Literature on remote sensing

Hi all.

I am involved in a project where we want to measure a
physical quantity by means of acoustics. We have tried
ultrasound pulse signals with a certain amount of
success, but it seems we have pushed the system
to the edge of the envelope. So we need to explore other
options to reach the goal of the project.

My background is from seismics and underwater
acoustics where all attention is focused on pulsed
signals. I need to read up on other ways of doing
things. I presume "other ways" mainly means "radar",
but "tomography" may also be relevant.

Basically, I need tips on literature. The ideal book(s)
would be general in scope but on an advanced level.

I have heard of the Skolnik book, but I can't find it.
Well, I can, but the book is a bit dated (it was
published in the mid 60s?), and I would like to hear
if there are newer texts on general radar processing
available before spending time and $$ on finding the
Skolnik text. 

Rune

Rune Allnor wrote:
> Hi all.
>
> I am involved in a project where we want to measure a
> physical quantity by means of acoustics. We have tried
> ultrasound pulse signals with a certain amount of
> success, but it seems we have pushed the system
> to the edge of the envelope. So we need to explore other
> options to reach the goal of the project.
>
> My background is from seismics and underwater
> acoustics where all attention is focused on pulsed
> signals. I need to read up on other ways of doing
> things. I presume "other ways" mainly means "radar",
> but "tomography" may also be relevant.
>
> Basically, I need tips on literature. The ideal book(s)
> would be general in scope but on an advanced level.
>
> I have heard of the Skolnik book, but I can't find it.
> Well, I can, but the book is a bit dated (it was
> published in the mid 60s?), and I would like to hear
> if there are newer texts on general radar processing
> available before spending time and $$ on finding the
> Skolnik text. 
>   
The second edition of the Skolnik book was published around 1980, and 
was substantially updated. However, it is still heavily biased towards 
radars which emit pulses. I seem to remember it covers FM techniques a 
bit, and completely fails to address things like the transmission of 
wideband noise as a stimulus.

I haven't worked in the radar area since the mid 80s, so I don't know 
much about more modern texts. However, any in depth book on radar is 
biased very much towards stealth, since detecting targets is the easy 
part, and LPI is where it starts to get interesting. :-) If you are 
targeting a civilian application they probably don't have a lot to teach 
you.

You didn't actually say what limits you have reached. Is it range, 
resolution, sensitivity, etc.? That etc. can be the one that really gets 
you. :-)

Regards,
Steve

Steve Underwood wrote:
> Rune Allnor wrote:
> > Hi all.
> >
> > I am involved in a project where we want to measure a
> > physical quantity by means of acoustics. We have tried
> > ultrasound pulse signals with a certain amount of
> > success, but it seems we have pushed the system
> > to the edge of the envelope. So we need to explore other
> > options to reach the goal of the project.
> >
> > My background is from seismics and underwater
> > acoustics where all attention is focused on pulsed
> > signals. I need to read up on other ways of doing
> > things. I presume "other ways" mainly means "radar",
> > but "tomography" may also be relevant.
> >
> > Basically, I need tips on literature. The ideal book(s)
> > would be general in scope but on an advanced level.
> >
> > I have heard of the Skolnik book, but I can't find it.
> > Well, I can, but the book is a bit dated (it was
> > published in the mid 60s?), and I would like to hear
> > if there are newer texts on general radar processing
> > available before spending time and $$ on finding the
> > Skolnik text.
> >
> The second edition of the Skolnik book was published around 1980, and
> was substantially updated. However, it is still heavily biased towards
> radars which emit pulses. I seem to remember it covers FM techniques a
> bit, and completely fails to address things like the transmission of
> wideband noise as a stimulus.
>
> I haven't worked in the radar area since the mid 80s, so I don't know
> much about more modern texts. However, any in depth book on radar is
> biased very much towards stealth, since detecting targets is the easy
> part, and LPI is where it starts to get interesting. :-) If you are
> targeting a civilian application they probably don't have a lot to teach
> you.
>
> You didn't actually say what limits you have reached. Is it range,
> resolution, sensitivity, etc.? That etc. can be the one that really gets
> you. :-)

All of the above...

We are working in a noisy area (acoustically, electrically) and in
a high-loss, modest-coherence material and try to detect relatively
weak signals with as high precision and at as long range we can.
We can, of course, spend tens of thousands of $$ on high-power
amplifiers and transducers, but I can't really see any benefit
of that. So I want to try to increase signal energy by increasing the
time-bandwidth product of the signal rather than the emitted power
of the signal.

Something that covers frequency-sweep radar ought to do nicely
for this application. Anything more than that is at least interesting
reading, maybe an idea for the next project.

