Instrument Information
IDENTIFIER urn:nasa:pds:context:instrument:uwo_meteor_radar.cmor.cmor_inst::1.1
NAME CANADIAN METEOR ORBIT RADAR (CMOR)
TYPE RADIO-RADAR
DESCRIPTION The Canadian Meteor Orbit Radar (CMOR) is located at the University of WesternOntario (UWO) meteor radar complex near Tavistock, Ontario, and has been in operationsince late 2001. It consists of three separate interferometric radars, synchronizedin transmission and reflection and operating from a single site. Details of thesystem may be found in Jones et al. (2005) and Webster et al. (2004).The three systems operate at 17.45, 29.85, and 38.15 MHz. The "orbit" component ofthe system applies only to the 29.85 MHz system which has two outlying remotestations (6.2 and 8.1 km respectively from the main site) providing reflections fromportions of the meteor trail not directly accessible from the specular reflections tothe main site. For these echoes, the interferometry from the main site providessufficient information to permit measurement of velocity vectors for individualmeteors.Each of the three systems has seven antennae and seven separate receivers. For the17 and 38 MHz systems all seven receivers are used for reception (to boost signal tonoise levels) but only five are used for determination of the measured echo directionusing interferometry. The 29 MHz system uses the two extra receivers to recordsignals from the two outlying stations.The transmit and receive antennae have broad (nearly all-sky) gain patterns. Thetransmit antenna is a vertically directed horizontally-polarized three-element Yagiwith G = 7.6 dB(i) (relative to an isotropic radiator) and a beam width to the 3 dBpoints of 30 degrees. The receive antennae are all two-element vertically directedhorizontally polarized Yagis with G = 6.5 dB(i) and beam widths of 45 degrees to the3 dB points. Directions to each echo are measured using the relative phasedifference between the antennae within each of the 5-element interferometer arrays. The interferometric error is less than 0.5 degrees for echoes with elevations above30 degrees found for simulation for echoes with SNRs of 15 dB. Due to thedegradation in interferometric accuracy at low elevations, no echoes are processedwith their nominal elevation is below 20 degrees.All receivers are cosmic noise limited. The variation in noise levels is controlledprincipally by galactic cosmic noise at HF/VHF frequencies and produces a diurnalnoise variation of 2 dB for the 29 and 38 MHz systems. The 17 MHz system suffersfrom heavy terrestrial interference during the day, limiting useful echo detectionsto night-time hours only. For the 29 MHz orbital system, the absolute minimaldetectable signal strength corresponds to meteors with radio magnitudes near +9. However, effective counting statistics for 29.85 MHz are complete only to +8 due tothe roll-off in sensitivity as the absolute detection threshold is reached - this isthe effective detection limit for the radar and corresponds to meteoroids of ~10^-7kg mass for an average velocity of 30 km/sec.References:Jones, J., P. Brown, K.J. Ellis, A.R. Webster, M. Campbell-Brown, Z. Krzemenski, andR.J. Weryk, The Canadian Meteor Orbit Radar: system overview and preliminary results,Planetary and Space Science 53, 413-421, 2005.Webster, A.R., P.G. Brown, J. Jones, K.J. Ellis, and M. Campbell-Brown, CanadianMeteor Orbit Radar (CMOR), Atmos. Chem. Phys. Discuss. 4, 1181-1201, 2004.
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REFERENCES Webster, A.R., P.G. Brown, J. Jones, K.J. Ellis, and M. Campbell-Brown, CanadianMeteor Orbit Radar (CMOR), Atmos. Chem. Phys. Discuss. 4, 1181-1201, 2004.

Jones, J., P. Brown, K.J. Ellis, A.R. Webster, M. Campbell-Brown, Z. Krzemenski, andR.J. Weryk, The Canadian Meteor Orbit Radar: system overview and preliminary results,Planetary and Space Science 53, 413-421, 2005.