Attila,
From reading at the abstract, it looks interesting - bird tracking!
But essentially the same problem I'm trying to solve. I was looking for
a copy of the paper on the web as I'm not sure I want to purchase it.
Thanks,
-Bob
On 04/18/2015 04:02 PM, Attila Kinali wrote:
Moin,
On
Moin,
On Mon, 06 Apr 2015 07:37:53 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
Thank you very much for the references. I had come across [4] when
searching on Kalman filters for GPS aiding of INS measurements. I
didn't pay much attention to the GPS chapter at the time but I'll
Hi Jim,
On 04/08/2015 12:46 AM, Jim Lux wrote:
On 4/7/15 11:33 AM, Magnus Danielson wrote:
Hi,
O
One might look at the available frequencies and see if there is a
telemetry band available which allows wider bandwidth. For the
application, I don't see that very much transmitted power is
On Mon, 06 Apr 2015 23:02:01 +0200
Magnus Danielson mag...@rubidium.dyndns.org wrote:
You want to keep your chip-rate up to make the integer ambiguity of the
carrier phase simple. The carrier frequency divided by chipping rate
ratio indicate how difficult problem it is to solve (GPS L1 C/A
Hi,
On 04/07/2015 02:08 PM, Attila Kinali wrote:
On Mon, 06 Apr 2015 23:02:01 +0200
Magnus Danielson mag...@rubidium.dyndns.org wrote:
You want to keep your chip-rate up to make the integer ambiguity of the
carrier phase simple. The carrier frequency divided by chipping rate
ratio indicate
On 4/7/15 11:33 AM, Magnus Danielson wrote:
Hi,
O
One might look at the available frequencies and see if there is a
telemetry band available which allows wider bandwidth. For the
application, I don't see that very much transmitted power is needed.
If the OP is a licensed amateur radio
Attila,
On 04/06/2015 11:14 AM, Attila Kinali wrote:
Moin,
On Fri, 03 Apr 2015 22:51:34 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
On 04/03/2015 10:12 PM, Robert Watzlavick wrote:
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some
Hi Attila,
On 04/06/2015 11:21 AM, Attila Kinali wrote:
On Sat, 04 Apr 2015 08:49:01 +0200
Magnus Danielson mag...@rubidium.se wrote:
This is on either side of the amateur 23 cm band. That's also the first
band where you have bandwidth enough to fool around with stuff like this
without
Moin,
On Fri, 03 Apr 2015 22:51:34 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
On 04/03/2015 10:12 PM, Robert Watzlavick wrote:
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some driver software for an IQ
demodulation board but I
On Sat, 04 Apr 2015 08:49:01 +0200
Magnus Danielson mag...@rubidium.se wrote:
This is on either side of the amateur 23 cm band. That's also the first
band where you have bandwidth enough to fool around with stuff like this
without breaking the bandplan.
This shouldn't be much of a problem.
On 4/6/15 2:14 AM, Attila Kinali wrote:
Moin,
On Fri, 03 Apr 2015 22:51:34 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
On 04/03/2015 10:12 PM, Robert Watzlavick wrote:
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some driver software for
On 4/6/15 2:21 AM, Attila Kinali wrote:
On Sat, 04 Apr 2015 08:49:01 +0200
Magnus Danielson mag...@rubidium.se wrote:
This is on either side of the amateur 23 cm band. That's also the first
band where you have bandwidth enough to fool around with stuff like this
without breaking the bandplan.
Attila,
Thank you very much for the references. I had come across [4] when
searching on Kalman filters for GPS aiding of INS measurements. I
didn't pay much attention to the GPS chapter at the time but I'll look
at it again. I just downloaded [3] and it appears to have a good mix of
Jim,
On 04/06/2015 03:13 PM, Jim Lux wrote:
On 4/6/15 2:21 AM, Attila Kinali wrote:
On Sat, 04 Apr 2015 08:49:01 +0200
Magnus Danielson mag...@rubidium.se wrote:
This is on either side of the amateur 23 cm band. That's also the first
band where you have bandwidth enough to fool around with
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some driver software for an IQ demodulation
board but I have to admit, I would have no idea how to begin setting up
that system as initially described by Attila and expanded by you and
others. I have a
Hi Bob,
The actual receiver logic is that you have some sampling point in time,
the tracking phase of a channel is being sampled. As you do for multiple
channels, the relative phase of each channel is sampled.
