On September 18, 2026, the PRIDE team released PRIDE DBAlign 1.0, an open-source toolkit for the day-boundary alignment of precise satellite products. The software is used for the day-boundary discontinuity alignment of GNSS precise orbit/clock/bias products. The source code, user manual, and processing examples are publicly available. Researchers and users in relevant fields are welcome to download and try out the software, and to provide suggestions.

Discontinuities in GNSS precise products at day boundaries can affect positioning and time/frequency transfer across days. PRIDE DBAlign aligns precise satellite products from two adjacent days to support continuous ambiguity processing across day boundaries and help mitigate day-boundary “jumps” in the GNSS solutions. We make this software package open source with the goal of promoting the implementation of United Nations (UN) International Committee on GNSS (ICG) 2025 recommendation, "Continuous GNSS Time Transfer across Day Boundaries using IGS Products" (https://www.unoosa.org/documents/pdf/icg/2025/ICG-19/ICG-19_WG-D_Recommendation_B_.pdf).

PRIDE DBAlign utilizes several library functions, header files, and table files from PRIDE PPP-AR ( https://github.com/PrideLab/PRIDE-PPPAR ), another open-source software developed by the same team. As a standalone tool, it provides product processing support for precise positioning and time transfer across day boundaries. PRIDE DBAlign supports Linux and macOS and is released under the GNU General Public License, version 3 (GPLv3).

The main features of PRIDE DBAlign 1.0 include:

1) Support for GPS, Galileo, and BDS-2/3;

2) Support for the alignment of precise satellite products on baseline frequencies (e.g., GPS L1/L2);

3) Provide a DOCB module in the Bias-SINEX format for day-boundary alignment residuals;

4) Aligned precise products are consistent with the latest IGS conventions: the Bias-SINEX bias file format;

5) An additional plotting function is provided to display day-boundary alignment residuals, facilitating data analysis for researchers.

Instructions for downloading, installing, and using the software are provided below:

1) Software download:

https://github.com/PrideLab/PRIDE-DBAlign 

2) Installation and validation:

Step 1: Make sure you have installed some essential programs in advance.

i.e. bash, make, gfortran

Step 2: Run script ./install.sh to install the program automatically.

This script builds the CUI applications using the Makefile and adds the installation directory (~/.PRIDE_DBAlign_BIN) to the system PATH. If you see the prompt shown in the picture below, the installation is completed normally.

Figure 1. Output after successful installation

Step 3: Input y/Y to run the example.

The script test.sh in example/ folder is used to validate the correctness and effectiveness of the installation and execution. Running “test.sh” executes the WUM Rapid product day-boundary alignment example. During data processing, progress and status information will be printed to the screen. After the run is complete, compare the generated result files with the reference results to verify that the software has been installed correctly and is functioning properly.

3) General operation steps

Step 1: Make sure PRIDE DBAlign has been installed successfully and that the pdba command is available in your terminal.

Step 2: If you need to customize the processing options or satellite selection, prepare a configuration file based on table/config_template in the software package. Refer to Section 4.4 of the user manual for command-line options and configuration settings.

Step 3: Prepare uncompressed precise clock (CLK), orbit (SP3), and code/phase bias (BIA) products for both the target day and the preceding day, and place all six files in the same directory.

Step 4: Run pdba with the target-day products to perform day-boundary alignment:

pdba -clk path-to-products/target-day.CLK \

-bia path-to-products/target-day.BIA \

-sp3 path-to-products/target-day.SP3 \

[-cfg path-to-config/config] [other options]

Replace the example paths with the actual product filenames. For multi-day processing, run pdba separately for each target day.

Step 5: After processing, check the aligned clock and bias products with the _aligned suffix, the algirc-MJD.out log, and the generated config_pdba_YYYYDDD configuration in the product directory. Additional _predicted CLK or SP3 files are generated when extrapolation is required. To visualize the day-boundary discontinuities and alignment residuals, run:

pdba_plot path-to-products

Plotting requires Python 3 and Matplotlib.

References

[1] Lin J, Geng J, Zhang Q (2025) Aligning GPS/Galileo/BDS satellite integer clock products across day boundaries for continuous time and frequency transfer. J Geod 99, 35.

https://doi.org/10.1007/s00190-025-01955-5

[2] Wen Q, Geng J, Deng Y, Zhang Y (2025) Validating the IGS products in mitigating day-boundary discontinuities of kinematic positioning and time transfer. GPS Solut 29, 170.

https://doi.org/10.1007/s10291-025-01929-2

[3] Geng J, Wang Y, Wen Q, Lin J, Tagliaferro G (2026) Quantifying all-frequency day-boundary discontinuities for GPS/Galileo/BDS satellite products. (under review）