High Precision Satellite Positioning

High-precision GNSS  is not like the single-point, code-measurement-based positioning provided by handheld or vehicle-based navigation systems. High-precision GNSS (providing cm-level or better positioning repeatability at intervals of seconds to hours) requires the simultaneous analysis of data from multiple satellites and receivers (typically two and two, respectively) to reduce or eliminate noise sources to enable a convergence in which critical ranging parameters can be resolved.  Or it requires the resolution or modeling of atmospheric and satellite biases which are provided to field stations via global or regional communications infrastructure.  

While some high-precision processing is enabled by receiver-based firmware (RTK), that requires a greater investment in field equipment (wireless and power) and the virtual elimination of raw measurements as a GPS network product.  In contrast, we bring the raw measurements into the computer for processing and archiving. We believe this is the optimal approach because it allows:

  1. Access to buffered measurement data enables the use of static processing in which data are processed over finite time periods (typically 15 minute to 24-hour intervals, depending on the application) to improve positioning precision. Having the measurements, plus the time to use them, permits the use of algorithms that can better model parameters to derive the highest precision results.
  2. Treatment of the raw measurement data as a primary network product.  Access to the raw measurements enables multi-processing and re-processing.
  3. Minimum investment in per-station hardware by eliminating infrastructure needed for firmware-based positioning.  This extends budgets.

These issues directly influenced the design and capabilities of the InteTrak software.