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bviator
USA
21 Posts |
 Posted - 28 mai 2006 : 01:14:46
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So, the unit you tested is not for sale yet to the general public?
If that is the case, how do you think the current i-blue with Nemerix chipset and version 3.8 will compare as far as accuracy? |
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gpspassion
93389 Posts |
Posted - 28 mai 2006 : 01:23:22
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Correct the SBAS enable M5 I used will be available for purchase in June it seems. The current iBlue is the one I used as the other part of the "Nemerix pair" for non-SBAS, but it's 3.2.7, not 3.8 ? Is there a mention of 3.8 somewhere, if yes that would be a typo I need to fix ;-)
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Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer? |
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gpspassion
93389 Posts |
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gpspassion
93389 Posts |
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bviator
USA
21 Posts |
Posted - 07 juin 2006 : 20:13:13
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Interesting quote from the article:
"Please be aware that although some of the marketed GPS receivers can process the MSAS test signals, test signals are NOT necessarily valid as GPS augmentation information for some of the marketed GPS receivers."
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bviator
USA
21 Posts |
Posted - 10 juin 2006 : 03:42:53
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I will have an i-trek M5 with Nemerix chipset by next week. I also own a SirfII and and a SirfIII gps unit. I would like to do some testing for accuracy, especially repeatability of accuracy on different days with different satellite orientations. I would also like to see what WAAS is doing over here in the U.S. as far as improving accuracy. Of course, I stil have not been able to get WAAS on my Sirf III unit, so that may be a limitation.
Question: I have access to an RTK system, a very high end system (costs over 24,000 US dollars) used in precision agriculture that has accuracy of less than one inch. It utilizes a base station to generate localized correction signals to the mobile unit mounted on farm equipment.
I imagine I could use this equipment to get a somewhat "true" reference point to compare accuracy to the consumer gps units. Would I still need Delorme's GPSPostPro or is there some free software I could use. I do have some aricultural software on my IPAQ that can log points every few seconds over a given amount of time, and can export these points into standard arc shape files. Any suggestions on how best to do this in order to measure accuracy in comparison to the reference point? |
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gpspassion
93389 Posts |
Posted - 10 juin 2006 : 23:25:40
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Oh that sounds like it would do the job fine, if you have an accurate geodetical marker in your area you can make sure it is working properly but I suppose it has some kind of error checking built-in ;-)
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Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer? |
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bviator
USA
21 Posts |
Posted - 14 juin 2006 : 03:42:32
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What software (especially inexpensive)can be used to calculate average deviation from a fixed point? I am not too concerned about logging over a period of time nor getting an accurate reference point. But how was GPSPassion able to calculate the average deviation from the fixed point?
I am excited about doing a little more accuracy testing in the field of precision agriculture, and especially encouraged about GPSPassions intitial results on the Nemerix chipset. Great job!
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Haicom 303III (SirfIII)
Globalsat BC-307 (SirfII)
I-Trek M5 (Nemerix)
Holux GM-270
Ipaq 2200 Series
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gpspassion
93389 Posts |
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bviator
USA
21 Posts |
Posted - 24 juin 2006 : 03:09:10
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Received my M5 a week ago and love it. First, it got WAAS correction right away. Still no WAAS from my two SirfIII units. My SirfII Globalsat unit is getting WAAS everytime. I have about given up on my Haicom 303III and BT-338. I have done every possible tweak with GPSTweak, SirfDemo, MMSirf, etc.
Back to M5, comparing it to my arc view maps underlayed on the location marker of the gps location, I find it is dead on. As GPSPassion saw in the testing, much less jumping around and wandering of the calculated location. But is this a "true" phenomena or some sort of "static navigation" processing?
The shape file fields boundries I am using as an underlay of my gps postion was measured using a sub-meter gps. It seems darned close. I am looking forward to the fall when I will have time to some testing. I just wish I could get WAAS to work on those SirfIII units for the testing.
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Haicom 303III (SirfIII)
Globalsat BC-307 (SirfII)
I-Trek M5 (Nemerix)
Holux GM-270
Ipaq 2200 Series
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bviator
USA
21 Posts |
Posted - 24 juin 2006 : 03:11:30
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By the way,
The GPSPassion testing article indicated that the Nemerix chipset was actually somewhat more accurate without SBAS enabled. What software does one use to disable SBAS on a Nemerix chipset?
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Haicom 303III (SirfIII)
Globalsat BC-307 (SirfII)
I-Trek M5 (Nemerix)
Holux GM-270
Ipaq 2200 Series
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gpspassion
93389 Posts |
Posted - 24 juin 2006 : 03:23:52
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Thanks for keeping us posted. No software I'm aware of to turn SBAS on/off on a Nemerix bsaed receiver.
Good to hear you're getting some good accuray results. Not sure how they do it, but there must be some astute filtering going on to have so little wandering, nothing like SN though that just freezes the position completely. Navigation accuracy on foot is good too, so again no SN.
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Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer? |
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Leif
Sweden
141 Posts |
Posted - 24 juin 2006 : 13:15:56
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quote:
What software does one use to disable SBAS on a Nemerix chipset?
From NS1030 GPS Software, Datasheet, NS1030-GPS-SW-ds15 – Rev. 1.5 – November 2005.
$PNMRX114,0,0*xx : disable SBAS functions
$PNMRX114,1,1*xx : enable SBAS functions with normal handling of type 0 messages
(to be used on WAAS satellites, for example).
$PNMRX114,1,0*xx : enable SBAS functions and ignore type 0 messages
(to be used on EGNOS satellites, for example).
So any software that can transmit a user defined NMEA message and add a calculated checksum. SiRFDemo, menu Action, Transmit Serial Message. SirfTech, NMEA, Set.
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bitslizer
9 Posts |
Posted - 25 juin 2006 : 19:40:32
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| so how to go about calculating the checksum? i assume the *xx is the checksum? |
Edited by - bitslizer on 25 juin 2006 19:47:00 |
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Leif
Sweden
141 Posts |
Posted - 04 juil. 2006 : 16:01:18
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You don't have to. SirfTech and SiRFDemo calculates it for you. Just enter the NMEA data that should go between the $ and * and the $, * and checksum is added before transmission.
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SBAS and GPS Accuracy - Side by Side Testing
