Instruction Manual

Standard Positioning Service (SPS) Online

FCT/UNESP

Bruno C. Vani, Joao F. Galera Monico and Milton H. Shimabukuro

v. 2017-10-20

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Summary

About the SPS Online Software................................................................................3

Main features...........................................................................................................4

Instructions..............................................................................................................4

Step 1 – Input RINEX (upload)..............................................................................6

Step 2 – Choose the GNSS System and Observable.............................................7

Step 3 – Setup elevation mask and Application of Models...................................8

Step 4 – Output configuration..............................................................................8

Processing Examples...............................................................................................9

Example 1: Processing RINEX v.2.11 – GPS Data..................................................9

Example 2: Processing RINEX v.2.11 – Galileo Data...........................................12

Example 3: Submitting observation and navigation RINEX v.3.03 – Galileo Data

...........................................................................................................................13

Final Remarks.........................................................................................................14

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About the SPS Online Software

This document present Instructions for processing GPS or Galileo data with

the Software Standard Positioning Service (SPS) Online.

This scientific software was developed and has been maintained at Faculty

of Science and Technology - Univ. Estadual Paulista (FCT/UNESP) – Presidente

Prudente/Brazil, in the context of the Space Geodesy Study Group and Graduate

Programme in Cartographic Sciences.

This software is designed to be a scientific tool with applications to

research and educational purposes. Error-free solutions are not warranted. Please,

contact the authors to provide suggestions, implementations or to report any bug

or inconsistency. Corresponding authors:

• Bruno C. Vani (brunovani@ifsp.edu.br)

• Joao F. Galera Monico (galera@fct.unesp.br)

• Milton H. Shimabukuro (miltonhs@fct.unesp.br)

This software is available online at http://is-cigala-calibra.fct.unesp.br/pps

(or via the section of online softwares of the Space Geodesy Study Group

website).

The first version of the Software was released in 2012 and was capable to

process only GPS C1 data. Thereafter, the software has been maintained and

updated following the advances in the GNSS technology, such as the emerging of

Galileo satellites and the new standards for RINEX files to supply new observation

types.

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Main features

The SPS Online is designed to simulate the real conditions experienced by

several non-assisted / non-professional GNSS units. The processing is made only

considering broadcast products (ephemeris and satellite clock corrections).

The main features of the SPS Online include:

• Read user’s input RINEX files (the users can upload RINEX files

through a graphical user interface);

• Support to RINEX v. 2.11 and 3.xx: currently, the support is updated

according to RINEX v.3.0.3 specification;

• Process GPS or Galileo pseudorange observables;

• Apply broadcast products only (ephemeris and satellite clock

corrections): the system download broadcast ephemeris file from IGS

(as well as to read navigation files in RINEX format submitted by the

user);

• Possibility to apply global models for troposphere (Hopfield) and

Ionosphere (Klobuchar);

• Provide a high-level report, including the step-by-step computation to

support research and educational purposes.

A scientific paper about the software is available (in portuguese) at the

Brazilian Maganize of Geomatics (http://dx.doi.org/10.3895/rbgeo.v2n1.5441),

including theoretical background and discussions about the implementations.

Please, consider to include a citation if you apply any output of this software in

scientific research.

Instructions

The english version of the main graphical user interface is shown in Fig. 2

and will be explained in the next subsections.

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Fig. 1: Graphical user interface to upload data and setup processing

configurations..

Step 1 – Input RINEX (upload)

There are five different options to upload input RINEX data for processing:

a) Upload observation RINEX v.2.11 file: the maximum file size is 10MB.

If necessary, the file can be compressed within the “.zip” format.

b) Upload observation and navigation files (RINEX v.2.11): in this case,

the files must follow the convention for file naming (according to

RINEX v.2.11 specification). The both navigation and observation files

must be compressed within the “.zip” format before submission.

c) Upload observation RINEX v.3.xx file: the maximum file size is 10MB. If

necessary, the file can be compressed within the “.zip” format.

d) Upload observation and navigation files (RINEX v.3.xx): in this case,

the files must follow the convention for file naming (according to the

RINEX v.3.03 specification). The both navigation and observation files

must be compressed within the “.zip” format before submission.

e) Automatic upload – Brazilian RBMC Network Data: specify station

name, year and day of year. The RINEX file will be automatic loaded

from the RBMC Server. This option can be slow because the RINEX file

need to be retrieved via FTP.

If only the observation RINEX file is provided, the navigation data

(broadcast ephemeris) will be automatically downloaded from the IGS

repositories.

Notice that only the “.zip” format is accepted when submitting

compressed files. Other compression types, such as “.gz”, “.rar” and “.7z” can not

be handled and will result in errors.

Remark: the approximated coordinates (present in the header of the

observation RINEX file) will be applied for processing and used as reference

coordinates to produce graphical results (plots with positioning discrepancies

between the achieved solution epoch-by-epoch and the reference coordinates). If

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the observation RINEX file doesn’t contain approximated coordinates, the first

achieved solution will be used as reference coordinates.

Step 2 – Choose the GNSS System and Observable

There are options to choose between processing data from GPS or Galileo.

