Dear Antonio
2. By EKF are you referring to "extended Kalman filter"? I suppose that
"extended Kalman filter" is KF applied to non-linear mathematical models.
Am I right?
Yes.
If either the system-model or the measurement-model
is non-linear, "extended" KF is used. In the RTKLIB case,
only the measurement-model is nonlinear. The system-
model is not nonlinear.
Someone use it only for a non-linear system-model. If
so, RTKLIB just employs KF.
regards,
*********
Tomoji TAKASU
--------------------------------------------------
From: "António Pestana" <[email protected]>
Sent: Tuesday, November 01, 2011 10:38 PM
To: "Open Source GPS-related discussion and support"
<[email protected]>
Subject: Re: [FOSS-GPS] Position modes in RTKPOST
Dear Mr. Takasu
Once again I must thank you for your patience and kindness.
Regarding your answer to my questions:
1. Yes, you are right: I mean "least square".
2. By EKF are you referring to "extended Kalman filter"? I suppose that
"extended Kalman filter" is KF applied to non-linear mathematical models.
Am I right?
Best regards
Antonio
I think that a) and b) are not suitable to RTK positioning because of
the
ill-conditioning of the design matrix (very short observation time
spans,
frequently one solution per epoch). I'm I right?
Not right.
KF can handle only one epoch observations
(but usually has no meaning). LS or KF is just
a design selection.
1. RTKPOST "static" is like c.1)?
2. RTKPOST "kinematic" is like c.2) or c.3)?
3. And RTKPOST "single"? Is it LMS/WLMS?
In "single", RTKPOST uses weighted LS.
In other modes, RTKPOST uses EKF.
regards,
*********
Tomoji TAKASU
------------------------------**--------------------
From: "António Pestana" <[email protected]>
Sent: Tuesday, November 01, 2011 6:48 AM
To: "Open Source GPS-related discussion and support" <
[email protected]>
Subject: Re: [FOSS-GPS] Position modes in RTKPOST
Dear Mr. Takasu an other list members:
I am aware (not really aware, I've just heard off...) of the following
solutions to the positioning problem we are dealing with (GNSS
positioning):
a) Least mean square (LMS)
b) Weighted least mean square (WLMS)
c) Kalman filter
c.1) static positioning: coordinates of the receiver are constants and
the
estimated clock offset of the receiver is white noise with zero mean
c.2) kinematic positioning for high receiver velocity: coordinates and
clock offset are modelled as zero mean white noise
c.3) kinematic positioning for low velocity: the coordinates are
modelled
as a random walk
I think that a) and b) are not suitable to RTK positioning because of
the
ill-conditioning of the design matrix (very short observation time
spans,
frequently one solution per epoch). I'm I right?
If I'm right then it follows that in RTK we are using some sort of
"Kalman
filter" type solutions. And if we are using "Kalman filters" type
solutions
then the following questions arise:
1. RTKPOST "static" is like c.1)?
2. RTKPOST "kinematic" is like c.2) or c.3)?
3. And RTKPOST "single"? Is it LMS/WLMS?
Regards
Antonio
2011/10/28 Tomoji TAKASU <[email protected]>
Dear Antonio
Can anyone explain give me a brief explanation regarding the
differences
between the position modes options in RTKPOST? I am especially
interested
in
the following modes: Single, Kinematic, Static, Moving-base and Fixed.
I think they are generally common terminologies
among GNSS positioning area except for "Fixed".
So see the manual and search by Google.
"Fixed" is special in RTKLIB. In the mode, the user
position is fixed to a priori values specified by user
options and other parameters like ionosphere,
troposphere are estimated. It is also used for the
analysis of measurement noise and multi-path with
residuals.
regards,
*********
Tomoji TAKASU
------------------------------****--------------------
From: "António Pestana" <[email protected]>
Sent: Saturday, October 29, 2011 3:34 AM
To: "Open Source GPS-related discussion and support" <
[email protected]>
Subject: [FOSS-GPS] Position modes in RTKPOST
Can anyone explain give me a brief explanation regarding the
differences
between the position modes options in RTKPOST? I am especially
interested
in
the following modes: Single, Kinematic, Static, Moving-base and Fixed.
Regards
Antonio
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