Indicates the length of the current data block, including the BLOCK LENGTH byte.

GPS week number of the observation.

Receiver time (milliseconds of the week) of the observation.

3-byte signed integer representing the receiver-to-GPS clock offset in milliseconds. Increment 2^19.

Number of SVs reported in this epoch.

Bitmapped field having the following values:

Bit 0: Reserved

Bit 1: GPS-GLONASS system time offset value present

Bit 2,3: Reserved

Bit 4: RAIM info present

Bit 5: Inter System Clock Offset Present

Bit 6: Reserved

Bit 7: If set, indicates a subsequent flag byte is appended.

3-byte signed integer representing the GPS-GLONASS system time offset in units of milliseconds. Increment 2^22.

Inter-System Clock Offset Block: Available if bit 5 is set in EPOCH FLAGS

Indicates the length of the current data block, including the BLOCK LENGTH byte.

Indicates what data is loaded, is valid, etc:

Bit 0–3: Satellite clock system to which time offsets are referenced:

0: GPS
1: SBAS (WAAS, EGNOS, MSAS, etc.)
2: GLONASS
3: Galileo
4: QZSS
5: BeiDou
6: NavIC

Bit 4–6: Number of System Time Offsets stored (n = 0–7).

Bit 7: One more header byte follows.

Repeated for the Number of System Time Offsets stored

Bit 0–3: Satellite clock system:

0: GPS
1: SBAS (WAAS, EGNOS, MSAS, etc.)
2: GLONASS
3: Galileo
4: QZSS
5: BeiDou
6: NavIC

Bit 4–6: Number of bytes (“M”).

Bit 7: One more info byte follows.

This is an M-byte signed integer in units of milliseconds/2^28. The lowest bit has a value of 0.0037 ns or 1.12 mm. Divide the integer by 2^28 to get milliseconds. The range based on the number of bytes is:

1 bytes: +/- 0.47 ns

2 bytes: +/- 122.07 ns

3 bytes: +/- 31250.00 ns (31 us)

4 bytes: +/- 8 ms

5 bytes: +/- 2.048 s

6 bytes: +/- 524.29 s

7 bytes: +/- 37.283 hours ( LSB = 4.48 mm if top 2 bits of 7th byte are used )

Measurement Header (SV ID and SV data are repeated for the number of SVs in this epoch. Trimble recommends using the BLOCK LENGTH to determine the number of SVs).

Indicates the length of the current data block, including the BLOCK LENGTH byte.

PRN of the SV observed.

Bits 0–5: SV TYPE is the GNSS system or satellite type.

Bottom 6 bits = SV Type / Top two bits are Antenna Number. Defined values are:

0: GPS
1: SBAS (WAAS, EGNOS, MSAS, etc.)
2: GLONASS
3: Galileo
4: QZSS
5: BeiDou (Pre-ICD SV numbering)
7: BeiDou (ICD SV Numbering)
9: NavIC
10: BeiDou

Bits 6–7: ANTENNA indicates the antenna/receiver which recorded this observation (applicable to the BD982/BD992):

0: Position antenna
1: Vector antenna (if dual-antenna is enabled)

The FDMA channel (appropriate only for GLONASS SVs), otherwise physical channel number may be indicated. It is recommended that this byte be ignored for non-GLONASS SVs.

Indicates how many Measurement Blocks are appended for this SV. Typically 1 block per frequency band, but it can be more if multiple codes are tracked on the same frequency.

the Satellite elevation above the horizon (degrees).

the Satellite azimuth, clockwise from North (2-degree steps).

Bitmapped field having the following values:

Bit 0: Reserved

Bit 1: Multipath reduction

Bit 2: Code smoothing

Bit 3: Phase smoothing

Bit 4: Satellite Unhealthy (CLEAR = satellite healthy)

Bit 5: RAIM fault

Bit 6: Pseudo-IODE present

Bit 7: When set another flags byte follows

Bitmapped field having the following values (not used in real-time data):

Bit 0: Reserved

Bit 1: GPS alert flag. Signal URA may be worse than indicated, use SV at your own risk.

Bit 2–6: Reserved

Bit 7: When set another flags byte follows

(A change in this value indicates an ephemeris update)

Measurement Block (SV ID and SV data are repeated for the number of SVs in this epoch. Trimble recommends using the BLOCK LENGTH to determine the number of SVs).

Indicates the length of the current data block, including the BLOCK LENGTH byte.

Indicates the SV frequency band for this observation (see Table of SV frequency bands below).

Indicates the SV signal being tracked in this observation (see Table of SV signals below).

The signal-to-noise ratio, in units of dBHz*10.

PSEUDORANGE: The first block (subchannel) in the message is a 4-byte unsigned integer value in units of m. Increment 2^7 (or Increment 2^6 for SBAS or QZSS SVs.

DIFFERENTIAL PSEUDORANGE: The subsequent blocks are 2-byte signed integer value in units of m. Increment 2^8 different to the L1-C/A signal.

A 6-byte signed integer representing phase. Increment 2^15. For GLONASS, it is in cycles for the given FDMA channel, no scaling is performed in the receiver. To convert to meters, you need to scale by the appropriate wavelength.

