MARS 4.3 / Pathfinder II

Metirionic Releases MARS 4.3 with Upgraded Pathfinder II for Bluetooth® Channel Sounding

Sep 2026

MARS 4.3 / Pathfinder II

Metirionic today announced MARS 4.3, giving Bluetooth® Channel Sounding developers improved sub-meter distance accuracy on Nordic Semiconductor’s nRF54L15 (nRF Connect SDK v3.4.0).

The MARS release centers on the Pathfinder II algorithm featuring improved ranging accuracy with the largest gains observed in multipath-rich indoor environments, support for Inline PCT Transfer (IPT), and concurrent distance computation and angle estimation.

Metirionic also expanded its public GitHub presence with Channel Sounding firmware samples (MIT), the MARS Bluetooth HCI crates (MIT), and the Channel Sounding Evaluation Application for Windows, each now available at github.com/metirionic.

1.1     Open source

Metirionic open sources the data path:

  • Channel Sounding firmware (mars-cs-nrf54l, MIT) captures the raw I/Q samples for every tone step of a Channel Sounding Procedure on Nordic’s nRF54L15, optimizes system parameters, and serializes the I/Q data and tone quality indicator samples
  • The MARS Bluetooth HCI crates (mars-bluetooth-hci, MIT) provide the C interface — the same interface MARS itself uses — and serialize the I/Q data for further processing
  • The Channel Sounding Evaluation Application for Windows visualizes the measurements

Two processing paths share this interface: the CS evaluation application processes the serialized I/Q data on the PC, visualizing distances and signal quality; an embedded MARS library processes the same data directly on the nRF54L15, turning it into meaningful distances and angle estimates.

This serves two audiences: chip companies that want to utilize the CS evaluation application can easily port the HCI crate to any other device that supports Channel Sounding, and customers who want to embed MARS into their nRF54 products can evaluate the performance and accuracy before they license it. MARS is a licensed Metirionic product: embedding it in your own firmware requires a Metirionic license.

1.2     Pathfinder II

MARS 4.3 centers on the Pathfinder II algorithm, which delivers:

  • Accuracy improvements, largest gains observed in multipath-rich indoor environments. In line-of-sight multipath-rich indoor ranging campaigns, the Pathfinder II algorithm delivers 0.83–0.95 m accuracy at 2σ — 95% of measurements — on all three platforms: Nordic development kits, Nordic tags, and Ezurio development kits, using the Bluetooth Ranging Service (RAS).
  • Inline PCT Transfer (IPT) support (Bluetooth Core 6.3) — the reflector’s phase data is carried in-line during the ranging session instead of being relayed separately, trimming relaying overhead for higher update rates and better coexistence
  • Concurrent distance and angle estimation for indoor and outdoor positioning allowing applications to be spatially aware

1.3     How to engage

  • Nordic tags and development kits — flash MARS firmware as initiator or reflector on the nRF54L15 DK and TAG; both RAS and IPT firmware versions are available on GitHub
  • Module ecosystem — MARS signal processing firmware runs natively on the nRF54L15-based modules with their respective GitHub initiator and reflector flashed images, both RAS and IPT, for:
    • Ezurio (BL54L15u)
    • Fanstel (BM15C)
    • Insight SIP (ISP2454)
    • Minewsemi (ME54BE01)
    • Raytac (AN54LV-K15)
    • u-blox (NINA-B40)
  • Channel Sounding Evaluation Application — real-time distance monitoring GUI for Windows, paired with MARS firmware; the freemium tier provides distances for a predefined and optimized parameter configuration, while the Professional tier enables developers to modify those parameters and tune them to their requirements — download it here
  • Engineering services — MARS algorithm tuning, proofs of concept, and joint commercial development for product companies as well as enablement of partner silicon; inquire by emailing sales@metirionic.com
  • Open source — evaluate the raw-data path on GitHub (capture firmware, HCI crates, evaluation application); embedding MARS requires a Metirionic license
  • Request a consultation — understanding the attributes and capabilities of what’s possible with Bluetooth Channel Sounding may require a deeper dive about your use case, operating environment, and requirements. In many cases, Channel Sounding can provide you with the spatial awareness necessary for advanced applications, without requiring a separate UWB radio. If UWB is required or Channel Sounding needs augmentation, we can support your exploration of that too as our experience extends across multiple radio technologies.

1.4     Get MARS 4.3

Explore the MARS open-source components on GitHub or request MARS 4.3 at metirionic.com/products-and-services/mars/.

Metirionic – We know the Distance

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