Rune

On Tue, 21 Feb 2006 03:56:18 -0800, Rune Allnor wrote:

> So I want to try to increase signal energy by increasing the
> time-bandwidth product of the signal rather than the emitted power
> of the signal.

Most radar books contain a chapter on "pulse compression," which is the
radar jargon for increasing the pulse energy while keeping the peak pulse
power constant, and without decreasing the achievable time/range
resolution.

The classic text is the 1967 volume "Radar Signals" by Cook and Bernfeld.
Levanon and Mozeson have written a new book with the same old title,
"Radar Signals," which Wiley released in 2004.

-Leif

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Rune Allnor wrote:
> Steve Underwood wrote:
>   
>> Rune Allnor wrote:
>>     
>>> Hi all.
>>>
>>> I am involved in a project where we want to measure a
>>> physical quantity by means of acoustics. We have tried
>>> ultrasound pulse signals with a certain amount of
>>> success, but it seems we have pushed the system
>>> to the edge of the envelope. So we need to explore other
>>> options to reach the goal of the project.
>>>
>>> My background is from seismics and underwater
>>> acoustics where all attention is focused on pulsed
>>> signals. I need to read up on other ways of doing
>>> things. I presume "other ways" mainly means "radar",
>>> but "tomography" may also be relevant.
>>>
>>> Basically, I need tips on literature. The ideal book(s)
>>> would be general in scope but on an advanced level.
>>>
>>> I have heard of the Skolnik book, but I can't find it.
>>> Well, I can, but the book is a bit dated (it was
>>> published in the mid 60s?), and I would like to hear
>>> if there are newer texts on general radar processing
>>> available before spending time and $$ on finding the
>>> Skolnik text.
>>>
>>>       
>> The second edition of the Skolnik book was published around 1980, and
>> was substantially updated. However, it is still heavily biased towards
>> radars which emit pulses. I seem to remember it covers FM techniques a
>> bit, and completely fails to address things like the transmission of
>> wideband noise as a stimulus.
>>
>> I haven't worked in the radar area since the mid 80s, so I don't know
>> much about more modern texts. However, any in depth book on radar is
>> biased very much towards stealth, since detecting targets is the easy
>> part, and LPI is where it starts to get interesting. :-) If you are
>> targeting a civilian application they probably don't have a lot to teach
>> you.
>>
>> You didn't actually say what limits you have reached. Is it range,
>> resolution, sensitivity, etc.? That etc. can be the one that really gets
>> you. :-)
>>     
>
> All of the above...
>
> We are working in a noisy area (acoustically, electrically) and in
> a high-loss, modest-coherence material and try to detect relatively
> weak signals with as high precision and at as long range we can.
> We can, of course, spend tens of thousands of $$ on high-power
> amplifiers and transducers, but I can't really see any benefit
> of that. So I want to try to increase signal energy by increasing the
> time-bandwidth product of the signal rather than the emitted power
> of the signal.
>
> Something that covers frequency-sweep radar ought to do nicely
> for this application. Anything more than that is at least interesting
> reading, maybe an idea for the next project.
>
> Rune
>   
Chirping certainly cuts the peak power, and has been almost universal in 
pulsed radars since the middle of the second World War. They got their 
output powers up to the point where flashover in the waveguides forced a 
rethink of brute force narrow pulses. It sounds like your issues are 
similar. Surprisingly it took many years before a proper mathematical 
analysis of the topic was available. In my limited experience of sonar, 
chirping also seems pretty normal there.

Some form of continuous transmission really seems the way to go there 
days, though. Either FM schemes, or the transmission of wideband noise. 
FM has been used for a long time in radar, with a mix of + and - 
qualities over chirping (e.g. the Foxhunter radar used on many Tornado 
fighters is a continuous transmission FM system). Noise based radars 
were in the research stage last time I worked on radar. The research 
systems were offering very interesting results, so I guess that has 
worked its way into production systems now the compute requirement is 
fairly easy to meet.

Regards,
Steve


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Rune Allnor wrote:
<blockquote
 cite="mid1140522978.071385.319240@z14g2000cwz.googlegroups.com"
 type="cite">
  <pre wrap="">Steve Underwood wrote:
  </pre>
  <blockquote type="cite">
    <pre wrap="">Rune Allnor wrote:
    </pre>
    <blockquote type="cite">
      <pre wrap="">Hi all.

I am involved in a project where we want to measure a
physical quantity by means of acoustics. We have tried
ultrasound pulse signals with a certain amount of
success, but it seems we have pushed the system
to the edge of the envelope. So we need to explore other
options to reach the goal of the project.

My background is from seismics and underwater
acoustics where all attention is focused on pulsed
signals. I need to read up on other ways of doing
things. I presume "other ways" mainly means "radar",
but "tomography" may also be relevant.

