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When Will Garmin's New X Series Be Discounted?


comphelp
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I see GPSCity are saying that the Vista C has been discontinued but they are still selling the Vista Cx at $349 (a $100 premium over the old Vista C). Has the unit really been dicontinued or are they just not stocking it?

 

I know Garmin have a policy of forcing their dealers to sell at full retail price but how long does this usually last? When can we expect to see some dicounting on these models? Is it for a fixed term or just until the initial demand dies down?

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I see GPSCity are saying that the Vista C has been discontinued but they are still selling the Vista Cx at $349 (a $100 premium over the old Vista C). Has the unit really been dicontinued or are they just not stocking it?

 

I know Garmin have a policy of forcing their dealers to sell at full retail price but how long does this usually last? When can we expect to see some dicounting on these models? Is it for a fixed term or just until the initial demand dies down?

 

Probably not until major new models (or technology) supercede these new units which may be anywhere from 6 month to 18 months. This is what I usually see being a Garmin dealer for 15 years now.

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Like Didjeerydo said.

Garmin does not drop products very offten. As long as people want to buy an item Garmin will keep it in stock. Some dealers may have discontinued the Vista C. It is not discontinued on garmis web site.

 

I was a GPS buyer for many years before I retired, but now I took on a job in another shop to set up the GPS dept. I am onl ordering anything newer products like the Garmin X series and the newer Magellans Explorist 210, 500. and 600 to start them out with. I do not want to stock older products with the exception of the yellow e-trex.

 

Garmin does not force the retailers to sell at full retail, that is illegal. But they do have a minimum advertised price on newer products. A dealer can sell at any price they want to, but they cannot advertise any price they want to.

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I'm not sure what the current SIRF chipset is in the x units. The newest SIRF chipset allows for geoid correction for the WGS84 projected ellipsoid. WGS84 assumes a perfect ellipsoid approximating the shape of the earth, the mean for all locations on earth averages to 0. With the SIRF II chipset, v 2.3.3 onward the Geoid separation is now reflected with corrections to show MSL altitude. Therefore the sensor (S) units will sooner or later be replaced with SIRF II+ chipsets to obtain Geoid separation corrections instead of relying on barameter readings.

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I'm not sure what the current SIRF chipset is in the x units. The newest SIRF chipset allows for geoid correction for the WGS84 projected ellipsoid. WGS84 assumes a perfect ellipsoid approximating the shape of the earth, the mean for all locations on earth averages to 0. With the SIRF II chipset, v 2.3.3 onward the Geoid separation is now reflected with corrections to show MSL altitude. Therefore the sensor (S) units will sooner or later be replaced with SIRF II+ chipsets to obtain Geoid separation corrections instead of relying on barameter readings.

 

I'm not sure what your point is here. The new Garmins use the SiRFstarIII chips which should do a correct ellipsoid to geoid correction, but the older Garmins using their own chips already provided for that correction. The NMEA GGA message specifies the ellipsoid vs. geoid separation that's being applied in the altitude reading.

 

Barometric altimeters can never give absolute measurements above MSL by themselves anyway since they rely on some type of external calibration to correct for meteorological conditions.

Edited by peter
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I'm not sure what the current SIRF chipset is in the x units. The newest SIRF chipset allows for geoid correction for the WGS84 projected ellipsoid. WGS84 assumes a perfect ellipsoid approximating the shape of the earth, the mean for all locations on earth averages to 0. With the SIRF II chipset, v 2.3.3 onward the Geoid separation is now reflected with corrections to show MSL altitude. Therefore the sensor (S) units will sooner or later be replaced with SIRF II+ chipsets to obtain Geoid separation corrections instead of relying on barameter readings.

Only the 60CX, 60CSX, 76CX and 76CSX are getting SIRF III chipsets. the E-trex CX and Vista CX are not getting a GPS chipset upgrade.

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I'm not sure what the current SIRF chipset is in the x units. The newest SIRF chipset allows for geoid correction for the WGS84 projected ellipsoid. WGS84 assumes a perfect ellipsoid approximating the shape of the earth, the mean for all locations on earth averages to 0. With the SIRF II chipset, v 2.3.3 onward the Geoid separation is now reflected with corrections to show MSL altitude. Therefore the sensor (S) units will sooner or later be replaced with SIRF II+ chipsets to obtain Geoid separation corrections instead of relying on barameter readings.

 

All modern handheld GPS units have a geoid model built in, and none that I know of rely on the barometer to give you elevation above MSL. Sounds like the difference here will be that the geoid model will be integrated into the chipset, offloading those calculations from the main processor.

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pg. 61 of the GPS60CSx manual:

 

"Because the GPSmap 60CSx relies on the Barometric pressure to determine the elevation and the pressure at any given elevation can fluctuate, you can calibrate the altimeter to increase its accuracy."

