From ccarilli@aoc.nrao.edu Tue Aug 6 11:55:51 2002 Date: Thu, 01 Aug 2002 08:57:23 -0600 From: Chris Carilli To: Steve Rawlings Subject: space craft review forms Dayton Jones wrote: > Chris, > Here is my short form review of the Canadian concept from the > spacecraft tracking and navigation working group. I am sending > this to Steve Rawlings also, but I no longer have the previous > short forms I sent to you for the initial six white papers. Could > you please forward those to Steve? Thank you. I will fill out > short forms for geodesy for each concept and send them to both > you and Steve next week. > Bob Preston had a suggestion for the Groningen meeting: If we > go with serial discussions of the major issues (frequency range, > configuration, etc.) instead of parallel breakout sessions, there > should be a way to record the points made during the discussions. > This will be more difficult for a large group. Perhaps we can > find one person per major topic to act as secretary so it isn't > too onerous for any one person. > Cheers, > Dayton > > > Subject: Canadian design summary form > > Canada: LAR > ------------------------------------------------------------------------------ > Level 1 science program: Title and text here > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > A/T m^2/K 20000 1.4 GHz > > FoV sq.deg 1 1.4 GHz, 19x19 FP array > > Multibeam > number 1 many within FoV > beam sep (deg) > # subarrays > > response time s 100 > > Freq range GHz 8 and 32 0.1-22 partially meet > > Correlator: > Bandwidth GHz 4 > # spec channel > sampling time s > > Configuration: > max baseline km > 1000 ? could meet > 50% area baseline > T_b sens K > > #independent IFs 1 > max sep of IFs > > DNR: > spatial 1e5 > spectral > polarization > > # spatial pixels > > ----------------- > Special requirements: Spacings between 200m and 1 km present an > interesting challenge. > > Major problem(s): Can cover 8 GHz spacecraft telemetry band, but not higher > priority 32 GHz band. Limited sky coverage. > > Possible Compromises: It might be possible to extend frequency coverage to > include 32 GHz, but cost of this is unknown. > > Notes: total = 2 G$ (could decrease by factor 2 by decreasing > FoV by factor 4). Unblocked aperture => low sidelobes. > Loose collecting area with large zenith angle. 60 elements, 200m. > > ------------------------------------------------------------------------------ Dayton Jones wrote: > Chris, > Here is another iteration of the short review forms. I have > kept only the items directly related to the level 1 requirements > for spacecraft tracking and navigation as presented at the > Bologna SKA workshop. Not surprisingly, coverage of spacecraft > telemetry frequencies is by far the most critical of these. > I will be able to provide more info, including any feedback on > updates to the requirements from other members of the spacecraft > tracking working group, after I return on July 22. > Cheers, > Dayton > > ------------------------------------------------------------------------------ > China proposal: KARST > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.3-6 fail Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 300 fail Less critical than > frequency coverage > ----------------- > > Major problem(s): Unable to cover any spacecraft telemetry frequencies > > Possible Compromises: It might be possible to extend frequency coverage to > 8.4 GHz, but not to the higher priority 32 GHz range > > Notes: Limited sky coverage, very limited FoV, and difficulty of multi-beaming > and sub-arraying are all problems for spacecraft tracking & navigation > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------ > European Design: Integrated Aperture Arrays > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.15-1.5 fail Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 2000 meet Less critical than > frequency coverage > ----------------- > > Major problem(s): Unable to cover any spacecraft telemetry frequencies > > Possible Compromises: None forseen - limitation is imposed by ant. technology > > Notes: If the lack of high frequency coverage could somehow be resolved, this > concept has the most flexible multi-beaming and sub-arraying options > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------ > India: Preloaded parabolic dishes > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.15-10 partially meet Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 5000 meet Less critical than > frequency coverage > ----------------- > > Major problem(s): Can cover 8.4 GHz, but not higher priority 32 GHz range > > Possible Compromises: Can antennas be pushed to operate usefully at 32 GHz > using solid panels on inner areas? How much collecting > area could this approach provide at 32 GHz? > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------ > Australia 1: Refracting concentrators > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.1-5 fail Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 3000 meet Less critical than > frequency coverage > ----------------- > > Major problem(s): Unable to cover any spacecraft telemetry frequencies > > Possible Compromises: Frequency coverage might be extended to 8.4 GHz, but > not to the higher priority 32 GHz range > > Notes: If upper frequency limit could be extended, this concept has excellent > FoV, multi-beaming, and sub-arraying capabilities > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------ > Australia 2: Cylindrical Reflector > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.1-9 partially meet Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 10000 meet Less critical than > frequency coverage > ----------------- > > Major problem(s): Does not cover high priority 32 GHz spacecraft frequencies > > Possible Compromises: Can cover 8.4 GHz, but extension to 32 GHz unlikely > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------ > USA proposal: N/d > ------------------------------------------------------------------------------ > > Spec Requirement Design fail/meet/exceed comments > ---- ----------- ------- ---------------- -------- > > Freq range GHz 8 and 32 0.15-34 meet Fundamental requirement > for spacecraft tracking > Configuration: > max baseline km > 1000 5000 meet Less critical than > frequency coverage > ----------------- > > Major problem(s): None > > Possible Compromises: If necessary to reduce cost, it would be far better to > reduce the antenna efficiently at 32 GHz rather than > dropping 32-34 GHz coverage completely. > > Notes: Only concept that meets level 1 requirements for both spacecraft > telemetry reception and angular navigation > > ------------------------------------------------------------------------------ > ------------------------------------------------------------------------------