Chapter 7 |
File Formats |
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7.1Overview of the File Formats
7.2CFG File
The configuration (CFG) file stores all the options in a project. It is rare to need to edit a CFG manually. However, such a situation arises when using callgps, which is the command-line processor. When editing a CFG file, be careful to follow the exact syntax. To learn the commands of CFG files, you should look at those created by GrafNav and refer to Appendix A for a list of all the commands and their meanings.
Information contained in the records
Position Record
Contains the receiver-computed latitude, longitude, height and clock offset. It also contains the correct GPS time (seconds since Sunday), and status bits for position validity and process mode (static or kinematic). The new format handles times not on the whole epoch better.
Measurement Record
Contains the measurements for each satellite, including the PRN number, C/A code range, L1 phase, L1 phase rate (Doppler), L2 phase, P2 code range and locktime. For those fields that do not exist, zero is present. The new format also contains space for C/N0 of L1, C/N0 of L2, L2 locktime and P1 range.
7.3GPS Data Files
This section concerns the format of those files (GPB/EPP/STA) created upon the conversion from a raw data format to Waypoint’s proprietary format.
7.3.1GPB File
Binary measurement data is stored in Waypoint’s custom GPB format. This format is receiver-independent and only stores necessary information to minimize disk space requirements. This format contains one position record and a measurement record for each satellite being tracked, for every epoch.
There exists a new and old version of the GPB format. The new version has L1 and L1/L2 records sizes, additional header information that is, receiver information, software name, and version number. The new version also has C/NO, L2C indicators, and P1 + P2 codes. GPBView is a useful utility for inspecting and modifying GPB files.
You can export this file to ASCII from the GPBViewer, or convert to RINEX via the GPB to RINEX utility.
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7.3.2STA File
New Station File Format
As of Version 6.03, the format of the station files has changed.
The old station file format remains compatible with the new software. However, any changes to such a station file will be saved in the new format. The new format has two possible file extensions: NST or STA.
Every station file must have the following string at the top or else it will not load.
$STAINFO
The station file may have a header record. The header is optional and will not be present in most cases. The following is a description of the header format.
Hdr { |
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Proj: |
“Name of Project” |
Field project name |
User: |
“User Name” |
Name of field operator |
Time: |
hh:mm:ss LOCAL/GMT |
Start time |
Date: |
mm/dd/yyyy |
Start date |
RxName: |
Receiver |
Receiver type |
RxSub: |
Model |
Receiver sub type |
Hi: |
Hi_m VERT/SLANT |
Antenna height, measured vertically or slanted |
Ant: |
V_Offset H_Offset "Name" |
Antenna info (vertical offset to phase centre, |
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horizontal distance to measurement mark, |
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antenna model name) |
Pos: |
phi lamda ht ELL/ORTHO |
Computed position of antenna |
Mode: |
SP/DGPS/RTFL/RTFX/RTK/FIX |
Mode of solution (RTFL=float, RTFX=fixed, |
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RTK=float/fixed not known, SP=single point, |
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GPS=DGPS, FIX=known) |
}
The following is the format for the stationary station marks:
Sta { |
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*ID: |
"Station ID" |
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*GTim: |
SecOfWeek [WeekNo] |
GPS Time |
UTim: |
SecOfWeek [WeekNo] |
UTC Time could be used instead of GTim but this |
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is not recommended and often not supported. |
Pos: |
phi lamda ht ELL/ORTHO |
Computed position of antenna |
Mode: |
SP/DGPS/RTFL/RTFX/RTK/FIX |
Mode of solution (RTFL=float, RTFX=fixed, |
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RTK=float/fixed not known, SP=single point, |
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DGPS=DGPS, FIX=known) |
Std: |
SdE SdN SdH |
Standard deviation, in meters |
Hi: |
Hi_m VERT/SLANT |
Antenna height, measured vertically or slanted |
Ant: |
V_Offset H_Offset "Name" |
Antenna info (vertical offset to phase centre, |
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horizontal distance to measurement mark, |
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antenna model name) |
OffR: |
Range TrueAzimuth DH |
Offset to actual point (2D range in meters, azimuth |
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in degrees, height difference in meters) |
OffL: |
DE DN DH |
Offset in local level frame, in meters |
OffB: |
DX DY DZ |
Body frame offset, where X-RightWingPos, |
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Y-ForwardPos, Z-UpPos |
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Att: |
roll pitch heading |
Attitude, in degrees |
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Desc: |
"description” |
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Rem: |
"remarks" |
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Nsv: |
NumSats NumGPS NumGlonass |
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Dop: |
PDOP HDOP VDOP |
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Rms: |
L1Phase CACode |
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Age: |
Sec |
Age of last correction or RTK receipt |
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Enable: |
1/0 |
Used in GrafNav |
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} |
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* indicates a required field.
