Simple GPS Tracker?

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qquake2k

qquake2k

Captain Low-N-Slow
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Excuse my ignorance, but is there such a thing as a GPS tracker that will transmit coordinates to a smart phone?
 
Not that I'm aware of.

I don't know about where you fly, but I wouldn't want to rely on one, as I cannot guarantee reliable coverage.

-Kevin
 
Things like the Garmin GTU 10 and this device that somebody posted about on a recent new thread can do this. It depends where you fly. These devices use the cell phone network, so if your rocket lands in a "dead spot" or you're standing in one when you try to download the map, you've got problems.

I haven't used a tracker of any kind, but am just starting to get into the kind of flying where it would be helpful, if not essential. I've been reading up on the options. Budget constraints are the only reason I've looked beyond the Beeline or Telemetrum, and I haven't decided whether to try a cheaper option while saving up for one of those units.

If the cell phone/GPS is workable in your area, then it's certainly cheaper than something like the Beeline. But it's likely not as reliable, and some here have stated that it is illegal to use "cell phones" at altitude (although it's hard to imagine any harm or legal consequences coming from doing so).

At some point, somebody will develop (if they haven't already) an APRS decoder that attaches to a smart phone and will remove the need for an expensive radio unit or a laptop in the field.
 
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I'm working on building one for myself as we speak. To me, is seems silly to buy a stand alone gps or radio tracker when I have a vastly more powerful device in my pocket already (i.e. a smartphone). google maps will show you where it the rocket is in a beautiful, full color satellite image.

that's my plan, anyways.
 
Derek said:
I'm working on building one for myself as we speak. To me, is seems silly to buy a stand alone gps or radio tracker when I have a vastly more powerful device in my pocket already (i.e. a smartphone). google maps will show you where it the rocket is in a beautiful, full color satellite image.

that's my plan, anyways.
Click to expand...

Fly it at Black Rock, and tell us how it works for you.... :)

Seriously, it all comes down to cellular coverage, and in my experience, that's spotty at most fields, especially when it comes to data.

-Kevin
 
troj said:
Fly it at Black Rock, and tell us how it works for you.... :)

Seriously, it all comes down to cellular coverage, and in my experience, that's spotty at most fields, especially when it comes to data.

-Kevin
Click to expand...

I never stated the radio in the rocket would rely on cell coverage... :D

This would work on tablets like my nexus 7, too.
 
Sully said:
Things like the Garmin Astro and this device that somebody posted about on a recent new thread can do this. It depends where you fly. These devices use the cell phone network, so if your rocket lands in a "dead spot" or you're standing in one when you try to download the map, you've got problems.

I haven't used a tracker of any kind, but am just starting to get into the kind of flying where it would be helpful, if not essential. I've been reading up on the options. Budget constraints are the only reason I've looked beyond the Beeline or Telemetrum, and I haven't decided whether to try a cheaper option while saving up for one of those units.

If the cell phone/GPS is workable in your area, then it's certainly cheaper than something like the Beeline. But it's likely not as reliable, and some here have stated that it is illegal to use "cell phones" at altitude (although it's hard to imagine any harm or legal consequences coming from doing so).

At some point, somebody will develop (if they haven't already) an APRS decoder that attaches to a smart phone and will remove the need for an expensive radio unit or a laptop in the field.
Click to expand...

Did you mean Garmin GTU 10? https://buy.garmin.com/shop/shop.do?pID=67686 I'm pretty sure the Astro is a dedicated GPS reciever and transmitter and will work without cell coverage.

Cheers
 
When it comes down to it the values of 'simple' and 'cheap' do not relate to each other in a GPS tracker.
The simplest two I found are the Garmin Astro system and the BRB 900. Easy way to work out if these are of value is.

is $(rocketcost+buildcost+timespent+electronics) > $(GPScost)

if the value of the rocket is over the cost of the GPS system, then it is worth installing one 'just in case' the rocket gets lost. I think of it as $400 insurance covering a bunch of rockets which may value at $thousands.

