This document is the user guide for Rikaline GPS-21 / 21-LP GPS Engine Board, describing the features and technical specifications of the product.
The Rikaline GPS-21 / 21-LP GPS Engine Board is a compact, low‑power GPS receiver based on the SiRF Star II chipset. It supports dual‑channel RS‑232/TTL communication, built‑in WAAS/EGNOS, and a Trickle‑Power mode for extended battery life. The guide covers hardware connectors, pin assignments, power options, and software interfaces such as NMEA and RTCM.
Key sections include an overview of features, technical specifications, hardware and software interfaces, Earth datum configuration, ordering information and warranty details. The manual also explains power‑saving modes like Trickle‑Power and Push‑to‑Fix, and provides detailed pin‑out tables for the 20‑pin and 10‑pin connectors.
| Physical dimensions | 36 × 24 × 6 mm |
|---|---|
| Weight | 7 g |
| Operating temperature | -40 °C to +85 °C |
| Storage temperature | -55 °C to +100 °C |
| RF frequency | L1 1,575.42 MHz |
| Number of channels | 12 |
| 5 V version supply current | 170 mA typical |
| 3.3 V version supply current | 100 mA typical |
| Backup current | 10 µA typical |
| Backup period (pack‑up) | 230 h (9.6 days) |
| Position accuracy (non‑DGPS) | 5‑25 m CEP |
| DGPS position accuracy | 1‑5 m |
| Maximum altitude | 18 000 m (60 000 ft) |
| Maximum velocity | 515 m/s (1 000 knots) |
| Maximum acceleration | 4 g |
A cold start typically requires about 45 seconds to achieve a position fix.
The backup current is 10 µA typical.
The receiver can track up to 12 satellites at the same time.