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Difference between revisions of "QZSS Signal Plan"

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Latest revision as of 09:36, 30 September 2021


FundamentalsFundamentals
Title QZSS Signal Plan
Author(s) J.A Ávila Rodríguez, University FAF Munich, Germany.
Level Advanced
Year of Publication 2011

QZSS and GPS have the highest level of interoperability among all the Satellite Navigation Systems as we will see in the following tables. In fact, the spectral properties are equivalent to those of GPS. The characteristics of the different signals in particular are summarized in detail in the following tables. For the case of the L1 band the technical characteristics of the QZSS signals are presented next:

Table 1: QZSS L1 signal technical characteristics.


Equally, for L2, L5 and E6, the technical characteristics of the QZSS signals are summarized in the following table. As we can clearly recognize, except for the LEX(L6) signal in E6, QZSS and GPS are practically identical. It is interesting to note that this signal makes use of a very interesting multiplexing scheme for its experimental LEX(L6) signal, based on Code Shift Keying (CSK) [QZSS SIS ICD][1].

Table 2: QZSS L2, L5 and E6 signal technical characteristics.


As a summary, the signal plan of QZSS is shown in the next figure and table [2][3][4]

Figure 1: QZSS planned signals.
Frequency Band L1 L2 L5 L6
Signal name L1C/A L1C/B L1C L1S L2C L5 L61 (Block I) L62 (Block II)
Modulation method BPSK BOC (Block IIA) BOC (Block I)
TMBOC (Block II)
BOC BPSK BPSK QPSK BPSK BPSK
PRN code name C/A L1CP L1CD L1S L2CL L2CM I5 Q5 L6 (code 1) L6 (code 2) L6 (code 1) L6 (code 2)
Overlay code name - L1CO - - - - Neuman-Hoffman Neuman-Hoffman - - - -
Message name LNAV(L1C/A, L1C/B) - CNAV2(L1C) L1S - CNAV(L2C) CNAV(L5) L6D - L6D L6E
Chip rate 1023 Mcps 1023 Mcps 1023 Mcps 1023 Mcps 0.5115 0.5115 10.23 10.23 2.5575 Mcps 2.5575 Mcps 2.5575 Mcps 2.5575 Mcps
Length 1023 chips 10230 chips 10230 chips 1023 chips 767250 10230 10230 10230 10230 chip 1048575 chip 10230 chip 10230 chip
Period 1 ms 10 ms 10 ms 1 ms 1.5 s 20 ms 1 ms 1 ms 4 ms 410 ms 4 ms 4 ms
Overlay Code - L1CO
Length: 1800 bits
Period: 18 s
- - - - Neuman-Hoffman
Length: 10 bits
Period: 10 ms
Neuman-Hoffman
Length: 20 bits
Period: 20 ms
- - - -
Bit rate 50 bps Approx. 50 bps 250 bps 25 bps 50 bps 2000 bps 2000 bps 2000 bps
Symbol Rate - 100 sps 600 sps 25 sps 100 sps 250 sps 250 sps 250 sps
Period (min. Frame) 6 s 18 s 1 s 12 s 6 s 1 s 1 s 1 s
Encoding method Hamming Code CRC, BCH, LDPC
Interleave
CRC
Convolutional code
CRC
Convolutional code
CRC
Convolutional code
RS (255, 223) RS (255, 223) RS (255, 223)
Nominal carrier frequency 1575.42 MHz (=154 x f0) 1227.60 MHz (=120 x f0) 1176.45 MHz (=115xf0) 1278.75 MHz (=125xf0)
Block I 24.0 MHz (+- 12.0 MHz) 24.0 MHz (+- 12.0 MHz) 24.9 MHz (+- 12.45 MHz) 39.0 MHz (+- 19.5 MHz)
Block II 30.69 MHz (+- 15.345 MHz) 30.69 MHz (+- 15.345 MHz) 24.9 MHz (+- 12.45 MHz) 42.0 MHz (+- 21.0 MHz)
Minimum received power Block I -158.5 dBW - -158.5 dBW -163.0 dBW -161.0 dBW -160.0 dBW (Sum of L2CL and L2CM) -157.9 dBW -157.9 dBW -155.7 dBW
(Total power of Code 1 and Code 2)
Block II -158.5 dBW
(-164.0 dBW for SV ID=7)
-158.5 dBW (for Block IIA-Q) -158.25 dBW
(-162.4 dBW for SV ID=7)
-163.0 dBW
(-167.2 dBW for SV ID=7)
-158.5 dBW -158.5 dBW (Sum of L2CL and L2CM) -157.9 dBW -157.9 dBW -156.82 dBW
(Total power of Code 1 and Code 2)

References

  1. ^ [QZSS SIS ICD, 2007] Quasi Zenith Satellite System Navigation Service, Interface Specification for QZSS (IS-QZSS), Japan Aerospace Exploration Agency, January 22, 2007.
  2. ^ Quasi-Zenith Satellite System Interface Specification: Satellite Positioning, Navigation and Timing Service (IS-QZSS-PNT-004), Cabinet Office, January 25, 2021.
  3. ^ Quasi-Zenith Satellite System Interface Specification: Sub-meter Level Augmentation Service (IS-QZSS-L1S-004), Cabinet Office, December 27, 2019.
  4. ^ Quasi-Zenith Satellite System Interface Specification: Centimeter Level Augmentation Service (IS-QZSS-L6-004), Cabinet Office, July 14, 2021.


Credits

The information presented in this NAVIPEDIA’s article is an extract of the PhD work performed by Dr. Jose Ángel Ávila Rodríguez in the FAF University of Munich as part of his Doctoral Thesis “On Generalized Signal Waveforms for Satellite Navigation” presented in June 2008, Munich (Germany) and has evolved to reflect the system’s development, being updated by GMV.