rf distance measurement...

[Hul Tytus]

Clifford - I took a look at the inards of Harbor Freight\'s \"Ames Laser Distance Meter\".
Along with some discretes there was what appeared to be a microcontroller (~64 pin tqfp),
and, close to the laser reciever & transmitter, a 10 pin ic and an 8 pin one, both gull wing
types. At the moment I don\'t have any magnifying means to read the id\'s.
What is most impressive is the gaget\'s resolution: 1/16 inch. That suggests use
of a 5ghz counter with a healthy dose of averaging.

Hul

Clifford Heath <no_spam@please.net> wrote:

On 10/9/22 00:38, jlarkin@highlandsniptechnology.com wrote:
On Fri, 09 Sep 2022 09:17:22 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Fri, 9 Sep 2022 00:08:39 -0700 (PDT)) it happened Ricky
gnuarm.deletethisbit@gmail.com> wrote in
ec0dd418-095c-4eba-a026-5bda091795c1n@googlegroups.com>:

On Thursday, September 8, 2022 at 10:40:16 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <h...@panix.com
wrote:
Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul
Reflections will be a big error source.

Not if an active transponder retransmits the received signal with a fixed delay. That\'s how they measure distance in the TACAN
system on airplanes. They use different frequencies which prevents an issue with echos.

Why use RF?
For 2 $ 50 centst you van get an ultrasonic distance measuring module on ebay
I have several.

500 feet?


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

Why can\'t the OP use the guts of (or chips from) a laser tape measure?

Or put a PA on one of the Infineon 24GHz radar chips?

I don\'t think the Decawave modules would get the required range.

Clifford Heath.

 

[Mike Monett VE3BTI]

bilou <bilou@sfr.fr> wrote:

Look at the design of radio altimeters.
Use of directional aerials on the source or/and the target can
improve performances a lot.

Radio altimiters are not very directional. They have to accept bank angles
of 45 degrees or more and still give valid altitude measurements.

The radio altimeter on my Piper Malibu never gave invalid measurements no
matter how much maneuvering I had to do to acquire and maintain lock on the
ILS signals during landing approaches.

It should be noted that radio altimeters only work below 2,500 feet, so the
distance is not large and the signals are quite strong. Directional aerials
are not needed.

Radio interference from cellular phones is an issue, due to the recent
opening of frequencies close to the radio altimeter band. In order to
combat this, cellular stations are prohibited in a certain radius around
airports.

Outside this radius, you are on your own, although why anyone would be
tooling around at altitudes below 2,500 feet is questionable.



--
MRM

 

[Phil Allison]

Ricky Trolling POS Asshole wrote:
================================

A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.


The troll raises he head and surveys the scene.

** Fuck off you VILE CUNT

Fake is your middle name - asshole.

 

[Mike Monett VE3BTI]

piglet <erichpwagner@hotmail.com> wrote:

Don\'t know all the details but the Apollo ranging system used 1960s RF
technology to get foot scale accuracy across quarter million miles.
Loads of info should be on the web.

piglet

The Apollo Ranging System did not reflect the signals. It was a
transponder.

Quote:

\"As the Apollo program proceeded, redundancy became a requirement for all
crew safety functions. One critical period of the Apollo missions was the
rendezvous of the Command Module and the Lunar Module. The rendezvous radar
provided the critical range, range rate, and angle measurements necessary
to complete the rendezvous. Use of a redundant radar for backup was out of
the question because of its 80-lb weight. It was, however, found that the
voice radios could be adapted to perform the ranging function. Slight
modifications of the VHF voice radios and the addition of a ranging
interrogator and transponder at a weight of less than 10 lbs total would
provide an accuracy of 100-ft rms at several hundred miles. The Apollo VHF
ranging system demonstrated that it is feasible to achieve highly accurate
range measurements with conventional voice radios.\"

https://ui.adsabs.harvard.edu/abs/1977isa..conf..429N/abstract

Quote:

\"How could range (distance), position, and speed then be measured? The
answer is one that [Ken] aptly describes as fractal: Each layer of
complexity hides beneath it another layer of complexity. Using equations
dating from 3rd century China as well as cutting edge weak signal
telemetry, Apollo engineers devised a complex but workable system that used
an S-Band transponder to take data transmitted from a powerful ground
station and send it back on another frequency. One great hack was to use
Phase Modulation to encode the downlink instead of Frequency Modulation so
that Doppler data gained on the uplink wouldn’t be lost on the downlink.

