At Blue Planet Geomatics, we support professionals across Canada who depend on high-precision, mission-critical GNSS performance – surveyors, construction crews, UAV operators, marine teams, agriculture specialists, and more. Across every one of these fields, multipath remains a persistent challenge. Because reflected GNSS signals can degrade accuracy by metres, Blue Planet prioritizes technology that maintains integrity in real-world conditions. That’s one of the reasons we carry Septentrio receivers: their APME+ multipath mitigation consistently delivers cleaner, more reliable results where other systems struggle.
Multipath occurs when GNSS signals reflect off nearby surfaces such as buildings, equipment, vehicles, or the ground. Instead of receiving one clean signal from the satellite, the receiver sees a mixture of direct and reflected paths. This distorts pseudorange and carrier phase measurements, reducing both accuracy and stability. Short-delay reflections – those originating within about 20 metres of the antenna – are especially difficult to handle because the reflected signal arrives almost simultaneously with the direct one. In many of the environments where our clients operate, this kind of multipath is the main source of GNSS error.
Septentrio’s APME+ (A-Posteriori Multipath Estimation) offers an elegant and highly effective solution. Unlike methods that alter the tracking loops inside the receiver – often introducing unwanted biases – APME+ adds additional correlators that estimate the multipath component after tracking. The system then subtracts that estimate from the measurements in real time. Because the tracking loop is left untouched, the underlying measurements remain bias-free, making the technology suitable for demanding workflows such as RTK, PPP, long-baseline surveying, and scientific applications. In field conditions, APME+ typically reduces multipath errors by more than half, resulting in smoother positioning, fewer jumps, and higher-quality data.
This performance is especially important in Canadian environments where clean sky views are often hard to come by. Urban corridors, construction sites, open-pit mines, agricultural machinery, waterfront operations, and UAV flights near structures all generate significant signal reflections. APME+ is specifically designed to address the short-delay multipath common in these scenarios, helping users maintain accuracy even when antenna placement is less than ideal.
Another strength of APME+ is its transparency. The multipath corrections applied to each individual measurement are available through Septentrio’s SBF messages, allowing advanced users to analyze or even reverse the corrections if needed. For organizations that value insight into their data, this level of visibility is a major advantage.
APME+ comes enabled by default on all Septentrio receivers offered through Blue Planet Geomatics. Whether deployed in rugged field receivers, OEM boards, or compact GNSS modules, the technology works continuously in the background to ensure the cleanest possible measurements.
If your operations depend on precise, dependable GNSS performance in reflective or obstructed environments, Septentrio’s APME+ provides a meaningful accuracy advantage. Blue Planet Geomatics offers expert guidance and support across Canada to help you select the right receiver for your applications.