ALFA Surveys Workshop: 10-11 december 2009

CIMA STATUSRfi update

2009 ALFA Surveys Workshop

Phil Perillat

ALFA Surveys Workshop: 10-11 december 2009

Talk Outline

• CIMA status– CIMA versions– Position errs alfa outer beams in mock data.

• RFI:– Radars, Satellites, intermods.– Monitoring available at AO.

Online: http://www.naic.edu/~phil/talks/talks.html alfaSurveys09

ALFA Surveys Workshop: 10-11 december 2009

CIMA Versions

•Moving to mock single pixel V3.2

• includes functionality of previous versions.

•Lets you specify projid for commensal observer’s files.

•Requires update of config files for mock parameters.

Name Highlights

Mock 3.2 Mock single Pixel rcvrs.Users:none

Untested

b.b

Pulsar cals

Users: p2030 pulsar search

Smart

3.1

Smart basket weaving

Users:alfalfa,ages,auds,galfacts, igalfa,

ALFA Surveys Workshop: 10-11 december 2009

CIMA: Running wapps&mock

• Scan mode (start,stop many times):– Mocks start 3 secs after wapps and finish 3 secs after

wapps. Scan takes 6 secs longer• Continuous mode (start once, leave running)

– alfalfa/p2030– Wapps run scan mode, mocks started once and left

running. No impact on wapp running.• Single pixel:

– Wapp IF=250/275, Mock IF=325 so can’t be run together (Not so nice for pulsar verification). Will fix this in the future.

ALFA Surveys Workshop: 10-11 december 2009

ALFA outer beam position errors in Mock fits files

• Problem only in mock fits files: cima and psrfits.• azPos= azCenter + azBmOffGc/sin(za)

– azBmOffGc= -azLen0*cos(th)– Th=(beamNum-5)*60 - rotationAngle

• Error was:– azPos= azCenter + azBmOffGc*sin(za)– Th=(beamNum-5)*60 + rotationAngle– All positions then back computed from az,za

• When problem was fixed: – 1/sinza: 17nov09 cimaV2.01,psrfVer:3.41– Rotation Error: 01dec09. cimaV2.02, psrfVer:3.42– See http://www.naic.edu/~phil/modhistory.html -->30nov09 – Will write program to correct positions in files.

ALFA Surveys Workshop: 10-11 december 2009

Rfi Known culprits

• Radars: (http://www.naic.edu/~phil/rfi/rfi.html)– 1330/1350 faa radar– (1261/1246),(1256,1242) Aerostat balloon– (1270),(1290) remy radar (1 or the other)– (1232,1274,1241,1256) punta salinas modeA

ALFA Surveys Workshop: 10-11 december 2009

Global Navigation SatellitesSatellite Carrier NotesGPS

L2

1227.6 Pcode:10.23 Mhz

L2C: 1Mhz

Glonass

L2

1246+k*Fs

k=-7,13

Fs=437.5 Khz

Std: .511 Mhz

hiAccuracy:5.11 Mhz

Compass2 1268.52 BPSK: 10.23 Mhz

•Galileo:(E6 1260-1300) commercial service coded.

•Giove-B launched 27apr08 uses E6.(5.115 Mhz) till 18mar09.

ALFA Surveys Workshop: 10-11 december 2009

• GPS L2 @ 1227.6 Mhz

• Glonass L2 and compass.

Examples of rfi with alfa/mocks

ALFA Surveys Workshop: 10-11 december 2009

•Compute intermods first alfa mixer to 10th order

•Use 1375 Mhz cfr – galfacts,auds,ages,p2030.

•Use 1385 Mhz cfr – alfalfa, p2030 commensal

•Examples of intermods:

•Auds:1375,1402,1425,1475,1480 birdies.

•Complete table of 1st mixer mocks/wapps, 2nd mixer mocks

•http://www.naic.edu/~phil/mbeam/problems/rdr_intermods_pdev.html

Mock/Wapp 1st Mixer Radar Intermods

Rdr

Freq:

1233

Ps

1242

PS

Aero

1248

PS

1257

PS

Aero

1246

Aero

1261

Aero

1270

Rmy

1290

Rmy

1330

FAA

1350

FAA

Mock

1375

1288

1343

1514

1333

1425

1441

1363

1394

1478

1510

1321

1408

1473

1356

1405

1466

1515

1237

1285

1431

1455

1325

1420

1475

1240

1340

1390

1525

1325

1475

1480

1325

1375

Wapp

1385

1258

1283

1303

1365

1511

1333

1418

1464

1378

1391

1500

1513

1326

1406

1475

1355

1401

1495

1255

1285

1445

1460

1380

1455

1470

1415

1440

1525

1275

1425

ALFA Surveys Workshop: 10-11 december 2009

Alfa long recovery times

• Alfa amps were taking > 30 secs to recover from radar saturation.

• sep09 bias adjusted, recovery < 1sec

• Oct09 alfa brought to labs, leds installed in amps. In lab this fixed the problem.

• Verification of recovery times waiting for final led bias adjustments.

ALFA Surveys Workshop: 10-11 december 2009

Rfi Monitoring at AO

• location= http://www.naic.edu/~phil– Rfi: fractional occurrence by month (wapp,icorr data)

• Using telescope data, compute the fraction of time the rms noise in a channel is 3 sigma > than expected.

• Display is a histogram of fractional occurrence vs frequency

– Rfi: hilltop monitoring. Plots of previous day.• Uses spectrum analyzer and an omni directional antenna. Tsys

is about 1000K, Channel width=3 Mhz, 60 sec peak holds.• /pkg/aosoft/common/bin/imgui to display individual spectra

(on AO computers) of any date.• Screen shot of program with data from a2133 data 18apr09

ALFA Surveys Workshop: 10-11 december 2009

Summary• CIMA

• Write programs to correct alfa outer beam positions for mock fits files (cimafits and psrfits).,

• Commensal observering using 2 mock spectrometers might want to migrate to Version mocksp so they can specify the 2nd project id filename(may not be worth it).

• Running mocks and wapps together, mocks start, finish 3 seconds after wapps.

• Rfi• GNS satellites at 1220-1270 cause rfi

• IDL routines to measure distance from beam. Probably can go a few days into the future and still have reasonable error.

• Radar intermods occuring in 1st/2nd mixing stages.• Questions?