lora-ranging

Relative location over LoRa: RTToF (round-trip time of flight) ranging between two LR11xx radios, ported to Rust from Semtech's lr11xx_ranging_demo application.

A ranging session pairs a manager (initiator, collects results) with a subordinate (responder). After a plain-LoRa handshake, both sides hop through a 39-channel plan in lockstep, performing one RTToF exchange per channel; the manager reads a raw distance and RSSI per exchange and reports the median distance, which is robust to per-channel multipath outliers.

Crates

• lora-ranging — no_std session logic, sans-io: state machines consume radio/timer Events and emit radio Actions. The embedding firmware owns the radio (e.g. lora-phy's Lr1110 driver, which carries the matching RTToF command surface) and the timers. The full two-device protocol runs under simulation in tests/exchange.rs.

Planned: firmware for the Seeed WM1110 (nRF52840 + LR1110) dev kit and a host-side collection service.

Requirements

• LR11xx transceiver firmware ≥ 0x0401 (RTToF support)
• Both devices configured with the same channel plan, spreading factor, bandwidth (125/250/500 kHz only), response symbol count and RX/TX delay calibration (delay::recommended_rx_tx_delay_indicator)

License

BSD-3-Clause-Clear, matching the Semtech sources the protocol logic and calibration tables derive from.