GNSS External

If the reception of GNSS information is done through an external system, the user must configure it in this menu, so that system can be included in the navigation filters. After properly configuring the communication protocol on the corresponding channel (RS 232, RS485, CAN…) the GNSS External variables of interest must be filled in this interface:

Configuration

GNSS External - Configuration Menu

GNSS External - Configuration Menu

Check GNSS External device communication protocol before filling this menu.

The user should create a Custom Message according to the communication protocol used by the external sensor, so that its readings are stored in system variables. Then, the user can select this variables to configure the following parameters:

  • Period. Defines the period of incoming information from the external system.

  • Fix bit. Data provided by the external device which is important to know the status of the positioning.

  • Time of week. Variable extracted from the communication protocol defining the time of the week.

  • GPS Week. Variable extracted from the communication protocol defining the week.

  • GPS Position. Variable defining latitude, longitude and height from GNSS. Usually Moving Object variables are used in Pipe.

  • Horizontal/Vertical Position Error. Defined by the GNSS External device provider.

  • Velocity north/east/down. Variables extracted from the communication protocol defining GNSS velocity measured.

  • Horizontal/Vertical velocity error. Defined by the GNSS External device provider.

  • Distance to mass center. Define the distance between the uav mass center and the position of the external GNSS antenna.

NMEA Parser

Another way to add an external GNSS device is to use the NMEA Parser Consumer (I/O Manager). This consumer allows to receive NMEA 0183 messages and parses them directly. The NMEA Parser configuration menu includes the following parameters:

  • Time out. Defines the period of incoming information from the external system.

  • Feature. Variable extracted from the message defining the GNSS position. Usually Moving Object variables are used in Pipe.

  • Utc. Variable extracted from the message defining the UTC.

  • Fix. Data provided by the external device which is important to know the status of the positioning.

Once the NMEA message has been parsed, the variables used for Fix and Feature can be selected in the GPS External configuration menu as Fix Bit and GPS Position. The variable used for Utc can be selected in the GPS External configuration menu as Time of week. The other parameters of the GPS External configuration must be defined according to their definitions shown above.

NMEA Parser - Configuration Menu

NMEA Parser - Configuration Menu

Estimation Error

See section Setup - Devices - Sensors - GNSS - GNSS 1 & 2 Configuration.