Tuesday, February 22, 2011

GPS progress....

I built a GPS front end using a MAX2769... alas it does not work and I do not know why. I have it connected to an FPGA (PK70 FPGA blade board) . I spent all day Saturday and Sunday trying to find sats in the data record. So this evening after work I took a working GPS, An old Novatel Superstar II, and wired on some jumpers between the front end and the correlator. When I record that data stream and change my constants for a different Fsample and Fcenter I get Sats! I can ! even compute a positionSo all my basic hardware chain is working, just not the front end that is an exact implementation of a commercial IC reference design. Not the part of the design I expected to be bad. Progress.... now to decide if I want to just shell out 2K for a small
Non COCOM GPS that can do what I want or if I should spend a month or so finishing what I started, and have something to offer the community.

Sunday, February 06, 2011

Saturday Testing...

We went out to FAR on Saturday. It was a normal Saturday at FAR.
  • UCLA was fireing a 2Klb Nitrous Hybrid Motor.of their own design. They had a good firing and learned a lot.
  • There were several EX solid flights including an M.
  • An experimental Steam Hybrid Motor.
  • The site next door, RRS fired a large 10K lb (my guess) biprop liquid for a 10 seconds or so a good rumble.
  • We fired our small Gasoline/H2O2 regen 3D printed DMLS stainless motor.
We had a good firing, basic results:
  • Our Cat pack issue is resolved, it started right up and ran perfectly. It looks like lots of anti channel rings are really important.
  • The motor is running a bit lean as the flame was completely transparent.
  • We ran for about 60 seconds so we reached thermal equilibrium.
  • We are completely paranoid about material compatibility on the H2O2 side of the test stand. It appears we need to be more paranoid about the fuel side as the gasoline ate the seals out of one of our fuel valves.
  • I'll try to publish data this week.
  • We should also have access to video later this week.
Unreasonable is basically testing with a two person team. This makes it really hard to take proper pictures and video of the testing. On Saturday there were some guys from a couple of LA hacker spaces (crash space and null space) that came out to FAR and were filming everything. They took a bunch of pictures and videoed the test. When they post these we will post a link here. So... if anyone wants to comne otu to the site and take pictures you are always welcome. We expect to be testing on the first and third Saturday of every month for the foreseeable future.