Navisys GR-U01W USB PPS Timing GNSS — GPSD / NTP Ready (~0.5 ms)

The NaviSys GR-U01W is a Timing / NTP GNSS receiver built on u-blox’s M10 engine. It delivers a 1PPS timing reference over a standard USB connection—no dedicated PPS wire required—with host time-transfer precision typically around 0.5 ms. Use it when you need a simple USB GNSS mouse for clock synchronization (NTP / GPSD) as well as multi-constellation L1 positioning. It is the current Macx-1 “W” model and the recommended successor to the well-known GR-601W, GR-701W, and GR-801W (also known as GR-8013W). Like the rest of the GR-U01 family, the GR-U01W is compact (40 × 45 × 16 mm), IP67 waterproof, fully EMI shielded, and rated for industrial temperatures from −40°C to +85°C. PPS over USB · typically 0.5 ms host precision · GPSD / NTP ready · u-blox M10 · 1.5 m accuracy · Up to 18 Hz · Concurrent GPS + GLONASS + Galileo + BeiDou · IP67 · 1.5 m USB cable PPS over USB — Built for Timing Most USB GNSS receivers output NMEA position only. The GR-U01W also exposes a 1PPS (one pulse per second) timing reference through the USB interface itself. PPS events appear as DCD state transitions to the host’s PL2303 USB-serial driver No separate PPS cable or GPIO wiring Compatible with open-source GPSD PPS support for Linux / BSD timing stacks Host time-transfer precision is bounded by the USB polling interval—typically 0.5 ms (W-series about 0.5–1 ms) → Plug into USB, feed GPSD / NTP, and use GNSS-disciplined time without a dedicated PPS line Where It Fits NTP / Stratum-1 Style Time Sources Low-cost USB GNSS reference for NTP Works with GPSD as a time source on Linux and BSD Useful for servers, routers, and lab clocks that need GNSS lock → USB-simple timing when microsecond-class serial PPS is not required Timing-Critical Applications Precise clocks and synchronized devices Network / traffic timing and delay analysis Multi-device time alignment over a shared GNSS reference → One USB mouse for both position and a 1PPS time tick W-Series Background The Navisys “W” models were created so that 1PPS could travel over a normal USB cable. The first unit, GR-601W, was developed with input from Eric S. Raymond and the Bufferbloat community and earned the nickname Macx-1. It became a familiar choice in GPSD / NTP discussions for USB-based timing. The line then moved through GR-701W and GR-801W (also known as GR-8013W) as the GNSS chipsets advanced. The GR-U01W is the current generation: same Macx-1 USB-PPS idea, now on u-blox M10 with concurrent four-constellation L1 tracking. For new Timing / NTP deployments, GR-U01W is the model to choose. The older W receivers remain historically important; GR-U01W is the modern replacement. → Same USB-PPS Macx-1 concept hobbyists and timing users already know—updated to M10 Key Features 1PPS over USB 1PPS timing reference on the USB cable Presented as DCD events to the PL2303 driver Typically 0.5 ms host precision (about 0.5–1 ms for W-series) GPSD PPS compatible → The defining difference versus GR-U01U (navigation USB without PPS-over-USB) u-blox M10 · Multi-Constellation Concurrent GPS, GLONASS, Galileo, BeiDou (L1) QZSS + SBAS (WAAS, EGNOS, MSAS, GAGAN) Default 1 Hz; up to 18 Hz (GPS only) 1.5 m horizontal (GPS + QZSS + SBAS) → Modern L1 engine for both timing lock and navigation Interference & Spoofing Awareness Anti-jamming support RF interference detection Spoofing detection and reporting → Extra resilience when the RF environment is noisy or hostile Industrial USB Form Factor 40 (W) × 45 (L) × 16 (H) mm IP67 waterproof · built-in magnet Fully EMI shielded Operating temperature: −40°C to +85°C 1.5 m USB Type-A cable · 