manual.txt

这是国外关于卫星导航方面一书的源代码

- In the program directory there always has to exist the complete set of 
  files (program package after installation) to work correctly. Even text
  files (like solution files) must not be removed, because the program needs
  access to the recently generated.

- You can use windows specific keyboard operations like copy-paste and 
  delete when working on text files and/or dialog box fields. Use
     CTRL-C     for copy
     CTRL-V     for paste (verbose)
     DEL        for delete
  after marking a text area with the mouse (drag) by holding down the left 
  mouse button.

- Win95 allows directory or file names containing blanks like e.g. 
  "c:\Program Files"; the file browser of MatLab5 rejects it. 
  So please consider that when creating file and directory names related to
  this program GPSLab.


1.6 restrictions:
-----------------
- only for small data sets (<< 1000 epochs) of statically observed two
  markers (rapid static), that means 1 baseline.
- you cannot process data from stop&go or multistation-multisession projects.
- there is not network processing: you have to process baselines 
  successively and to import the results into a program like GeoLab.
- Some modules allow to produce results (time series) from kinematic
  observations: the epochwise solutions from SPP or DGPS should supply you
  reasonable values.
- data containing epoch offsets from the integer second > 10 msec or
  registration rates < 1 sec cannot be processed due to the simplifications
  made while programming this software package.


1.7 starting the program:
-------------------------
After starting MatLab5.x you have to change to the directory, you have 
placed the GPSLab M-files in. Now type in "gpslab".
Do not start GPSLab twice ore more, because everything is displayed in 
the same graphics window (in MatLab called: figure) with the handle 
number 99 and so the graphics menu can show erroneous behaviour.
So wait until a preceding GPSLab run is really finished, before you 
restart it. For that purpose you do not have to exit MatLab, but you can
continue your session.
While GPSLab is running you can open additional figures of course. But
please insure that you do not use figure number 99, that is reserved
for GPSLab main window.
This allows you the reuse of the variables and parameters created by 
GPSLab modules for displaying them in other figures simultaneously.


1.8 breaks, exits, program terminations:
----------------------------------------
You can force a running module as well as any other the MatLab program
to stop by typing the key combination CTRL-C (german keyboard: STRG-C).
To avoid complications you should exit GPSLab (with deleting workspace)
and restart it.
A program termination is normally accompanied by a warning or information
in a dialog window. If you see MatLab error reports in the command window,
some problems in the program handling of GPSLab can appear. By rerunning
and , if necessary, reimporting data (in the case of corrupted data) the
normal state should be reestablished.


2. the processing of GPS data - in 10 steps
-------------------------------------------
You can of course perform the data processing in any way you like, but 
some modules force you to do one step after another: So you have to
produce results just before visualizing them, e.g., because variables
only are resident in the workspace and are not totally stored in files 
and reloadable from them. Only a part of the variables are stored in a
solution text file, that can be called by "view results".
If you do not only want to visualize orbits but also want to determine
coordinates or coordinate differences, you have to pay attention to the
fact, that optimal approximate coordinates are introduced for the 
respective analysis. If no sufficiant accurate approximate coordinates
exit, for DGPS you should calculate some from SPP and for CDGPS(amf)
from DGPS. With the test data sets accompanying the program come solution
files resulting from processing by a commercial software (GeoGPS/
GeoGenius by SpectraPrecision TerraSat) in cm accuracy.
So it is recommended to act stepwise. An automation of these stepwise
procedure can be realized but is not yet, because you should learn from
performing the data analysis step by step.
Please always check the reference and approximate coordinates (rover) and
the antenna heights. If necessary correct them in the header files.

Basically the structure of the menu bar is arranged logically in such a 
way that you start from left and end at the right side. Help you will get
via the "Infos" menu contents.

