[Loadstone] MTK chipset, was Re: royaltek rbt 2110

Kevin Chao g.unit89 at clearwire.net
Sat Jun 23 22:40:20 BST 2007


Rob ,

If from my email it appeared that all of the multi-path issues are eliminated completely this is not true nor what I am attempting to say; what I am saying however is the issue with multi-path has been improved by a great measure. I am not sure of what calculations nor methodology has been put into making this decrease in the issue of multi-path. Yes, it is true that many of the MTK chipsets are using some method of averaging the  heading to smooth out multi-path issues when traveling over 4 KMH. 

But, many of hte MTK chipsets out on the market currently have issues with speeds below 4 KMH as their averaging methodology seems to do something  quite odd at slower speeds. The issues faced at slower speeds (below 4 KMH) may include any of the following: may report speeds like 39 MPH or even 100 MPH at pedestrian speeds, may have issues with HDOP values below 1.0 and report a poor reading with accuracy of worst than 500 feet, heading information can be thrown off (may be heading west, but will report east), may report that you have gone a quarter of a mile when standing still, may report that destination is a quarter of a mile when in fact you are right next to it.  

Not all recievers have the issues that are outlined above, but it seems to be something quite common with the MTK chipsets. This is something that MTK is actively working on--resolving the issues below 4 KMH. I can say however the Holux M-1000 does not have any of the issues outlined above and works wonderfully in San Francisco where this is the city of the multi-path test. The M-1000 also has a lot longer battery life with only using a 1000 mAh battery. 

Kevin  

 
  ----- Original Message ----- 
  From: Rob Melchers 
  To: loadstone at loadstone-gps.com 
  Sent: Saturday, June 23, 2007 3:26 PM
  Subject: [Loadstone] MTK chipset, was Re: royaltek rbt 2110


  Hi Kevin,

  Could you, without revieling the mysteries around this new super receiver, explain waht has caused this superior suppression of signals distorted by multi path reflection? In theory, MPR is responsible for a plus minus 3 meters degradation of accuracy. To say that the MTK chipset drastically improves on distortion by MPR, means it should be eliminated completely. Propagation in the ionospheric layers still is the major cause of inaccuracy in GPS. I don't think the folks at MTK have found a way to prevent sporadic E-layer reflection in the L1 band, reduced the effects of magnetic distortion in the S-layer and know how to controll sunspots. The results as I have seen them so far from receivers using the MTK chipset show no superiorty over existing receivers. What I have seen is that a predictive averaging model outpputs a smooth track at speeds of over 4 KpH and that reducing a number of DOP masks results in a higher satellite count. All this fits in nicely in the marketting efforts that MTK are using to get their fair share in the receiver market. However, I'd rather wait until I have something more solid to go on before committing to 'the latest and therefore the best'.

  Rob


  At 6/23/2007, you wrote:

    Jürg,

    Well, the Holux M-1000 is using the MTK chipset which has all of the 
    benefits of the SirfStar III chipset but has many  improvements. I am 
    currently testing out a reciever using hte MTK chipset, but since this 
    reciever is still under testing; I cannot mention its name. But, I can say 
    that the MTK chipset has fixed the multi-path issue dramatically that was 
    faced in using the SIrfStarIII chipsets. The sensativity of the receiver has 
    also been greatly improved, it receives waas about 80% of the time, and this 
    is a true waas reporting in the US as it is easier to pinpoint locations 
    within a 3 meter radius. The MTK chipset also consumes less battery power 
    than the SirfStarIII chipsets, this is why the Holux M-1000 is able to 
    receive over 17 hours of battery life with a 1000 mAh battery.    If the 
    reciever were using an auto on/off feature, the battery life would probably 
    reach close to 30 hours

    Kevin

    ----- Original Message ----- 
    From: "Cathomas Jürg" <Juerg.Cathomas at sbv-fsa.ch>
    To: <loadstone at loadstone-gps.com>
    Sent: Saturday, June 23, 2007 12:21 AM
    Subject: Re: [Loadstone] royaltek rbt 2110


    > Hi Hasan,
    > ; And it is more sensitive than a typical SiRf3 Unit.
    > That's interesting. Please let us know whether the real accuracy, not only 
    > the theoretical accuracy is better.
    > In cities, according to my experience, the problem of unreliable 
    > indications due to reflexion is a much bigger problem than the number of 
    > satellites.
    > Kind regards
    > Jürg
    >
    >
    >
    > _______________________________________________
    > Loadstone mailing list
    > Loadstone at loadstone-gps.com
    > http://www.loadstone-gps.com/mailman/listinfo/loadstone
    > 


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