RTK capability: (base-station) receive RTCM (1005, 1077 and 1087) corrections

[AlexisTM]

Is it possible to use this library on the UBX M8P for RTK purpose (base-station)?

configure dynamic model
get the RTCM3 corrections (1005, 1077 and 1087)
If not, do you plan on supporting it, is this project open for contributions?

[mcmayer]

RTK isn't supported, yet. We progressed exactly as much as needed for a project of ours, and no further. RTK is not on the horizon, so we're not going to work on that in the foreseeable future. But it's 'just' a matter of adding the necessary commands and you're very much welcome to contribute!

[AlexisTM]

It should be only configuring messages output and forward the raw data to the UGV/UAV and write the same raw data on the GPS.

[AlexisTM]

It finally seems pretty simple, you can configure the messages via UBX-CFG-MSG, using:

#define UBX_CLASS_RTCM3	0xF5

/* UBX ID for RTCM3 output messages */
/* Minimal messages for RTK: 1005, 1077 + (1087 or 1127) */
/* Reduced message size using MSM4: 1005, 1074 + (1084 or 1124)  */
#define UBX_ID_RTCM3_1005	0x05	/**< Stationary RTK reference station ARP */
#define UBX_ID_RTCM3_1074	0x4A	/**< GPS MSM4 */
#define UBX_ID_RTCM3_1077	0x4D	/**< GPS MSM7 */
#define UBX_ID_RTCM3_1084	0x54	/**< GLONASS MSM4 */
#define UBX_ID_RTCM3_1087	0x57	/**< GLONASS MSM7 */
#define UBX_ID_RTCM3_1124	0x7C	/**< BeiDou MSM4 */
#define UBX_ID_RTCM3_1127	0x7F	/**< BeiDou MSM7 */
#define UBX_ID_RTCM3_1230	0xE6	/**< GLONASS code-phase biases */
#define UBX_ID_RTCM3_4072	0xFE	/**< Reference station PVT (u-blox proprietary RTCM Message) - Used for moving baseline */

#define UBX_MSG_RTCM3_1005	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1005 << 8)
#define UBX_MSG_RTCM3_1077	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1077 << 8)
#define UBX_MSG_RTCM3_1087	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1087 << 8)
#define UBX_MSG_RTCM3_1074	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1074 << 8)
#define UBX_MSG_RTCM3_1084	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1084 << 8)
#define UBX_MSG_RTCM3_1124	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1124 << 8)
#define UBX_MSG_RTCM3_1127	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1127 << 8)
#define UBX_MSG_RTCM3_1230	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_1230 << 8)
#define UBX_MSG_RTCM3_4072	((UBX_CLASS_RTCM3) | UBX_ID_RTCM3_4072 << 8)

The important messages are: 1005 + 1077(GPS) + 1087(Glonass)/1127 (Beidou) + 4072 (for moving baseline)

I finally "just made it": https://github.com/AlexisTM/rtk_ros