Net_Diff is a software for GNSS Download, Positioning and Analysis.

It enables users to perform SPP/PPP/PPP-AR/DSPP/DPPP/RTK/PPP-RTK. All the signals of the current GPS/GLONASS/BeiDou/Galileo/QZSS/IRNSS are supported from single-frequency to triple-frequency. It can also be applied in SPP/PPP with BeiDou augmentation information (authorized user).

It supports data analysis, including coordinate plotting, coordinate comparison, satellite number, PDOP, satellite skyview, satellite visibility, cycleslip, troposphere, ionosphere, observation minus correction, positioning residuals plotting and KML file writing.

It provides GNS observation data and products download from many public FTP servers.

It also provides some useful tools such as time and coordinate system transferring, RTCM data receiving through Ntrip and TCP/IP, raw data converting, RINEX editing, ssr dumping, CLALIB and so on.

It provides a simple satellite orbit simulation.

Moreover, it supports multi-station PPP, clock estimation, DCB estimation based on GNSS net (authorized user).

We also provide online PPP/RTK Service:

http://www.shao.ac.cn/shao_gnss_ac/

http://129.211.69.159:8090/Main.aspx

Net_Diff_splash

1. Install gzip

   Click gzip-1.3.12-1-setup.exe and install gzip. 
   For example, after install it, gzip.exe is under C:\Program Files (x86)\GnuWin32\bin\
   

2. Install Net_Diff

   a) If you have installed MATLAB R2017a or MATLAB Runtime version 9.2 (R2017a) on your computer.

   Open /for_redistribution_files_only/ and click Net_Diff.exe
   

   b) If not.

   Open /for_redistribution/ and click Net_Diff_Installer_web.exe to install MATLAB Runtime and Net_Diff.exe
   Please keep your computer connected to internet while installing.
   It will take a few minutes to download MATLAB Runtime, please be patient.
   If error occurs in connecting MathWorks, try to rerun the installer, or check the firewall, proxy server or virus scanner settings.
   If error occurs in downloading MATLAB Runtime 9.2, please download or update it by hand from: 
   https://ww2.mathworks.cn/products/compiler/matlab-runtime.html
   As space is not allowed while uncomressing the downloaded files, it is better not to install Net_Diff under a directory that contains space, such as C:\Program Files\. 
   After installationg, you can find the execute file from the installed program directory, for example C:\Net_Diff\application\. 
   

3. Set environment variables

   This step is to automatically unzip the downloaded file and convert the crx file to rinex file if you want to download or update files in Net_Diff. 
   To do this, please add the path of gzip.exe (C:\Program Files (x86)\GnuWin32\bin\) and crx2rnx.exe (C:\Net_Diff\application\) to the PATH of system environment variables on your computer:
   My computer-->Properties-->Advanced system setting-->Environment variables-->Edit the PATH environment variable-->Add path
   If you have problems in setting the environment variables, you can simply copy C:\Program Files (x86)\GnuWin32\bin\gzip.exe to C:\Net_Diff\application and run Net_Diff from C:\Net_Diff\ application. 
   When running Net_Diff from the Windows Start or the Desktop, you should also copy C:\Program Files (x86)\GnuWin32\bin\gzip.exe and C:\Net_Diff\application\crx2rnx.exe to the folder of C:\Windows\System32 or Desktop.
   

• 1. If you run Net_Diff from the Windows Start or Desktop, please select the correct directory of the EOP file, Ant File and GLO%Leap file in the Input folder (C:\Net_Diff\application\Input) every time. Therefore, it is recommended to run Net_Diff from the execute file (You can also copy the folder of C:\Net_Diff\application to any other directories).
• 2. If the directory of Net_Diff.exe is not allowed to write files, try to run Net_Diff.exe from the administrator.
• 3. When updating Net_Diff, you only need to copy the updated files in for_redistribution_files_only/ to C:\ Net_Diff\application.
• 4. As for the use of Net_Diff, please refer to the help document "A guide to use Net_Diff.pdf".
• 5. The document "A Comparison of Net_Diff and RTKLIB.pdf" compares the performance of Net_Diff and RTKLIB for a better understanding of Net_Diff.
• 6. Source code is under the src branch.