Now... a CATO or shred may destroy ALL of the above, but........
 
I'm curious how the GPS trackers work. Bear with me as, while I have my general arl, I know nothing of the details about how telemetry and interface work*. Could you get a cheap HT like this: https://www.amazon.com/dp/B007UMQUPA/?tag=skimlinks_replacement-20, patch cable, and an app like this :https://itunes.apple.com/app/packet-pad/id385609173?mt=8 to catch something like a BeeLine? Not that I'm ready to go that far, but getting the receive side for $45 vs $400+ for a HT that can decode ARPS data would certainly go a long way to making it possible for me.


*Technically, I know squat about amateur radio - I read the Tech law and lingo question pool twice to pass the Technician test, and when I passed they let me take General, and I passed that as well. It's like building a G-Force and flying a H128, then turning around and slapping a K into a RTF pyramid to get your L2 on the same day. It ain't right, but I don't make the rules.
 
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JordanT said:
I'm curious how the GPS trackers work. Bear with me as, while I have my general arl, I know nothing of the details about how telemetry and interface work*. Could you get a cheap HT like this: https://www.amazon.com/Baofeng-136-174-400-470MHz-Dual-Band-Display-Two-way/dp/B007UMQUPA, patch cable, and an app like this :https://itunes.apple.com/app/packet-pad/id385609173?mt=8 to catch something like a BeeLine? Not that I'm ready to go that far, but getting the receive side for $45 vs $400+ for a HT that can decode ARPS data would certainly go a long way to making it possible for me.

*Technically, I know squat about amateur radio - I read the Tech law and lingo question pool twice to pass the Technician test, and when I passed they let me take General, and I passed that as well. It's like building a G-Force and flying a H128, then turning around and slapping a K into a RTF pyramid to get your L2 on the same day. It ain't right, but I don't make the rules.
Click to expand...

In theory, it would work. Practically speaking, it would suck - there are too many components to carry and deal with.

I started out with a BeeLine GPS,a PicPac, and a Yagi antenna. I then also needed a GPS to tellme where the point in the packet was. The result? I quickly ran out of hands to carry things

-Kevin
 
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Short of buying a $600 HT that decodes APRS directly and contains a GPS unit, is there really any other option? I'd end up with a HT, my phone (=APRS decoder and GPS in one), and a small Yagi (presumably to track the last hundred feet or so I wouldn't need more than 4 elements). I presume that once I got to the GPS spot, the phone would go back in my pocket and the yagi would come out.

What HT do you track with?
 
JordanT said:
Short of buying a $600 HT that decodes APRS directly and contains a GPS unit, is there really any other option? I'd end up with a HT, my phone (=APRS decoder and GPS in one), and a small Yagi (presumably to track the last hundred feet or so I wouldn't need more than 4 elements). I presume that once I got to the GPS spot, the phone would go back in my pocket and the yagi would come out.

What HT do you track with?
Click to expand...

The Yaesu VX-8GR is $385 from hamradio.com and the Kenwood TH-D72 is $454.
 
JordanT said:
Short of buying a $600 HT that decodes APRS directly and contains a GPS unit, is there really any other option? I'd end up with a HT, my phone (=APRS decoder and GPS in one), and a small Yagi (presumably to track the last hundred feet or so I wouldn't need more than 4 elements). I presume that once I got to the GPS spot, the phone would go back in my pocket and the yagi would come out.

What HT do you track with?
Click to expand...

You're missing a piece -- you'll also have the GPS in your hand -- the app you found is going to display the GPS coordinates in the packet, but isn't going to do anything with them, so you also need a hand-held GPS.

I use a VX-8GR; I tried juggling multiple pieces of equipment, and found that it was a pain in the patoot. With many of the group I fly with also carrying ham radios, and the -8GR being able to receive APRS on one tuner, and voice on another, having one radio serving dual purposes makes it that much better.

