Sensor Mesh Coverage
VC-MET-311 — the percentage of PhytoSense Mesh nodes reporting online and in-spec, the telemetry-availability measure that underwrites every sensor-derived metric in the facility.
Definition
Sensor Mesh Coverage (SMC) is the percentage of commissioned PhytoSense Mesh nodes that are reporting online and in-spec at the census instant. A node counts as covered only if it has delivered a valid heartbeat within the staleness window and its self-test is healthy; nodes that are offline, stale, or flagging a self-fault are excluded from the numerator. SMC is the facility's telemetry-availability figure — it measures how much of the plant-health sensing fabric is actually returning trustworthy data.
Why it matters
Nearly every other metric in Sector-7 — vitality, pressure, dosing, drone charge — is built on PhytoSense Mesh telemetry. When mesh coverage drops, those metrics silently lose their evidentiary base: a healthy-looking reading may simply be a stale forward-fill from a dead node. SMC is therefore the integrity backstop for the entire metric estate. CHLORA degrades the confidence of any downstream metric whose contributing nodes fall offline and headlines SMC on the Operations Dashboard as a data-trust indicator.
Formula
SMC is the fraction of commissioned nodes reporting valid, fresh telemetry:
SMC = 100 · ( N_online / N_commissioned )
where a node is ONLINE iff:
- heartbeat received within staleness window (< 90 s), AND
- node self-test = PASS, AND
- reported values within physical plausibility bounds
N_commissioned excludes nodes in planned MAINTENANCE so scheduled
work does not depress the availability figure.
Spatial-gap guard (published alongside):
if offline nodes cluster (≥ 3 adjacent in one cell) →
flag COVERAGE_HOLE — a localized blind spot is worse than
the same node count scattered facility-wide.
Census runs every 60 s off the Mycelial Data Fabric heartbeat
collector; node count reconciled against the commissioning registry.
Inputs
| Channel | Role | Cadence | Reference | Source |
|---|---|---|---|---|
| Node heartbeats | Online / stale determination | 1 min | < 90 s freshness | Mycelial Data Fabric |
| Node self-test | In-spec health gate | 1 min | PASS / FAIL | PhytoSense Mesh |
| Commissioning registry | Denominator of active nodes | Event-driven | Excludes maintenance | CHLORA |
| Node location map | Spatial-gap clustering check | Static | Cell adjacency | CHLORA |
Units & Scale
SMC is a percentage on a 0–100 scale, reported to one decimal place. It is the ratio of online to commissioned nodes; per-cell coverage is published alongside the facility figure because a spatial cluster of failures (a coverage hole) is operationally worse than the same count of scattered failures. Nodes in planned maintenance are excluded from the denominator so scheduled work does not register as an availability loss. A COVERAGE_HOLE flag is raised when three or more adjacent nodes go offline in one cell.
Sampling & Source
- Census every 1 minute by CHLORA off the Mycelial Data Fabric heartbeat collector.
- A node counts as online only with a fresh heartbeat (< 90 s), a passing self-test, and plausible values.
- Maintenance nodes are excluded from the denominator; node count reconciled against the commissioning registry.
- Stale handling: collector outage → SMC held and marked STALE; adjacent-node cluster offline → COVERAGE_HOLE raised.
Thresholds
OK
Telemetry fabric fully trustworthy. No action.
WARN
Node attrition; dispatch mesh maintenance.
CRIT
Telemetry integrity compromised; downstream metrics degraded.
Recent Trend
Facility mesh coverage in percent nodes online, last 14 one-minute census cycles:
Interpretation Guidance
| SMC Band | Reading | Likely Driver | Action |
|---|---|---|---|
| 99.5–100% | Full coverage | Healthy mesh, fresh heartbeats | None; log as reference. |
| 99.0–99.4% | Nominal | Routine node churn | None; normal operating band. |
| 97.0–98.9% | Thinning | Battery attrition or RF interference | Schedule mesh maintenance sweep. |
| 93.0–96.9% | WARN degraded | Multiple node failures or backbone fault | Dispatch maintenance; check MDF backbone. |
| < 93.0% | CRIT compromised | Power/comms outage or coverage hole | Invoke mesh-restoration SOP; flag downstream metrics. |
Related Metrics
Dispatch Queue Depth
Node faults raise dispatch tickets.
VC-MET-303Alarm Acknowledgement Latency
Mesh faults are a major alarm source.
VC-MET-304Pollinator Drone Charge
Drone telemetry rides the mesh.
VC-MET-308Energy per Specimen
Mesh power is a metered sub-load.
VC-MET-001Canopy Vitality Index
Coverage gaps degrade its confidence.
VC-MET-102VPD
Sensor-derived; depends on mesh uptime.
Related SOPs
- SOP Library — mesh maintenance, node-replacement, and restoration procedures.
- Coverage-hole response & mesh restoration on WARN/CRIT — see the SOP Library.
- Heartbeat census & downstream-confidence propagation — Monitoring Systems.