Shanker KC

20 Questions 10 Answers 0 Followers

Questions related from Shanker KC

Where can I download multi-GNSS precise orbit products?

In IGS website, only GPS precise orbit is available. I want to perform PPP analysis with multi-GNSS combination which requires precise orbit of other constellations along with GPS orbits. How can...

31 May 2023 7,608 5 View

What is the minimum amount of observation period to perform precise point positioning (PPP) in RTKLIB software?

We are trying to perform PPP analysis for 1h observation period. Is 1h of data sufficient for doing PPP analysis?

06 May 2023 9,046 2 View

How can convert rinex 3.04 to other version of rinex?

I have got rinex observation file of rinex version 3.04. But I needed to convert it to rinex 3.02 so that rtklib can take it as input. I checked the website of rtklib, it seems, rtklib can only...

02 April 2023 8,489 2 View

What is vertical datum?

What does vertical datum refer to? Is it Mean Sea Level (MSL)? Is it a zero mark in the tide gauge? Is it some other height value than zero, far from the tide gauge? Is it one reference benchmark?...

16 March 2023 1,030 3 View

Why "we don't we have sufficient knowledge about the density structure of the entire Earth"?

I am reading text on physical geodesy. It says, we can not compute the gravity potential directly because we don't have sufficient information of density structure of the Earth. Why is so?

10 March 2023 4,793 2 View

What is quasigeoid?

Geoid: there are infinitely many level surfaces (equipotential surfaces) and the one which coincides with MSL is called a geoid. But what is the quasigeoid?

10 March 2023 2,579 1 View

How can I compute orthometric height from geopotential difference using Helmert's hypothesis?

I have determined the geopotential difference between two stations. Now I want to compute the orthometric height difference between these two stations using Helmert's height formula. But I am...

05 February 2023 5,421 2 View

How precisely we can determine the ionospheric delay in GNSS positioning?

What is the range of values of ionospheric delay and its uncertainty in GNSS positioning?

22 January 2023 4,196 5 View

How does ionospheric-free linear combination eliminate ionospheric effect from GNSS measured range?

How does this ionospheric-free linear combination work?

21 November 2022 8,720 1 View

How did geodesist define/determine/observed the direction of the earth's axis rotation?

How people infer the direction of earth's axis rotation because its invisible. How did they observe the earth's axis of rotation, how did they define and determine this axis?

14 November 2022 9,041 10 View

How did geodesist find/determine position of the equatorial plane?

If i happen to be at equatorial line, how do I know I am at zero degree latitude?

14 November 2022 3,449 5 View

What does it mean by tide free geoid model?

GEOID2022 of the USA follows the "tide free" tide system. I want to understand how the geoid model will be tide-free.

26 October 2022 2,122 3 View

Is it possible to process multiple days GNSS CORS data using RTKLIB in PPP positioning mode?

I have downloaded the 7 days GNSS observation data from one of the UNAVCO listed CORS station. So there are 7 different 24h files for each day for the same CORS station. Can I perform PPP in...

30 August 2022 9,792 1 View

What are the reasons behind convergence time period for PPP?

In precise point positioning (PPP) mode, the smooth positioning is obtained after only certain period, which is called convergence period? What causes for convergence period?

30 August 2022 4,120 1 View

How does PPP Static differ from PPP Fixed from PPP Kinematic?

Inside RTKPOST software, there is various positioning modes available. Among, three are: PPP Static, PPP Fixed, & PPP Kinematic. How is one different from another?

30 August 2022 7,344 2 View

What is the modern international gravity datum after IGSN71?

IGSN71 is the international gravity datum defined in 1971. Is there any updated modern international gravity datum that replace IGSN71?

07 August 2022 6,409 5 View

How do I compute the height of tallest skyscraper of Wuhan (Wuhan Greenland center) from S1A images using radar geometry?

26 April 2022 1,729 3 View

Which is more accurate, the ellipsoidal height from SLR or GNSS?

Satellite Laser Ranging (SLR) and Global Navigation Satellite System (GNSS) both measure the ellipsoidal heights. Which measurement of ellipsoidal height is more accurate?

17 February 2022 7,454 2 View

What does it mean GOCE aims to provide precise geoid information globally with 1-2 cm accuracy at a spatial resolution of about 100 km?

GOCE aims to provide precise geoid information globally with 1-2 cm accuracy at a spatial resolution of about 100 km.

11 December 2021 1,517 3 View

How does one compute gravity anomaly when gravity is observed at place which is below MSL?

Gravity reduction for gravity measured at topography below MSL.

21 November 2021 1,506 3 View