Basically, I need tips on literature. The ideal book(s)
would be general in scope but on an advanced level.

I have heard of the Skolnik book, but I can't find it.
Well, I can, but the book is a bit dated (it was
published in the mid 60s?), and I would like to hear
if there are newer texts on general radar processing
available before spending time and $$ on finding the
Skolnik text.

      </pre>
    </blockquote>
    <pre wrap="">The second edition of the Skolnik book was published around 1980, and
was substantially updated. However, it is still heavily biased towards
radars which emit pulses. I seem to remember it covers FM techniques a
bit, and completely fails to address things like the transmission of
wideband noise as a stimulus.

I haven't worked in the radar area since the mid 80s, so I don't know
much about more modern texts. However, any in depth book on radar is
biased very much towards stealth, since detecting targets is the easy
part, and LPI is where it starts to get interesting. :-) If you are
targeting a civilian application they probably don't have a lot to teach
you.

You didn't actually say what limits you have reached. Is it range,
resolution, sensitivity, etc.? That etc. can be the one that really gets
you. :-)
    </pre>
  </blockquote>
  <pre wrap=""><!---->
All of the above...

We are working in a noisy area (acoustically, electrically) and in
a high-loss, modest-coherence material and try to detect relatively
weak signals with as high precision and at as long range we can.
We can, of course, spend tens of thousands of $$ on high-power
amplifiers and transducers, but I can't really see any benefit
of that. So I want to try to increase signal energy by increasing the
time-bandwidth product of the signal rather than the emitted power
of the signal.

Something that covers frequency-sweep radar ought to do nicely
for this application. Anything more than that is at least interesting
reading, maybe an idea for the next project.

Rune
  </pre>
</blockquote>
Chirping certainly cuts the peak power, and has been almost universal
in pulsed radars since the middle of the second World War. They got
their output powers up to the point where flashover in the waveguides
forced a rethink of brute force narrow pulses. It sounds like your
issues are similar. Surprisingly it took many years before a proper
mathematical analysis of the topic was available. In my limited
experience of sonar, chirping also seems pretty normal there.<br>
<br>
Some form of continuous transmission really seems the way to go there
days, though. Either FM schemes, or the transmission of wideband noise.
FM has been used for a long time in radar, with a mix of + and -
qualities over chirping (e.g. the Foxhunter radar used on many Tornado
fighters is a continuous transmission FM system). Noise based radars
were in the research stage last time I worked on radar. The research
systems were offering very interesting results, so I guess that has
worked its way into production systems now the compute requirement is
fairly easy to meet.<br>
<br>
Regards,<br>
Steve<br>
<br>
</body>
</html>

--------------020402080006070200020305--

Steve Underwood wrote:

   ...

> Some form of continuous transmission really seems the way to go there 
> days, though. Either FM schemes, or the transmission of wideband noise. 
> FM has been used for a long time in radar, with a mix of + and - 
> qualities over chirping (e.g. the Foxhunter radar used on many Tornado 
> fighters is a continuous transmission FM system). Noise based radars 
> were in the research stage last time I worked on radar. The research 
> systems were offering very interesting results, so I guess that has 
> worked its way into production systems now the compute requirement is 
> fairly easy to meet.

Please educate me. The T/R tube was one of the finest bits of invention 
in early radar, protecting the receiver's sensitive input from the 
transmitter's blast of power. How does the receiver cope with continuous 
transmission?

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins wrote:
> Steve Underwood wrote:
> 
>   ...
> 
>> Some form of continuous transmission really seems the way to go there 
>> days, though. Either FM schemes, or the transmission of wideband 
>> noise. FM has been used for a long time in radar, with a mix of + and 
>> - qualities over chirping (e.g. the Foxhunter radar used on many 
>> Tornado fighters is a continuous transmission FM system). Noise based 
>> radars were in the research stage last time I worked on radar. The 
>> research systems were offering very interesting results, so I guess 
>> that has worked its way into production systems now the compute 
>> requirement is fairly easy to meet.
> 
> 
> Please educate me. The T/R tube was one of the finest bits of invention 
> in early radar, protecting the receiver's sensitive input from the 
> transmitter's blast of power. How does the receiver cope with continuous 
> transmission?
> 
> Jerry

Well these days for pulsed systems you can get maybe 60dB isolation with 
a high quality circulator at microwave frequencies, and then use PIN 
diodes to protect the receiver. Great until someone drops something 
metal in front of the antenna. Then, the PIN diodes can turn a little 
spectacular. :-)

For continuous transmission things are more interesting. You have less 
intense power, and a circulator will still give you 60dB. That means the 
transmitter won't blow the receiver apart. Actually making things work 
is left as an exercise for the reader.

