GPS mod (Some may say upgraded)

[SARDG]

...I just need to find a battery with at lest 400mhA of capacity (looking for a 3 year life or more), fits within the board and is surface mount - haven't had any luck finding a battery of battery mount/clip.

In saying all this if you disable UDR the unit work perfectly fine with Solo.

Is there room in the design for two, easily accessible 2032s in parallel? Probably not flat on the board, but another poster (@cynfab)had a mod with a single 2032 mounted vertically.
GPS Battery

 

[Doug Benson]

How much would the shipping be to the states (Miami, Florida)? I would buy one too.

 

[Pedals2Paddles]

OK. I'll bite. How is this GPS unit accomplishing dead reckoning??

 

[Mode-S]

How much would the shipping be to the states (Miami, Florida)? I would buy one too.

If I use Australia post and economy air ( 9 working days) it about $25 to the US, cheaper then I first thought. If I use Fedx, DHL e.t.c they say its about $80 - what?!

OK. I'll bite. How is this GPS unit accomplishing dead reckoning??

As per the documentation freely available on the u-blox website…

By for going an inbuilt LNA/SAW, this frees up space for gyros/accelerometers which are the key elements for any inertial navigation systems (INS). Sure INS can have a greater degree of error and add up over time but in this application it is a foison between GNSS and DR (that’s the term they use) technology - basically dead reckoning aids the GPS.

This link gives a basic run down, Please note that immediate position at every start function cannot be used because the vehicle (drone) is moved when turned off which voids this ability.
UDR - Untethered Dead Reckoning

 

[cynfab]

Mode-S,
I'm in the US and have bought stuff from these folks is Oz:
FDX-B/HDX RFID Reader Writer with TTL serial port [RFIDRW-E-TTL] - $41.00 : Priority 1 Design. Speciality Electronics design and manufacture, Priority 1 Design. Speciality Electronics design and manufacture
Small electronics boards of about 1/2 the value of your proposed M8U based board (yeah I know it's end user cost vs BOM cost). I typically pay ~$US20 or so for shipping.
Economy Air, NO tracking, but the times I have bought stuff from them I've always received it promptly and usually less than the estimated time.
Your estimate of $US25 seems reasonable to me, and I think shipping from Oz to US is pretty reliable.
To reduce costs maybe the customer could source and install his own u-blox module. It probably wouldn't effect the shipping charges but would effect the overall value of the item shipped. Not everyone can install SMD parts. but a castellated (sp) u-blox module is a lot easier than the LNA/SAW part.
I would take that option if available.

... just a couple of thoughts as I think your design (except for the battery) is really great.

 

[DavidJ]

Hello, how do you like this NEO-M8U ? Is UDR functional and is it useful for drones ? I would have thought the fusion would be constrained to the physical model of a car (slow acceleration, slow turns, slow movement in height). Thank you !

 

[Deleted member 5038]

Hi all,

Once I figure out the best approach for a issue with the design I'll see what the cost is going to be for a small patch run so people can get they hands on one(or two).

All right what is the issue? its nothing that is going to affect the normal operation of the unit or solo but has to do with the untethered Dead Reckoning (DR) side of the unit, two things

1. When dead reckoning is enabled and the GPS unit has a fix of 3D+DR (GPS fix + Dead Reckoning) solo indicates this as a GPS fail, I assume this is something to do with the software code of Solo itself because of an unknown GPS fix indication.

2. If I do go down the line of making the dead reckoning side fully functional a better backup power supply is needed to hold the calibration data for dead reckoning while off, other wise it needs to self calibrate even time you use it and what I have read from the manual this take some time - basically making the dead reckoning function pointless for a UAV application due to the flight time of the typical UAV.

I just need to find a battery with at lest 400mhA of capacity (looking for a 3 year life or more), fits within the board and is surface mount - haven't had any luck finding a battery of battery mount/clip.


In saying all this if you disable UDR the unit work perfectly fine with Solo.

Hi,
What is the difference between your revolutionary GPS and the one developed by Jordi ?

 

[Hyper]

Hi all,

Once I figure out the best approach for a issue with the design I'll see what the cost is going to be for a small patch run so people can get they hands on one(or two).

All right what is the issue? its nothing that is going to affect the normal operation of the unit or solo but has to do with the untethered Dead Reckoning (DR) side of the unit, two things

1. When dead reckoning is enabled and the GPS unit has a fix of 3D+DR (GPS fix + Dead Reckoning) solo indicates this as a GPS fail, I assume this is something to do with the software code of Solo itself because of an unknown GPS fix indication.

2. If I do go down the line of making the dead reckoning side fully functional a better backup power supply is needed to hold the calibration data for dead reckoning while off, other wise it needs to self calibrate even time you use it and what I have read from the manual this take some time - basically making the dead reckoning function pointless for a UAV application due to the flight time of the typical UAV.

I just need to find a battery with at lest 400mhA of capacity (looking for a 3 year life or more), fits within the board and is surface mount - haven't had any luck finding a battery of battery mount/clip.


In saying all this if you disable UDR the unit work perfectly fine with Solo.

So if your user name is "Mode" and your middle initial is "S" I would have to believe that your last name would have to be "Transponder"?? Just say'n

H-
[p.s. nice write up]

 

[Mode-S]

Hello, how do you like this NEO-M8U ? Is UDR functional and is it useful for drones ? I would have thought the fusion would be constrained to the physical model of a car (slow acceleration, slow turns, slow movement in height). Thank you !