5 VDC USB powered → Outdoor-ready mouse receiver, not a bare module u-blox U-Center 2 Tool The GR-U01W uses the u-blox M10 chip and is fully compatible with the latest u-center 2 software for GNSS receiver configuration. u-blox provides user and developer documentation to support evaluation and development. U-center 2 is designed for u-blox M10 and F10 products. It is free from the u-blox website, and a copy is also available in the Product Resources section of this page. Navisys NaviViewerUx Tool In addition to U-Center 2, Navisys provides NaviViewerUx for convenient configuration and diagnostics of the GR-U01W GNSS receiver. Receiver Specifications GNSS Receiver Type u-blox M10 engine GPS, SBAS: L1 C/A — 1575.42 MHz QZSS: L1 C/A/S — 1575.42 MHz Galileo: E1 B/C — 1575.42 MHz GLONASS: L1OF — 1598.0625~1605.375 MHz BeiDou: B1I — 1561.098 MHz; B1C — 1575.42 MHz Accuracy & Timing Horizontal position 1.5 m (GPS + QZSS + SBAS) CEP, 50%, 24 hr static, −130 dBm, 6+ SVs for each system Velocity <0.05 m/s (speed) · <0.3° (heading) · 50% @ 30 m/s Time pulse (chip) RMS: 30 ns · 99%: <60 ns PPS over USB (host) Typically 0.5 ms via USB DCD / PL2303 Bounded by USB polling interval; W-series about 0.5–1 ms Output: 1PPS TTFF (Time to First Fix) Hot start 1 s Cold start 28 s: GPS + GAL 23 s: GPS + GAL + GLO 27 s: GPS + GAL + BDS B1I (default) 28 s: GPS + GAL + BDS B1C 23 s: GPS + GAL + GLO + BDS B1C Sensitivity (Autonomous) Acquisition −148 dBm (GPS & Galileo or more) Tracking −167 dBm (GPS & Galileo or more) Measurement Data Output Interface: USB Type-A (PL2303); NMEA / UBX over virtual serial UART framing: N,8,1 · baud 4800, 9600, 19200, 38400 (default), 57600, 115200, 230400, 460800, 921600 NMEA versions 2.1, 2.3, 4.0, 4.10, and 4.11 (default) UBX (u-blox proprietary) Sentences: GGA, GLL, GSA, GSV, RMC, VTG, TXT Datum: WGS-84 Navigation Update Rate Default 1 Hz GPS + GAL + GLO + BDS B1C 5 Hz GPS + GAL + BDS B1C 8 Hz GPS + GAL + BDS B1I 5 Hz GPS + GAL + GLO 7 Hz GPS + GAL 10 Hz GPS only 18 Hz Dynamics & Limits Max. altitude < 80,000 m Max. velocity < 500 m/s Dynamics < 4 g Augmentation SBAS: WAAS, EGNOS, MSAS, GAGAN · QZSS (L1S SLAS) Power Power consumption (29 GNSS SVs fixed for tracking) USB: 59 / 56 mA (acquisition / tracking) Power supply 5 VDC (USB) Backup power 3.3 V (backup battery for faster fix) Mechanical & Environment Dimension 40 (W) × 45 (L) × 16 (H) mm Weight 68.8 g (with 1.5 m cable and USB-A) Cable / connector 1.5 m USB Type-A (GR-U01W) Waterproof IP67 · built-in magnet · fully EMI shielded Operating temperature −40°C to +85°C (−20~60°C for backup battery) Storage temperature −40°C to +85°C (−40~60°C for backup battery) What's in the Box Navisys GR-U01W Timing / NTP GNSS Receiver × 1 Product Resources Official Documents GR-U01W Product Flyer U-Center 2 User Guide NaviViewerUx Quick Guide Downloads For Windows 10, Windows 11, Android, and Linux, native drivers are already included with the operating system. There’s no need to download or install additional drivers. Simply plug in the GNSS receiver, and it will be recognized and start working immediately. USB Drivers Windows Drivers WinCE for x86 WinCE for ARM/xScale macOS driver Linux Driver for Linux Kernel V2.6.15 to V5.4 USB GNSS driver already built into Linux OS 5.5 and above — no download needed Tools u-blox U-Center 2 Navisys NaviViewerUx How-to Articles and Blogs How to connect a GPS/GNSS Receiver to Google Earth on Windows? How to connect a USB GPS receiver to a Linux computer? How to connect a USB GPS receiver with an Android device? Tech Support Topics and Forums How to change the Update Rate of a Navisys GR-U01 (u-blox M10) GNSS Receiver?