Product management and systems engineering

Three documents in docs/product_management/, written against the measured state of this repository rather than an aspiration. Every number in them is tagged [M] measured, [D] derived, [C] configured, [E] estimate or [P] proposed, and the two that are not verifiable today are marked NOT VERIFIED rather than omitted.

Document	ID	What it settles
System Requirements Specification	PM-SRS-001	The three operational user needs, 32 technical requirements, and a per-requirement verdict. Only one OUN passes in full.
SWaP-C and Sensor Selection Trade-off	PM-SWAPC-002	Three platform profiles, IMU grades, cost and power bands, and the rule for when to move off pure ESKF dead reckoning.
FDIR and Adversarial Spoofing Strategy	PM-FDIR-003	Threat taxonomy, the two-stage defence architecture, and what the operator is actually shown.

Start with the SRS if you want one number: AC-03 and AC-04 fail, so the filter is not yet trustworthy under GNSS denial, and the cause is a model error rather than a tuning error.