By knowing the precise position of the ground station and the very large
parabolic antennae, not only could the distance and speed be measured, but
a good estimation of the spacecraft’s position in 3d space could also be
had.\"

https://hackaday.com/2022/04/25/the-apollo-digital-ranging-system-more-
than-meets-the-eye/



--
MRM

 

[Ricky]

On Saturday, September 10, 2022 at 6:30:10 PM UTC-4, palli...@gmail.com wrote:

Ricky Trolling POS Asshole wrote:
================================


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.


The troll raises he head and surveys the scene.
** Fuck off you VILE CUNT

And he speaks!


> Fake is your middle name - asshole.

No, my middle name is Philisadickhead

--

Rick C.

++ Get 1,000 miles of free Supercharging
++ Tesla referral code - https://ts.la/richard11209

 

[Clifford Heath]

On 10/9/22 10:49, Phil Allison wrote:

Clifford Heath wrote:
================


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.


** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.

The company was Martin Communications, who did a wide range of
interesting projects, including sat-phones (too many projects, perhaps,
not enough focus to get any one of them to go big-time). Very reputable
crowd.

You are welcome to speak with Bruce, who can describe the system in
detail - he wrote the DSP code for it (on Blackfin chips, I believe).
Email me privately and I\'ll give you his phone#.

If I recall correctly the transducers were in the 60-80Khz range. The
huge dish gave them massive gain, or it wouldn\'t have worked. The system
was extensively tested out at Tullamarine Airport, but never sold
commercially.

Clifford Heath

 

[Anthony William Sloman]

On Sunday, September 11, 2022 at 7:57:40 AM UTC+10, Hul Tytus wrote:

Clifford Heath <no_...@please.net> wrote:
On 10/9/22 00:38, jla...@highlandsniptechnology.com wrote:
On Fri, 09 Sep 2022 09:17:22 GMT, Jan Panteltje
pNaonSt...@yahoo.com> wrote:

On a sunny day (Fri, 9 Sep 2022 00:08:39 -0700 (PDT)) it happened Ricky
gnuarm.del...@gmail.com> wrote in
ec0dd418-095c-4eba...@googlegroups.com>:

On Thursday, September 8, 2022 at 10:40:16 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <h...@panix.com
wrote:
Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul
Reflections will be a big error source.

Not if an active transponder retransmits the received signal with a fixed delay. That\'s how they measure distance in the TACAN
system on airplanes. They use different frequencies which prevents an issue with echos.

Why use RF?
For 2 $ 50 centst you van get an ultrasonic distance measuring module on ebay
I have several.

500 feet?


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.
Why can\'t the OP use the guts of (or chips from) a laser tape measure?

Or put a PA on one of the Infineon 24GHz radar chips?

I don\'t think the Decawave modules would get the required range.

You are still top-posting. Try to compose your responses so that your text follows the text you are responding to, so that somebody reading the text has read what you are responding to before they start reading your response.

Clifford - I took a look at the inards of Harbor Freight\'s \"Ames Laser Distance Meter\".
Along with some discretes there was what appeared to be a microcontroller (~64 pin tqfp),
and, close to the laser reciever & transmitter, a 10 pin ic and an 8 pin one, both gull wing
types. At the moment I don\'t have any magnifying means to read the id\'s.
What is most impressive is the gaget\'s resolution: 1/16 inch. That suggests use
of a 5Ghz counter with a healthy dose of averaging.

It shouldn\'t. The wavelength of a 5GHz electromagnetic wave in air is about 6 cm, a bit over two inches. The device has to work by measuring phase shift, and you can do that pretty precisely if you are careful. 1/16 inch is 2..6% of the wavelength at 5GHz, but 0.26% of the wavelength at 500MHz, and 0..05% at 100MHz, all of which are attainable.

Processing 5GHz signals is an expensive pain. Lower frequency signal are easier to cope with.

--
Bill Sloman, Sydney

 

[Clifford Heath]

On 11/9/22 08:35, Mike Monett VE3BTI wrote:

piglet <erichpwagner@hotmail.com> wrote:

Don\'t know all the details but the Apollo ranging system used 1960s RF
technology to get foot scale accuracy across quarter million miles.
Loads of info should be on the web.

piglet

The Apollo Ranging System did not reflect the signals. It was a
transponder.

