GPS Module for High Precision GNSS: Positioning Technologies, Features, and Applications

From metre-level to centimetre-level, and what actually has to change to get there

A GPS module for high precision GNSS is often specified by the accuracy number alone, which is the least useful way to choose one. Metre-level, decimetre-level, and centimetre-level positioning are produced by different techniques, require different correction sources, and depend on different antenna arrangements. A module that reaches two centimetres with RTK corrections will fall back to metres when those corrections stop, and a product team that did not plan for that behaviour will ship a device that behaves unpredictably in the field.

This guide explains the accuracy tiers available today, why a GPS-only receiver cannot reach centimetre level on its own, how multi-frequency and multi-constellation reception change the picture, and how to select a module based on the application rather than on the datasheet headline.

The Accuracy Tiers and What Produces Each One

Four tiers are commonly quoted, and each corresponds to a different technique rather than to a different quality of hardware.

The hardware requirement rises with each tier, but not in the way most buyers expect. The receiver does not become dramatically more sensitive; it gains the ability to measure carrier phase, to process multiple frequencies, and to apply corrections. A high-precision module in single-point mode is not more accurate than an ordinary module. It only becomes more accurate when the corrections and the antenna support it.

Why a GPS-Only Receiver Cannot Reach Centimetre Level

The name GPS is often used generically, but a module that tracks only the GPS constellation on L1 has three structural limits. It has fewer satellites available, so geometry is weaker and the fix is fragile in obstructed environments. It has only one frequency, so it cannot correct the ionospheric delay that dominates single-frequency error. And it has limited redundancy, so a single satellite outage affects the solution more.

A GPS module for high precision GNSS, in practice, tracks multiple constellations and at least two frequencies. BDS, GPS, GLONASS, Galileo, and QZSS together provide far more satellites than GPS alone, and a second frequency allows the ionospheric delay to be estimated directly instead of modelled. That combination is what makes fast, reliable ambiguity resolution possible.

For buyers, this means the specification to examine is the frequency and constellation matrix, not the product name. A module labelled as GPS that supports L1, L2, and L5 across five constellations is a high-precision engine. A module labelled as GNSS that supports L1 only across three constellations is not.

The Antenna Is Half of the Accuracy

Module specifications assume an antenna that delivers a clean signal. In practice, antenna choice limits performance more often than the receiver does.

• Band coverage. If the antenna does not cover L5, the module cannot use it. Multiplying the receiver's capability by the antenna's bandwidth is the first check in any high-precision design.
• Phase centre stability. RTK measures carrier phase at the antenna's phase centre. If that point moves with temperature or elevation, the solution moves with it, and no amount of receiver processing can recover the lost accuracy.
• Ground plane. A patch antenna without an adequate plane radiates backwards, receives multipath from below, and detunes. The plane is part of the antenna, not an accessory.
• Cable and connector loss. Every decibel lost between antenna and receiver reduces the signal-to-noise ratio the module has to work with, which slows ambiguity resolution and reduces availability in marginal conditions.

Choosing the Correction Strategy

The correction source often determines the product architecture more than the module does.

A local base station gives the best accuracy over short baselines and full control over availability, at the cost of hardware, a monument, and a radio link. A network RTK service removes the base station but depends on cellular coverage and on the network operator's continuity. PPP requires no local infrastructure but needs a convergence period, which suits applications that operate continuously rather than starting and stopping. PPP-RTK combines the two, offering faster convergence than PPP while removing the base station.

Each option imposes a requirement on the module: the ability to accept RTCM corrections in the right format, to handle a network mount point, or to process SSR corrections. Confirm that the module's firmware supports the correction type before the hardware design is fixed, because adding it later may mean a different part.

Bandwidth is the constraint that is usually discovered late. A network RTK stream carrying every constellation at full rate can exceed the capacity of a narrowband radio link, so the module must accept a reduced message set without losing the fixed solution. In practice this means checking which message types the module can process independently, and testing the behaviour on a link that delivers only the subset your infrastructure can actually carry.

Matching the Module to the Application

A consumer tracker, a survey rover, and a machine control system all need different answers to those questions, and the same module rarely serves all three well. The most expensive mistake in this category is buying more accuracy than the correction infrastructure can deliver, because the product then carries the cost of a high-precision engine without ever achieving high-precision results.

Yonghao Innovation GPS and GNSS Module Range

Yonghao Innovation Tech is a national high-tech enterprise established in 2014, based in Shenzhen, Guangdong, China. We integrate research, manufacturing, and sales, and we supply GNSS satellite antennas, positioning terminals, data communication products, and customized high-precision BeiDou solutions for surveying and monitoring, aerospace, communication time service, autonomous driving, machine control, and intelligent transportation.

Our GPS module range covers both general positioning and high-precision work. The AD56UB8 is a BeiDou and GPS professional positioning module for products that need reliable positioning without RTK infrastructure. Where centimetre accuracy is required, the RTK GNSS module family provides multi-frequency, multi-constellation engines.

For compact products that cannot accommodate a separate antenna and cable, the YM-450Q integrates the antenna with the module, which removes the connector loss and the ground plane uncertainty that a separate antenna introduces. Complete terminals built around these engines are listed under GPS receiver, and our technical support team can review correction-source compatibility for your region.

Conclusion

Selecting a GPS module for high precision GNSS is a systems decision, not a component decision. The accuracy tier determines the technique, the technique determines the correction source, and the correction source determines what the product must carry. Once those are settled, the module choice narrows quickly to parts whose constellation and frequency support, correction format, and quality reporting match the design. Starting from the datasheet accuracy figure instead usually leads to a product that is expensive and still not accurate where it matters.