M8N GPS Bestar BN-880 setup

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anyone here has the experience mounting gps module bestar bn-880? Its M8N gps. Is it good? Will it make my solo better than the stock gps in term of gps lock?
 

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I don't know anything about the Bestar. I bought the M8N at www.readytoflyquads.com and installed it.

It gets satellite lock faster than stock and I get more satellites than I did with the stock GPS.

I flew late in the day yesterday and had 20 sats with HDOP of 1.2.
 
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I don't know anything about the Bestar. I bought the M8N at www.readytoflyquads.com and installed it.

It gets satellite lock faster than stock and I get more satellites than I did with the stock GPS.

I flew late in the day yesterday and had 20 sats with HDOP of 1.2.
Are all m8n built equally? Or one is better than the others? Im so newbie in this quadcopter world
 
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I don't know anything about the Bestar. I bought the M8N at www.readytoflyquads.com and installed it.

It gets satellite lock faster than stock and I get more satellites than I did with the stock GPS.

I flew late in the day yesterday and had 20 sats with HDOP of 1.2.

I read somewhere that you can't really trust the HDOP number when you convert to M8N. Something to do with the way the number is calculated. The implication was that although you have a lower HDOP number, your signal strength could actually be worse, but not accurately represented.

Any one chime in on this? Experiences after converting?
 
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I read somewhere that you can really trust the HDOP number when you convert to M8N. Something to do with the way the number is calculated. The implication was that although you have a lower HDOP number, your signal strength could actually be worse, but not accurately represented.

Any one chime in on this? Experiences after converting?
I think you meant to say "can't" really trust the HDOP? I don't know but if you have, say, 15 or more satellites, I think you're pretty safe to fly.
 
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I think you meant to say "can't" really trust the HDOP? I don't know but if you have, say, 15 or more satellites, I think you're pretty safe to fly.
Oops, you're right. Typo, I fixed it.

Well it was my understanding that the way M8N works, it's not necessarily reliable to count on the number of satellites. I think even the original satellite hardware is the same way, it's the HDOP that counts. But when you convert to M8N, the way the HDOP is calculated is thrown off, making the number inaccurate.

Even right now, sometimes I get "FLY" at 7 satellites, sometimes it takes 12. But what's consistent is that I need to have an HDOP or around 2.2 or lower before "FLY" appears.
 
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Oops, you're right. Typo, I fixed it.

Well it was my understanding that the way M8N works, it's not necessarily reliable to count on the number of satellites. I think even the original satellite hardware is the same way, it's the HDOP that counts. But when you convert to M8N, the way the HDOP is calculated is thrown off, making the number inaccurate.

Even right now, sometimes I get "FLY" at 7 satellites, sometimes it takes 12. But what's consistent is that I need to have an HDOP or around 2.2 or lower before "FLY" appears.
I don't know anything about the calculations, but you are right about the HDOP. No matter how many satellites I have, Solo won't "FLY" until its about 2 or lower.
 
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RTF version. Had it for 6 months now. Never a problem, always at least 14 sats at TO, usually 17-18 and HDOP in air of 1.1, 1.2. Central Florida, heavy wifi area.
 
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RTF version. Had it for 6 months now. Never a problem, always at least 14 sats at TO, usually 17-18 and HDOP in air of 1.1, 1.2. Central Florida, heavy wifi area.
Sweet. Is a configuration necessary? Or you just toss it with default config?
 
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No configuration necessary. Only things to watch are there is only one screw on the M8N to hold in place as it doesn't exactly fit the stock holes. Just put a drop of loc-tite on the screw. Second, need to cut wires, and resolder as in the video. Get it right the 1st time!! And make sure you don't have a cold solder joint. Other than that,,never a problem through all the updates, etc. The preferred way in my opinion would be to have a custom cable made with the correct wiring and connectors but not necessary if you are handy with a soldering tool.
 
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I read quite a bit on the FB Solo groups, and there are some 3DR techs in there, as well as people who actually worked on designing the solo (his name is all over the schematics). All equivocally state that the 8N has a higher sensitivity is more susceptible to noise than the 7N. They did extensive testing with both versions, all over the planet, when developing Solo. They also claim that yes, while you will indeed "show" more sats, Solo isn't using them internally. I understand this works for some people and lots are singing its praise. This also voids your warranty if any crashes occur due to gps issues since it's not their stock gps and you cut wires in the solo to install it. You might be able to replace the stock GPS before sending it in, but the wires will still be shredded. Just a bit of caution from what I've read from people who know a lot more about the Solo than the majority of us end users.