-Kevin
 
Presuming that the rocket is no longer moving once it lands, the coordinates should remain nominally fixed (0.01 minutes is several times basic GPS accuracy) yes? All smart phones, i or a, have apps to enter the coordinates and track to a point, even with zero data connection. The phone is both the decoder and GPS tracker - though in different "apps."

I can't argue that a single piece of equipment is better than two, and much more convenient. But once you have a lock on the position, it doesn't seem that using both the GPS unit and the RF beacon tracker have much overlap -or enough overlap to justify the additional $300-400. Having used a handheld GPS in the past (before phones got GPS), it's really just a "hey - your target is somewhere in this 50-100 foot circle; time to do a sweep search".

I may be more jazzed about an excuse to get a better HT after I meet some local hams.
 
troj said:
You're missing a piece -- you'll also have the GPS in your hand -- the app you found is going to display the GPS coordinates in the packet, but isn't going to do anything with them, so you also need a hand-held GPS.
Click to expand...

no, all iphones have gps built in. what you are missing is some software to tell you which direction and distance the rocket is. youl might be able to set the rocket's location as a waypoint and use a navigation app to get you there, though.
 
Derek said:
no, all iphones have gps built in. what you are missing is some software to tell you which direction and distance the rocket is. youl might be able to set the rocket's location as a waypoint and use a navigation app to get you there, though.
Click to expand...

I realize that.

However, since the iPhone will be listening and decoding packets for display, it's not going to be telling you where that GPS point is.

And copying coordinates between the two apps is going to be cumbersome, at best.

It gets even more fun if you're trying to track a rocket that's moving -- been there, done that. At LDRS 30, I was helping someone track a rocket; someone else had picked it up, and had it in their truck, so we were very much following a moving object. It's not that uncommon.

-Kevin
 
troj said:
It gets even more fun if you're trying to track a rocket that's moving -- been there, done that. At LDRS 30, I was helping someone track a rocket; someone else had picked it up, and had it in their truck, so we were very much following a moving object. It's not that uncommon.

-Kevin
Click to expand...

Yeah, I spent quite a bit of time DFing a GPS equipped rocket that some overly-helpful person had locked in their car along with a bunch of other rockets for later transport to the launch site. Very annoying...
 
I never said it would be easy, I just gave an example of a solution that would work.

troj said:
I realize that.

However, since the iPhone will be listening and decoding packets for display, it's not going to be telling you where that GPS point is.

And copying coordinates between the two apps is going to be cumbersome, at best.

It gets even more fun if you're trying to track a rocket that's moving -- been there, done that. At LDRS 30, I was helping someone track a rocket; someone else had picked it up, and had it in their truck, so we were very much following a moving object. It's not that uncommon.

-Kevin
Click to expand...
 
WillMarchant said:
Yeah, I spent quite a bit of time DFing a GPS equipped rocket that some overly-helpful person had locked in their car along with a bunch of other rockets for later transport to the launch site. Very annoying...
Click to expand...

that is pretty funny!
 
In my experience, things that are difficult to use don't get used. This is especially true with trackers, and other things not required to fly

If someone wants it, I have a fully assembled and working PicPac, with the APRS software loaded, that is part with for $50 - plug it into the headphone jack on a radio, and away you go....once you tweak the volume level so that it doesn't saturate the input
 
If your transmitter is high-enough power and the flight not going too incredibly high, you can do tracking with just a rubber duck on the receiving end on the handheld APRS receiver/GPS device.
 
I'm working on and off on a GPS tracker that works with a smart phone or a tablet. The setups is dead-simple, feature-lean and comes in at under $50 in parts.

The idea is to take a GPS module and feed its serial output into an FSK transmitter on an unlicensed band. The receiver demodulates the serial transmission and feeds it (through a voltage shifter) to the phone's audio port. The phone parses NMEA and determines distance and direction from its own internal GPS. If you have cell coverage, I can draw a map for you; if you're out, but have a magnetometer on your phone, I draws you an arrow with distance. If you're on a really low end device, without GPS, cell coverage or magnetometer, I can still draw a map of the rocket's flight path--presumably you know where the pad is, and you can figure out where North is.

