GNS/INS (Inertial Navigation System) integration

In summary, the GPS receiver estimates the error state and provides an estimate for the future evolution of error.
  • #1
ramesses
17
0
Hi
I'm working on a GPS/INS model.

Now I developped the mecanization equations for the INS.

I have a kalman filter which estimate the error state (position error with respect to north and east).

it takes as an input the diffrence between GPS and INS and gives its estimation .

I have developped a gauss-markov process which very similar to sensor noise (after applying wavlet).

Now, I don't know what can I do during the GPS outage ?

Because the mesaures are not available during this periode; I can't use Kalman filter.

Documentation that I have, doesn't say clearly what to do during GPS outage.
 
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  • #2
ramesses said:
Hi
I'm working on a GPS/INS model.

Now I developped the mecanization equations for the INS.

I have a kalman filter which estimate the error state (position error with respect to north and east).

it takes as an input the diffrence between GPS and INS and gives its estimation .

I have developped a gauss-markov process which very similar to sensor noise (after applying wavlet).

Now, I don't know what can I do during the GPS outage ?

Because the mesaures are not available during this periode; I can't use Kalman filter.

Documentation that I have, doesn't say clearly what to do during GPS outage.

I googled Inertial Navigation During GPS Outage, and got some pretty good hits. Maybe have a look through some of them to see if they give you some ideas...

https://www.google.com/search?sourc...s+outage&gs_l=hp...0.0.0.7637...0.uCHzFb-uDEc

:smile:
 
  • #3
ramesses said:
Now, I don't know what can I do during the GPS outage ?
During the GPS outage your GPS fix has infinite, or perhaps some really large, variance. So what happens to your Kalman filter when that happens?
 
  • #4
@berkeman
Thank you :)
olivermsun said:
During the GPS outage your GPS fix has infinite, or perhaps some really large, variance. So what happens to your Kalman filter when that happens?
Kalman filter doesn't work until a new GPS's measure comes. unless the Kalman filter can't be used
 
Last edited:
  • #5
Doesn't your Kalman filter have at least one input which is the integrating model from your INS?
 
  • #6
Hello;
the system starts its loop after receiving the initiale position, bearing and speed from the GPS receiver.
this loop, presented in the first figure, is used during GPS outage.
2B4qVqQZVPD0.png

Now, when a new measure comes from a the GPS receiver, the distance between the GPS and INS positions will be used as input for the kalman filter.
2B4qkWENiM1S.png

the measurement equation, as in [1],is
2B4r14BBjQsU.png


I followed the same model as ([1]), except I used Gauss-Markov process instead of autoregression.
2B4quCJX5Css.png

The vector in the right is called the error state vector. It is used to estime the INS error.
αuN and αvN are the parameters of the 4 ordre autoregression process for the 2 accelerometer axes.

If I have well understand, the use of the process parameters inside this matrix serve for the prediction step. it gives an estimation for the evolution of the error for the epoch t+(1/INS_frequency)
but after giving its feedback, the error state vector will reset to zeros

What do you think about it ?

Sorry for my english

[1]Park, Minha, and Yang Gao. "Error and performance analysis of MEMS-based inertial sensors with a low-cost GPS receiver." Sensors 8.4 (2008): 2240-2261.
link to document: http://www.mdpi.com/1424-8220/8/4/2240/htm
link to PFE document: http://www.mdpi.com/1424-8220/8/4/2240/pdf
 
  • #7
your opinion is very important to me, because I'm not very sure, that I used kalman filter correctly.
thank you
 

1. What is GNS/INS integration?

GNS/INS integration refers to the combination of two navigation systems - the Global Navigation Satellite System (GNSS) and the Inertial Navigation System (INS) - to provide accurate and reliable positioning, navigation, and timing information.

2. How does GNS/INS integration work?

The GNSS uses signals from satellites to determine the receiver's position, while the INS uses accelerometers and gyroscopes to track changes in velocity and orientation. The two systems are combined through a process called sensor fusion, where the INS measurements are used to correct and enhance the GNSS data, resulting in more accurate navigation information.

3. What are the benefits of GNS/INS integration?

GNS/INS integration offers several benefits, including improved accuracy and reliability, enhanced navigation in areas with poor GNSS signal coverage, and increased resistance to jamming and spoofing. It also provides a more continuous and smooth navigation solution, especially in dynamic environments such as aviation or maritime applications.

4. What are some applications of GNS/INS integration?

GNS/INS integration is used in various industries, including aviation, maritime, land navigation, and autonomous vehicles. It is also commonly used in military applications for navigation and targeting purposes.

5. Are there any limitations of GNS/INS integration?

While GNS/INS integration offers significant advantages, it is not without its limitations. The INS component relies on initial calibration and can experience drift over time, which can affect the accuracy of the integrated solution. Additionally, GNS/INS integration can be costly and complex to implement, requiring specialized equipment and expertise.

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