The WiFi upgrade has also proven to not actually help. Time after time we get someone who has a great idea for an improvement, implements it and a bunch of us lemmings follow suite, with no actual evidence that it works other than the persons claims.

I'm not saying you won't get a lock faster. There is just more going on behind the scenes than you realize, and getting a faster lock may not be as important as some of the other factors. Do what you wish, though :) I'd just wait til your warranty is expired.
 
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This also voids your warranty if any crashes occur due to gps issues since it's not their stock gps and you cut wires in the solo to install it.
This is my number 1 reason for not doing it. Unless someone could absolutely guarantee a reliable GPS lock 100% of the time, it's simply not worth it. If you have any kind of GPS related crash, you're out of luck in terms of warranty. I like having the peace of mind that if Solo crashes due to a malfunction, 3DR will step up.
 
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I read quite a bit on the FB Solo groups, and there are some 3DR techs in there, as well as people who actually worked on designing the solo (his name is all over the schematics). All equivocally state that the 8N has a higher sensitivity is more susceptible to noise than the 7N. They did extensive testing with both versions, all over the planet, when developing Solo. They also claim that yes, while you will indeed "show" more sats, Solo isn't using them internally. I understand this works for some people and lots are singing its praise. This also voids your warranty if any crashes occur due to gps issues since it's not their stock gps and you cut wires in the solo to install it. You might be able to replace the stock GPS before sending it in, but the wires will still be shredded. Just a bit of caution from what I've read from people who know a lot more about the Solo than the majority of us end users.

The WiFi upgrade has also proven to not actually help. Time after time we get someone who has a great idea for an improvement, implements it and a bunch of us lemmings follow suite, with no actual evidence that it works other than the persons claims.

I'm not saying you won't get a lock faster. There is just more going on behind the scenes than you realize, and getting a faster lock may not be as important as some of the other factors. Do what you wish, though :) I'd just wait til your warranty is expired.
This is my number 1 reason for not doing it. Unless someone could absolutely guarantee a reliable GPS lock 100% of the time, it's simply not worth it. If you have any kind of GPS related crash, you're out of luck in terms of warranty. I like having the peace of mind that if Solo crashes due to a malfunction, 3DR will step up.
Yes im agree with your point about warranty. But i got this situation last week. Me and my friend fly above a football stadium. Im using 3dr solo while my friend using his handmade quadcopter w/ m8n gps. I got 9 gps lock when i take off, but when im right above the stadium, suddenly my solo is lose gps signal lock when my friend's quadcopter flew just fine and solid gps lock. It makes me wonder does m8n is better than solo stock gps. Im quite ashamed bcs my solo cost 2000 dollar while his quadcopter doest cost more than 600

Ps. I live in indonesia, i fly @ 10.00 am. I dont know if that affect my gps performance or not
 
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I read somewhere that you can't really trust the HDOP number when you convert to M8N. Something to do with the way the number is calculated. The implication was that although you have a lower HDOP number, your signal strength could actually be worse, but not accurately represented.

Any one chime in on this? Experiences after converting?
HDOP stands for 'Horizontal Dilution of Precision'. It has nothing to do with signal strength but rather with the number of satellites the receiver can see and where they are located. You need at least 4 satellites for a fix. It should be pretty clear that if you have 4, or 40, satellites all due north of you that you would be unable to determine where you are with respect to east and west and so HDOP would be infinite. If the 4 are more favorably dispersed, with 3 spaced 120° apart on the horizon (one north and the other two at bearings of 120° and 240 °) with the 4th directly overhead HDOP would be 1.33. OTOH if the 3 on the horizon were north, east and south of you it would jump to 2. HDOP is a component of GDOP - the Geometric Dilution of Position. It depends only on the geometry of satellites and receiver.
 
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HDOP stands for 'Horizontal Dilution of Precision'. It has nothing to do with signal strength but rather with the number of satellites the receiver can see and where they are located. You need at least 4 satellites for a fix. It should be pretty clear that if you have 4, or 40, satellites all due north of you that you would be unable to determine where you are with respect to east and west and so HDOP would be infinite. If the 4 are more favorably dispersed, with 3 spaced 120° apart on the horizon (one north and the other two at bearings of 120° and 240 °) with the 4th directly overhead HDOP would be 1.33. OTOH if the 3 on the horizon were north, east and south of you it would jump to 2. HDOP is a component of GDOP - the Geometric Dilution of Position. It depends only on the geometry of satellites and receiver.
Great response!

