Radar Data Samples Taken at Arecibo, April 8, 2000

Rick Fisher, NRAO, Green Bank, WV

Contents

Introduction

On Sunday, April 8, 2001, Phil Perillat (NAIC), Steve Ellingson (OSU), and I recorded a variety of radar signals seen by the 1.1-1.8 GHz Arecibo radio astronomy receiver. The planetary radar complex sampler was used for data acquisition. Four radar signals were recorded: an air traffic control radar at 1350 MHz, the Aerostat radar at 1261.2 MHz, and AN/FPS-117 radar at 1232.75 MHz, and an unknown radar at 1269.0 MHz. An unknown pulsed signal at 1106 MHz was alo recorded. A few properties of the signals can be found at Phil Perillat's NAIC site, but other details are expected to be derived from the data.

The geographic coordinates of the FAA radar at 1330/1350 MHz are 18 deg 16' 14.3" N, 65 deg 45' 31.2" W. The Aerostat balloon tether point is at 17 deg 58' 45" N, 67 deg 04' 55" W. For more specs click here.

The receiver conversion chain used in these measurements is shown in Figure 1. This is the "L-Wide" receiver used for HI and OH astronomical observations at Gregorian focus of the Arecibo telescope. The Gregorian reflector/receiver system was parked at azimuth 450 degrees, zenith distance 10 degrees.

Figure 1. Arecibo telescope "L-Band-Wide" receiver conversion path and data sampler.

Data Format

Twenty five data files were recorded, each 101,340,224 bytes long. The first 8 files involved experiments with the sampling rate and baseband filter bandwidth before settling on the best parameters. The last two files contain calibration data: white, high level noise and a pure sine wave. Each radar was recorded three times for about 15 seconds separated by 5-minute intervals to provide radar 'pictures' than can distinguish between moving and fixed-location echoes. The A/D convertor full scale is +/-2.5 Volts (20 mV digitization level spacing), and the rms noise level was usually set to about 70 mV.

The data format is the standard Arecibo planetary radar binary data format in groups of 60,000 data bytes consisting of 30,000 complex data samples (2, two's complement, 8-bit words for I and Q) preceded by a 792-byte header. The header is defined by several C-language header files available from me along with a C program for printing out the first header as shown in the appendix below.

Data Files

Any or all of the data files are available from me on request. Below is a brief description of each with the following mnemonics: CF is the RF center frequency corresponding to 0 Hz baseband; AST is the approximate Atlantic Standard Time when the data were recorded (see data header for more exact time); SN is the scan number; BW is the baseband filter bandwidth; and SP is the complex data sample period.

FAA airport or air traffic control radar

File: rfradar.000, CF=1350 MHz, AST=10:39, SN=109800007, BW=1.0 MHz, SP=0.5 seconds, too much aliasing due to combination of bandwidth and sample period.

File: rfradar.001, CF=1350 MHz, AST=10:44, SN=109800008, BW=1.0 MHz, SP=0.5 seconds, too much aliasing due to combination of bandwidth and sample period.

File: rfradar.002, CF=1350 MHz, AST=10:49, SN=109800009, BW=1.0 MHz, SP=0.5 seconds, too much aliasing due to combination of bandwidth and sample period.

File: rfradar.003, CF=1350 MHz, AST=11:00, SN=109800010, BW=0.9 MHz, SP=0.5 seconds, too much aliasing due to combination of bandwidth and sample period.

File: rfradar.004, CF=1350 MHz, AST=11:11, SN=109800011, BW=0.9 MHz, SP=0.3 microseconds, first useful data set.

File: rfradar.005, CF=1350 MHz, AST=11:19:30, SN=109800012, BW=0.9 MHz, SP=0.3 microseconds, mistake of one of complex sample signals disconnected.

File: rfradar.006, CF=1350 MHz, AST=11:24:30, SN=109800013, BW=0.9 MHz, SP=0.3 microseconds, mistake of one of complex sample signals disconnected.

File: rfradar.007, CF=1350 MHz, AST=11:29:30, SN=109800014, BW=0.9 MHz, SP=0.3 microseconds, mistake of one of complex sample signals disconnected.

File: rfradar.008, CF=1350 MHz, AST=11:33:00, SN=109800015, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.009, CF=1350 MHz, AST=11:40:40, SN=109800016, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.010, CF=1350 MHz, AST=11:45:40, SN=109800017, BW=0.9 MHz, SP=0.3 microseconds.

