This manual introduces the features and characteristics of the GR-87 series positioning engines, including electrical characteristics, environmental characteristics, physical characteristics, software interface, mechanical dimensions, operation and testing, and ordering information.
The GR-87 is a compact, low‑power GPS engine board designed for integration into handheld and automotive navigation systems. It tracks up to 20 satellites, offers fast time‑to‑first‑fix, and includes dual CMOS 3 V serial ports for NMEA and RTCM communication.
The guide covers main features, electrical, environmental and mechanical specifications, software interface details, NMEA message formats, connector information, and ordering options, along with reference designs for RS‑232 integration.
| Frequency | L1, 1575.42 MHz |
|---|---|
| Channels | 20 |
| Position accuracy (open sky) | 10 m 2D RMS |
| Input voltage | 3.3 V–5.5 V DC |
| Input current (no antenna) | < 80 mA |
| Backup power | 3 V rechargeable Li‑cell, up to 500 h |
| Weight | 7 g |
| Active size | 25.4 mm × 25.4 mm × 7 mm |
| Antenna connector | MMCX, 2.8 VDC output |
| Reacquisition time | 0.1 s average |
The device operates from –10 °C to +60 °C.
It can track up to 20 satellites simultaneously.
The default communication parameters are 4800 baud.
A 3 V rechargeable lithium cell battery provides up to 500 hours of backup power.