v1.2.0

This release introduces a new feature: PPP-AR with Observable-specific Signal Bias (OSB) products. Currently, this feature has been tested with COD and WHU phase bias products, though occasional wrong fixing may still occur, especially with the EKF solver.

Additionally, this release includes minor bug fixes and performance improvements, along with updates to the user manual.

Bug fixes:

1. Resolve an issue in reading RINEX-2 obs files containing multi-GNSS data (e.g., Galileo and BeiDou). Only GPS and GLONASS observations will now be processed for RINEX-2.

Performance improvements:

1. Implement PPP-AR. The LAMBDA and rounding methods are used to resolve integer ambiguities for EKF and FGO solvers, respectively. The Antenna Phase Center (APC) correction is also considered for Wide-Lane fixing.
2. Correct station antenna NEU offset and PCO for spp/tdp/rtk as well
3. Enable antenna PCV correction for rtk
4. Add pseudorange OMC-based outlier detection for rtk
5. Output messages for unhealthy broadcast ephemeris as info instead of warning

Updates to pppx.ini:

1. Add a new option [estimation] ppp_ar to enable PPP-AR
2. Rename [estimation] enable_ar to rtk_ar for RTK
3. Change the default value of [estimation] sol_mode from spp to ppp
4. Enable default values for [product] src and [output] level
5. Make [table] oceanload optional