New radar research overcomes nearly century-old trade-off between wavelength and distance resolution...

F

Fred Bloggs

Guest
\"New interference radar functions employed by a team of researchers from Chapman University and other institutions improve the distance resolution between objects using radar waves. \"

\"This first proof-of-principle experiment opens a new area of research with many possible applications that can be disruptive to the multi-billion dollar radar industry.\"- okay


\"By employing functions with both steep and zero-time gradients, the researchers showed that it was possible to measure extremely small changes in the waveform to precisely predict the distance between two objects while still being robust to absorption losses. To an archaeologist, this creates the ability to distinguish a coin deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html
 
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html
Click to expand...

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX
 
On 2023-08-07 21:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX
Click to expand...

This looks a lot like some guys totally ignorant of common radar
practice who re-invented the wheel and think they were the first
to do so.

Jeroen Belleman
 
On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.
Click to expand...

It looks suspiciously like PR word salad to me.

But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.
Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX
Click to expand...


--
Martin Brown
 
Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.

But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX
Click to expand...

Looks like pretty vanilla wavelet stuff at first glance.

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
 
On Monday, August 7, 2023 at 9:08:55 PM UTC+1, jeroen wrote:
On 2023-08-07 21:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX

This looks a lot like some guys totally ignorant of common radar
practice who re-invented the wheel and think they were the first
to do so.

Jeroen Belleman
Click to expand...

Exactly. Evaluated and used very similar concepts in the mid 80\'s.
 
On a sunny day (Mon, 7 Aug 2023 20:34:38 -0000 (UTC)) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<uarkgu$30j9v$1@dont-email.me>:

Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.

But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX




Looks like pretty vanilla wavelet stuff at first glance.
Click to expand...

Right, nothing really new there that I would not have tried at home...
 
On Monday, August 7, 2023 at 11:41:34 PM UTC-4, Jan Panteltje wrote:
On a sunny day (Mon, 7 Aug 2023 20:34:38 -0000 (UTC)) it happened Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote in
uarkgu$30j9v$1...@dont-email.me>:
Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:
On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03 AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.

But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.

Maybe a couple of chirps would be enough for that sort of thing.

-- john, KE5FX




Looks like pretty vanilla wavelet stuff at first glance.
Right, nothing really new there that I would not have tried at home...
Click to expand...

They\'re not exactly premium grade experimentalists bragging about driving an ARB into a digital acquisition scope and acting amazed with how this totally unrealistic experiment worked out so well.
 
On Mon, 7 Aug 2023 21:17:40 +0100, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03?AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.
Click to expand...

I did mostly follow it, but will re-read it when I have more time.


But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.
Click to expand...

They were designed for the overlapping echoes to interfere, yielding a
super-resolution peak.


>> Maybe a couple of chirps would be enough for that sort of thing.

I suspect that chirps don\'t have the needed special properties.

Which may be a big problem in practice, because extreme pulse
compression is needed to achieve sufficient total pulse energy on
target with a practical amplifier chain, and without causing the air
in front of the antenna from turning into a plasma fireball, the
reflected pulse energy blowing the receiver channels.

Joe Gwinn
 
On 2023-08-08 10:38, Joe Gwinn wrote:
On Mon, 7 Aug 2023 21:17:40 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03?AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.

I did mostly follow it, but will re-read it when I have more time.


But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.

They were designed for the overlapping echoes to interfere, yielding a
super-resolution peak.


Maybe a couple of chirps would be enough for that sort of thing.

I suspect that chirps don\'t have the needed special properties.

Which may be a big problem in practice, because extreme pulse
compression is needed to achieve sufficient total pulse energy on
target with a practical amplifier chain, and without causing the air
in front of the antenna from turning into a plasma fireball, the
reflected pulse energy blowing the receiver channels.

Joe Gwinn
Click to expand...

Yup. There\'s a lot more to the SNR and processing gain than just the
time-domain waveform, for sure.

I\'m not a radar guy, but have built a lot of high-resolution coherent
lidars, including FMCW and fancy chirp things to do fast combination
scanning. (By chirping a diode laser and using a compound
diffraction-grating gizmo, you can combine fast scanning with
range/Doppler disambiguation.)

In that world, it\'s all about your SNR.

For ground-penetrating radar, I imagine that the clutter problem would
be the main issue.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Tuesday, August 8, 2023 at 11:53:47 AM UTC-4, Phil Hobbs wrote:
On 2023-08-08 10:38, Joe Gwinn wrote:
On Mon, 7 Aug 2023 21:17:40 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 07/08/2023 20:54, John Miles, KE5FX wrote:
On Monday, August 7, 2023 at 7:36:03?AM UTC-7, Fred Bloggs wrote:
\"By employing functions with both steep and zero-time gradients,
the researchers showed that it was possible to measure extremely
small changes in the waveform to precisely predict the distance
between two objects while still being robust to absorption losses.
To an archaeologist, this creates the ability to distinguish a coin
deep underground from a pottery shard.\"

https://phys.org/news/2023-08-radar-century-old-trade-off-wavelength-distance.html

That actually is pretty interesting. One of those obvious-in-retrospect ideas. I don\'t
know what \"functions with both steep and zero time gradients\" are, but it\'s not hard
to imagine a couple of independent outgoing signals modulated with Gold codes or
something similar, which you could use to help resolve the carrier phases of the
reflected signals.

It looks suspiciously like PR word salad to me.

I did mostly follow it, but will re-read it when I have more time.


But they might just be onto something iff their claims can be verified
independently. They got it into Phys Rev Lett here:

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.131.053803

The waveform doesn\'t look anything like as special as I expected to see.

They were designed for the overlapping echoes to interfere, yielding a
super-resolution peak.


Maybe a couple of chirps would be enough for that sort of thing.

I suspect that chirps don\'t have the needed special properties.

Which may be a big problem in practice, because extreme pulse
compression is needed to achieve sufficient total pulse energy on
target with a practical amplifier chain, and without causing the air
in front of the antenna from turning into a plasma fireball, the
reflected pulse energy blowing the receiver channels.

Joe Gwinn

Yup. There\'s a lot more to the SNR and processing gain than just the
time-domain waveform, for sure.

I\'m not a radar guy, but have built a lot of high-resolution coherent
lidars, including FMCW and fancy chirp things to do fast combination
scanning. (By chirping a diode laser and using a compound
diffraction-grating gizmo, you can combine fast scanning with
range/Doppler disambiguation.)

In that world, it\'s all about your SNR.

For ground-penetrating radar, I imagine that the clutter problem would
be the main issue.
Click to expand...

Clutter, point and distributed, extended target, and multipath, maybe more, will make this quite a mess, maybe more of a mess. Not real sure, but the amplitude modulation will need to be encoded in FM or PM, for compatibility with modern power amps.

Way to plug yourself...you go.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
Click to expand...
 
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