Appendix 1: Use Of Nmea/Pps Signals; Concepts And Specifications; Purpose Of Nmea - quanergy M8 User Manual

Appendix 1: Use of NMEA/PPS Signals

This appendix is provided for users who need accurate, reliable timestamps on each data
point collected by the M8 system.
For the M8 system to enable the added value of a Coordinated Universal Time (UTC)
timestamp, two inputs are required, and Global Positioning System (GPS) units typically
provide them:
• National Marine Electronics Association (NMEA) message, called a sentence
• Pulse-per-second (PPS) signal
NOTE: Quanergy has not tested all GPS/IMU modules for all
situations, but supports the OXTS RT3003 and VectorNav200
GPS receivers. The Garmin GPS18x has also tested well in
outdoor conditions.

Concepts and Specifications

This section describes the purpose, definitions, and specifications related to the use of the
NMEA sentence and the PPS signal.

Purpose of NMEA

NMEA 0183 is an electrical and data specification for communication between GPS
receivers and instruments such as the M8 LiDAR sensor. This standard is controlled by the
National Marine Electronics Association.
When you need to know the precise time that a data point was recorded, such as for
creating a composite map, the NMEA sentence along with one PPS signal provides
absolute timestamping according to the Coordinated Universal Time (UTC) standard,
accurate up to five microseconds.
4 For more details, refer to http://www.actisense.com/wp-content/uploads/2017/07/NMEA-0183-Information-sheet-issue-4-1-1.pdf.
4
M8 Sensor User Guide, QPN 96-00001 Rev K Page 66