It demodulated the signal and modulated it onto a new signal, that was
phase-locked by frequency multiplication&division (ratio 221/240) to the
received signal. Not strictly a reflection, but I don\'t think the word
reflection is the worst he could have used to describe the process. It
is a lot like reflection, with gain at the reflector

The frequency/phase locking gives a two-way Doppler measurement. The
transponder could be pulled quite a fair way from its centre frequency,
which was critical during Apollo 13 - there were two transponders active
at the same location because the LEM and Command module were still
docked. The idea of pulling one transponder off frequency then acquiring
the other one was down to Mike Dinn, Station Director at Honeysuckle
Creek Tracking Station at the time. I introduce him talking about that
on this video (I had previously presented on Apollo USB comms):
<https://www.youtube.com/watch?v=Erbn8MVku8k>

Quote:

\"As the Apollo program proceeded, redundancy became a requirement for all
crew safety functions. One critical period of the Apollo missions was the
rendezvous of the Command Module and the Lunar Module. The rendezvous radar
provided the critical range, range rate, and angle measurements necessary
to complete the rendezvous. Use of a redundant radar for backup was out of
the question because of its 80-lb weight. It was, however, found that the
voice radios could be adapted to perform the ranging function. Slight
modifications of the VHF voice radios and the addition of a ranging
interrogator and transponder at a weight of less than 10 lbs total would
provide an accuracy of 100-ft rms at several hundred miles. The Apollo VHF
ranging system demonstrated that it is feasible to achieve highly accurate
range measurements with conventional voice radios.\"

https://ui.adsabs.harvard.edu/abs/1977isa..conf..429N/abstract

What does the landing and rendezvous radar have to do with the Apollo
USB ranging system?

Quote:

\"How could range (distance), position, and speed then be measured? The
answer is one that [Ken] aptly describes as fractal: Each layer of
complexity hides beneath it another layer of complexity. Using equations
dating from 3rd century China as well as cutting edge weak signal
telemetry, Apollo engineers devised a complex but workable system that used
an S-Band transponder to take data transmitted from a powerful ground
station and send it back on another frequency. One great hack was to use
Phase Modulation to encode the downlink instead of Frequency Modulation so
that Doppler data gained on the uplink wouldn’t be lost on the downlink.

By knowing the precise position of the ground station and the very large
parabolic antennae, not only could the distance and speed be measured, but
a good estimation of the spacecraft’s position in 3d space could also be
had.\"

https://hackaday.com/2022/04/25/the-apollo-digital-ranging-system-more-
than-meets-the-eye/

Rather badly described, as we have come to expect from Hackaday articles.

The Chinese Remainder Theorem does not date to the 3rd century, only the
riddle that it solved, c.f. Wikipedia \"Sun-tzu\'s work contains neither a
proof nor a full algorithm\". The first algorithm was in the 6th century
by an Indian mathematician.

The Chinese Numbers used (2, 11, 31, 63, 127) created a repeating
sequence length of 5456682, at a bit rate of 992kbps, to reach a maximum
unambiguous two-way range of over 1650,000km, roughly half a million
miles one way. The actual ranging correlated the returned signal (after
Doppler de-embedding) over repetitions of length 11,31,63,127, and got
the remainders for each. The Chinese remainder theorem then allowed a
cold start ranging to be achieved in only 232 correlations, instead of
over 5 million. In practice, a cold start was almost never necessary.
Doppler was used continuously, and occasionally the ranging would be
used to run one or two of the short sequences to get confirmation.

996kbps creates a 1-bit uncertainty of 150m (two-way distance). Accurate
phase measurement got the theoretical uncertainty down to about 1m.

Clifford Heath.

 

[Jan Panteltje]

On a sunny day (Sat, 10 Sep 2022 10:13:56 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<dahphh1bth6l2rkk4p2sr81f2mrdcba6la@4ax.com>:

On Sat, 10 Sep 2022 00:27:33 -0700 (PDT), Phil Allison
pallison49@gmail.com> wrote:

whit3rd wrote:
===========

Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered.

** Fuck off moron.

FYI idiot , \" ultrasonic sound \" = f > 20kHz.


