Architecture note
Passive Radar as One Layer Among Many
Passive coherent location earns its place by joining other sources, not by standing alone.
Evidence levelE0Concept
In brief
Passive coherent location uses transmissions that are already in the air to observe the airspace. It is a useful layer. On its own it cannot say what an object is, and its view depends on the transmitters and the terrain around it.
The question
What role should passive coherent location play in a multi-source airspace model?
Context
It adds no emitter of its own, which is its appeal. But it depends on illuminators it does not control, on geometry and on the environment. Other sources fill other gaps: cooperative aviation data identifies, optical sensors can suggest a class in good light, and passive RF sensing gives a bearing.
How we approach it
We treat it as one observation, kept with its identity, its time and its quality. Observations are correlated before they are fused, and the page for each source says where it contributes and where it does not. Nothing public shows real frequencies, real sites or a scan, because the principle needs none of them.
What follows
The value shows in the joining, not in any single source. This is an architecture note at E0; no range, accuracy or coverage has been measured or is claimed.
What this does not establish
- That a passive coherent location system detects or tracks anything at a stated distance.
- That passive coherent location can replace any other source.
Limitations
- This is an architecture note, not a performance claim.
- It treats passive coherent location in general terms, with no real transmitter, frequency or site.
- How well any source joins another depends on conditions that have not been tested.