NORAD Radar Gate Adjustments: DOW-UAP-D042 Record

DOW-UAP-D042 source map

Record ID

DOW-UAP-D042

Release

PURSUE Release 04, published July 24, 2026

Commands

North American Aerospace Defense Command (NORAD) & USNORTHCOM

System Context

AN/FPS-117 long-range air surveillance radar and E-3 Sentry AWACS telemetry

Classification

Declassified aerospace defense technical correlation report

How radar filter adjustments changed military detection

This technical report provides the single clearest explanation of why military shootdowns occurred in rapid succession in February 2023: radar sensors did not change, but data filtering thresholds were systematically widened.

Incident summary

Historically, NORAD radar networks utilized velocity gate filters designed to track high-speed ballistic missiles and combat aircraft while ignoring slow-drifting objects. DOW-UAP-D042 details the technical parameters adjusted in early 2023, revealing that radar gates had routinely discarded contacts traveling below 50 knots or exhibiting low radar cross-sections.

What the NORAD technical file discloses

• DOW-UAP-D042 was declassified by the Department of War in PURSUE Release 04 on July 24, 2026.
• The document details how NORAD modified its automated radar data processing filters following the February 2023 Chinese balloon shootdown.
• Opening radar velocity gates immediately exposed dozens of small, slow-moving aerial contacts previously filtered out as atmospheric clutter.
• The file provides technical radar plots correlating the Lake Huron F-16 intercept with ground-based radar hits.

Velocity gate filtering and clutter rejection algorithms

• Examine the velocity threshold tables before and after the February 2023 operational directive.
• Cross-reference with DOW-UAP-PR071 (Lake Huron shootdown video) to match radar return tracks with pilot targeting pod lock.
• Pay attention to notes regarding atmospheric temperature inversions and radar false alarm rate management.

What the technical radar data demonstrates

The document proves that modifying radar velocity gates revealed persistent low-Doppler objects previously filtered out of defense feeds.

How radar adjustments revealed slow-moving objects

• Analyze how AN/FPS-117 and AN/TPS-75 radar systems process low-Doppler radar returns.
• Determine how many newly detected contacts were positively identified versus remaining categorized as unresolved.
• Assess whether modern commercial drone traffic overwhelms military early-warning networks when clutter gates are relaxed.

The mechanics of velocity gate filtering

Air defense radars process millions of atmospheric returns daily. Automated clutter-rejection algorithms discard objects whose Doppler shifts fall below operational thresholds to prevent operator display overload.

• Lowering minimum speed thresholds immediately populated combat screens with slow-moving contacts.
• Demonstrates that anomalies were present in airspace long before sensor settings were adjusted.
• Highlights the trade-off between detecting small anomalous objects and maintaining clear tactical airspace displays.

Radar resolution limits and multi-path anomalies

It does not prove that all newly detected slow-moving objects were anomalous; many were subsequently identified as research balloons or hobbyist devices.

Questions on unreleased raw radar datalinks

What are the current automated radar filtering thresholds maintained along North American coastal defense perimeters?

Tags

Frequently asked questions

Sources

• Department of War Release 04 portal - Official PURSUE portal catalog view for Release 04.
• Department of War PURSUE UFO portal - Primary official portal for PURSUE UAP releases.
• House Oversight July 26, 2023 UAP Hearing Record - Official House Oversight Committee hearing transcript and sworn witness statements by Grusch, Fravor, and Graves.