As payloads become more complex the number of RF paths to test during AIT and IOT increases significantly, which increases the overall duration of the payload testing when conventional test methods are employed. Since payload testing is on the critical path of satellite AIT and IOT activities, this leads directly to a longer program schedule with associated commercial impacts.
The test duration can be shortened considerably by using innovative test methods. These include the implementation of fast RF measurements requiring parallel TM/TC processing and a faster dialogue with the satellite platform, convergence between the operational interfaces and the test benches, as well as the ability to perform different tests simultaneously. This was evaluated during the first phase of the JAMES Project.
As a specific contribution to these global objectives, the CCN3 intended to develop and validate a RF-optical-RF interface module with multiplexing capability of 2 channels, while improving the RF performances of the overall set-up.
Specific attention had to be put on the behavior under TVAC of available optics components, most of them being off-the-shelf commercially available items.
Calibration of the whole set-up was challenging, and required a great attention and skillful care on data processing.
Major benefit from this activity is the expected simplification of Assembly Integration and Test means to be used for complex programs, as the connectivity of large payloads is actually going into significant growth.
TAS expect that introduction of optics in this area will allow to properly handle huge number of RF paths, increase the quality of our tests while keeping the schedule under control.
The final outcome of the development is a fully defined link characterization approach, involving wavelength multiplexing, and stabilized components allowing to run TVAC sequences with simplified connectivity between test set-up and payloads under test.
They will expend the James Baseline test bed capabilities, which already included:
- New techniques for performing fast RF measurements.
- Methods for telemetry data acquisition to facilitate such measurements.
- Use of flight-representative payload test signals.
- Testing over a wide bandwidth (300 MHz).
- Harmonization of AIT and IOT software.
A first test- set-up was elaborated, allowing to make a full optical interconnection of an RF payload featuring numbers of RF paths, through a set of optical devices, thus reducing significantly the number of physical paths to, implement.
This test bed was used to characterize and stabilize the performances of the links
Based on this first step, an innovative set-up was built, allowing to evaluate the potential of wavelength multiplexing in order to reduce even more the volume of HW to be included
Both steps were successfully evaluated through TVAC testing of the full chains
Links mock-up tested under CCN 3 are to be used for further activities on this overall topic of complex and innovative payloads AIT