Whats OTOH?
 
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I read quite a bit on the FB Solo groups, and there are some 3DR techs in there, as well as people who actually worked on designing the solo (his name is all over the schematics). All equivocally state that the 8N has a higher sensitivity is more susceptible to noise than the 7N.
Higher sensitivity is a good thing. It means the internal noise of the radio is lower. I would want to talk to an engineer about what 'more susceptible to noise means. You may have misinterpreted what they said but, OTOH, if the 8N has poorer filtration, signal processing algorithms etc. it might be less able to reject out of band interference for example. It's pretty clear from much of what I have seen on the web that the shielding of the GPS module was poorly done in this design. The attempt to fix with the sheet of copper which apparently worsened the problem without the after market spacer and the ferrite bead on the wiring harness apparently help.

They did extensive testing with both versions, all over the planet, when developing Solo. They also claim that yes, while you will indeed "show" more sats, Solo isn't using them internally.
A receiver will use all the satellites it receive that pass the RAIM (Receiver Automatic Integrity Monitoring) requirement. As I mentioned in an earlier post the more satellites you have the better the HDOP but that's only part of the story. HDOP is the uncertainty in position in feet given that the receiver's pseudorange measurements to all the satellites are accurate to 1 foot. The HDOP for 9 satellites depends on where they are in the sky. Throwing them up there randomly the average (over all the random arrangements) HDOP is 1.19. Ninety five percent of random arrangements give an HDOP of less than 2.36. I got 1.6 with the Solo stock receiver a few minutes ago. Increasing the number of satellites to 15 implies an average HDOP of 0.5. HDOP decreases almost as fast as the square of the ratio of the number of satellites so having the Glonass satellites in the solution conveys a large dividend in location accuracy provided the pseudorange error from the GPS/Glonass receiver is as good or better than the pseudorange error from the GPS only receiver. If HDOP improves by a factor of .5/1.19 in going from 9 GPS only satellites to 9 GPS plus 6 Glonass but the new receiver delivers pseudorange error performance worse by a factor of 1.19/.5 you are right back where you started in terms of actual knowledge of where you are in the horizontal plane. I have no idea as to whether the 8N is worse than the 7N in this regard. Spec's should tell but I don't have them for either receiver. The receivers themselves should put out pseudorange residuals data from which one can calculate the probable position error (that's where the circle on you smartphone map comes from. Maybe that data is buried in the SOLO's log files.

I understand this works for some people and lots are singing its praise.
That suggests that the 8N is not noise susceptible and/or that it has a better search strategy for locking up to satellites than the G7.

This also voids your warranty if any crashes occur due to gps issues since it's not their stock gps and you cut wires in the solo to install it.
Not much to say about that one!

Along those lines the GPS module in the newest delivery's (just got mine this week) seem to be different from the one's I've seen in the YouTube how-to videos. They have 6 wires issuing from them with the extra 2 being labeled differently from the other two (compass) wires on the 8N. I'll leave it to someone else to demonstrate the the 8N is still a 'drop in' replacement.

The WiFi upgrade has also proven to not actually help. Time after time we get someone who has a great idea for an improvement, implements it and a bunch of us lemmings follow suite, with no actual evidence that it works other than the persons claims.
By increasing WIFI power from 300mw to 500 mw (2.2 dB) you increase your theoretical range by a factor only 29% as sqrt(500/300) = 1.29. That's not a whole lot but every dB helps!
 
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When you change batteries or come back to the same location it gets the satellites super fast (almost as fast as the Phantom 3) cuz it caches them in memory from what I'm told.
These things work by calculating how far away each satellite is, measuring that and using the differences to correct the assumed position. At startup it has to synchronize its clock(s) to the satellite system(s) clock(s) and it does that by moving gates around time values near those predicted by the calculated ranges. If it is near where it was shut down and the satellite ephemeris data is fresh it should be able to lock up pretty quickly. If you shut it down in LA and bring it back up in Sydney 6 mos later it will have to search code by code (each satellite has its own) over a wide range of delays until is can lock to one and then download the Nav Message to update the satellite ephemerides. There are many strategies for this but the almanac download takes a long time.
 

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