Aerostat radar

File: rfradar.011, CF=1261.2 MHz, AST=11:57:30, SN=109800018, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.012, CF=1261.2 MHz, AST=12:13:20, SN=109800019, BW=0.9 MHz, SP=0.3 microseconds, 14 dB of gain added to programmable filter.

File: rfradar.013, CF=1261.2 MHz, AST=12:19:00, SN=109800020, BW=0.9 MHz, SP=0.3 microseconds.

AN/FPS-117 radar

File: rfradar.014, CF=1232.75 MHz, AST=13:30:40, SN=109800021, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.015, CF=1232.75 MHz, AST=13:35:40, SN=109800022, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.016, CF=1232.75 MHz, AST=13:40:40, SN=109800023, BW=0.9 MHz, SP=0.3 microseconds.

Unknown air trafic control radar

File: rfradar.017, CF=1269.0 MHz, AST=13:58:10, SN=109800024, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.018, CF=1269.0 MHz, AST=14:03:10, SN=109800025, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.019, CF=1269.0 MHz, AST=14:08:15, SN=109800026, BW=0.9 MHz, SP=0.3 microseconds.

Unknown pulsed signal also seen at 1110 and 1130 MHz

File: rfradar.020, CF=1106.0 MHz, AST=14:21:30, SN=109800027, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.021, CF=1106.0 MHz, AST=14:26:30, SN=109800028, BW=0.9 MHz, SP=0.3 microseconds.

File: rfradar.022, CF=1106.0 MHz, AST=14:31:36, SN=109800029, BW=0.9 MHz, SP=0.3 microseconds.

Calibration signals

File: rfradar.023, CF=N/A, AST=15:00:30, SN=109800030, BW=0.9 MHz, SP=0.3 microseconds, white noise approximately 400 mV rms.

File: rfradar.024, CF=N/A, AST=15:07:00, SN=109800031, BW=0.9 MHz, SP=0.3 microseconds, sine wave at 0.8333333 MHz baseband injected before last mixer at 260.8333333 MHz.

Header Example Appendix

Data header information as printed out by a C-language program available from the author.

hdrMarker : hdr_
hdrlen    : 792
reclen    : 60792
id        : riraw   
version   :  2.1
date      : 2001098
time      : 51672   seconds since midnite (end of record)
expNumber : 1234
scanNumber: 109800027
recNumber : 1
stScanTime: 51672
HDRAO_SEC:
  inp : 17301552
  iflo: 170459272
  proc: 0
  time: 0
  pnt : 186253552
  misc: 218824944
grpNum    : 1
grpTotRecs: 1
grpCurRec : 1
dataType  : p  
azTTD     : 4500002  (az position end rec. 1/10000 degrees)
grTTD     : 100000  (gr position end rec. 1/10000 degrees)
chTTD     : 88344  (za position end rec. 1/10000 degrees)
posTmMs   : 51671028  (position time stamp millisecs)
hdrlen    : 792
reclen - hdrlen : 60000
sizeof(HDRAO_STD): 128

Radar Interface Header:
extTiming      : 0       (FALSE: use rtg timing)
smpMode        : 1       (-1: ipp no gwcount, 0: acontinuous,
                          1: ipp with gwCnt)
packing        : 8 bits
muxAndSubCycle : 0       (0: none, 1: mux, 10: cyclemode, 11: both)
fifoNum        : 1       (1, 2, or 12)
smpPairIpp     : 30000       (smp 1 pair/ipp)
ippsPerBuf     : 1       (ipps in 1 buf)
ippNumStartBuf : 1       (varies each rec.1st ipp of buf. cnt from 1)
ipp            :  9000.0 (ipp in usecs .1 usec accuracy)
gw             :     0.3 (gw in usecs .1 usec accuracy)
startOn        : 1       (0: immediate, 1: 1-sec tick,
                          10: 10-sec tick, 99: external tick)
sizeof(HDRAO_RI): 48

id       : proc
ver      :  1.0
procName : calonoff
procVer  : 1.0
srcName  : 21305+2118
dar      : 0.000000 0.000000
         : 0.000000 0.000000
         : 0.000000 0.000000
         : 0.000000 0.000000
         : 0.000000 0.000000
iar      : 10  0
         :  0  0
         :  0  0
         :  0  0
         :  0  0
car      : 111 102 102   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
         :   0   0   0   0   0   0   0   0
sizeof(HDRAO_PROC): 240

