ERMTGSRR(17)029016r1
Title*: / Summary RX-Requirement discussionfrom Source*: / WG/TG Chairman
Contact: / Michael Mahler
input for Committee*: / ERM TGSRR
Contribution For*: / Decision
Discussion / X
Information
Submission date*: / 2017-10-265
Meeting & Allocation: / ERMTGSRR#29 -
Relevant WI(s), or deliverable(s):
ABSTRACT: Summarization of discussions on RX-requirements during TG SRR#29
The current “values” for the requirements are a proposal for vehicular usage within 76 to 77GHz (covered by EN 301 091-1).
Action: clarification of the values and specification for the other EN.
Changes within Measurement standard EN 303 396
4.2 Product information
Add: Manufacturer shall declare “EUT output update rate”.
Add: Manufacturer shall declare classification of radar, see ITU M2057, …:
USRR: up to 20m ???
SRR: up to 50m
MRR: up to 100m
LRR: up to 250m
Super LRR: more than 250m
Add: Manufacturer shall declare “the typical output of the sensor”, like target tracking list, warning flag,….. (list needs to be defined and specified à definition section)
To be discussed
Add: Manufacturer to declare RF input power for RF 1dB compression point.
Add Manufacturer to declare RF input power for LF clipping point
or shall a test be prepared? Or no need?
Additional:
Action: needs to specified: EUT output update rate, Object output list, radar cycle time,…..
Action: for target simulator add an annex within EN 303 396
(TG SRR#29: A. John/Hella will prepare a first draft)
Points for new annex on radar target reflectors
· Direct reflector without Doppler shift (corner reflector, sphere, plate, …)
· Direct reflector with Doppler shift (rotating fan, …)
· Delay line reflector with or without Doppler shift (wound-up waveguide)
· Analogue electronic target reflector
· Digital electronic target reflector
Action: confirmed RCS overview for different kind of objects (related frequency) à additional annex for EN 303 396
Proposal for a new informative annex on radar sensor Rx chain:
Note: also explains why test signals and test output points are not generally available. EUT is presented as “black-box”.
Only typical EUT output information could be used, like warning light flag, detection list of object, track list of objects, …
This is necessary because on RE-D the EUT needs to work as intended (no specific test software)
Tab. X: Rx processing stages in EUT and interference evaluation.
Component / Output signal / Interference effect and impact / RemarksRx antenna / Analogue RF signal
(for each Rx channel) / Nonet.b.d / Not suitable as interference test criterion as normally no connection point available.
RF homodyne downconverter / Analogue LF signal
(for each Rx channel) / Large interference power can lead to exceeding the RF 1dB compression point. Exceeding the RF 1dB compression point can cause generation of harmonic frequencies which could be interpreted as ghost targets.
LF amplifier with bandpass characteristics / Analogue LF signal
(for each Rx channel) / Large interference power can lead to exceeding the LF 1dB compression point. Exceeding the LF 1dB compression point can cause generation of harmonic frequencies which could be interpreted as ghost targets.
AD converter / Digital values
(for each Rx channel) / Outliers. / Not suitable as interference test criterion as ADC values are not available at outer connector of sensor.
FFT / 2D spectrum
(for each Rx channel) / Increase of noise level and downgrading of S / N / Not suitable as interference test criterion as FFT spectrum normally is not available at outer connector of sensor.
Raw signal processing
(detect peaks in FFT spectrum, from peaks compute target distance, …) / At the end of each radar cycle:
List of raw targets, each described by distance, speed, azimuth angle, reliability / Reduced accuracy of raw target properties, loss of raw targets, generation of pseudo raw targets.
Object tracking
(improve result reliability by checking plausibility, …) / At the end of each radar cycle:
List of objects, each described by distance, speed, azimuth angle / Reduced accuracy of object properties, delayed generation of objects, loss of objects / Not suitable as interference test criterion here because object properties are influenced by driving situation. Given measurement setup is not a realistic driving situation.
Warning algorithm, action to vehicle brakes, … / At the end of each radar cycle:
Message to the driver or to the vehicle / Wrong warning / action, delayed warning / action. / Not suitable as interference test criterion here because warning / action is influenced by driving situation. Given measurement setup is not a realistic driving situation.
