Custom Query (104 matches)

I have a suspicion that the degradation of the GLONASS ephemeris may have been corrupting the RTCM MSM GLONASS measurements and would like to ask if this is something you are aware of. The reason I am asking is because I had problems with solutions involving MGEX GLONASS observations but the solutions based on IGS-sourced RINEX files and conventional RTCM streams from the RTS appeared to behave well. Is there a reliance on the GLONASS ephemeris within the RTCM MSM encoding software that could be affected by the corrupted messages?

message from fgnievinski@…:

There are a few issues when saving RINEX observation files, though.

(a) Two mandatory header lines are missing (RINEX version 3.02):

"GLONASS SLOT / FRQ #" "GLONASS COD/PHS/BIS"

(b) The default skeleton includes observation codes that could benefit from some improvement, as follows:

(b.1) C5, D5, L5, S5 are invalid, as they lack the third character, denoting the attribute (tracking mode or channel); most commonly it's "X", thus C5X, D5X, L5X, S5X.

(b.2) The modernized GPS L2 signal ("L2C") is being reported under observation codes C2C, D2C, L2C, S2C. Actually, the "C" attribute is reserved for the C/A signal (as in C1C, D1C, L1C, S1C), whose transmission in the L2 band remains a technical possibility (according to Table 3-III, "Signal Configuration", of the GPS ICD), even in pre-modernized or legacy GPS satellites, although as far as I know it is very rare. The L2C signal normally is reported under C2X, D2X, L2X, S2X.

(b.3) The legacy GPS L2 signal ("L2-P(Y)") is being reported under observation codes C2P, D2P, L2P, S2P. This is only true when anti-spoofing is disabled, which again is very rare. Under encrypted broadcast, observation codes C2W, D2W, L2W, S2W are employed for civilians (and C2Y, D2Y, L2Y, S2Y for military receivers).

(b.4) In summary, may I suggest the following new default GPS observation codes:

G 20 C1C L1C D1C S1C C1W L1W D1W S1W C2X L2X D2X S2X C2W SYS / # / OBS TYPES

L2W D2W S2W C5X D5X L5X S5X SYS / # / OBS TYPES

These correspond to the majority of stations, see, e.g.: <​http://www.bernese.unibe.ch/publist/2013/post/SL_euref2013_rinex3.pdf>

Message from Sara Gerrard:

I have been successfully downloading rtcm data, specifically message types 1057 and 1058 from your casters, but there are ways in which the messages seem inconsistent with the expected format .. I am still, however, interested in why the header appears in the middle of the 1057 message? .. I have just collected this small data set from products: IGS03. There are two files attached - the full data set and then one with just a 1057 message (first one that appears in full set).