For any problems or sugestions in using Net_Diff, please contact me (zhyize@163.com) or leave a message on GitHub

2018年07月24日

1. Modify GUI in Analysis panel

2. Modify RTK fix and hold mode

3. Change GLONASS satellite number from 24 to 27

2018年07月25日

1. Modify ISB model in PPP

2. Fix bugs of BeiDou PCO

2018年07月26日

1. Fix bugs in GUI

2018年08月09日

1. Modify GUI

2. Change selecting reference satellite method

3. Change settings in long baseline RTK

2018年08月17日

1. Use traditional KF algorithm in long baseline RTK and change some settings

2. Modify Galileo F/Nav and I/Nav broadcast ephemeris selection

3. Add GLONASS in RTK float solution

2018年08月21日

1. Change default ratio from 3 to 2

2. Fix bug of static long baseline RTK

2018年08月22日

1. Fix bugs in GUI

2018年08月24日

1. Change coordinate variance to 60m, modify outliers detection

2. Change troposphere constraint in long baseline RTK

2018年08月26日

1. Modify partial AR

2018年08月27日

1. Change settings for long baseline RTK

2018年08月30日

1. Change selection of reference satellite in RTK

2. Improve outlier detection in RTK

3. Change Galileo max satellite number from 31 to 36

2018年09月03日

1. Modify GUI

2018年09月06日

1. Fix bugs in GUI

2. Add GPS L2C observation

2018年09月13日

1. Fix bugs when there are too few satellites while cycle slip in RTK

2. Support Doppler selection in GUI

2018年09月16日

1. Support RINEX editing in GUI, modify GUI

2018年09月18日

1. Support Time and Coordinate Transfer in GUI.

2. Support command line file input function for Net_Diff.

2018年09月28日

1. Fix bugs in static SPP

2. Fix bugs in GUI

3. Support multi-GNSS tight combined RTK

4. Support posfile output available for RTKPLOT.

5. Support Coordinate.txt appended after Control.txt

2018年09月29日

1. Fix bugs in BDS WADS PPP mode

2. Modify GUI

2018年10月12日

1. Fix bug in BeiDou PCO of C13 for gbm

2. Modify tightly combined RTK

3. Modify GUI

2018年10月17日

1. Support GLONASS AR in tightly or loosely combined RTK

2. Modify tightly combined RTK

3. Support Android raw data convert to RINEX

4. Modify GUI

2018年10月20日

1. Fix bugs in non-L1L2 combination when using clock from sp3 file

2. Fix bugs tightly combined RTK

2018年11月08日

1. Fix bugs of single system SPP when ISB setting is true

2. Fix bugs of SPP for outlier detection

3. Fix bugs of PCV correction for Galileo and QZSS

4. Fix bugs of loosely combined GLONASS RTK

5. Change maximum time difference of RTK to 30s

6. Modify GUI

2018年11月16日

1. Support mix-frequency combination on each satellite system (only available in GUI)

2. Support mix-observation combination on each satellite system (only available in GUI)

3. Support PPP-AR (only available in GUI)

4. Support undifferenced uncombined PPP (only available in GUI)

5. Add output of ionosphere correction in uncombined PPP

6. Add phase windup correction in RTK

7. Reduce matrix size to improve processing efficiency

8. Changeable cycle slip detection threshold

9. Fix bug in LAMBDA

10. Fix bug of Galileo PCO correction

11. Modify GUI

2018年11月19日

1. Support triple-frequency undifferenced uncombined PPP (only available in GUI)

2. Change ionosphere initial value of undifferenced uncombined PPP

3. Fix bug of ionosphere correction when frequency combination is L2L3

4. Fix bug when cycle slip method is only LLI in RTK

5. Modify GUI

2018年12月14日

1. Support PPP-RTK (CLAS) (Authorized)

2. Change output file name for better parallel computing