id             : pnt 
ver            : 1.0 
PNTHDR_MEASURED:
  azTTD          : 4500002
  grTTD          : 100000
  chTTD          : 88344
  agcTmStamp     : 51671028
  turPosRd       : 5.000704
  turTmStamp     : 51671000
  tdPosIn        : 11.066006 10.806978 9.433997
  tdTmStamp      : 51671000 51671000 51671100
  platformHgt    : -0.000000 -0.000000 -0.000000
  platformTemp   : -0.000000
  platformTmStamp: 0
  terPos         : -0.000000 -0.000000 -0.000000
  terTmStamp     : 0
PNTHDR_REQ:
  ut1Frac        : 0.764711
  lastRd         : 0.796125
  mjd            : 52007
  yearDaynum     : 2001098
  reqPosRd       : 7.853981 0.174533
  reqOffRd       : 0.000000 0.000000
  reqRateRdSec   : -0.000000 -0.000000
  dayNumAstRateStart: 0.000000
  raJCumRd       : 0.612312
  decJCumRd      : 0.315259
  geoVelProj     : -0.000000
  helioVelProj   : -0.000035
  posCorrectionRd: 0.000000 0.000000
  modelLocDeg    : 0.000000 0.000000
  secMid         : 51671
errAzRd     : -0.000003
errZaRd     : 0.000000
PNTHDR_STAT:
  modelCor       : 1
  grMaster       : 1
  tracking       : 1
  coordValid     : 1
  coordSysPos    : 10
  coordSysOff    : 0
  coordSysRate   : 0
  allOk          : 1
  tdOk           : 1
  turOk          : 1
  terOk          : 0
  lrOk           : 0
  pntOk          : 1
  agcOk          : 1
sizeof(HDRAO_PNT): 240

id             : iflo
ver            :  1.0
HDRAO_IF1:
  IF1_HDR_STAT1:
    rfNum          : 5
    ifNum          : 2
    hybridIn       : 0
    lo1Hsd         : 1
    lbwLinPol      : 0
    syn1RfOn       : 1
    syn2RfOn       : 1
    lbFbA          : 16
    lbFbB          : 16
    useFiber       : 1
  IF1_HDR_STAT2:
    calRcvMux      : 5
    calType        : 0
    ac1PwrSw       : 0
    ac2PwrSw       : 3
    zmNormal       : 1
    zmDiodeOn      : 0
    zmDiodeToA     : 1
    sbShClosed     : 1
    lo2Hsd         : 15
  rfFrq         : 1106000000.000000
  lo1           : 1856000000.000000
  IF1_HDR_ATTN:
    rf             : 10 10
    ifA            : 0 0
    zm             : 0 0
    zmNDLev        : 0
  pwrDbm        : -39.902279 -39.884995
  pwrTmStamp    : 51504
  hybLoPh       : 0
  hybSigPh      : 0
HDRAO_IF2:
  synFreq       : 1010000000.000000 1010000000.000000
                : 1010000000.000000 1010000000.000000
  IF2_HDR_STAT1:
    ifInpFreq      : 2
    vlbaInpFrq     : 1
    xferNormal     : 1
    sbDopTrack     : 0
    noiseSrcOn     : 0
    dualPol30      : 1
    vis30Mhz       : 0
    calttlSrc      : 1
    pwrMToIf       : 1
  IF2_HDR_STAT4:
    Mixer1:
      synDest        : 3
      mixerCfr       : 0
      ampInpSrc      : 1
      ampExtMsk      : 7
    Mixer2:
      synDest        : 3
      mixerCfr       : 0
      ampInpSrc      : 1
      ampExtMsk      : 55
    Mixer3:
      synDest        : 3
      mixerCfr       : 0
      ampInpSrc      : 1
      ampExtMsk      : 23
    Mixer4:
      synDest        : 3
      mixerCfr       : 0
      ampInpSrc      : 1
      ampExtMsk      : 39
  pwrDbm        : -45.829628 -49.620945
  pwrTmStamp    : 51510
  gain          : 12 12
sizeof(HDRAO_IFLO): 136

Last modified April 17, 2001

rfisher@nrao.edu

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