Steve

Steve Underwood wrote:
> Jerry Avins wrote:
> 
>> Steve Underwood wrote:
>>
>>   ...
>>
>>> Some form of continuous transmission really seems the way to go there 
>>> days, though. Either FM schemes, or the transmission of wideband 
>>> noise. FM has been used for a long time in radar, with a mix of + and 
>>> - qualities over chirping (e.g. the Foxhunter radar used on many 
>>> Tornado fighters is a continuous transmission FM system). Noise based 
>>> radars were in the research stage last time I worked on radar. The 
>>> research systems were offering very interesting results, so I guess 
>>> that has worked its way into production systems now the compute 
>>> requirement is fairly easy to meet.
>>
>>
>>
>> Please educate me. The T/R tube was one of the finest bits of 
>> invention in early radar, protecting the receiver's sensitive input 
>> from the transmitter's blast of power. How does the receiver cope with 
>> continuous transmission?
>>
>> Jerry
> 
> 
> Well these days for pulsed systems you can get maybe 60dB isolation with 
> a high quality circulator at microwave frequencies, and then use PIN 
> diodes to protect the receiver. Great until someone drops something 
> metal in front of the antenna. Then, the PIN diodes can turn a little 
> spectacular. :-)
> 
> For continuous transmission things are more interesting. You have less 
> intense power, and a circulator will still give you 60dB. That means the 
> transmitter won't blow the receiver apart. Actually making things work 
> is left as an exercise for the reader.

Blowing the receiver apart isn't the only problem. Even 60 dB down is a 
whale of a lot of co-channel interference.

I once used a Gunn diode and a horn to make a traffic radar (to prove to 
the local cops that there was a problem they didn't want to know about). 
The return signal simply beat with the diode's output, and the beat 
signal went to a counter. I suppose Other continuous radars might work 
the same way, but I can imagine lits of issues, There are probably even 
more issues I can't imagine.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins wrote:
> Steve Underwood wrote:
> 
>> Jerry Avins wrote:
>>
>>> Steve Underwood wrote:
>>>
>>>   ...
>>>
>>>> Some form of continuous transmission really seems the way to go 
>>>> there days, though. Either FM schemes, or the transmission of 
>>>> wideband noise. FM has been used for a long time in radar, with a 
>>>> mix of + and - qualities over chirping (e.g. the Foxhunter radar 
>>>> used on many Tornado fighters is a continuous transmission FM 
>>>> system). Noise based radars were in the research stage last time I 
>>>> worked on radar. The research systems were offering very interesting 
>>>> results, so I guess that has worked its way into production systems 
>>>> now the compute requirement is fairly easy to meet.
>>>
>>>
>>>
>>>
>>> Please educate me. The T/R tube was one of the finest bits of 
>>> invention in early radar, protecting the receiver's sensitive input 
>>> from the transmitter's blast of power. How does the receiver cope 
>>> with continuous transmission?
>>>
>>> Jerry
>>
>>
>>
>> Well these days for pulsed systems you can get maybe 60dB isolation 
>> with a high quality circulator at microwave frequencies, and then use 
>> PIN diodes to protect the receiver. Great until someone drops 
>> something metal in front of the antenna. Then, the PIN diodes can turn 
>> a little spectacular. :-)
>>
>> For continuous transmission things are more interesting. You have less 
>> intense power, and a circulator will still give you 60dB. That means 
>> the transmitter won't blow the receiver apart. Actually making things 
>> work is left as an exercise for the reader.
> 
> 
> Blowing the receiver apart isn't the only problem. Even 60 dB down is a 
> whale of a lot of co-channel interference.
> 
> I once used a Gunn diode and a horn to make a traffic radar (to prove to 
> the local cops that there was a problem they didn't want to know about). 
> The return signal simply beat with the diode's output, and the beat 
> signal went to a counter. I suppose Other continuous radars might work 
> the same way, but I can imagine lits of issues, There are probably even 
> more issues I can't imagine.
> 
> Jerry

Of course. The received signal is at about the same frequency as the 
transmitted one, so the full power of the transmitter, less the modest 
attenuation you can achieve, is interferring with a tiny kTB limited 
signal. Its like the CDMA near/far problem on steroids. As I said, 
methods to deal with this are left as an exercise for the reader.

Remember: nothing is impossible - there's always kTB :-)

Regards,
Steve

Steve Underwood wrote:

 > ... As I said, methods to deal with this are left as an exercise for
 > the reader.
 >
> Remember: nothing is impossible - there's always kTB :-)

Well, as Tom Lehrer had Wernher Von Braun say, "That's not my 
department."* (And a good thing too!)

Jerry
__________________________________________
* Once the rockets go up, who cares where they come down.
"That's not my department" says Wernher Von Braun.
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������