According to the chosen option (as well as the version of the RINEX file as chosen

in Step 1), the available observables will be dynamically changed in the

observables list. Ex: If you choose “Upload observation RINEX file (v.2.11)” in the

Step 1 and choose the GNSS System “Galileo” in Step 2, the observables list will

be refreshed with the available observables for this scenario (in such case, C1, C5,

C7, C8 or C6) (see Fig. 2). When processing data from RBMC, the system will

automatically refresh the observables list with the RINEX v.2.11 observables.

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Fig. 2: Select observable according to RINEX version (v.2.11 or 3.xx) and GNSS

System (GPS or Galileo).

Step 3 – Setup Elevation Mask and Application of Models

The default elevation mask is 5°, but one can setup different elevation

masks such as 10°, 15° or 20° for performance evaluation. Please notice that

increasing the elevation mask will reduce the number of satellites available and

may cause loss of availability if less than 4 satellites are available at a given

epoch.

Concerning the application of models, the user can choose between to

apply (or not) Global Models for correcting ionospheric and tropospheric

refraction. The following models are available:

a) Ionosphere (Klobuchar Model): Just mark the checkbox to apply this

model. Although designed to operate with GPS, the Klobuchar Model

can be used with Galileo as well. The Klobuchar Model demands

coefficients (ion-alpha and ion-beta) to be proper applied. If

necessary, an additional navigation file will be automatically

downloaded to obtain the alpha and beta coefficients;

b) Troposphere (Hopfield Model): Just mark the checkbox to apply this

model. Remark: the Hopfield Model demands input information about

the atmospheric conditions. There are input fields to input

temperature (C°), pressure (mbar) and relative humidity (in

percentage). These fields are optional. If not provided, the model will

input values assuming a default atmosphere.

Step 4 – Output configuration

In this step, there are options to delimit the processing, setup processing

step and decide whether to include a step-by-step report with one computation

example.

The options to delimit the processing epochs allow to setup the “start” and

“end” time for processing the observations in the observation RINEX file. If not

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provided, the system will automatically consider to process between 00:00:00 to

24:00:00.

The “step” configuration allows to reduce the sampling output of the

results. Ex: if the RINEX file is sampled at 15s, one can choose step=4 to

processing just one epoch by minute. The default step configuration is step=1,

e.g., to process all epochs from the RINEX file.

Finally, the option to “include one step-by-step computation example”

enables the creation of a high-level detailed report demonstrating how the

software works. This report will include each step of the processing, such as

selecting the observables in the RINEX file, estimating satellites position, setup

the matrixes, performing the least-squares adjustment and obtaining the results.

Typically, this report will be generated only for the first processed epoch.

Processing Examples

After to setup the configurations, please insert your email address in the

proper feld and just click OK to process data. Your email address is required only

for support purposes.

The processing response time varies according to the upload time, file size

and the output sampling rate. It’s not necessary to refresh the page while the

process is running. If the page expires, please, try to upload the file again and

click to start a new processing.

Example 1: Processing RINEX v.2.11 – GPS Data

In this example, RINEX v.2.11 from the IGS station “SPTU” was processed

with GPS observable “C1” (DOY 200/2017). The Klobuchar and Hopfield models

were applied for mitigating ionospheric and tropospheric refraction, respectively.

The output was delimited between “20:00:00” and “21:00:00”. When the

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processing is finished, the response time will be displayed and a link will be

available to check the results (see Fig. 3).

Click “View Results” to check the report with graphical results and

additional information, or click “View step-by-step example” to check the detailed

report including the numeric computation.

In the graphical report, the applied configuration are displayed. There is a

link to download the numeric results (in “.txt” format), as well as plots for

graphical representation of the solutions. One example is presented in Fig. 4,

there one can see header of the report and the plot of discrepancies between the

approximated coordinates and the achieved ones.

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Fig. 3: Processing is finished.

In the step-by-step report, the numerical results for the first epoch in the

results data set is displayed. One can use the index in the right panel to navigate

on the steps of the processing. The first step is to read the observables in the

observation RINEX. The last step is to show the achieved results (XYZ), precision

and errors.

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Fig. 4: Results in the graphical report.

Example 2: Processing RINEX v.2.11 – Galileo Data

In this example, the same data as presented in example 1 is processedwith Galileo data (SPTU, DOY 200/2017, C1 observable). The Hopfield andKlobuchar models were applied.

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Fig. 5: First steps in the extensive step-by-step log. One can use the right-block to

navigate between the steps.

Example 3: Submitting observation and navigation RINEX

v.3.03 – Galileo Data

In this example, a RINEX file in the v.3.03 is processed. In this example, weconsider both observation and navigation files submitted by the user. Followingthe RINEX v.3.03 file naming convention, the files are named as:

• pru100____R_20172000000_01H_60S_MO.rnx (mixed observation file);

• pru100____R_20172000000_01H_EN.rnx (Galileo navigation file).

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Fig. 6: Example of graphical results from Galileo processing.

The both files can be compressed within the “.zip” format and thensummited in the graphical interface.

Final Remarks

This document presented instructions for using for the scientific softwareStandard Positioning Service Online, developed at FCT/Unesp, available online at .This software is designed to be a scientific tool being available without anywarranty for research and education purposes. Please, contact one of thecorresponding authors to provide suggestions, implementations or to report anybug or inconsistency.

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Fig. 7: Processing RINEX v.3.03. The top plot shows the “.zip” file content. The

bottom plot shows the corresponding upload option.