In the following a procedure is descibed that touches nearly all 
menu items:

2.1 RINEX DATA IMPORT

2.1.1 For processing new data sets: Import these by selecting the menu item
"File: start Rinex import". You will be asked to select Rinex-O as well 
as Rinex-N files for reference and rover station. For that purpose it is 
recommended to shutdown the virus scan software, if installed and running,
because it delays the process (see above: 1.5 hints / tips / recommended).
After finishing without errors a data set overview appears. Via a little
dialog window you are able to reduce the time span immediately. This can 
also be done later (see below); in this case push the cancel button.
In the case, that no simoultaneous data are available, a warning will be
displayed.

2.1.2 If you wish to process the data used previously, you can skip this 
item 1.

2.2 CHECK

Check your Rinex import by viewing the Log-Files and looking for error
messages or abnormal (format conversion) program termination by selecting
"File: view log-files".
This procedure is only necessary, if a problem appears while processing
data imported just now.

2.3 EDIT HEADER

For modifications of the approximate coordinates or the antenna heights
call the menu item "file: edit/view header". The headers for reference 
and rover can be edited seperately. A description of the format you can 
find in the "infos" menu. If you modify the format in an unappropriate 
way, this will possibly cause the program to run erroneaously.

2.4 DATA SET TIME SPAN REDUCTION

If you want to cut out a part of a total data set to process it, you 
can do that by selecting the menu item "file: time span definition".
There is the posibility to do that graphically or by setting start and
end of the desired time span in GPS week seconds. Because in this case
again files are opened you should disable or exit your virus scan 
software (MatLab5.x bug, see above: 1.5 hints / tips / recommended).

2.5 VISUALIZING ORBITS

For viewing figures of the GPS orbits of the satellites stored in the
RINEX-N files, you have to perform a processing of the necessary 
parameters. You can decide between an ECEF or an ECI presentation.
By the way remember that all variables in the MatLab workspace are
deleted when you start a new processing. 
Select "Orbits: calculate ...". 
For the creation of figures then select "Orbits: visualizing: ...".

2.6 SINGLE POINT POSITIONING (SPP)

Calculate reliable approximate coordinates by single point positioning
of reference and rover station. For that select "SPP: calculate".
Often the approximate coordinates stored by the receiver are not 
reliable but are away from the correct position by some kilometers.
After the calculations the results for this solution as well as for the
derived coordinate-DGPS can be displayed by selecting the menu item
"SPP: visualizing: ...". Important parameters are stored in a file that
is be shown when you select "SPP: view results".

Please do close the results file before rerunning the related module, 
because you won't get the new results displayed as long as the old is 
opened. In doubt check the processing time in the header of the results 
file.

Copy the approximate coordinates to the header files of reference and 
rover by hand or perform that by selecting the menu item 
"Tools: recent results -> header".

You can store all the variables of a program run before starting a new
program run of the same or another module by selecting the menu item
"file: save workspace". Give this file a name of your own choice. If
you want to reproduce this state in a new GPSlab session after a new 
start of MatLab, load the stored file by using the command LOAD (followed
by the name of the stored .MAT-file) typing it into the command window.

The meaning of the single variables in the workspace after the run of a 
specific module is documented in "Infos: variables after call of ...".
If you need additional information risk a look into the source code.

2.7 DGPS USING PSEUDORANGES

Just act analogously for "DGPS" positioning. Here you can also have access
to the results file or create some figures.

Please do close the results file before rerunning the related module, 
because you won't get the new results displayed as long as the old is 
opened. In doubt check the processing time in the header of the results 
file.

Copy the approximate coordinates to the header files of reference and 
rover by hand or perform that by selecting the menu item 
"Tools: recent results -> header".

You can store all the variables of a program run before starting a new
program run of the same or another module by selecting the menu item
"file: save workspace". Give this file a name of your own choice. If
you want to reproduce this state in a new GPSlab session after a new 
start of MatLab, load the stored file by using the command LOAD (followed
by the name of the stored .MAT-file) typing it into the command window.

The meaning of the single variables in the workspace after the run of a 
specific module is documented in "Infos: variables after call of ...".
If you need additional information risk a look into the source code.