The new station file format also handles event marks. Saving a project with event marks loaded will bring the event marks into the station file. The following is the event mark format.
Mrk { |
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*Event: |
Number |
Event number or name (no spaces) |
Desc: |
"Name" |
Roll name |
*GTim: |
SecOfWeek [WeekNo] |
GPS Time |
*UTim: |
SecOfWeek [WeekNo] |
UTC Time could be used instead of GTim but this is |
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not recommended and often not supported |
Pos: |
phi lamda ht ELL/ORTHO |
Computed position |
Mode: |
SP/DGPS/RTFL/RTFX/RTK/FIX |
Mode of solution (RTFL=float, RTFX=fixed, |
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RTK=float/fixed not known, SP=single point, |
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DGPS=DGPS, FIX=known) |
Std: |
SdE SdN SdH |
Standard deviation, in meters |
Vel: |
VE VN VH |
Velocity, in m/s |
Att: |
roll pitch heading |
Attitude, in degrees |
Rem: |
"remarks" |
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Nsv: |
NumSats NumGPS NumGlonass |
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Dop: |
PDOP HDOP VDOP |
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Rms: |
L1Phase CACode |
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Age: |
Sec |
Age of last correction or RTK receipt |
Enable: |
1/0 |
Used in GrafNav |
} |
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* indicates a required field.
GIS marks are also available in the new station file format. Note that GIS marks can only be created using Waypoint’s logging software, WLOG.
Gis {
Count: counter
Feat: "name"
Attrib1: "name"
Value1: "name"
Attrib2: “name"
Value2: "name"
Attrib3: "name"
Value3: "name"
Rem: "remarks"
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Type: |
POINT/LINE/POLYGON NONE/START/END/NODE NONE/CW/CCW |
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Feature type, position, direction |
GTim: |
SecOfWeek [WeekNo] |
GPS Time |
UTim: |
SecOfWeek [WeekNo] |
UTC Time |
Pos: |
phi lamda ht [ELL/ORTHO] |
Computed position |
Mode: |
SP/DGPS/RTFL/RTFX/RTK/FIX |
Mode of solution (RTFL=float, RTFX=fixed, |
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RTK=float/fixed not known, SP=single point, |
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DGPS=DGPS, FIX=known) |
Std: |
SdE SdN SdH |
Standard deviation in meters |
OffR: |
Range TrueAzimuth DH |
Offset to actual point (2D range in meters, azimuth |
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in degrees, height difference in meters) |
OffL: |
DE DN DH |
Offset in local level frame, in meters |
OffB: |
DX DY DZ |
Body frame offset, where X-RightWingPos, |
Hi: |
Hi_m VERT/SLANT |
Antenna height, measured vertically or slanted |
Ant: |
V_Offset H_Offset "Name" |
Antenna info (vertical offset to phase centre, |
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horizontal distance to measurement mark, |
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antenna model name) |
Nsv: |
NumSats NumGPS NumGlonass |
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Dop: |
PDOP HDOP VDOP |
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Rms: |
L1Phase CACode |
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Age: |
Sec |
Age of last correction or RTK receipt |
Enable: |
1/0 |
Used in GrafNav |
}
Another new data type handled in the station format is an RTK epoch, where every epoch can be recorded.
RTK { |
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*GTim: |
SecOfWeek [WeekNo] |
GPS Time |
*UTim: |
SecOfWeek [WeekNo] |
UTC Time |
*Pos: |
phi lamda ht [ELL/ORTHO] |
Computed position |
Mode: |
SP/DGPS/RTFL/RTFX/RTK/FIX |
Mode of solution (RTFL=float, RTFX=fixed, |
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RTK=float/fixed not known, SP=single point, |
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DGPS=DGPS, FIX=known) |
Std: |
SdE SdN SdH |
Standard deviation in meters |
Vel: |
VE VN VH |
Velocity, in m/s |
Att: |
roll pitch heading |
Attitude in degrees |
Nsv: |
NumSats NumGPS NumGlonass |
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Dop: |
PDOP HDOP VDOP |
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Rms: |
L1Phase CACode |
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Age: |
Sec |
Age of last correction or RTK receipt |
Enable: |
1/0 |
Used in GrafNav |
} |
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* indicates a required field.
7.3.3Old Station File Format
Feature points can be loaded into GrafNav via a station file. This station file is an ASCII file from which station names, GPS times, antenna heights and related information is read. GrafNav will select the nearest epoch time to extract the position, and will not interpolate in this situation. For interpolation, the user should select File | Camera Event Marks. The station file can contain a named station feature, or a GIS feature mark.
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