AVIGA Professional

Analysis of Visibility, Integrity, Geometry and Availability of global navigation satellite systems and their satellite and ground based augmentation systems

To download the AVIGA flyer in PDF format, please click here.

Areas of Application

AVIGA Professional (hereinafter AVIGA) provides for solution of the following tasks:

  • Prediction of satellite positions/velocities in ECEF frame for GPS, GLONASS, Galileo or user-defined satellites.

  • Analysis of satellite Visibility and DOP characteristics:

    • at a given space-time point for mask skyline angles specified by the user;

    • at regular space-time points within a definable geographic area.

  • Analysis of degraded Visibility & DOP characteristics.

  • Analysis of maximum, minimum, average Visibility & DOP characteristics.

  • Analysis of position accuracy based on DOP values.

  • View satellite positions on the azimuth/elevation sky plot.

  • Analysis of Integrity/Continuity characteristics.

  • Analysis of XPL/XNSE characteristics.

  • Analysis of Availability characteristics.

  • Analysis of GNSS characteristics along a specified air route.

Features

  • Automated downloading of the latest GPS and GLONASS almanacs from FTP servers

  • In the Visibility and Geometry tasks the user can simulate up to three satellite constellations amounting to a total of 180 satellites. Predefined constellations (based on almanacs e.g. for GPS, GLONASS or the Galileo theoretical constellation) or a user-defined constellation based on Kepler parameters. Additionally, the user can simulate pseudolites and geostationary satellites as fixed WGS-84 points.

  • A weighted observational matrix is used for altitude aiding.

  • Simplified position accuracy analysis at 67%, 95%, and 99.7% probability levels using DOP calculation results.

  • To account for probable satellite failures, the user can apply the operational probability model for each constellation based either on Durand-Caseau approach, or directly specifying failure probability coefficients for each constellation.

  • Analysis of Integrity/Continuity characteristics provided by the XPLsbas/raim approach. The basic input parameters for RAIM FD/FDE snapshot algorithms are false alarm and missed detection probabilities.

  • SBAS protection level XPLsbas is computed in accordance with RTCA/DO-229B.

  • Possibility of user input of K-values for the computation of SBAS protection levels.

  • The critical satellites concept is included in the XPL availability computation.

  • Stanford plot for analysis of Integrity/Continuity characteristics.

  • Computation of XDOP/XNSE 67th, 95th, and 99.7th percentiles directly from the simulated distributions.

  • The UERE can be defined in tabulated elevation dependent form.

AVIGA Professional offers the simulation of the following further features:

  • Galileo Module V1 (Integrity Concept according to USALGREQ document – Ref. 1) with

    • Galileo SISMA calculation

    • Galileo XNSE/XPL based on Galileo Integrity concept as specified in the Ref.1

    • Min, Max, Average XNSE/XPL with up to 6 planes in the 3dim output graph

    • Availability of Galileo XPL based on Galileo Integrity concept as specified in Ref.1.

  • Galileo Module V2 (new Integrity Concept based on Galileo Industries Publication at ION-GNSS 2004 – Ref. 2)

    • The new Galileo Integrity concept based on the direct computation of the Integrity Risk is implemented as a further module. This concept was published by Galileo Industries at the ION-GNSS 2004 conference (Ref. 2).

    • Computation of XPL based on the Integrity Risk.

  • GBAS / Local Element Module

    • The GBAS Module allows to determine the availability of Integrity of a GBAS according to the algorithms as specified in RTCA Do-245A and RTCA Do-253A. This module includes the computation of:

      • UDRE Model

      • XNSE Model

      • Predicted LPLs and VPLs

      • VPLH0 and HPLH0

      • Ephemeris error position bounds

      • Availability characteristics like

        • Availability of Accuracy

        • Availability of Integrity

        • Availability of Continuity

        • Availability of Service.

      The accuracy requirement parameters can be defined in form of GAD and AAD tables according to Do-245A or new tables can be defined by the user. Several inputs can be done by the user concerning the ground subsystem and the airborne performance, according to Do-245A and Do-253A. The user can also consider Do-253A Minimum or Maximum signal level as alternative to AAD(Do 245A).

    • The Galileo Local Element module further allows more flexible inputs for the performance computation of a Galileo Local Element. UDRE modelling can be considered as:

      • According to Do-253A

      • Constant

      • Elevation dependent

      • Residual Differential error components

  • AVIGA output results can be embedded into other Windows applications, for example MS Word. The documents allow different graphic representations: 2D plots, 2D static/animated area graphs, and 3D static/animated area graphs. The document images can be saved to either one of BMP, JPG, PNG formats. Besides, there is an option to save numerical results to ASCII files e.g. compatible with MS Excel.

AVIGA uses standard almanacs: ICD-200, ICD GLONASS, YUMA GPS / GLONASS, RINEX2 GPS / GLONASS. For Galileo and user-defined constellations, Keplerian almanacs are used.

AVIGA is running under WIN2000/XP and requires approximately about 30 MB of disk space.

Please contact us for information about pricing.

Examples

VNSE/VPL availability over 1°x1° grid in 5 minute steps over the 10day Galileo repeat cycle
VNSE/VPL availability over 1°x1° grid in 5 minute steps over the 10day Galileo repeat cycle

 

 

GPS+Galileo APV-II vertical RAIM availability considering space segment operational outages
GPS+Galileo APV-II vertical RAIM availability considering space segment operational outages

 

Galileo ground segment to satellite depth of coverage
Galileo ground segment to satellite depth of coverage

 

SISMA using 3-parameter estimation
SISMA using 3-parameter estimation

 

Maximum Galileo integrity risk (10day repeat cycle)
Maximum Galileo integrity risk (10day repeat cycle)

 

Snapshot view of the Galileo integrity risk probability in a normalised and logarithmic form
Snapshot view of the Galileo integrity risk probability in a normalised and logarithmic form

 

Galileo VPL availability
Galileo VPL availability