I've done a lot of work around serial communication over audio connections, so that, ironically, is the lowest-risk part of the project. (iphly.org, lazertag.com, etc.)

If anyone wants to help, particularly on the RF side, it can speed the project significantly.

Ari.
 
I've looked at those too, there's a bunch of people selling them for under $5 each. Most of the application threads that I've seen say that they're good for about 100M, so that pretty much takes them out of the loop for tracking.

Low-noise moderate-range (5KM or better) transceivers aren't the easiest things to design. I'm a digital guy, I tip my hat to the audio people because I think the stuff they do is a lot harder. It's way beyond me...

JordanT said:
Do you think a 555 or 556 feeding an audio-freq signal to one of these would make a small, cheap beacon tracker? https://www.dorji.com/pro/Modules/ASK_module.html If I read that correctly, it's 25mW on 443 MHz...but I don't really know what the limits are on the signal it accepts.
Click to expand...
 
JordanT said:
Do you think a 555 or 556 feeding an audio-freq signal to one of these would make a small, cheap beacon tracker? https://www.dorji.com/pro/Modules/ASK_module.html If I read that correctly, it's 25mW on 443 MHz...but I don't really know what the limits are on the signal it accepts.
Click to expand...

Something else to consider is that 433Mhz (which is what the modules you linked to say they use) is in the 70cm band, which means A) you have to have a license to use such a device, and B) it has to transmit your callsign on a regular interval. So, a simple timer oscillator circuit wouldn't meet the requirements.

The regular BeeLine TX (not the GPS) is $59 and fits in a 29mm coupler -- small and lightweight, plus you can program in your callsign.

-Kevin
 
I believe you cannot make ham devices on a technician license, you must get the general.
 
Your idea sounds very similar to the gps tracker I'm working on, however I plan on using bluetooth as the final link to the phone because I'm not a software engineer and I hope to leverage a lot of the stuff developed by the diy drones guys for their ground control stations (gcs). they have gcs sw for all sorts of different platforms, including android.

The bt link is a interim step for me as ultimately I'd like to use the usb host on the phone and plug the radio into it directly with a usb to serial adapter. But since the android gcs only supports bt, that's what I'm starting with. Originally I though about the audio serial interface too and that may be a better solution, but I initially want to prove the concept out with the least amount of sw modifications.

I've pretty much finished the rocket mounted gps rx and transceiver and I'm now working on the ground station side of the hardware in my free time. I've got a little arduino code to write to convert the nmea strings to mavlink (the format used by the gcs sw) and spit it out over bt. I happened to have an arduino and bt shield lying around, so that is why I'm using them for development.

Good luck with your project. I'm more than happy to share the components and knowledge I've picked up if anyone is interested.

Derek

iter said:
I'm working on and off on a GPS tracker that works with a smart phone or a tablet. The setups is dead-simple, feature-lean and comes in at under $50 in parts.

The idea is to take a GPS module and feed its serial output into an FSK transmitter on an unlicensed band. The receiver demodulates the serial transmission and feeds it (through a voltage shifter) to the phone's audio port. The phone parses NMEA and determines distance and direction from its own internal GPS. If you have cell coverage, I can draw a map for you; if you're out, but have a magnetometer on your phone, I draws you an arrow with distance. If you're on a really low end device, without GPS, cell coverage or magnetometer, I can still draw a map of the rocket's flight path--presumably you know where the pad is, and you can figure out where North is.

I've done a lot of work around serial communication over audio connections, so that, ironically, is the lowest-risk part of the project. (iphly.org, lazertag.com, etc.)

If anyone wants to help, particularly on the RF side, it can speed the project significantly.

Ari.
Click to expand...
 

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