In order to extend this phase into a pseudo-range, one needs to guess
how many
To head off a bunch of replies - I think I stumbled upon what is being
suggested. To extract the pseudorange, you have to figure out the
offset of the locally generated PN code against the one that is
received. In this reverse GPS case, I assume each ground station would
have to start their
We essentially propose that you mimic the GPS system.
The original GPS birds are relatively stupid.
In GPS, the core clock produces 10,23 Mhz (modern GPS rubidiums output a
different frequency, but that is not the point here), for C/A code it is
divided down with 10 to produce the C/A chipping
Hi,
On 03/26/2015 01:25 PM, Attila Kinali wrote:
On Wed, 25 Mar 2015 21:27:35 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
I'm working on a project that I could use some advice on and also might
be of interest to the list. If it's not appropriate for the list, my
apologies.
The
Remember that you can actually let each base-station transmit at a
different code, and you can then monitor them that way. You could even
keep them frequency and phase locked or just monitor it and adjust it in
the post-processing. Such an approach would be a nice complementary
solution to the
...@febo.com] On Behalf Of Chris
Albertson
Sent: Friday, March 27, 2015 9:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Need advice for multilateration setup
On Fri, Mar 27, 2015 at 10:29 AM, Chuck Harris cfhar...@erols.com wrote:
The biggest problem I see
Jim,
On 03/28/2015 10:01 PM, Jim Lux wrote:
On 3/28/15 10:27 AM, Bob Camp wrote:
Hi
So If the rocket continuously accelerates at 10,000 G’s, you will get
a 20 ppm shift
with typical sensitivity. If you do this for very long, you will also
get into time dilation issues.
(you hit 0.1C in
Hi
Calibrating the G sensitivity of the oscillator can be done much
more easily by simply rotating it 360 degrees while carefully reading
out the frequency. If you want the full vector, you will need to rotate
it through two circles, with the plane of one 90 degrees out relative to the
other.
I want to thank everybody for their help on this. Thanks to the list, I
have plenty of ideas that I can prototype so I'll keep you posted what I
end up trying and how well it works eventually.
-Bob
On 03/25/2015 09:27 PM, Robert Watzlavick wrote:
I want to develop a tracking system for an
Hi
The point being that, to even get acceleration into the picture, you need have
impossibly high accelerations …
At 10 G, your oscillator needs to be temperature stable to 0.01C to even see
the acceleration. If you are climbing 100K feet during the acceleration phase
the
oscillator will see
[mailto:time-nuts-boun...@febo.com] On Behalf Of Chris
Albertson
Sent: Friday, March 27, 2015 9:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Need advice for multilateration setup
On Fri, Mar 27, 2015 at 10:29 AM, Chuck Harris cfhar...@erols.com wrote
An idea occurred (always a surprise):
The rocket's acceleration increases from 1 g as the mass of fuel is
ejected energetically, according to f=ma, with pretty constant force
from the motor. At some point, the fuel and oxidizer tanks are empty
(MECO), causing the acceleration to revert to 1 g or
On 3/28/15 10:27 AM, Bob Camp wrote:
Hi
So If the rocket continuously accelerates at 10,000 G’s, you will get a 20 ppm
shift
with typical sensitivity. If you do this for very long, you will also get into
time dilation issues.
(you hit 0.1C in 2 minutes).
10,000G is more like an
but say nothing about
frequency stability.
Pete.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris
Albertson
Sent: Friday, March 27, 2015 9:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Need advice
On 03/26/2015 02:25 PM, Hal Murray wrote:
I want to develop a tracking system for an amateur rocket ...
Do you need the position in real time, or just after the rocket returns so
you can find it?
Near real-time would be nice but I guess not an absolute requirement.
40 ns is 25 MHz. It
I've already integrated an onboard IMU (Analog Devices ADIS16xxx) but
they have a lot of drift, especially in a high-g environment. I plan to
record the raw IMU data to a flash card and assuming I can recover the
card intact, I'll use it to tune a Kalman filter algorithm for the
future
On 03/26/2015 01:56 PM, Jim Lux wrote:
The key is that you don't need *real time* position.. a few seconds or
minutes delay is probably ok, right?
