Portable Footprint Monitoring involves using a temporary ‘flyaway’ receiver, in a number of selected locations (typically 4 locations) and to qualify new satellites, in particular during Begin-Of-Life operations as well as for regular in orbit testing.
The Portable Footprint Measurement system (PFMS) measures the transponder downlink PFD (Power Flux Density) and calculates the corresponding EIRP (Effective Isotropic Radiated Power). The four PFMS station antenna systems are designed to autonomously measure the satellite transponder’s EIRP. The system is automatically calibrated by a noise source and can be operated remotely. EIRP data is stored on a local disc and can be downloaded remotely. The system is synchronized to GPS.
A number of factors must be considered in chosing a location and PFMS location provider. Key among these factors are:
- Line of Sight
- Onsite support staff/expertise
- Connectivity: Ethernet or wireless link for data transmission to central location
- Back up Electrical supply (e.g. UPS) for guaranteed 24/7 operating capacity
- Relevant Government spectrum licenses if required
- Facilities for staff on 24hour testing duty.
CASE STUDY
On 19 August 2011, Astra set up a PFMS station on location at Elfordstown Earthstation. Elfordstown was selected, along with 3 other flyaway locations, to facilitate testing of Astras 1N satellite, launched earlier in the month from French Guiana.
For the duration of the testing phase, the satellite was positioned at 2deg east, and then moved to a temporary location at 28.2 east where it entered commercial service. Later in 2012 it will be moved to its permanent location at 19 deg east.
Data received over the week long testing period was sent via ethernet from Elfordstown to Astra’s headquarters in Betzdorf in Luxemburg. All four PFMS locations reported ‘as expected’ coverage, and tests were deemed successful.