This page is dedicated to the development of an RTCM3 Navigation data frames (NDF) message for the transport of raw GNSS messages.

== Message header ==
||=Data field=||=DF NUMBER=||=DATA TYPE=||=NO. OF BITS=||=NOTES=||
|| Message Number       || DF002 || uint12 || 12 || 4075 (proprietary number for this purpose) ||
|| Reference Station ID || DF003 || uint12 || 12 || stream identification ||
|| Reserved field       ||       || uint2  ||  2 || reserved bits, maybe used to separate different type 4075 message, always 0 for NDF ||
|| Frame Count (FC)     ||       || uint6  ||  6 || Number of frame entries to follow ||
|| Frame Entry          ||       ||        || depends on FC and frame size || frame data according to following table ||
||||
||=TOTAL=|| || || 32 + Frames || ||

== Frame Entry ==

||=Data field=||=DF NUMBER=||=DATA TYPE=||=NO. OF BITS=||=NOTES=||
|| Satellite system    || || uint5  ||  4 || 0 == GPS, 1 == GLONASS, 2 == Galileo, 3 = SBAS, 4 = QZSS, 5 = BDS ||
|| Satellite number    || || uint6  ||  6 || Satellite ID, specific for the satellite system always 6 bits (see table below) ||
|| Continuous Tracking || || bit(1) ||  1 || Tracking this satellite frame data was continous (1 = continous, 0 not continues or unset) ||
|| Epoch Time          || || uint30 || 30 || Epoch time, specific for the satellite system always 30 bits (see table below) ||
|| Signal Type         || || uint5  ||  5 || Signal type specification, index from MSM signal mask bit field (see DF395) ||
|| Frame Data Size (N) || || uint12 || 12 || Number of bits to follow ||
|| Frame Data          || ||        ||  N || Bit data from satellite (see data section below) ||
||||
||=TOTAL=|| || || 48 + N || ||

Layout of a frame block always follows this structure, so unknown satellite systems or satellites can be skipped in messages with more than one frame.

== Satellite ID (equal to MSM) ==

||=Satellite system=||=DF NUMBER(s)=||=NOTES=||
|| GPS || DF068 || 1 .. 32 ||
|| GLONASS || DF384 (with 6 bit) || 1 .. 24 ||
|| Galileo || DF252 || 1 .. 36 ||
|| SBAS || || 120 == 1, ... ||
|| QZSS || DF429 (with 6 bit) || 192 == 1, ... 202 == 10 ||
|| BDS ||  || 1 .. 37 ||

== Epoch Time (accuracy in milli seconds, equal to MSM) ==

||=Satellite system=||=DF NUMBER(s)=||=NOTES=||
|| GPS || DF004 || in milliseconds (0..604799.99 ms)
|| GLONASS || DF416 (3 bit) + DF034 (27 bit) || Like for MSM, Day of week (0 == Sunday, 6 == Saturday, 7 == unknown) + time of day in ms (0..86400.999 ms) ||
|| Galileo || DF248 || equals GPS ||
|| SBAS || || equals GPS ||
|| QZSS || DF428 || equals GPS ||
|| BDS || DF427 || similar to GPS, but with a 14 leap second difference ||

== Frame Data ==