Miniature GPS module with 10Hz update rate

It is not the module that provides the 1 Hz but the GPS system. There is just not more data. Except for those using the military version. I have no idea how precious these parts are nowadays, but at least for now you should forget them.

The reason why the current commercial GPS is not delivering more updates ? Even kids could build a cruise missile or similar.

Rene

--
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Un bel giorno Rene Tschaggelar digitò:

Are you sure? I knew that the military band just allowed to get better resolution by using the P-codes, but the fix frequency was just a matter of processing power. There are lots of 4 Hz consumer GPS (look at U-Blox), and I've seen non-military GPS up to 100 Hz.

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asd

It is completely untrue that the GPS system doesn't provide enough information to update (especially speed) more than once per second. The GPS unit can get the speed directly from Doppler on the various satellites, and it can (in principle) compute Doppler shift before it even decodes the messages.

I searched using Google with the terms "gps," "update," and "rate," and found several links in the first result page to non-military GPS's with a

5 Hz update rate. They are not OEM units like the OP is looking for, but this result disproves your assertion that 1 Hz is a system limitation.

There ARE export restrictions on some GPS units, but as far as I know, the export restrictions only apply when the unit has high altitude, speed, and acceleration envelopes.

Selective availability, AFAIK, has been turned off for several years, and anyway I don't think it had anything to do with update rate.

--Mac

If you're only interested in velocity there are other methods that may work better. You can buy chintzy but operational microwave speed guns for $60 or so from Ramsey. The Doppler shift is an audio output and could be hooked straight up to a microprocessor for sampling as fast as you want. Whether this'll work or not depends on how many axes you need and how far away it is to a known stationary object...

Tim.

From memory... GPS basic 'data rate' is 1000Hz. This is a 'bit' of data. Every bit is transmitted 20 times, so that's 50 bits per second of data. A navigation message (day/time/basic orbit of satellite) is 300 bits. So, ever 6 seconds or so you get a complete message for one satellite.

You can generate position information at the 1000Hz rate. It'll be very inaccurate.

The longer the period you integrate over, the less noisy it becomes.

Do you guys thin that a 5 or 10Hz GPS module exists?

I've seen some that sat .1S reacquisition time. Don't know if that means that a new speed is measured and ready to be polled in .1S or not.

Lets say this one for instance..

Do you guys thin that a 5 or 10Hz GPS module exists?

I've seen some that sat .1S reacquisition time. Don't know if that means that a new speed is measured and ready to be polled in .1S or not.

Lets say this one for instance..

[snip]

I have seen, touched and witnessed the functioning of two different GPS's with update rates of 10 Hz or better. Unfortunately, I don't remember the exact make or model. I will try to find some old notes when I go back to work on Monday (if I remember). They are NOT cheap.

There may not be a 10 Hz GPS which meets your size, power, and price points.

There are also integrated GPS and IMU units out there which can give you accurate position (and orientation, as long as you are moving) information at 100 Hz, but they definitely don't meet your size spec, and probably cost too much for your application by several orders of magnitude. To tell the truth the only one I actually know about is export restricted, meaning that you have to jump through some kind of hoops to get it if you are in the US, and probably can't get it outside the US.

--Mac

Un bel giorno Mook Johnson digitò:

As I've written, u-blox

sells low-cost 4-Hz GPS modules, they cost around 100$. If you need more speed, be prepared to spend a lot more (ten times minimum). Look for example Thales Navigation they have GPS modules up to 20 Hz.

Other links (but I haven't used their modules - by the way, someone has?):

modules up to 25 Hz (or 50-Hz raw data); modules up to 20 Hz.

No, reacquisition time is the time needed to restart the acquisition after a "short blackout" (10-30 s), e.g. when you enter a tunnel.

It looks like a 1 Hz model.

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asd

Small MEMS accellerometers and gyros can offer good performance in this range (giving info from second down to millisecond) That's probably the cheapest way.