I am working on project that get the longitude and latitude and it is everywhere, but I need to get the error estimation at least to draw a circle around my GPS point. How i can find this error in eclipse.
It is known that the total Potential error is around 15 m and the total Typical error is around 10 m. Do i need the average deviation to find the error?
I just need to know how to find the accuracy of my GPS and what values can i fetch using Eclipse?
Thanks alot.
Not sure about your "eclipse" As far as GPS error, there are some things to consider...
Some receivers can output a NMEA GST message with includes error estimates.
You can watch GDOP and HDOP values to get an idea as well as number of satellites tracked.
Assuming a GDOP < 6 and an HDOP <3 with more then 4 tracked satellites you should achieve the receivers specified RMS accuracy.
Another, more complicated method, which should be the basis for the results in then mentioned GST message is Range Residuals. Advanced receivers may output these RRE measurements for each satellite. Using this information you can even detect errors such as multipath, and RF interference. RRE values tell how well a satellites range measurements match the resolved position result.
Related
I need to monitor an AC Voltage waveform and record the RMS value when the breakdown happens. I roughly know how to acquire data from videos I have watched, however, it is difficult for me to produce a solution that reads the Breakdown Voltage Value. Ideally, I would also take a screenshot along with the breakdown voltage value,
In case you are not familiar with this topic, When a breakdown happens the voltage will drop immediately to zero. So what I need is to measure the voltage just before it falls to zero, and if possible take a screenshot. This is an image of a normal waveform (black) with a breakdown one (red).
Naive solution*:
Take the data and get the Y values (this would depend on the datatype you have, which would depend on how you acquire the data).
Find the breakdown point by iterating over the values and maintaining a couple of flags (I would probably say track "got higher than X" and once that's true, track "got lower than Y").
From that, I would just say take the last N points (Get Array Subset) and get the array max. Or just track the maximum value as you run.
Assuming you have the graph in a control, you can just right click and select Create>>Invoke Node>>Export Image.
I would suggest trying playing with that with a VI with static data which you can repeatedly run to check how your code behaves.
*I don't know the problem domain and an not overly familiar with the various analysis VIs that ship with LV, so there are quite possibly more efficient ways of doing this.
I have a Ublox NEO-6M and NEO-N8M, both ordered from China (possibly foreshadowing?).
When I wired the N8M up, it gave me a location in the middle of a lake 30 miles away. For context, I am in South Africa in the southern hemisphere.
I drove around logging two other locations, assuming it could be calibrated with a fixed point error by getting a fixed location reading and subtracting the real coordinates, and using that offset in future calculations.
It didn't work, the inaccuracy was too great, however a lot better, but obviously, it was not the solution.
I then used the 6M. To my absolute surprise, it gave me the exact same location as the first module, exactly in the middle of that same lake. So at this point, I'm starting to wonder, could this be related to the hemisphere? Is it the fact that it could be counterfeit?
The N8M used $GNGLL and the 6M used $GPGLL so I doubt it's a discrepancy with the GPS and GLONASS systems.
Any help would be appreciated, all I want is a really accurate fix on my location.
I stumbled the same way (~30 miles away) until re-reading the NMEA Protocol and realising that it was my fault. So maybe this may help you as well:
The format in the sentence for lat is ddmm.mmmm and for lon it is dddmm.mmmm so you have to do some calculations on your own:
Separate the (d)egrees and the (m)inutes. Divide minutes by 60.0 and add them to the degrees. Voila - you have your correct lat and lon.
I have two identical gps modules running the same program with antennas side by side. I get different results. I don't understand why
One example is 4211.41545 from the first unit and 4211.41481 from the second the timestamp is the same.
You don't say what the values you quote are so I will assume that the value you are showing is the Lat or Long value from the NMEA output data. If this is the case then the difference between the values is 0.00064 minutes of arc. The maximum physical distance that this will represent is around 1.1 metres (along a great circle). At 60 degrees north this would correspond to around 55cm in an E/W direction.
You do not say how far apart the antennae are or whether there are any obstructions above the level of their horizons which will introduce varying multipath signals that will be different for the two antennae. The two receivers will not necessarily be sampling the satellite signals at the same instants and so can have marginally different signal timings resulting in a different position result.
A typical consumer grade GPS will have a CEP figure of 2.5 metres meaning that 50% of the values for position in an unobstructed sky view position will lie within a 2.5 metre radius circle of the true position.
Taking this into account you should not expect any two adjacent GPS devices to give identical results.
I was working on the parsing logic for GPS. I'm trying to parse the GPGSV message, I was able to find 12 satellite's information of 4 parameters like PRN, SNR, Azimuth and Elevation. But I'm not sure which one of these 12 values would be the valid information to send out. And I'm not sure, whether if I calculate the average of these values, would make it valid to use it.
They are all valid. If you wish to summarise the information then I would suggest the number of satellites being reported and the average SNR.
I am working on fetching the current peak and average peak values using Core Audio, however I would also like to fetch A-Weighted, Flat, and C-Weighted dB values. I've searched the documentation, but failed to find anything on this concept.
CoreAudio does not provide such options. You can filter the signal, then calculate the peak/avg from the filtered signal.
You could use (full- or third-) octave band filters and use tabulated values to perform the A- or C- weighting for each band. Calculate the signal level in each band and add the tabulated weighting values found here.