[time-nuts] Tbolt altitude error

[AL1]

Hi all ,
i find some information about altitude given by a GPS.
The correction is contained in the sentence $GPGGA as follow:
**********************************
Bonjour,

Si vous prenez la phrase NMEA $GPGGA d'un GPS vous aurez l'indication de 
correction d'altitude( en rouge ci-dessous et souligné) à effectuer ce qui 
correspond à l'explication de Roland, mais la plus part des GPS normalement 
tiennent compte de cela et affiche la bonne altitude, sur mon garmin je n'ai 
rarement plus de 5 à 10 m d'écart avec la réalité

$GPGGA,065110.000,4544.5047,N,00438.9883,E,1,07,1.2,472.7,M,48.5,M,,0000*56

Robert F1GHO

*********************************************************
The indication is in red :48.5, after the 11th comma.
73
Alain
F4GBC


----- Original Message ----- 
From: <saidjack at aol.com>
To: <time-nuts at febo.com>
Sent: Friday, January 15, 2010 1:35 AM
Subject: Re: [time-nuts] Tbolt altitude error


>
> No,
>
> one is reporting in MSL, the other in GPS height.
>
> There is about a 30m difference between the two here in Santa Clara
> county, CA, similar to what you are seeing.
>
> bye,
> Said
>
>
> In a message dated 1/14/2010 15:23:09 Pacific Standard Time,
> rk at timing-consultants.com writes:
>
> Depends  on satellite geometry. Where they both tracking same satellites?
>
> Rob K
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] On
> Behalf Of John Green
> Sent: 14  January 2010 9:36 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts]  Tbolt altitude error
>
> I had a Tbolt and a Z3801 both fed from the same  antenna and they 
> indicated
> 26 meters differenence in altitude. The 3801  seemed closer to right. If
> geoid error were the cause, it seems that both  would indicate about the
> same.
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