3. Change threshold of outlier detection

4. Fix bug of IRNSS frequency

5. Modify GUI

2018年12月26日

1. Support triple-frequency ionosphere-free PPP (only available in GUI)

2. Support Android dual-frequency multi-GNSS raw data converted to RINEX

3. Fix bug of BDS PCO using new atx file in triple frequency PPP

4. Turn off time restriction of BSX file

2018年12月27日

1. Change maximum BeiDou satellite PRN to 37

2. Fix bug of satellite orbit value in sp3 file when it is 0.000

2019年01月25日

1. Support new signal of BDS (B1c/B2a) and GLONASS (G3), Galileo(E6), QZSS(L6)

2. Fix bug of doppler aided SPP/PPP

2019年02月04日

1. Support user self-named file selection in GUI

2. Fix bug of GLONASS AR

3. Speed up efficiency of matrix inversion and least square solution.

2019年02月14日

1. Add SNR depended stochastic model

2. Change elevation depended stochastic model in RTK, change phase noise from 1cm to 3mm

3. Fix bug of doppler aided RTK

4. Modify GUI

2019年02月25日

1. Support network PPP solution (Authorized)

2. Support loosely coupled PPP/INS and RTK/INS (Authorized)

3. Add threshold of success rate in AR

4. Add data-based and model-based combined AR

5. Fix bug of DCB correction for different frequency combination

2019年02月27日

1. Add ionosphere compensate in long baseline RTK

2. Use I/Nav when F/Nav is unavaliable for Galileo

2019年03月08日

1. Modify stochastic model of observations

2. Add DCB correction of L2C observation

2019年03月13日

1. Add forward and backward combined RTK

2. Fix bug of GLONASS velocity calculation

3. Add ionosphere process noise setting in long baseline RTK

4. Fix bug of GBM products download error

5. Fix bug of uncombined PPP

2019年03月20日

1. Modify tightly combined RTK

2. Modify elevation depended stochastic model

3. Fix bug of GNSS product downloading

2019年03月26日

1. Modify BDS3 PPP

2. Fix bug of RTK

3. Fix bug of BDS3 DCB correction

2019年04月04日

1. Fix bug of GLONASS IFB estimation in PPP

2. Modify EOP value selection and polar tide correction model

3. Change time difference tolerance of navigation ephemeris

4. Add WL elevation cutoff setting in RTK

5. Change ionosphere constraint and initial covariance in long baseline RTK

6. Modify GUI

2019年04月07日

1. Change code and phase raw measurement noise to 0.3/0.003m

2. Improve PPP performance in severe environment

2019年04月09日

1. Add QZSS code DISB estimation

2. Correct QZSS 1/4 cycle bias for Trimble receiver

3. Don't estimate GLONASS phase DISB when not fix GLONASS ambiguity

2019年04月15日

1. Support SSR correction based SPP/PPP

2. Support receive RTCM message from Ntrip (Adapt from goGPS)

3. Support dump RTCM SSR and conversion of various type of raw data to RINEX (Adapt from RTKLIB)

4. Change satellite velocity in ECEF

2019年05月16日

1. Fix bug of receiver type checking

2. Fix bug of non-GPS non-L1L2 frequency DCB correction

3. Fix bug of real-time broadcast ephemeris downloading

4. Fix bug of using Wuhan ultra-rapid multi-GNSS products

5. Fix bug of GLONASS IFB estimation in multi-GNSS PPP

2019年05月22日

1. Fix error of BDS observation data in RINEX 3.04 for JAVAD receiver

2019年06月07日

1. Change BDS-3 PCO value

2. Fix bug of undifferenced uncombined PPP in troposphere variance setting

3. Outtput total slant ionosphere delay rather than ionosphere correction

4. Resort broadcast ephemeris and delete dumplicated BDS ephemeris

2019年06月20日

1. Change PCO value of BDS GEO satellites when using new antenna file