Possible changes within EN 301 091 - 1
Action/Note: It is proposed to delete 4.2.2 out of the current version of EN 301 091-1. The wanted performance criteria are now proposed in the tables below (for each RX-requirement)
It was noted: sensors for future autonomous driving could need a more detailed evaluation of new/additional RX-requirements. It was noted that could lead to a specific sub-part/new specific EN
New clause for: Receiver empty test
Test Setup:
Test Details:
- Test time = 1000 * EUT output update rate
Wanted performance
Class / Given target / Given interferer / CriterionUSRR / None * / None / No object with constant D,v properties < 5 % of all radar cycles
SRR / None * / None / No object with constant D,v properties < 5 % of all radar cycles
MRR / None * / None / No object with constant D,v properties < 5 % of all radar cycles
LRR / None * / None / No object with constant D,v properties < 5 % of all radar cycles
Super LRR / None * / None / No object with constant D,v properties < 5 % of all radar cycles
* For example by covering sensor with absorber
New clause for: Receiver sensitivity test
For discussion/other idea:
not specify the sensitivity tests like below. Alternative to perform a measurement to find out the “minimum detectable target” à these information could be used for the “Blocking Test”.
Test Setup:
Test Details:
- Test time = 1000 * EUT output update rate
- Target positioned in main beam direction
Wanted performance
Class / Given target / Given interferer / CriterionUSRR / RCS = -10dBsm @ 10m / None / 95 % probability of detection (Note)
SRR / RCS = 0dBsm @ 20m / None / 95 % probability of detection (Note)
MRR / RCS = 10dBsm @ 50m / None / 95 % probability of detection (Note)
LRR / RCS = 10dBsm @ 150m / None / 95 % probability of detection (Note)
Super LRR / RCS = -10dBsm @ 500m / None / 95 % probability of detection (Note)
Note: How many “EUT output update rates“ show the given target at the given distance with an accuracy of up to +/- 5%.
If such long measuring distances are not possible within a certified test environment, then scaled down distances and scaled down RCS, or target simulators can be used.
Updated clause: Receiver blocking test
Test Setup:
Test Details:
- Test time = 1000 * EUT output update rate
- Target positioned in main beam direction
- The interference signal source is positioned within the 3dB beam width at the operating center frequency of the RX boresight.
Note: the current explanation on the EN could be reused
Wanted performance for in-band interferer
Class / Given target / Given interferer / CriterionUSRR / RCS = -10dBsm @ 10m / 55mV/m @ FMCW / 50 % probability of detection (Note)
SRR / RCS = 0dBsm @ 20m / 55mV/m @ FMCW / 50 % probability of detection (Note)
MRR / RCS = 10dBsm @ 50m / 55mV/m @ FMCW / 50 % probability of detection (Note)
LRR / RCS = 10dBsm @ 150m / 55mV/m @ FMCW / 50 % probability of detection (Note)
Super LRR / RCS = -10dBsm @ 500m / 55mV/m @ FMCW / 50 % probability of detection (Note)
Note: How many “EUT output update rates” show the given target at the given distance with an accuracy of up to +/- 5%.
Comments:
· Modulated interferer signal does not give constant interference. To get stable results a long measurement time might be needed.
· Action: Interferer FMCW details to be defined.
· 55mV/m is equal to an 10dBm (e.i.r.p) interferer in 10m distance
Further test details:
Check for given interferer parameters whether declared RF 1dB compression point is reached.
Check for given interferer parameters whether declared LF clipping point is reached.
Wanted performance for adjacent-band interferer
Class / Given target / Given interferer / CriterionUSRR / RCS = -10dBsm @ 10m / 173 mV/m @ f = fc ± F / 85 % probability of detection (Note)
SRR / RCS = 0dBsm @ 20m / 173 mV/m @ f = fc ± F / 85 % probability of detection (Note)
MRR / RCS = 10dBsm @ 50m / 173 mV/m @ f = fc ± F / 85 % probability of detection (Note)
LRR / RCS = 10dBsm @ 150m / 173 mV/m @ f = fc ± F / 85 % probability of detection (Note)
Super LRR / RCS = -10dBsm @ 500m / 173 mV/m @ f = fc ± F / 85 % probability of detection (Note)
Note: How many “EUT output update rates” show the given target at the given distance with an accuracy of up to +/- 5%.
