PwrPak7 satellite-navigation receiver

The PwrPak7 is a GNSS receiver in an enclosure from NovAtel, part of Hexagon, built on the OEM7 platform. It is a multi-frequency, multi-constellation satellite-navigation receiver for precise position, velocity and time, and it comes in three versions: the PwrPak7 GNSS receiver, the PwrPak7-E1 and the PwrPak7-E2, which add inertial navigation.

The receiver tracks GPS (L1 C/A, L1C, L2C, L2P, L5), GLONASS (L1 C/A, L2 C/A, L2P, L3), BeiDou (B1I, B1C, B2I, B2a, B2b, B3I), Galileo (E1, E5 AltBOC, E5a, E5b, E6), NavIC on L5, SBAS on L1 and L5, and QZSS (L1 C/A, L1C, L1S, L2C, L5, L6). It also has up to five L-band channels for correction services. Tracking many signals helps the receiver keep a solution in difficult sky views, and the signal reacquisition time is typically below 0.5 s on L1 and below 1.0 s on L2 and L5. Time to first fix is below 20 s on a hot start and below 34 s on a cold start.

The accuracy depends on the correction service, and the values are typical for ideal, open-sky conditions. Single-point positioning gives 1.5 m RMS on L1 and 1.2 m RMS on L1/L2, SBAS gives 60 cm RMS, and DGPS gives 40 cm RMS. TerraStar-L gives 40 cm RMS, while TerraStar-C PRO and TerraStar-X give 2.0 cm RMS, and RTK gives 1 cm + 1 ppm RMS. The TerraStar services need a subscription from NovAtel. Time accuracy is below 5 ns RMS, excluding RF and antenna delays, and velocity accuracy is below 0.03 m/s RMS. The velocity limit is 600 m/s because of export licensing.

For integration, the data rates matter. The PwrPak7 outputs measurements and position at up to 100 Hz. The PwrPak7-E1 outputs GNSS measurements and position at up to 20 Hz and the inertial position and attitude solution at up to 200 Hz, with raw IMU data at 125 Hz. The PwrPak7-E2 has the same rates, with raw IMU data at 200 Hz. A designer should choose the version by whether attitude and a high-rate navigation output are needed in addition to the GNSS position.

Typical applications are the position and timing source of large unmanned aircraft, survey and mapping payloads, precision agriculture and ground vehicles, and any system where centimetre-level positioning with RTK or a TerraStar correction is required. The correction service chosen sets the achievable accuracy and the subscription needs.