Seconds are probably ok, minutes might be a little long. PCs are pretty
fast though these days for signal processing I would think.
To compensate
Your second method is by far the best. But it can be simplified. All you
need is two very stable oscillators, one in the rocket and one some known
fixed location. Then you ground stations can be just dumb recorders that
record both signals. In post processing you compare the relative phases.
Robert;
It seems that a Doppler system should work for you.
But first, you have a problem. If you want to track your rocket
to 100K feet (20 miles) using some form of triangulation then you
need your receiving stations further apart than 1 mile. Your
triangle is too extreme and any
NASA uses the Doppler effect for deep space navigation, by integrating
the velocity.
You'd need a very stable oscillator, but you don't need a powered oven,
due to the short duration of the flight.
You only need one receiver. In fact, if it's possible for the rocket to
hear a ground signal and
On Thu, 26 Mar 2015 12:32:33 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
Thanks for the suggestion. Does the DSSS make it easier to correlate
between ground stations? I'm not sure how to handle the phase offset
on the 10 MHz ref clocks.
The DSSS allows you to make the integer
The biggest problem I see is the crystal oscillator in the
rocket is going to notice the G forces during acceleration
in a pretty big way. Time nuts easily notice the reversal
in a 1G force on a laboratory oscillator caused by flipping
it on its back for service.
But all is not even close to
On Fri, Mar 27, 2015 at 10:29 AM, Chuck Harris cfhar...@erols.com wrote:
The biggest problem I see is the crystal oscillator in the
rocket is going to notice the G forces during acceleration
in a pretty big way.
But all of the ground stations will see the same frequency shift on the
rocket's
I'm working on a project that I could use some advice on and also might
be of interest to the list. If it's not appropriate for the list, my
apologies.
I want to develop a tracking system for an amateur rocket that can allow
me to track the rocket even if onboard GPS is lost (as is typical
Thanks for the suggestion. Does the DSSS make it easier to correlate between
ground stations? I'm not sure how to handle the phase offset on the 10 MHz ref
clocks.
-Bob
On Mar 26, 2015, at 07:25, Attila Kinali att...@kinali.ch wrote:
On Wed, 25 Mar 2015 21:27:35 -0500
Robert Watzlavick
On Wed, 25 Mar 2015 21:27:35 -0500
Robert Watzlavick roc...@watzlavick.com wrote:
I'm working on a project that I could use some advice on and also might
be of interest to the list. If it's not appropriate for the list, my
apologies.
The gods have apporved of your request. You may speak
What's your budget?
Put a white-rabbit switch (3.5keur) in the middle, and install a mile of
single-mode fiber to each rx-station. Then use TDC or FDEL SPEC-cards
(1.5keur each) at the RX-stations to time-stamp the incoming pulse. 1 ns
systematic and 50 ps RMS random error should be doable. The
Budget is a concern but not an overriding concern. I'd like to keep the whole
system around $1k. I was planning on making it as portable as possible with
each ground station being self contained and sending their data to the launch
site over a serial RF modem at 9600 baud. I agree though -
Hi Bob:
There are many ways of doing this.
To test artillery shells they have a GPS front end in the shell and transmit the IF. A receiver at the gun is locked to
the satellites prior to firing. You would want one of the 10 Hz update rage GPS receivers for this.
Another method is to
I want to develop a tracking system for an amateur rocket ...
Do you need the position in real time, or just after the rocket returns so
you can find it?
I had thought 100 ns of timing accuracy in the received signals would be
good enough but I think I need to get down less than 40 ns to
Sounds over complicated. Why not use an onboard triple-axis accelerometer? A
few mm of real-estate, milliamp consumption, up to 16g, 600+ samples a sec. The
code is probably already available.
Le 26 mars 2015 à 03:27, Robert Watzlavick roc...@watzlavick.com a écrit :
I'm working on a
On 3/25/15 7:27 PM, Robert Watzlavick wrote:
I'm working on a project that I could use some advice on and also might
be of interest to the list. If it's not appropriate for the list, my
apologies.
I want to develop a tracking system for an amateur rocket that can allow
me to track the rocket
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