Why Sirf and not Nmea..??

yokeren · 01-11-2005, 10:56 AM

As the title says...?

SAScooby · 01-11-2005, 10:59 AM

I think SIRF is the chipset/aerial and NMEA is the protocol the information is delivered in

yokeren · 01-11-2005, 11:02 AM

Quote: Originally Posted by SAScooby

I think SIRF is the chipset/aerial and NMEA is the protocol the information is delivered in

Hmm..why do people in here prefere sirf insted of nmea.. Is it quicker or...?

ShawJohn · 01-11-2005, 11:03 AM

As far as I know SirF is the name of the chipset company who makes these GPS thingies...

BUT Sirf is also the name given to the binary protocol that the GPS Mouse uses to communicate with the PC. SirF uses binary at 19,200bps, and NMEA uses ASCII code sent at 4800bps.

Hence Sirf is faster, and also appears to be more accurate in use.

Thats how I understand it anyway.
:GOOGLE: if you want more...

John

edikp · 01-11-2005, 11:33 AM

Give http://www.sirf.com a browse.

Chairboy · 01-11-2005, 11:58 AM

Peeps keep saying it's faster, but that's immediately followed by 'Well, it's still 1hz.'

Which is it?

yokeren · 01-11-2005, 11:59 AM

Okay..thanks. I did try to run D3 beta in Sirf and in gps settings there is: find gps and set gps. When i press find, it finds the gps. When I press: set gps it says: com port is busy!! Anyone knows what im doing wrong?

yokeren · 01-11-2005, 12:08 PM

And how do I swith the gps back to NMEA? In the Sirf program.

Prindle19 · 01-11-2005, 12:16 PM

accuracy has nothing to do with sirf or nimea protocol, the update time difference is almsot indistinguishble. More important is whether or not the gps receiever is cable of receiving a differential correction signal either from the WAAS enabled satelites, or coast guard or LORAN-C beacons.

yokeren · 01-11-2005, 02:35 PM

Thanks

Trying Sirf now!

yokeren · 01-12-2005, 09:16 AM

How to switch back to NMEA? help

ShawJohn · 01-12-2005, 09:36 AM

Use winfast navigator to switch between modes...

Here's a snippet that I found about NMEA or Sirf:

Brief Introduction of SiRF and NMEA

Connecting to the GPS Receiver is the first hurdle to overcome, but first a brief introduction. Firstly there are two GPS Standards, NMEA and SiRF. Although SiRF is the up and coming new boy on the block, NMEA is the acquired standard and one used by 95% of GPS applications. Why two standards ? NMEA is getting old, it was designed to talk at 4800 baud (4kbps). Modem speeds today are 56kbps so you can see NMEA is slow. SiRF has brought about that change by increasing speeds and utilising full serial speeds up to 115200kbps. The thing is although NMEA is slow, some GPS Receivers will work at higher than 4800, but this is what NMEA prefers. The amount of GPS data sent down the serial port is very small and can easily be transmitted in 4800 baud so although you could reach higher speeds, there isn't really any necessary to do so. SiRF uses higher speeds because it can transmit the data quickly and put the processor into a wait state which in theory means it utilises less power, newer SiRF chipsets like SiRF IIe also have low power consumption which help even further with sustaining power to the GPS Receiver.

CLIPPED FROM: http://www.expansys.fr/forumthread.a...2533&thread=47

Sirf is able to transmit to the PC faster!
The positional accuracy and update speed seem supperior in Sirf mode, it also uses less power, and less CPU.

WHAT I MEANT BY FASTER: I know most receivers are 1hz ie 1/sec but if the GPS takes a second to output data, and the PC takes another second to calculate using the data, then at 30mph you GPS prog will show you around 20-30meters behind where you actually are.

I may be wrong but SirF mode definately runs smoother and appears to be more accurate on both altitude and position on my setup.

John

yokeren · 01-12-2005, 09:51 AM

Quote: Originally Posted by Tuned Vitesse

Use winfast navigator to switch between modes...

Here's a snippet that I found about NMEA or Sirf:

Brief Introduction of SiRF and NMEA

Connecting to the GPS Receiver is the first hurdle to overcome, but first a brief introduction. Firstly there are two GPS Standards, NMEA and SiRF. Although SiRF is the up and coming new boy on the block, NMEA is the acquired standard and one used by 95% of GPS applications. Why two standards ? NMEA is getting old, it was designed to talk at 4800 baud (4kbps). Modem speeds today are 56kbps so you can see NMEA is slow. SiRF has brought about that change by increasing speeds and utilising full serial speeds up to 115200kbps. The thing is although NMEA is slow, some GPS Receivers will work at higher than 4800, but this is what NMEA prefers. The amount of GPS data sent down the serial port is very small and can easily be transmitted in 4800 baud so although you could reach higher speeds, there isn't really any necessary to do so. SiRF uses higher speeds because it can transmit the data quickly and put the processor into a wait state which in theory means it utilises less power, newer SiRF chipsets like SiRF IIe also have low power consumption which help even further with sustaining power to the GPS Receiver.

CLIPPED FROM: http://www.expansys.fr/forumthread.a...2533&thread=47

Sirf is able to transmit to the PC faster!
The positional accuracy and update speed seem supperior in Sirf mode, it also uses less power, and less CPU.

WHAT I MEANT BY FASTER: I know most receivers are 1hz ie 1/sec but if the GPS takes a second to output data, and the PC takes another second to calculate using the data, then at 30mph you GPS prog will show you around 20-30meters behind where you actually are.

I may be wrong but SirF mode definately runs smoother and appears to be more accurate on both altitude and position on my setup.

John

Nice

It keeps telling me that there isnt enough sats..how many kbps are u running?