[FOSS-GPS] Position modes in RTKPOST

Tue Nov 1 10:51:02 EDT 2011

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" <afsm.pestana at gmail.com>
Sent: Tuesday, November 01, 2011 10:38 PM
To: "Open Source GPS-related discussion and support" 
<foss-gps at lists.osgeo.org>
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" <afsm.pestana at gmail.com>
>> Sent: Tuesday, November 01, 2011 6:48 AM
>>
>> To: "Open Source GPS-related discussion and support" <
>> foss-gps at lists.osgeo.org>
>> 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 <ttaka at yk.rim.or.jp>
>>>
>>>  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" <afsm.pestana at gmail.com>
>>>> Sent: Saturday, October 29, 2011 3:34 AM
>>>> To: "Open Source GPS-related discussion and support" <
>>>> foss-gps at lists.osgeo.org>
>>>> 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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