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Results obtained using operational four-way TAR data are analyzed and compared to results obtained with both 2-station range measurements and 1-station range and angle measurements. Four-way turn around ranging (TAR) is currently in use operationally by Measat for their new satellite, M-3a (formerly M-1R). The orbital accuracies being obtained for the TAR are similar to ones obtained using classical 2-station ranging when the same two stations used for the TAR are compared. TAR does not make the satellite operations more complex however there are slightly different calibrations that need to be performed. Several cases are considered, including free space propagation and maneuver estimation, both with solar radiation pressure scale factor estimation. The test cases were analyzed using GMV's focusGEO software. The tracking scenario using the full set of tracking measurement including TAR, range, and angles yields the baseline for orbital accuracies used for comparison to the other TAR scenarios. The TAR only orbit determination produces an orbit determination that is on par with the full measurement set solution as does the TAR plus range case. Therefore the use of TAR measurements in place of more costly scenarios is a viable option for GEO satellites. The test case demonstrate focusGEO's ability to consistently mix tracking data types while estimating dynamic parameters and produce a reliable orbit determination solution from TAR measurements independent of the ground stations producing the raw measurements.

For modern mission operations, ground systems need to provide powerful means to access and exploit mission data. Key capabilities have to be addressed for satellite telemetry data including the following: 1) Ability to efficiently, reliably, and transparently maintain all mission data available for the entire mission lifetime.2) Fully integrated capability to switch between viewing real-time data and historical data from the same display.3) High performance data retrieval and analysis capabilities: archiva allows retrieving several years of telemetry in a few seconds. 4) Wide data availability to users with different roles working from different environments. 5) Flexibility and configurability for computing, storage and visualization. GMV's new generation telemetry archiving and trending component is called archiva.It provides all these identified key capabilities to the end users. archiva is one of the components of the hifly product suite, a multi-satellite telemetry and command off-the-shelf product.The design was optimized to process efficiently original data and to derive statistical data to deliver lightning fast navigation through stored data with different levels of granularity to rapidly retrieve and analyze across several years worth of data. Different statistical levels are supported, including no-loss data. For each statistical level, mean, min, max, validity and standard deviation are available.This system is typically deployed in combination with hiflyViews (hifly's component for high-end data visualisation) to deliver to the end user high-end data visualization and analysis capabilities allowing users to quickly obtain in their workstations or desktop PCs trend diagrams in just a few seconds. Data can also be viewed from a web browser through a complete web application providing easy and fast access to the archiva data. Generation of advanced reports is also supported.archiva is fully integrated with the hifly core to provide fully integrated processing and visualization capabilities for real-time and historical data. In addition, it provides an interface to easily integrate with any other real-time system. In the case of the Landsat Data Continuity Mission (LDCM), archiva has been successfully integrated with the NASA Goddard Space Flight Center real-time system (ITOS). In addition, some advanced features allow adapting to any specific mission.

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