A transducer for soft tissues (baby imaging) or for brain
scanning

** You need one, cos you brain is missing or badly damaged.



I used to be able to hear 22 KHz and I could walk past a house and
hear the 15K from TV sets. I\'m down to about 8 KHz now, but there\'s
not a lot going on above that.

Right, and I could even hear if the 15625 Hz was in sync,
Same loss of very high frequencies here, tried it a few month ago with the signal generator and Sennheiser headphones,
But then I played \"jojo left his home in Tucson Arizona\" at eehh \"reasobale\" volume here few days ago
and the percussion came out really well on the 200 W stage amplifier and piezos for the high frequency part.
So that was cool.
Was a Beatle fan ,,

 

[server]

On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <ht@panix.com>
wrote:

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot.
The basic method of one device emitting a signal and another echoeing it
back would be attractive.

The use of an active reflector (with a.g.c) is nice, since the
received signal is proportional to the inverse of 2nd power of
distance. With passive reflections, the Rx power is proportional to
inverse 4th power of distance, making long distances impractical.

> Any recommendations?

How about a 10 GHz GunPlexer used in door openers ?

These are Doppler devices with a difference in the audio range for
slow movement. If you frequency modulate the Tx with a linear ramp,
the received signal frequency offset is directly proportional to
distance.

 

[Hul Tytus]

The laser range finder from Harbor Freight (Ames Laser Distance Meter, 100ft)
has a STM8L052 8 bit microcontroller, a dual 10mc op amp and MS5351M clock
generator with a 200mc max output.
The clock generator seems to fit the device into the frequency modulation
method you mention.

Hul

upsidedown@downunder.com wrote:

On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <ht@panix.com
wrote:

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot.
The basic method of one device emitting a signal and another echoeing it
back would be attractive.

The use of an active reflector (with a.g.c) is nice, since the
received signal is proportional to the inverse of 2nd power of
distance. With passive reflections, the Rx power is proportional to
inverse 4th power of distance, making long distances impractical.

Any recommendations?

How about a 10 GHz GunPlexer used in door openers ?

These are Doppler devices with a difference in the audio range for
slow movement. If you frequency modulate the Tx with a linear ramp,
the received signal frequency offset is directly proportional to
distance.

 

[Phil Allison]

Clifford Heath wrote:
================

A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.


** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.

The company was Martin Communications, who did a wide range of
interesting projects, including sat-phones (too many projects, perhaps,
not enough focus to get any one of them to go big-time). Very reputable
crowd.

** But YOU are not.

You are welcome to speak with Bruce, who can describe the system in
detail - he wrote the DSP code for it (on Blackfin chips, I believe).
Email me privately and I\'ll give you his phone#.

If I recall correctly the transducers were in the 60-80Khz range.

** Absorption about 2dB per METER in dry air.

> The huge dish gave them massive gain,

** 2.5m is tiny.

> or it wouldn\'t have worked.

** You have no clue if or how.

And you did not answer point, at all.
I do not believe in fairy tales.
======================

 

[server]

On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <ht@panix.com>
wrote:

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul

Reflections will be a big error source.

 

[Mike Monett VE3BTI]

Hul Tytus <ht@panix.com> wrote:

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to
one foot. The basic method of one device emitting a signal and another
echoeing it back would be attractive.
Any recommendations?

Hul

RF rangefinders would require interferometry which is very expensive and
not very selective.

As far as I know, most rangefiners use a laser to transmit a pulse, and a
simple current source into a capacitor driven by a photodiode receiver to
measure time to target. The laser spot gives pinpoint selectivity.

My KCH SW-E40 has a range of 40 meters with a resolution of 1 millimeter.
It uses 2 AAA batteries that last forever. It can measure distance, area,
volume, and has 4 Pythagoras modes. It can add and subtract measurements,
change units between feet, inches, and meters, and has a built-in level
gauge to measure horizontal distance.

There are numerous laser rangefinders on Amazon. Most go to 800-1,000
yards, and some go out to 1,500 yards. They all use lasers.

https://www.amazon.ca/s?k=laser+rangefinder





--
MRM

 

[bilou]

Le 09/09/2022 à 00:39, Hul Tytus a écrit :

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul

Look at the design of radio altimeters.
Use of directional aerials on the source or/and the target can
improve performances a lot.