Novatel OM-20000041 用户手册
E
Comparison Of RT-2 And RT-20
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MiLLennium GPSCard Software Version 4.50 Command Descriptions Manual Rev 1
RT-2 Performance
The RT-2 software provides the accuracies shown in Table E-3 & Figure E-1 (static mode) and Table E-4 &
Figure E-2 (kinematic mode) for “typical” multipath, ionospheric, tropospheric, and ephemeris errors, where
“typical” is described as follows:
Figure E-2 (kinematic mode) for “typical” multipath, ionospheric, tropospheric, and ephemeris errors, where
“typical” is described as follows:
•
A typical multipath environment would provide no carrier-phase double-difference multipath errors
greater than 2 cm or pseudorange double-difference multipath errors greater than 2 m on satellites at 11°
elevation or greater. For environments where there is greater multipath, please consult NovAtel Customer
Service.
elevation or greater. For environments where there is greater multipath, please consult NovAtel Customer
Service.
•
Typical unmodeled ionospheric, tropospheric and ephemeris errors must be within 2
σ
of their average
values, at a given elevation angle and baseline length. It is assumed that the tropospheric correction is
computed with standard atmospheric parameters. All performance specifications assume that at least 6
satellites above the mask angle (varies between 11 and 14 degrees) are being tracked on both L1 and L2.
computed with standard atmospheric parameters. All performance specifications assume that at least 6
satellites above the mask angle (varies between 11 and 14 degrees) are being tracked on both L1 and L2.
In Tables E-3 and E-4, accuracy values refer to horizontal RMS error, and are based on matched positions. There
are no data delays for a matched log and therefore no need to add anything. The level of position accuracy at any
time will be reflected in the standard deviations output with the position.
are no data delays for a matched log and therefore no need to add anything. The level of position accuracy at any
time will be reflected in the standard deviations output with the position.
Table E-3
RT-2 Performance: Static Mode
Table E-4
RT-2 Performance: Kinematic Mode
PRTK logs contain some error due to predictions from base station observations. The expected error of a PRTK
log will be that of the corresponding RTK log plus the appropriate error from Table E-5.
log will be that of the corresponding RTK log plus the appropriate error from Table E-5.
Table E-5
RT-2 Degradation With Respect To Data Delay
➀
See Section A.3, Page 64 for an overview of GPS positioning.
Baseline
length
Time since L2 lock-on with at least
6 satellites above mask angle
Horizontal accuracy at
the stated time
Runs meeting the stated
accuracy at the stated time
< 10 km
70 seconds + 1.5 sec/km
2 cm + 0.5 ppm
75.0%
< 10 km
5 minutes
1 cm + 1 ppm
75.0%
< 15 km
4 minutes
5 cm
66.7%
< 25 km
7 minutes
7 cm
66.7%
< 35 km
10 minutes
35 cm
66.7%
< 35 km
30 minutes
25 cm
66.7%
Baseline
length
Time since L2 lock-on with at least
6 satellites above mask angle
Horizontal accuracy at
the stated time
Runs meeting the stated
accuracy at the stated time
< 10 km
120 seconds + 1.5 sec/km
2 cm + 0.5 ppm
75.0%
< 15 km
8 minutes
8 cm
66.7%
< 25 km
14 minutes
10 cm
66.7%
< 35 km
20 minutes
40 cm
66.7%
< 35 km
60 minutes
25 cm
66.7%
Data Delay (sec)
Distance (km)
Accuracy (CEP)
0 - 2
1
+1 cm/sec
2 - 7
1
+2 cm/sec
7 - 30
1
+5 cm/sec
>30
1
single point or pseudorange differential positioning ➁
➀
Mode = Static or Kinematic
➁
After 30 seconds reverts to pseudorange positioning (single point or differential depend-
ing on messages previously received from the base station).
ing on messages previously received from the base station).