Iridium setup

reflexa micro sends its results through the Iridium satellite network with a Ground Control RockBLOCK 9704 modem (Iridium IMT messaging). It works anywhere on Earth with a view of the sky, without a mobile network.

Account checklist for a new unit

1. The modem’s IMEI registered in the Cloudloop account that will receive the data (subscriber activated, data pack available).

2. Topic 244 (RAW) provisioned for the subscriber.

3. A destination configured (webhook to the ingest service, MQTT, or CSV export routine).

4. Run Check modem (no traffic) once on site (Maintenance): signal bars and modem identity, no cost.

   

   Simulator

   Check modem (no traffic): the modem is powered, answers and reports its signal, then is switched off. No message, no cost.

How a message travels

1. The unit builds a compact message from the results not yet sent and transmits it on Iridium topic 244 (RAW).
2. Iridium delivers it to the Ground Control / Cloudloop account that owns the modem (the “Thing”, identified by the modem’s IMEI).
3. Cloudloop shows it in Cloudloop Data → All Messages and forwards it to the configured destinations: an HTTP webhook (BREVA’s ingest service), an MQTT broker, e-mail, or a CSV export from the console.
4. The receiving side decodes the payload (the field console has a decoder; the server uses the same code).

Cloudloop’s payload is exactly the message the unit built (the modem’s 2-byte checksum is not included), so it can be decoded as it is.

When it sends

Chosen in Settings → Iridium (or Schedule in Normal mode):

Policy	Behaviour
Never	Nothing is sent; everything stays on the unit for USB download.
End of session (usual)	After every session, whatever it produced; a session without results still sends a short “alive” message.
Every N results	When N new results are waiting.
Every N hours	At most every N hours, with whatever is waiting.
Daily at a time	Once a day at a fixed UTC time.

Rules common to all policies: the unit transmits only between sessions (the modem and the GNSS receiver never run together); a daily maximum; retry after a failed send (default one retry after 30 minutes); the battery guard can hold transmissions. Sent results stay on the unit until they are downloaded over USB or overwritten by the running buffer.

What a message contains

Format: compact, bit-packed, versioned (format byte C1…C4; older formats stay readable). Lossless for the scientific values at their stored resolution (reflector height to 1 mm).

Block	Content	Size
Header	format, blocks present, first record sequence, record count, time, configuration version	~8 B
Window summary (default)	median/weighted water distance (mm), spread, arcs used/seen, weak and edge arcs, peak-to-noise, time span, RH search range in use if the unit moved it	~6 B
Unit health (default)	battery (10 mV steps), reset reason, boot and watchdog counters, faults, queue fill, failed sends	~6 B
Station position (after a move or restart; optional always)	latitude/longitude (~0.1 m), height, accuracy, distance moved	~11–13 B
Per-arc results (optional)	per arc: satellite, signal, RH (mm), sigma, peak-to-noise, samples, quality	~7–9 B per arc

Typical sizes: default message ≈ 21–23 bytes (below the 25-byte minimum billed), ≈ 34 bytes with the position, ≈ 100 bytes with ten per-arc results.

Example: a decoded message

A 40-byte message, format C3, with two records, as the decoder shows it:

Field	Value
Window	15:41–16:13 UTC (32 min), configuration version 44
Arcs	11 seen, 11 used (3 weak, 0 at the edge of the search band)
Water distance	2.276 m, spread 27 mm, median peak-to-noise 3.6
Health	battery 3.36 V, no faults, queue empty
Position	latitude, longitude (~0.1 m), 333.7 m ellipsoidal height, ±1.1 m

Costs (Cloudloop prepaid, October 2026)

Item	Price
Data packs	64 KB €27 (≈ €0.42/KB), 512 KB €191, 2 MB €689, 4 MB €1,229, 8 MB €2,160 (≈ €0.26/KB); packs expire after 24 months
Minimum billed per message	25 bytes
Monthly access fee	€15 per subscriber
Activation	€20 (plus a proration fee), 3-month minimum commitment

At €0.42/KB a default message costs about €0.01. Four messages a day are about €1.25 per month of airtime plus the €15 access fee. The field console computes the size and cost of the chosen configuration live.

Reading messages in the Cloudloop console

Cloudloop Data → All Messages lists every message with time, Thing, direction, size and the payload in hexadecimal. Paste a payload into the field console (Advanced → Maintenance → Diagnostics → Decode a received message) to read it. The decoder also reads TAHMO/Tiger station packets (21 bytes: battery, temperature, charger state, boot count and one reflector height per 4-hour window, 0–20 m in 16 bits).

Simulator

A payload pasted from Cloudloop and decoded: window summary, water distance, unit health.

Note

The app keeps the modem IMEI and firmware in memory only; it stores no account, token or secret.