Comment:
· Interferer: CW as current EN version
· 173mV/m is equal to an 20dBm (e.i.r.p) interferer in 10m distance
· F= permitted operating bandwidth.
Wanted performance for remote-band interferer
Class / Given target / Given interferer / CriterionUSRR / RCS=-10dBsm @ 10m / 173 mV/m @ f = fc ± 10 × F / 95 % probability of detection (Note)
SRR / RCS=0dBsm @ 20m / 173 mV/m @ f = fc ± 10 × F / 95 % probability of detection (Note)
MRR / RCS=10dBsm @ 50m / 173 mV/m @ f = fc ± 10 × F / 95 % probability of detection (Note)
LRR / RCS=10dBsm @ 150m / 173 mV/m @ f = fc ± 10 × F / 95 % probability of detection (Note)
Super LRR / RCS=-10dBsm @ 500m / 173 mV/m @ f = fc ± 10 × F / 95 % probability of detection (Note)
Note: How many “EUT output update rates” show the given target at the given distance with an accuracy of up to +/- 5%.
Comment:
· Interferer: CW as current EN version
· F= permitted operating bandwidth.
If such long measuring distances are not possible, then scaled down distances and respectively corrected RCS, for example:
Distance scaling factor / RCS correction0,5 / -12 dB
0,1 / -40 dB
Exemplary radar cross sections and reflector dimensions
Corner reflector RCS / dBsm / Corner reflector dimension / mm @ 76 GHz / Spherical reflector dimensions(diameter in mm)
-40 / 4,4 / 11.4
-30 / 7,5
-20 / 14
-10 / 24
0 / 42
10 / 78
Alternatively, target simulators can be used like a wound-up waveguide or an electronic simulator.
Open points/for discussion:
· Some radar sensors need a Doppler reflector. They have no simple RCS formula.
· Some sensors may report blindness error in Receiver empty test.
· Values needs to be checked and approved à for each EN could be different
· followed by: usability for testing (e.g. distance values), realizable test methods
· For F: permitted or occupied bandwidth shall be used (for remote band)
· For the for adjacent-band a fixed value from the edge could be used (instead of F)
· Evaluation of ground reflections: they could influence tests in larger distances
· Points why TG SRR EUT are not comparable with maritime/avionic radars (not for the EN but for argumentation on EC level)
New: idea/discussions on NF measurement technique.
Discussions on NF measurement technique.
Slight variations in the procedures are possible. Eg move the target towards to the EUT and note the range at which is it detected, rather than check whether it is detected at a given range. This means that the operation of the EUT is the same for the detection test and the non-detection test.
One issue is the indication or output from the EUT. But this is the same issue for any type of Rx test.
Biggest problem identified is injecting the ENR noise signal in a radiated measurement.
A path loss calculation showed the noise source has to be at least 35 dB ENR. Commercially available noise sources are only up to 15 dB ENR.
So one question is: Is there a standard technique for a radiated NF measurement on a radar?
Summary:
TGSRR investigated the feasibility of a NF measurement, as described in https://docbox.etsi.org/ERM/ERMTGSRR/05-CONTRIBUTIONS/2017//ERMTGSRR(17)029015r1_Noise_Figure_approach_to_Rx_specifications.docx
Additional contribution/for discussion:
https://docbox.etsi.org/ERM/ERMTGSRR/05-CONTRIBUTIONS/2017/ERMTGSRR(17)029021_Probablity_of_Detection_approach_to_Rx_specifications.docx
The technique is interesting, but the problem is that it would have to be performed as a radiated rather than a conducted measurement.
It would not be easy for a test house to perform this test. It would require assembly of test equipment and there would be a difficulty of calibration.
No examples have been found of other bodies performing radiated NF measurements.
Other Notes
The value of Rx sensitivity (or similar) measurement is questionable.
It cannot be separated from a system performance measurement and is therefore not actually a Rx measurement.
Regarding the RED requirement to use the spectrum effectively and efficiently, the value of a measurement such as Rx NF is questionable. It could be argued that the manufacturer has to produce an EUT with a reasonable NF or he does not have a working product.
Discussed during the meeting: “function of an “Sensor””
9/9