 

All GPS models have a built in elipsoid model based on the WGS84 system, the geoid is the actual shape of the earth and differs from the elipsoid model, therefore, the x series is destined soon to obsolecense since the correction cannot be made mathematically but must rely on barometric pressure.

 

This becomes an issue not about which SIRF chipset is being used, but about Garmin's inability (or decision) not to incorporate it with its current models. It's just a matter of time, not if, but when?

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pg. 61 of the GPS60CSx manual:

 

"Because the GPSmap 60CSx relies on the Barometric pressure to determine the elevation and the pressure at any given elevation can fluctuate, you can calibrate the altimeter to increase its accuracy."

 

All GPS models have a built in elipsoid model based on the WGS84 system, the geoid is the actual shape of the earth and differs from the elipsoid model, therefore, the x series is destined soon to obsolecense since the correction cannot be made mathematically but must rely on barometric pressure.

 

This becomes an issue not about which SIRF chipset is being used, but about Garmin's inability (or decision) not to incorporate it with its current models. It's just a matter of time, not if, but when?

 

You're very confused above. Yes, it's true that GPS receivers initially determine altitude above the WGS-84 ellipsoid. But almost all models then apply a correction based on a model of how the geoid varies from that idealized ellipsoid shape. All my Garmin receivers, going back about 10 years, have applied a geoid correction factor and therefore have reported an altitude above mean sea level and *not* the height above the WGS-84 ellipsoid. That is also true of all current Garmin (and Magellan) models. [i believe it's true of all current Lowrance models as well but IIRC it was not true of the old Lowrance GM-100.]

 

The statement you're quoting from the manual is about the use of the pressure sensor in the 'S' models to give a more stable and accurate altitude measurement than is possible with GPS alone and has nothing at all to do with ellipsoid vs. geoid considerations.

 

Pressure-based altimeters need some form of calibration and the one in the Garmin 'S' models offers the user three alternatives: 1) calibrate at a location of known altitude, 2) calibrate to a known pressure, and 3) automatically track the GPS vs. pressure altitude and gradually adjust the pressure calibration based on the time-averaged GPS readings. The last of those options is an improvement over what can be done with stand-alone pressure altimeters and it also uses the built-in geoid vs. ellipsoid model that Garmin has in all their models.

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Pressure-based altimeters need some form of calibration and the one in the Garmin 'S' models offers the user three alternatives: 1) calibrate at a location of known altitude, 2) calibrate to a known pressure, and 3) automatically track the GPS vs. pressure altitude and gradually adjust the pressure calibration based on the time-averaged GPS readings. The last of those options is an improvement over what can be done with stand-alone pressure altimeters and it also uses the built-in geoid vs. ellipsoid model that Garmin has in all their models.

I don't see "3)automatically track the GPS vs. pressure altitude and gradually adjust the pressure calibration based on the time-averaged GPS readings."

Example, menu in the Altitude page: "Calibrate Altimeter" - "Do you know the correct elevation?" No. "Do you know the correct pressure?" No. "Do you want to use the current GPS altitude?" No. "You do not have sufficient information to calibrate the altimeter."

Are you saying the if you use the "current GPS altitude" option that it will gradually adjust the pressure over a period of time? In that case, when do you know when it's finished calibrating?

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I don't see "3)automatically track the GPS vs. pressure altitude and gradually adjust the pressure calibration based on the time-averaged GPS readings." ...

Are you saying the if you use the "current GPS altitude" option that it will gradually adjust the pressure over a period of time? In that case, when do you know when it's finished calibrating?

 

If you look on page 76 of the manual you'll see the option under Altimeter setup to turn Auto Calibration either on of off. When left 'on' the unit will continue to adjust the calibration based on the time-averaged GPS measurements with a time-scale of about 30 minutes. It'll never be "finished" since atmospheric conditions are always subject to change so this way the unit will automatically follow such changes.

 

I've responded to your questions here since that's where they were asked, but I agree with 'fuzzybunny' that this is far off track from the original question of the thread. If you still have concerns about the way the geoid vs. ellipsoid measurements are handled or other issues on altimeter calibration it would be best to start a new thread with a more appropriate title.

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I just noticed amazon has the 60cx listed for $394, but it isn't amazon that actually ships it but another outfit. The 6 month feedback on this company 1800 reviews, 93% positive. I can't speak to it though since I've never ordered from them.

 

As mentioned earlier, lakepowellmarine has a 50 buck gift card good at several stores and free overnight shipping, and gpsdiscount.com has nice deals on packages (488 on the cx, autonav kit). I've seen some a bit cheaper for a 60cx, but from places I've never heard of (found some good prices on pricegrabber.com and froogle.google.com, searching for a 'garmin 60cx'. Some of the lowest prices were around 469, but again I don't know how good the stores are.

Edited by drbugs
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