Hello,
Long ago I was involved in a project that has something to do with test
cannons. They used a doppler radar (a commercially available equipment,
but I don't remember the manufacturer) for measuring the speed of the
bullet (a rather big one... if I was right, it was a 155mm caliper :) )
during its travel from the cannon aperture to the end point (about 500m
distance or so).
Regards,
Javier
El 31/10/2010 13:56, Michael Baker escribió:
Hello, Time-Nutters--
A real-world precision timing need:
As a dedicated long-range rifle shooter and
ballistics enthusiast, I am in the early stages
of a project I am getting started on...
The object is to measure the velocity of a
rifle bullet both at the muzzle and downrange at
various distances up to 800 yards/meters or so.
Conventional optical sky-screens will will be
used for measuring the velocity at both ends.
However, I also need time-of-flight and this
requires knowing the timing relationship between
the time the bullet crosses the muzzle sky-screen
and the downrange sky-screen. Bullet muzzle velocities
will be between 1900 to 3200 feet-per-second.
Additionally, I will be using the output from an
array of 4 ultrasonic sensors located on the
corners of a 4-foot PVC pipe square to determine
the size of the shot group at the far end and
telemeter this info back to a laptop at the
shooting bench.
I can use a 10-MHz crystal for the sky-screen clocks
and the for the 4 ultrasonic bullet shot location
sensors. However, determining the time-of-flight is
a more difficult task as this requires syncing clocks
together at both ends to a moderate degree of accuracy.
Out to 100 yards I can send the time-of-flight
far-end pulse back by wire and compare it to the
muzzle-end sky-screen pulse but this is not practical
to do by wire out at 800 yards.
This project is on a tight budget-- namely, MY
wallet, so cost is a major concern. Suggestions
will be most welcome!!
Thanks!!
Mike Baker
Gainesville, Florida, USA
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--
------------------------------------------------------------------------
Javier Herrero EMAIL: [email protected]
Chief Technology Officer
HV Sistemas S.L. PHONE: +34 949 336 806
Los Charcones, 17 FAX: +34 949 336 792
19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com
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