From the way I see it... yes UDR is useful in a drone as it provides an extra fail safe option (just like an inertial navigation system in a real plane). If you have a loss in GNSS reception (less face it, its going to happen sooner or later - I've lost GPS mid flight a few times on the stock GPS) the unit will be able to provide information as though it had GNSS vs solo just going into manual mode.

I don't know about you but there are some cars out there that are quicker then solo ;-) Plus you can configure the GPS units application profile, e.g "automotive", "airborne < 1G"

Hi,
What is the difference between your revolutionary GPS and the one developed by Jordi ?

As far as the core operations of the units they are basically the same, NEO-M8N vs NEO-M8U operate the same, with some very minor differences... The major differences come from the components / module used.

• Jordi uses the ublox M8N which has an inbuilt LNA/SAW > I use the ublox M8U which has gyros/accelerometer inbuilt meaning I have to use an extra LNA.
• Jordi backup supply is a coin battery > i use a Super capacitor for basic backup power with a JST connector for external battery and charging circuit via USB.
• Jordi has just made the USB data pin "available" > I've broken out the USB port to a USB connector which allows for direct interfacing with the unit using "U-Center" and flashing of "u blox assistnow offline"
• Jordi uses a GP.1575.25.4.A.02 antenna > i use a CGGBP.25.4.A.02 antenna.

 

[Mode-S]

UPADTE:

I've done my thinking and here is the lasted design, I've gone with a super capacitor to supply the basic backup power when flying (it will give about 17 hours of standby power) but I have also added a small 1 cell Lipo battery connector and charger circuit the battery can be picked up from most online hobby electric shops to power the unit when your solo is off.

I'm getting a very small patch of 15 made - just have to wait the 25 day lead time

Specification:
GNSS unit : u-Blox NEO-M8U
NEO-M8U sensitivity : -160dBm
Antenna gain : GLONASS +3.5 GPS +1.5dBi
LNA high gain: +15.5dB
LNA noise: +1.55dB
SAW band rejection: +55dBc
SuperCap backup: 17hours

 

[SurfnSkate81]

Like I said before, put me down for two please.


Sent from my iPhone using Tapatalk

 

[DavidJ]

Hello, sorry but I mean : does it actually work ? Does the module report its status as UDR active ? I'm scared it will disable sensor fusion itself if the platform isn't stable as a car would be. Thank you.

 

[Deleted member 5038]

From the way I see it... yes UDR is useful in a drone as it provides an extra fail safe option (just like an inertial navigation system in a real plane). If you have a loss in GNSS reception (less face it, its going to happen sooner or later - I've lost GPS mid flight a few times on the stock GPS) the unit will be able to provide information as though it had GNSS vs solo just going into manual mode.

I don't know about you but there are some cars out there that are quicker then solo ;-) Plus you can configure the GPS units application profile, e.g "automotive", "airborne < 1G"



As far as the core operations of the units they are basically the same, NEO-M8N vs NEO-M8U operate the same, with some very minor differences... The major differences come from the components / module used.

• Jordi uses the ublox M8N which has an inbuilt LNA/SAW > I use the ublox M8U which has gyros/accelerometer inbuilt meaning I have to use an extra LNA.
• Jordi backup supply is a coin battery > i use a Super capacitor for basic backup power with a JST connector for external battery and charging circuit via USB.
• Jordi has just made the USB data pin "available" > I've broken out the USB port to a USB connector which allows for direct interfacing with the unit using "U-Center" and flashing of "u blox assistnow offline"
• Jordi uses a GP.1575.25.4.A.02 antenna > i use a CGGBP.25.4.A.02 antenna.

Hi Mode-S:
Impressive. I wish to fly test it.
I fly two Solo's, one has stock GPS, and the other one has the Jordi's one.
I will replace the stock one by yours.
I'd like to buy Two units. Please provide me with terms.

 

[Mode-S]

Hello, sorry but I mean : does it actually work ? Does the module report its status as UDR active ? I'm scared it will disable sensor fusion itself if the platform isn't stable as a car would be. Thank you.

Yes the module does report its fix type as "3D+DR" (when UDR is enabled) but unfortunately this fix type has not been programmed in the Phixhark2, to run the NEO-M8U with UDR enabled it will requires the autopilot reconfiguration.

data sent from U-Blox to Phixhark2/solo
UBX-NAV-PVT ( Navigation Position Velocity Time Solution )
GNSSfix Type,

• 0x00 = No Fix
• 0x01 = Dead Reckoning only (This one is programmed as FIX_NONE, thus solo reports GPS fail)
• 0x02 = 2D-Fix
• 0x03 = 3D-Fix
• 0x04 = GPS + dead reckoning combined (This hex code has not been programmed into the solo firmware, thus solo reports GPS fail as it is an unknown code and falls back to manual mode of flight)
• 0x05 = Time only fix

If UDR fails it will go into 3D fix only, the thing to remember is that GNSS and UDR are different systems that work together as a fusion but at the same time can work on its own if the other one fails. In saying this all I have not try UDR a lot as I'm flight the solo in manual due to fix type issue. Until the firmware is modified to allow the different fix types the UDR selection of the NEO-M8U must be disabled as to allow correct operations with solo, so this is how I've been flying.

Hi Mode-S:
Impressive. I wish to fly test it.
I fly two Solo's, one has stock GPS, and the other one has the Jordi's one.
I will replace the stock one by yours.
I'd like to buy Two units. Please provide me with terms.

More then likely I'll just post it on Tindie as it provides a safe place for both buyer and seller.