Pascal Gosselin | 9 Dec 21:11 2012

5Hz GPS operation using the GTA04 ?


The GTA02 has a pretty good GPS receiver, and the fact that it can do 
4Hz is critical to our application (Flight Data Monitoring).

Has anyone succeeded in being able to get 5Hz position updates from the 
GTA04 with either the  W2SG0004i (SiRFstarIII GPS chip) or the more 
recent GTA04 with W2SG0084i (SiRFstar IV chip ) ?

The W2SG0004i apparently uses a SIRF GSC3LTf.  According to the 
datasheet that I downloaded, the Max update rate is 1Hz which is 
terrible. I'd like to know if there are any hacks to get at least 5Hz 
(not holding my breath...).

The W2SG0084i uses the CSR/SiRF GSD4E.

I did find this regarding the W2SG0008i from 
http://www.wi2wi.com/products/datasheets/W2SG0008i_Datasheet_Rev1.35.pdf

"3.5 1 Hz updates with future 5Hz updates

The current W2SG008i uses a Sirf Star 4 Signature Series ROM 1.3 which 
supports 1 Hz updates of the messages from the satellites vehicle 
solution. In a future release of the internal ROM code version 2.0 and 
later 5 Hz updates will be supported. Contact a Wi2Wi sales office for 
future release dates."

Almost a year has gone by.... is this new firmware available for the 
W2SG0084i ?

-Pascal
(Continue reading)

Timo Juhani Lindfors | 9 Dec 21:25 2012
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Re: 5Hz GPS operation using the GTA04 ?

Pascal Gosselin <pascal <at> aeroteknic.com> writes:
> The GTA02 has a pretty good GPS receiver, and the fact that it can do
> 4Hz is critical to our application (Flight Data Monitoring).

It can do 20 Hz too btw.
Pascal Gosselin | 9 Dec 21:28 2012

Re: 5Hz GPS operation using the GTA04 ?

On 2012-12-09 3:25 PM, Timo Juhani Lindfors wrote:
> Pascal Gosselin <pascal <at> aeroteknic.com> writes:
>> The GTA02 has a pretty good GPS receiver, and the fact that it can do
>> 4Hz is critical to our application (Flight Data Monitoring).
> It can do 20 Hz too btw.
>
>
That's pretty amazing. Tell me more !  I still have a couple of hundred 
GTA 02s that will eventually be installed in airplanes and helicopters.

-Pascal
Timo Juhani Lindfors | 9 Dec 21:43 2012
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Re: 5Hz GPS operation using the GTA04 ?

Pascal Gosselin <pascal <at> aeroteknic.com> writes:
> That's pretty amazing. Tell me more !  I still have a couple of
> hundred GTA 02s that will eventually be installed in airplanes and
> helicopters.

Find the UBX specification. Look at the CFG-RATE command and set
navigation rate to 50 ms.

I have some code to do this in

http://lindi.iki.fi/lindi/git/ubx.git/

(it's derived from ogsmd).
Timo Juhani Lindfors | 9 Dec 22:02 2012
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Re: 5Hz GPS operation using the GTA04 ?

Timo Juhani Lindfors <timo.lindfors <at> iki.fi> writes:
> (it's derived from ogsmd).

I mean ogpsd
francesco.devita | 9 Dec 23:55 2012

Re: 5Hz GPS operation using the GTA04 ?

 >The GTA02 has a pretty good GPS receiver, and the fact that it can do 
4Hz is critical to our application (Flight Data Monitoring).
 >[...]
 >I still have a couple of hundred GTA 02s that will eventually be 
installed in airplanes and helicopters.
 >
 >-Pascal

If I may ask, what kind of activity is yours? Are you using GTA02s as a 
sort of airborne devices.. for what? I had a couple of ideas about 
airborne applications, so I'm just curious about it. Thank you.

Regards
Joif
Pascal Gosselin | 10 Dec 00:52 2012

Re: 5Hz GPS operation using the GTA04 ?


On 2012-12-09, at 5:56 PM, "francesco.devita <at> mailoo.org" <francesco.devita <at> mailoo.org> wrote:

> >The GTA02 has a pretty good GPS receiver, and the fact that it can do 4Hz is critical to our application
(Flight Data Monitoring).
> >[...]
> >I still have a couple of hundred GTA 02s that will eventually be installed in airplanes and helicopters.
> >
> >-Pascal
> 
> If I may ask, what kind of activity is yours? Are you using GTA02s as a sort of airborne devices.. for what? I
had a couple of ideas about airborne applications, so I'm just curious about it. Thank you.

In a typical Wi-Flight application, the GTA 02 is mounted on top of the instrument panel, on the glareshield
of the aircraft. Power is a TomTom 12/24V USB and we use a simple Line-Level to Mic Level conversion circuit
to capture the pilot's audio jack via the GTA 02 Mic Jack. Ambient audio is captured on a second channel,
using the GTA 02's built-in microphone.

The result is a full-featured dual channel Cockpit Voice Recorder and Flight Data Recorder that records
4Hz GPS, accelerometer data, ambient audio pitch (via aubio) for propeller RPM determination and
optional Baro altitude, rate gyro and magnetometer via NavBoard V3. RS-232 and ARINC 429 could can also be
collected via external USB devices.

Eventually we will have a Kalman filter to do attitude determination (such functionality is surprisingly
lacking at the OS level on all smartphone platforms !!!!).

The data is stored on the SD card in various data package types. Upload is to our Cloud-based servers using
Wi-Fi but we are working on some GPRS functions and of course full 5.76Mbps on the GTA 04.  Upload priority
let's us analyze data as quickly as 1 minute after the aircraft shuts down.  It's all 100% automated.

(Continue reading)

robin | 14 Dec 12:37 2012
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Re: 5Hz GPS operation using the GTA04 ?

I reread the thread to see if anyone could actually answer the question if the
gta04 can do more than the very low 1Hz sampling, but am I right that this has
not been answered and as you pointed out the datasheet currently only speculates
about 5Hz in the future?

br

robin

Gmane