RTKXYZ

RTK Cartesian position and velocity

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7

This log contains the receiver’s low latency position and velocity in ECEF coordinates. The position and velocity status fields indicate whether or not the corresponding data is valid. See Figure: The WGS84 ECEF Coordinate System for a definition of the ECEF coordinates.

The velocity measurements have a latency associated with them. The time of validity is the time tag in the log minus the latency value.

With the system operating in an RTK mode, this log reflects if the solution is a good RTK low latency solution (from extrapolated base station measurements) or invalid. A valid RTK low latency solution is computed for up to 60 seconds after reception of the last base station observation. The degradation in accuracy due to differential age is reflected in the standard deviation fields. See also the DGPSTXID command.

The velocity is computed from consecutive RTK low latency updates. As such, it is an average velocity based on the time difference between successive position computations and not an instantaneous velocity at the RTKVEL time tag. The velocity latency to be subtracted from the time tag is normally half the time between filter updates. Under default operation, the RTK low latency filter is updated at a rate of 2 Hz. This translates into a velocity latency of 0.25 seconds. The latency can be reduced by increasing the update rate of the RTK low latency filter by requesting the BESTXYZ message at a rate higher than 2 Hz. For example, a logging rate of 10 Hz would reduce the velocity latency to 0.05 seconds. For integration purposes, the velocity latency should be applied to the record time tag.

See also the BESTXYZ log and MATCHEDXYZ log.

The position coordinates are provided in the datum configured by the OUTPUTDATUM command.

Message ID: 244

Log Type: Synch

Recommended Input:

log rtkxyza ontime 1

ASCII Example:

#RTKXYZA,USB1,0,64.5,FINESTEERING,2211,235074.000,02000020,40ee,16809;SOL_COMPUTED,NARROW_INT,-1632848.2305,-3662159.5450,4944902.5890,0.0074,0.0088,0.0110,SOL_COMPUTED,NARROW_INT,-0.0010,0.0011,-0.0005,0.0063,0.0067,0.0102,"K250",0.250,1.000,0.000,37,31,31,30,0,01,3f,37*969e6a51

Field

Field type

Description

Format

Binary Bytes

Binary Offset

1

Log header

RTKXYZ header

For information about log headers, see ASCII, Abbreviated ASCII or Binary.

 

H

0

2

P-sol status

Solution status, see Table: Solution Status

Enum

4

H

3

pos type

Position type, see Table: Position or Velocity Type

Enum

4

H+4

4

P-X

Position X-coordinate (m)

Double

8

H+8

5

P-Y

Position Y-coordinate (m)

Double

8

H+16

6

P-Z

Position Z-coordinate (m)

Double

8

H+24

7

P-X σ

Standard deviation of P-X (m)

Float

4

H+32

8

P-Y σ

Standard deviation of P-Y (m)

Float

4

H+36

9

P-Z σ

Standard deviation of P-Z (m)

Float

4

H+40

10

V-sol status

Solution status, see Table: Solution Status

Enum

4

H+44

11

vel type

Velocity type, see Table: Position or Velocity Type

Enum

4

H+48

12

V-X

Velocity vector along X-axis (m)

Double

8

H+52

13

V-Y

Velocity vector along Y-axis (m)

Double

8

H+60

14

V-Z

Velocity vector along Z-axis (m)

Double

8

H+68

15

V-X σ

Standard deviation of V-X (m)

Float

4

H+76

16

V-Y σ

Standard deviation of V-Y (m)

Float

4

H+80

17

V-Z σ

Standard deviation of V-Z (m)

Float

4

H+84

18

stn ID

Base station identification

Char[4]

4

H+88

19

V-latency

A measure of the latency in the velocity time tag in seconds. It should be subtracted from the time to give improved results.

Float

4

H+92

20

diff_age

Differential age in seconds

Float

4

H+96

21

sol_age

Solution age in seconds

Float

4

H+100

22

#SVs

Number of satellites tracked

Uchar

1

H+104

23

#solnSVs

Number of satellites used in solution

Uchar

1

H+105

24

#ggL1

Number of satellites with L1/E1/B1 signals used in solution

Uchar

1

H+106

25

#solnMultiSVs

Number of satellites with multi-frequency signals used in solution

Uchar

1

H+107

26

Reserved

Char

1

H+108

27

ext sol stat

Extended solution status (see Table: Extended Solution Status)

Hex

1

H+109

28

Galileo and BeiDou sig mask

Galileo and BeiDou signals used mask (see Table: Galileo and BeiDou Signal-Used Mask)

Hex

1

H+110

29

GPS and GLONASS sig mask

GPS and GLONASS signals used mask (see Table: GPS and GLONASS Signal-Used Mask)

Hex

1

H+111

30

xxxx

32-bit CRC (ASCII and Binary only)

Ulong

4

H+112

31

[CR][LF]

Sentence terminator (ASCII only)

-

-

-