2.8 DGPS USING CARRIER PHASES AND THE AMBIGUITY FUNCTION METHOD (CDGPS/amf)

Just act again analogously for "CDGPS(amf)" positioning. Here you can also 
have access to the results file or create some figures.
But running this module you will however be asked to select a tropsphere
model, an elevation mask and whether you want to use a laning method or not.
In the second section of the menu "CDGPS(amf)" you get the possibility to 
select standard proposals. For the correct use of the various linear
combinations one should have a little bit of expert knowledge and it is 
recommended to follow the literature references given in the file AMFLANE.M.
Furthermore I refer you to my Ph.D. thesis (sorry: only in german) that you
can find on the GPSLab-Website for free download. It contains all the 
algorithms this program is based on and describes the examinations for
validating the source code. In this manual you will find additional 
information relating the use of this module "CDGPS(amf)" (cf. item 3.13).
Information about literature references you can extract from the menu item
"Info: literature".

Reliable approximate coordinates are here of special interest. Actually
it turned out, that approximate coordinates from pseudorange DGPS are
not sufficient in any case and there is need for a carrier phase triple 
difference solution module. This would have to be positioned between DGPS
and CDGPS(amf), but this is not realized yet and is set on top of the list
of work on this program package.

Please do close the results file before rerunning the related module, 
because you won't get the new results displayed as long as the old is 
opened. In doubt check the processing time in the header of the results 
file.

You can store all the variables of a program run before starting a new
program run of the same or another module by selecting the menu item
"file: save workspace". Give this file a name of your own choice. If
you want to reproduce this state in a new GPSlab session after a new 
start of MatLab, load the stored file by using the command LOAD (followed
by the name of the stored .MAT-file) typing it into the command window.

The meaning of the single variables in the workspace after the run of a 
specific module is documented in "Infos: variables after call of ...".
If you need additional information risk a look into the source code.

2.9 COORDINATE TYPE CONVERSION

The menu item "Tools: coordinate conversion (...)" allows you to transform
coordinates from one representation (XYZ, latitude/longitude/height=BLh or 
GK projection coordinates) to another. For that you have to select a 
reference ellipsoid and for GK a reference meridian. You can transform
the coordinates of reference or rover found in the header files (default)
or you can change these values before pushing the OK button.
(remark: GK stands for a Gauss-Krueger projection according to the so 
called main triangular network of the german surveying administration; it
is one out of many realizations of the transverse Mercator projection as
well as UTM.

2.10 EXIT

You can exit GPSLab with and without exiting MatLab; in the second case
you can additionally select to close only the GPSLab window to keep the
the variables in the workspace or to delete them all.

2.11 BEFORE / WHILE / AFTER ITEM 1 TO 10

Informations relating the status of GPS an so on you will find in the WWW
by selecting the menu item "Info: web links: GPS information and 
observation system (BKG)". It connects your web browser to the 
corresponding web site of the german federal office for cartography and
geodesy (BKG) in Leipzig.

For all the web links it is possible that you need to start the browser
before selecting the menu item (the newer Netscape versions do not start
automatically when running a web link from MatLab).

3. description of the modules / menu items
==========================================




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Hinter den Men黳unkten verbergen sich im allgemeinen 1 bis 3 M-Files, die
nacheinander aufgerufen werden und eventuell auf 1 bis 2 Routinen (M-Files)
im Sinne von Unterprogrammen zugreifen. Einer dieser M-Files ist meistens
f黵 die Berechnung der Parameter zust鋘dig, einer f黵 das Ausgeben von 
Ergebnissen auf Textdateien und einer f黵 das Visualisieren der Ergebnisse 
in Plots, die im Graphikfenster von GPSLab dargestellt werden. Zum Teil 
werden auch Dateibrowser und Dialogfenster ge鰂fnet. Im folgenden werden
diese Hauptmen黳unkte, z.T. aber auch Untermen黳unkte zusammenfassend
als Module betrachtet. Angegeben wird der Men黷itel.
Eine Kurzbeschreibung aller Dateien finden Sie weiter unten.

3.1 File: RINEX2 Dateien importieren
-------------------------------------
conversion von RINEX Files in f黵 MatLab verwertbare Files:
W鋒len Sie nach "Rinex Import Starten" im DATEI-Men