$GPGSV, $GLGSV, $QZGSV - GNSS satellites in view

Number of satellites (SV) in view, satellite ID numbers, elevation, azimuth and SNR value.

Four satellites maximum per transmission, additional satellite data sent in second or third message. Total number of messages being transmitted and the number of the message being transmitted is indicated in the first two fields. If multiple GPS, GLONASS, etc. satellites are in view, separate GSV sentences with different talker IDs are sent.

    $GPGSV, x, x, xx, xx, xx, xxx, xx .............., xx, xx, xxx, xx*CC<CR><LF>
        1   2  3   4   5   6   7   8

The fields are:

  • 1 - Sentence identifier. The three NMEA talkers are:
    • GPGSV - GPS
    • GLGSV - GLONASS
    • QZGSV - QZSS
  • 2 - Message number (see note 1), 1 to 9
  • 3 - Total number of messages (see note 1), 1 to 9
  • 4 - Total number of satellites in view
  • 5 - Satellite ID number (see note 3)
  • 6 - Elevation, degrees (90 degrees maximum)
  • 7 - Azimuth, degrees true, 000 to 359
  • 8 - SNR (C/No) 00-99 dB-Hz, null when not tracking

NOTE 1 Satellite information may require the transmission of multiple messages, all containing identical field formats. The first field specifies the total number of messages, minimum value = 1. The second field identifies the order of this message (message number), minimum value = 1. For efficiency it is recommended that null fields be used in the additional sentences where the data is unchanged from the first sentence.

NOTE 2 One to four sets of "Satellite ID-Elevation-Azimuth-SNR" are allowed per message. Null fields are not required for unused sets when less than four sets are transmitted.

NOTE 3 Satellite ID numbers. To avoid posssible confusion caused by repetition of satellite ID numbers when using multiple satellite systems, the following convention has been adopted:

  • GPS satellites are identified by their PRN numbers, which range from 1 to 32.
  • The WAAS system has reserved numbers 33 through 64 to identify its satellites.
  • Numbers 65 through 96 are reserved for GLONASS satellites.
    • GLONASS satellites are identified by 64 plus satellite slot numbers.
    • The slot numbers are 1 through 24 for the full GLONASS constellation of 24 satellites, thus giving a range of 65 through 88.
    • The numbers 89 through 96 are available if slot numbers above 24 are allocated to on-orbit spares.
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