Distributed Passive Radar Network

Data status: Illustrative

One passive receiver sees a conditional slice of the sky. Coverage that depends on geometry has holes, and a single point of failure makes those holes sudden. A region needs many quiet observers that cover for one another, and it needs to say honestly what it can still claim when one goes dark.

• Node observationsWhat each receiver contributes, with its own quality and its own geometry. No site or number of nodes is published.
• Node healthWhich receivers are contributing now, so that a missing contribution is told from an empty sky.
• OverlapWhere several nodes can support the same cell of airspace and where only one can.

1. Collects the observations of many passive receivers into one regional state.
2. Keeps track of which cells are supported by several nodes and which by one.
3. Steps its claims down as nodes drop out, instead of keeping the same wording over a thinner base.

• A regional state that degrades by steps, not by cliff.
• Loss is not proportional: a node that covers cells nobody else covers costs more.
• The wording of a claim changes before anything else does.
• No node is a hidden single point of failure.

The network is a spatial source at the start of the chain, built from many passive receivers. It combines their observations into a regional state whose confidence follows the overlap, and hands it to fusion and to the awareness layers above.

Read the architecture

Evidence ladder

1. E0 · Concept reached
2. E1 not reached
3. E2 not reached
4. E3 not reached
5. E4 not reached
6. E5 not reached

Project assurance panel

Mission and context

Give a region a passive picture that survives the loss of a node and says how much it still supports.

Primary contribution

A regional state that combines many passive observations, keeps their overlap and reports what remains when nodes drop out.

Decision value

Lets a reviewer see how much a regional claim depends on each node, and when its wording has to be weaker.

Evidence status

Evidence level: E0 · Concept Concept and research direction only. No specification, prototype, test result or deployment is claimed.

Next validation step

Write down how node overlap turns into regional confidence, then specify a first check on synthetic layouts before any claim is made.

Behaviour when degraded

When a node drops out, the regional confidence falls without going to zero, the cells it alone covered are marked unsupported and the claim wording steps down first. If most nodes are lost, the state says it cannot support a regional claim.

Role in integration

Would supply a regional spatial state to fusion and node health to system monitoring. It depends on the receivers that feed it.

Human review

A person reviews any regional state that contributes to an action, and reads which nodes it rests on.

Public-safe limitation

Node positions on this page are symbolic. No site, count, spacing or range is described, and the values are invented.

Open unknowns

How overlap should be turned into confidence, how many nodes a region needs and how the network should be kept in step are not yet known.

When a node drops out, the regional confidence falls without going to zero, the cells it alone covered are marked unsupported and the claim wording steps down first. If most nodes are lost, the state says it cannot support a regional claim.

• A city or region that wants low-altitude awareness without active emitters

  Why it matters here

  Coverage from one point has holes that a region cannot accept.

  What it contributes

  A shared picture whose strength follows the overlap of its nodes.

  What it does not replace

  Active sensors where a site requires them.

• A network that must keep working while a node is down

  Why it matters here

  Maintenance and faults take nodes out at awkward times.

  What it contributes

  A state that weakens in steps and says so.

  What it does not replace

  A repair, or a commitment to coverage.

Would supply a regional spatial state to fusion and node health to system monitoring. It depends on the receivers that feed it.

Write down how node overlap turns into regional confidence, then specify a first check on synthetic layouts before any claim is made.

• This is a concept. There is no specification, prototype or measured result behind it.
• Node positions and coverage cells are symbolic. They show a rule about overlap, not a layout.
• Regional confidence in the simulator is an invented score. It is not a probability of detection.
• Many nodes do not remove the conditions of passive geometry. Each node's coverage stays conditional.

• Passive Coherent Location (PCL) RadarEvidence level: E1

  Passive coherent location is the single-node method that the network repeats and combines.

• Passive RF Sensing NodeEvidence level: E1

  Passive RF nodes can join the same regional state as another kind of source.

• Multi-Sensor Fusion EngineEvidence level: E0

  Fusion combines the regional state with other sources and keeps its overlap.

• City / Regional Low-Altitude Airspace NetworkEvidence level: E0

  City and regional low-altitude networks are the wider setting that a regional passive network is meant to serve.

• Near-Ground Airspace Intelligence NetworkEvidence level: E0

  Near-ground airspace intelligence is where extra viewpoints matter most, because terrain and structures break line of sight.

• Port & Coastal Air-Surface IntelligenceEvidence level: E0

  Port and coastal intelligence is an application that uses a regional passive network over a stretch of coast.