PPK (Post-Processed Kinematic) is a technique used in inertial navigation systems (INS) to enhance the accuracy of positioning by using post-processing of GNSS data. PPK involves the reprocessing of GNSS data after the data has been collected to achieve higher precision than real-time GNSS positioning, which is often affected by noise, multipath errors, and ionospheric delays.
How PPK Works in INS?
Data Collection – The GNSS receiver collects raw data in real-time, typically along with IMU (Inertial Measurement Unit) data, which provides accelerometer and gyroscope measurements.
Post-Processing – After the mission or data collection, the GNSS data is processed using differential corrections from a base station or a reference station. This helps eliminate errors such as atmospheric delays, clock errors, and satellite geometry issues.
Enhanced Accuracy – After processing, the corrected GNSS data is combined with the INS data to generate a more accurate position solution that has much higher accuracy than the real-time GNSS solution.
Applications of PPK in INS
✔ Aerial Surveying & Mapping – PPK is widely used in drone-based surveying for high-precision geographic mapping and land surveying.
✔ Geophysical Surveys – Used in geophysical exploration to accurately map geological features in remote areas.
✔ Autonomous Vehicles – Provides accurate positioning for autonomous navigation when GNSS signals are inconsistent or unreliable.
Advantages of PPK in INS
✔ Higher Precision – Post-processing improves GNSS positioning accuracy, making it suitable for survey-grade applications.
✔ Reduced GNSS Errors – PPK can correct for ionospheric delays, multipath errors, and other signal issues that affect real-time GNSS.
✔ Works in GNSS-Challenged Environments – Even in urban canyons or forests, PPK can still provide precise positioning after the data is processed.
Challenges of PPK in INS
✔ Time-Consuming – Since PPK requires post-processing, it takes longer to obtain results compared to real-time GNSS positioning.
✔ Requires Base Station or Reference Data – PPK depends on access to a base station or reference station for differential corrections, which may not be available in some remote locations.
