Tool/software: Code Composer Studio
Hi ,I want to verify the values i get on the estimator.
here's the screenshot
The required configuration is:
IWR6843ODS
3Tx, 4Rx
max range 20[m]
range resolution:15[cm]
maximum velocity 23.04 Km/Hr =6m/sec
velocity resolution 0.36km/hr = 0.1 m/sec
I've loaded with a bit different configuration than this regarding the velocities because the resulting values are different:
1. as appear at the screenshot ,there are 64 doppler bins, when each bin has 0.1 [m/sec]
Therefore ,the maximum velocity is 64*0.1=6.4m/sec =6.4*3.6=23.04 Km/Hr
pay attention that at the estimator, the required max velocity is 10.8 Km/Hr
Why is it so ?
Maybe the 23.04/2=11.520 is close to 10.8 Km/hr ?
2.Range=0.9*Fs*c/(2*Slope)=0.9*3000e3*3e8/(2*7.97e12)=50[m]
While i requested 20[m]
3.Range resolution=c/(2*B)
B=Tchirp*Frequency_slope=1.057e9[Hz]
Range resolution=c/(2*B)= 0.14191[m]
While at the estimator output the range resolution appears as 0.11[m]
4. Tchirp
Tchirp=B/Frequency_slope=1.057e9/7.97e12=132.63e-6[sec]
Therefore, Tchirp is actually according to this calculation and from the estimator GUI is the ramp end time.
4. Vmax=(c/f)/(4*Tchirp)=(c/60e9)/(4*132.62e-6)=9.4254[m/sec]
This contradicts the resulting max velocity as appears from the velocity_resolutionXnumber_of_doppler_bins =64*0.1=6.4[m/sec]
Also,the Vmax = 9.4254[m/sec] = 33.931 [Km/Hr]
Please follow the calculations,
I've read other posts that showed such difference:
{
"configGenerator": {
"createdBy": "mmWaveSensingEstimator",
"createdOn": "2019-07-23T11:04:35.708Z",
"isConfigIntermediate": 0
},
"currentVersion": {
"jsonCfgVersion": {
"major": 0,
"minor": 4,
"patch": 0
},
"DFPVersion": {
"major": 1,
"minor": 2,
"patch": 0
},
"SDKVersion": {
"major": 3,
"minor": 0,
"patch": 0
},
"mmwavelinkVersion": {
"major": 1,
"minor": 2,
"patch": 0
}
},
"lastBackwardCompatibleVersion": {
"DFPVersion": {
"major": 1,
"minor": 1,
"patch": 0
},
"SDKVersion": {
"major": 2,
"minor": 0,
"patch": 0
},
"mmwavelinkVersion": {
"major": 1,
"minor": 1,
"patch": 0
}
},
"systemConfig": {
"summary": "",
"sceneParameters": {
"ambientTemperature_degC": 20,
"maxDetectableRange_m": 20,
"rangeResolution_cm": 15,
"maxVelocity_kmph": 10.8,
"velocityResolution_kmph": 0.54,
"measurementRate": 10,
"typicalDetectedObjectRCS": 1
}
},
"regulatoryRestrictions": {
"frequencyRangeBegin_GHz": 77,
"frequencyRangeEnd_GHz": 81,
"maxBandwidthAllowed_MHz": 4000,
"maxTransmitPowerAllowed_dBm": 12
},
"processingChainConfig": {
"detectionChain": {
"name": "",
"detectionLoss": 1,
"systemLoss": 1,
"implementationMargin": 2,
"detectionSNR": 12,
"theoreticalRxAntennaGain": 9,
"theoreticalTxAntennaGain": 9
}
},
"mmWaveDevices": [
{
"mmWaveDeviceId": 0,
"rfConfig": {
"summary": "",
"waveformType": "singleFrameChirp",
"MIMOScheme": "TDM",
"rlChanCfg_t": {
"rxChannelEn": "0xF",
"txChannelEn": "0x7"
},
"rlAdcOutCfg_t": {
"fmt": {
"b2AdcBits": 2,
"b8FullScaleReducFctr": 0,
"b2AdcOutFmt": 2
}
},
"rlLowPowerModeCfg_t": {},
"rlProfiles": [
{
"rlProfileCfg_t": {
"profileId": 0,
"pfVcoSelect": "0x0",
"pfCalLutUpdate": "0x0",
"startFreqConst_GHz": 60,
"idleTimeConst_usec": 5,
"adcStartTimeConst_usec": 6.4,
"rampEndTime_usec": 132.73333333333332,
"txOutPowerBackoffCode": "0x0",
"txPhaseShifter": "0x0",
"freqSlopeConst_MHz_usec": 7.966160774230957,
"txStartTime_usec": 1,
"numAdcSamples": 376,
"digOutSampleRate": 10000,
"hpfCornerFreq1": 0,
"hpfCornerFreq2": 0,
"rxGain_dB": "0x1E"
}
}
],
"rlChirps": [
{
"rlChirpCfg_t": {
"chirpStartIdx": 0,
"chirpEndIdx": 0,
"profileId": 0,
"startFreqVar_MHz": 0,
"freqSlopeVar_KHz_usec": 0,
"idleTimeVar_usec": 0,
"adcStartTimeVar_usec": 0,
"txEnable": "0x1"
}
}
],
"rlRfCalMonTimeUntConf_t": {
"calibMonTimeUnit": 1
},
"rlRfCalMonFreqLimitConf_t": {
"freqLimitLow_GHz": 77,
"freqLimitHigh_GHz": 81
},
"rlRfInitCalConf_t": {
"calibEnMask": "0x1FF0"
},
"rlRunTimeCalibConf_t": {
"oneTimeCalibEnMask": "0x0",
"periodicCalibEnMask": "0x0",
"calibPeriodicity": 10,
"reportEn": 1,
"txPowerCalMode": 0
},
"rlFrameCfg_t": {
"chirpEndIdx": 0,
"chirpStartIdx": 0,
"numLoops": 41,
"numFrames": 0,
"framePeriodicity_msec": 16.933
}
},
"rawDataCaptureConfig": {
"rlDevDataFmtCfg_t": {
"iqSwapSel": 0,
"chInterleave": 1
}
},
"monitoringConfig": {}
}
]
}
Thank you
Gil