2. Fix bug in reading RINEX 2 observation file

3. Change ionosphere covariance in single frequency SPP or Graphic PPP

2019年07月05日

1. Fix bug of triple-frequency PPP

2019年07月18日

1. Fix bug of Kalman Filter in RTK

2. Delete incorrect BDS ephemeris

2019年07月28日

1. Support DCB estimation

2. Surport barycentric based net solution

3. Fix bug of PPP-RTK(CLAS)

4. Support CLASLIB

2019年10月19日

1. Seperate GPS and QZSS in RTK

2. Fix bug of satellite velocity in SSR based PPP

3. Change BDS PCO

4. Fix bug of PPP ambiguity re-initialization in outlier detection

5. Fix bug of cycle slip detection in P1L1 method

6. Fix bug of initial coordinate error in Bancroft

7. Fix bug of ionosphere estimation when only psudo-range observation

2019年11月22日

1. Fix bugs of tgd correction in using BDS B1c and B2a signal

2. Fix bug of reading RINEX observation data when clock offset is larger than 0.01 s

3. Fix bug of BDS satellite type classification

4. Change BDS maximum satellite PRN to 38

5. Change QZSS PCO when using gbm products

6. Fix bug of ionosphere output

7. Fix bug of receiving RTCM message

2019年12月07日

1. Support satellite orbit simulation

2. Surport ublox for PPP-RTK(CLAS) (Tolerance of time difference and support Galileo E5b)

3. Fix bug of figure plotting

2019年12月17日

1. Support Galileo E5 signal in PPP-RTK(CLAS)

2. Improve in handing cycle slip and outlier detection

3. Change maximum BDS satellite PRN to 40

2019年12月28日

1. Support GBM new product downloading and BDS-3 PPP based on it.

2. Fix bug of BDS-3 satellite data/pilot observation, attitude mode and PCO correction.

3. Fix bug of approximate coordinate estimation.

4. Fix bug in tightly combined RTK

2020年01月03日

1. Fix bug of valid period of the Planet ephemeris file

2020年01月11日

1. Modify GUI for easier and friendier use.

2. Fix bug of ephemeris matching

3. Add observation data type of GPS

2020年02月03日

1. Fix DCB bug of BDS-3 new signals

2. Fix bug of outlier detection in uncombined PPP

3. Support different triple-frequency ionosphere-free PPP

4. Add B1IB2a combination of BDS-3

5. Fix bug in bancroft

6. Fix bug in SSR-based PPP

2020年02月11日

1. Fix bug of ocean load correction

2. Add ssr to osr and RINEX in CLAS

3. Change maximum BDS satellite PRN to 46

2020年02月22日

1. Fix bugs of DCB corrrection, observation, clock correction, and satellite PRN for BDS3

2. Add option of BDS GEO AR

3. Update the help document

2020年02月26日

1. Enable GEO satellite of BDS3

2020年03月06日

1. Support moving baseline RTK

2. Support FCB from WHU for PPP-AR

3. Fix bug of PPP-RTK(CLAS)

4. Change constraint and walking step of ionosphere parameter in uncombined PPP

5. Fix bug in reading high rate data (>1Hz)

2020年03月10日

1. Allow space among observation file name

2. Fix bug when input approximate coordinate is wrong

2020年03月13日

1. Support format of SSR file from BNC

2. Support ionosphere-free combination based RTK and PPP_AR

3. Fix bug of L5 frequency-related GPS PPP

2020年03月23日

1. Support triple-frequency RTK/PPP-AR

2020年04月07日

1. Fix bug in reading the time of the first epoch and the antenna file

2. Downweight observation during satellite eclipse period in PPP

3. Automatically change to long baseline RTK mode when baseline length exceeds 30km

4. Fix bug of cycle slip in forward+backward mode

5. Add tropospheric delay model of SHAtropE

2020年04月13日

1. Support output of receiver clock

2. Fix bug of installation directory restriction