# 📐 L2 Spec — Ground Penetrating Radar (GPR) Mismatch-Only Spec
**ID:** `L2-104-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-104`](/artifact/l1/L1-104)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41554201
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| F mhz | MHz | 25 – 2000 |
| Snr db | dB | 0.0 – 30.0 |
| Clutter | — | 0.0 – 0.5 |
| N traces | — | 64 – 1024 |
| N samples | — | 128 – 2048 |
| Depth range m | m | 0.1 – 100 |
| Antenna coupling | — | 0.0 – 0.3 |
| Attenuation depth | — | 0.1 – 2.0 |
| Soil permittivity variation | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
12.0 + 0.2 * SNR_dB - 15.0 * soil_permittivity_variation - 8.0 * clutter
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`b7ef5ef657df5e045992c61a3f9b68a37bf9fa47db764724d56d65c490d6a317`
## 5. On-chain Registration
- **Chain hash:** `0x0c2fc5d2d492e16b2bd9a9c00407c3e5be4d82b3a20c2cdd3eee5924192c39af`
- **Chain tx hash:** `0x7eb67400c95f2009a4865cb17c48e442424823241ac2076cbd40fccefa7bbb0e`
- **Chain block:** `41554201`
---
## File Mapping
This bundle consists of: `L2-104-001.md`, `L2-104-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-104-001.md` | Source of truth — edit this | Human or LLM |
| `L2-104-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-104-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._