Open-Source Modular RTK-GNSS Enclosure (for SparkFun ZED-F9P or ZED-X20P)

Official Project Page & Documentation: https://www.qzss4survey.com/jps/jusinki/osm-gnss

1. Project Mission / プロジェクトの理念

[English]

High-precision RTK-GNSS surveying equipment has traditionally been too expensive and complex for many field engineers, researchers, and local communities around the world—especially in developing regions.

At JPS LLC (Japan), our corporate mission is "Making Positioning Simpler."

We designed this rugged, ultralight, and modular enclosure system so that anyone in the world with access to a consumer 3D printer, a standard SparkFun ZED-F9P (or next-gen All-band ZED-X20P) board, and basic hardware-store nuts can build a professional-grade RTK-GNSS rover at a fraction of the traditional cost.

[日本語]

高精度なRTK-GNSS測量機は従来は非常に高価で、発展途上地域をはじめとする世界中の現場技術者や研究者等にとって、その導入には高いハードルがありました。

弊社は「位置計測をよりカンタンに」という理念のもと、一般的な3Dプリンターと市販の汎用基板（SparkFun製 ZED-F9P または 次世代オールバンド対応 ZED-X20P）、そして世界中のどこの金物店でも手に入る一般的な「金属ネジと六角ナット」だけで組み立てられる実用的なRTK-GNSS筐体を開発し、その3D設計データを世界に公開しました。

2. Key Design Highlights / 設計の4大特徴

1. 100% Standard Metal Hex Nuts (No Heat-Set Inserts Required!)

Does not require special brass heat-set inserts or soldering irons. All mounting threads (5/8"-11, 1/4"-20, M6, and M3) use standard hexagonal nuts embedded inside precision pockets for maximum durability anywhere in the world.

（特殊な熱圧入インサートナットやハンダごては不要。すべてのネジ部に市販の金属六角ナットを内蔵する高耐久設計です）

1. Tool-less 2-Way Snap-Fit Arca-Swiss Mount

Features a 3D-printed cantilever spring latch on the Φ130mm antenna base. Attach the ZED-F9P case to the survey pole or release it with one thumb for handheld smartphone photogrammetry.

（一体成型の板バネラッチにより、5/8インチ測量ポールへの装着とスマホハンディ計測を1秒で着脱可能）

1. 4-Direction Rotatable Foot (38 × 38 mm)

The symmetrical Arca-Swiss foot allows the receiver case to be locked in any 90-degree orientation for stress-free USB-C and SMA cable routing.

（前後左右4方向から差し込み可能で、ケーブルの向きを自在に選べます）

1. Sealed Internal Ground Plane (Φ124mm)

A 0.4mm recessed pocket inside the top cover seals an aluminum sheet (or heavy-duty aluminum/copper foil) to block multipath interference and prevent corrosion.

（天板内部のポケットに直径124mmの薄アルミ板や金属箔を密閉し、マルチパスを防ぎます）

3. Bill of Materials (BOM) / 必要な部品リスト

  3-1. 3D Printed Parts (STL Files) / 3Dプリント部品リスト

  01_F9P_Case_Bottom.stl (Lower case with 4-way Arca-Swiss foot)

  02_F9P_Case_Top.stl (Upper cover with interlocking lip & JPS logo)

  03_Antenna_Base_130mm.stl (Main Φ130mm base with snap-fit rail & 3 bosses)

  04_Antenna_Top_Cover_130mm.stl (Top plate with Φ124.5mm ground plane pocket)

  05_Hex_Pressing_Ring.stl (Spacer ring for 5/8"-11 nut & GND connection)

  06_Optional_Receiver_Plate.stl (Standalone Arca-Swiss receiver mount with captive 1/4"-20 slot)

3-2. Electronics & Off-the-Shelf Hardware / 市販の汎用基板・金具リスト

• GNSS Board: SparkFun GPS-RTK-SMA ZED-F9P (GPS-16481) or ALLBAND GNSS RTK ZED-X20P (GPS-28871) × 1

• GNSS Antenna: Multi-band RTK-GNSS Antenna (SMA connector) + SMA Cable × 1

• Ground Plane: Φ124mm Aluminum sheet (thickness: up to 0.4mm) or Heavy-duty Aluminum/Copper Tape × 1

• Survey Pole Nut: 5/8"-11 Hex Nut (Standard survey thread) × 1

• Camera Mount Nut: 1/4"-20 Hex Nut (Standard tripod thread) × 1

• Fasteners: M6 Screws & Hex Nuts (×3 sets for antenna base bosses), M3 Screws & Hex Nuts (for case assembly)

4. Recommended 3D Print Settings / 推奨プリント設定

• Filament Material（推奨素材）:

      ASA or PETG (White or Light Gray is strongly recommended to minimize solar heat absorption under direct sunlight.

      直射日光下での温度上昇を防ぐため「白」または「ライトグレー」を推奨)

• Layer Height（積層ピッチ）:

      0.20 mm (Nozzle: 0.4 mm, Wall Generator: Arachne)

• Wall Loops（壁の周回数）:

      4 loops (Essential for strong M6/5/8" bosses and consistent snap-fit spring tension / ボスと板バネの強度確保のため壁4周を推奨)

• Infill（インフィル充填率）: 25% (Gyroid or Grid)

• Print Orientation & Supports（配置の向きとサポート設定）:

Case Top (02):

Flip 180° upside down (place top logo face on the build plate). No supports needed.

Case Bottom (01):

Place foot flat on the build plate (Z=0). Enable Normal Support (Snug) for the step overhang (or print foot and body separately).

Antenna Base (03):

Place the flat front surface (Z=0) on the build plate. Enable Normal Support (Snug) only underneath the cantilever spring pocket (2.2mm gap) and finger lever. Remove the support material after printing to free the spring.

5. Free Companion App & Web Tools / 無料の観測アプリ・計算WEBツール

• Android App: "RTK NMEA Log" (Free on Google Play)
  Connect your smartphone to the receiver via a single USB-C cable (USB OTG). The app features a built-in NTRIP client to feed RTK correction data to the ZED-F9P or ZED-X20P and records high-precision NMEA logs (.txt) with a single tap.
  (https://play.google.com/store/apps/details?id=com.jps.rtk_nmea_log)

• Web App: "Simplified Control Point & GCP Calculator" 
  Drag and drop your recorded NMEA log files (.txt) into your PC browser. To prevent "False Fix" errors in the field, this tool automatically evaluates two independent observation sets (Set 1 & Set 2), checks horizontal (≤20mm) and vertical (≤30mm) tolerances, and exports a professional accuracy evaluation report in Excel or PDF format. Supports both Universal Transverse Mercator (UTM) for global use and Japanese coordinate systems.
  (https://nmea-gcp-calc.vercel.app/)

Credit / Attribution (CC BY-SA 4.0):
Designed by JPS LLC (合同会社ＪＰＳ) — Making Positioning Simpler.

Official Website: https://www.qzss4survey.com/