A 256-value rolling cycle slip counter.

Bitmapped field having the following values:

Bit 0: Phase loaded

Bit 1: Range loaded

Bit 2: Doppler loaded and present

Bit 3: Cycle slip

Bit 4: Half-cycle phase

Bit 5: Data sync

Bit 6: Positive lock point

Bit 7: When set another flags byte follows.

Bitmapped field having the following values:

Bit 0: Range diff overflow byte is present.

Bit 1 Pseudorange overflow. The pseudorange has been stored as (true pseudorange - RANGE_OVERFLOW_LIMIT) to avoid overflow. The true pseudorange must be reconstructed. RANGE_OVERFLOW_LIMIT is currently 33554431.0 m.

Bit 2–6: Reserved.

Bit 7: When set another flags byte follows.

Bitmapped field having the following values:

Bit 0–1: Reserved

Bit 2: If set, this signal is 'unhealthy' and measurements should not be used for positioning

Bit 3–6: Reserved

Bit 7: When set another flags byte follows

Bitmapped field having the following values:

Bit 0–6: Reserved

Bit 7: When set another flags byte follows.

a 3-byte signed integer (if present, see MEASUREMENT FLAGS bit 2), units of Hz. Increment 2^8.

a 1 byte extension to the 2-byte DIFFERENTIAL PSEUDORANGE. It should be appended as the most significant byte to the 2-byte differential pseudorange, to form a 3-byte differential pseudorange. This byte extends the limits of the differential pseudorange from +/- 127 m to +/- 32768 m.

L1 (GPS / GLONASS / Galileo / SBAS / QZSS / BeiDou B1C)

L2 (GPS /GLONASS / QZSS)

L5/E5A - 1176.45 MHz (GPS / SBAS / Galileo E5A / QZSS / BeiDou B2A / NavIC)

E5B - 1207.14 MHz (Galileo E5B, BeiDou B2, BeiDou B2B)

E5A+B - 1191.795 MHz (Galileo Combined E5A/B - AltBOC)

E6 - 1278.75 MHz (Galileo E6)

B1 - 1561.098 MHz (BeiDou B1)

B3 - 1268.52 MHz (BeiDou B3)

E1 - 1589.742 MHz (BeiDou-2 L1-2)

G3 - 1202.025 MHz (GLONASS G3 CDMA)

C/A (GPS / GLONASS / SBAS) / BOC(1,1) Galileo / NavIC L5 C/A and S-Band C/A

P

Enhanced Cross Correlation

L2C (CM)

L2C (CL)

L2C (CM+CL)

L5 (I) (GPS L5 / QZSS L5 / BDS-III B2A/B2B)

L5 (Q) (GPS L5 / QZSS L5 / BDS-III B2A/B2B)

L5 (I+Q) (GPS L5 / QZSS L5 / BDS-III B2A/B2B)

Y

M

BPSK(10)-PD (Galileo E5A or E5B - Pilot and Data)

BPSK(10)-P (Galileo E5A or E5B - Pilot only)

BPSK(10)-D (Galileo E5A or E5B - Data only, BeiDou-2 B2 and B3)

AltBOC-Comp-PD (Galileo Component Mode AltBOC - Pilot and Data)

AltBOC-Comp-P (Galileo Component Mode AltBOC - Pilot only)

AltBOC-Comp-D (Galileo Component Mode AltBOC - Data only)

AltBOC-PD (Galileo Non-Component Mode AltBOC - Pilot and Data)

L2 Enhanced Cross Correlation (L1 estimate derived from P1 estimate)

L1 Enhanced Cross Correlation (W-code tracking)

BOC(1,1) Pilot & Data - Galileo E1 / GPS L1C / BDS-III B1C

BOC(1,1) Pilot Only - Galileo E1 / GPS L1C / BDS-III B1C

BOC(1,1) Data Only - Galileo E1 /GPS L1C / BDS-III B1C

MBOC(1,1) Pilot & Data - Galileo E1 / GPS L1C / BDS-III B1C

MBOC(1,1) Pilot Only - Galileo E1 / GPS L1C / BDS-III B1C

MBOC(1,1) Data Only - Galileo E1 / GPS L1C / BDS-III B1C

BPSK(2) (BeiDou-2 B1)

BPSK(2) (BeiDou-2 B1-2, deprecated)

BPSK(2) (BeiDou-2 B2)

BPSK(10) (BeiDou-2 B3)

QZSS SLAS (L1 C/A SBAS like signal)

QZSS LEX signal (pilot component only)

G3-PD (GLONASS G3 CDMA BPSK(10) - Pilot and Data)

G3-P (GLONASS G3 CDMA BPSK(10) - Pilot)

G3-D (GLONASS G3 CDMA BPSK(10) - Data)

E6-PD (Galileo E6 BPSK(5) - Pilot and Data)

E6-P (Galileo E6 BPSK(5) - Pilot)

E6-D (Galileo E6 BPSK(5) - Data)

L5S-PD (QZSS L5S BPSK(10) - Pilot and Data)

L5S-P (QZSS L5S BPSK(10) - Pilot)