[FOSS-GPS] Position modes in RTKPOST

Tue Nov 1 09:38:31 EDT 2011

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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