Problems with Rockwell's GPS support ?........ me too :(

>It is important to know that the Companys we buy from
>make availible enough information for us to use the
>product, that it does its job and that it is what we
>were led to believe it was
>If they don't, then others should be warned

Didn't want to spam the list with such off-topic matter but your message
triggered me, Peter.

>How else will we know what programers to buy,
>what developement systems to use
>and that F is the sixth letter in the alphabet
>(as in PIC16F**)
>
>In my opinion this sort of feedback should be encouraged

Agree.

My complaints are not for the Rockwell GPS itself, but for the lack of GOOD
support. If you have a technical question you will never be able to talk
with the people who developed the hardware and firmware and your request
will be routed to a bunch of so called "sales-eng.". This guys have just
read the manual (as best) and NEVER worked with the product in the field. Is
a waste of time to try to get valuable info from them. Better to read the
manuals again or make your own tests.

But sometimes it is HARD to make your own test. That happened to us:

We purchased a Microtracker-LP (Low Power 5 Channel GPS board) from our
local Rockwell distributor. This was intended to be the main navigation
instrument for a balloon payload carrying radioamateur radios. We had some
warnings from other ballooners in the US talking about the COCOM export
rules and their application to commercial GPS receivers. This rules are
applied in all the firmware of commercial GPS boards exported. In order to
prevent other countries using this GPS boards for missile navigation there
are two limitations implemented:

                        Maximum speed < 2 Mach
                        Maximum height < 60.000 feet

The real pain is that this two limitations are taken as an "OR" value in
most of the cases. This makes the GPS unusable for our balloon as it takes
higer than 60.000 feet BUT never gets that 2Mach fast. Motorola has a
firmware version for their OnCore GPS which takes this two variables as an
"AND". This firmware was developed for balloon applications.

The Rockwell's Microtracker GPS data sheet states as 40.000 feet the maximum
height. So the questions were:

What happens when it gets higer than that, but at very low speed ?
Does it turns to 2D navigation and stop providing 3D fixes or just gets blocked?
Will it work again when going down under 40.000 feet ?
Need to reset it or may be something is written in the EEPROM and the unit
becomes unusable for undetermined (for ever?) time period ?

All this questions were addressed trought the corresponding channel
(distributor-European distributor-Rockwell headqueaters) but apparently got
lost during such a long trip. Then I used e-mail to spam directly at
Rockwell's web page and got some feedback from their European distributor
site in Italy. Months later I got a "response" from a "technician". There
was no response to my concrete questions in that mail, just a bunch of
pseudo technical arguments explaining that the unit will not work over
40.000 feet.

In the meantime we had to launch our balloon and LEARNED that GPS does not
respond to any command when it gets 40.000. It is no possible to reset the
unit when the payload gets down. May be we would have needed a
power-on-then-off reset.

That test cost us the payload lost and I'm still waiting for a proper answer
to my questions from Rockwell.


Excuse the bandwith, but I wanted to tell the whole story.

Feel better now ;-)



Luis Fernandez Cormenzana
RadioBit Sistemas, S.L.
        Vehicle fleet control systems
        Patrol presence controllers

Fax/Tel:+34-6-585 64 57
e-mail: radiobit@dragonet.es
http://www.dragonet.es/users/radiobit