# Re-Tweeted GPS Messages

If the DVL is set to re-tweet (forward, relay, pass thru) GPS messages, any message (sentence) coming in the GPS hardware port is forwarded to the main communication link to the host. Differing GPS units may output various kinds of NMEA sentences. Messages are forwarded line-by-line (sentence-by-sentence). Each message is appended to the string “GPS:” to differentiate it from the DVL’s $GPRMC output message. Messages may be delayed by up to 0.25 seconds.

The re-tweeted GPS sentences from the Cerulean Sonar GPS may include:

| Message              | Description                                                   |
| -------------------- | ------------------------------------------------------------- |
| $GPGSA and/or $GNGSA | GPS dilution of position and active satellites                |
| $GPGSV               | Number of SVs in view, PRN, elevation, azimuth, and SNR       |
| $GPVTG and/or $GNVTG | Actual track made good and speed over ground                  |
| $GPGGA and/or $GNGGA | Time, position, and fix related data                          |
| $GPGLL and/or $GNGLL | Position data: position fix, time of position fix, and status |
| $GPTXT               | Free text, manufacturer defined                               |
| $GPRMC and/or $GNRMC | Minimum recommended Position, Velocity, and Time              |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.ceruleansonar.com/c/dvl-75/communicating-with-the-dvl/outgoing-message-formats-dvl-to-host/re-tweeted-gps-messages.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.