common and simplest interface, outputting NMEA 0183 messages and accepting RTCM corrections. USB suits PC-based systems, CAN suits vehicles and machinery, and Ethernet suits fixed installations. Choose based on the host system, cable length, data rate and the environment the product works in.
Do I need a special antenna for an RTK module?
Yes. RTK performance depends heavily on the antenna. Use a multi-band active antenna that covers all the signals the module tracks, with a stable phase centre and good multipath rejection. Patch antennas need an adequate ground plane. A low-cost single-band antenna can prevent a multi-band module from reaching a reliable RTK fix.
Is it cheaper to integrate a GNSS board or buy a smart antenna?
For high volumes with in-house RF engineering, integrating a module or board usually gives the lowest unit cost. For low to medium volumes, a smart antenna or finished receiver is often cheaper overall, because it avoids RF design, antenna testing, enclosure development and certification effort, and reaches market faster.
Need equipment for this work?
Tell us the job, the country and the quantity. An engineer replies with a configuration and price within one business day. MOQ is one unit; OEM is available.
