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  1. #1
    Join Date
    22nd January 2009
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    Palo Alto, CA
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    2,049

    New tracker range test result

    I have been working on a GPS tracker for the last 8 months, and I finally got far enough with the system to do a little range test. I set up a tracker radio in my backyard in Palo Alto, and then headed to the San Jose airport for my flight to Denver, where I work. Once the plane took off, I held up one of my radios representing the ground station to look out the window. I was getting packets while the distance to my backyard was 62kft until the plane banked away. The transmitter on the ground was set for 14 dBm output, (25 mW) and both radios had simple omnidirectional stub antennas. Considering the trees and houses near the transmitter I'm not sure that I had a clear line of sight to the plane. I know the receiver looking out the window had a view to every 915MHz transmitter in silicon valley, so I'm happy that it could pick my transmitter out of the noise. I'm looking forward to testing with some rockets transmitting from a clear sky, particularly at BALLS next month.

    When I get a little farther with the firmware and testing I'll give a complete description of the product. I've been trying to avoid announcing anything until I got far enough along to be sure that the tracker and ground station would really go into production. I'm not quite at that point yet but I couldn't help but say something today since today's test was pretty encouraging.

    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  2. #2
    Join Date
    6th February 2015
    Posts
    661
    12 miles on 915MHz and 25mW, nice! How did you calculate the distance?



  3. #3
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
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    Quote Originally Posted by CORZERO View Post
    12 miles on 915MHz and 25mW, nice! How did you calculate the distance?
    Thanks. The goal is to get get as much range as anyone could want, while still using small batteries and antennas.

    I used a GPS app on my phone that was navigating to a waypoint at my house. Soon I'll be able to use my own GPS but that part of the software isn't done yet.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  4. #4
    Join Date
    26th November 2009
    Posts
    4,712
    Increasing efficiency is a very good goal so GPS tracking can be put into smaller and smaller projects. Saves on losing rockets and if used, the pricey reusable motor casings. I've been leary to fly some of my small AT casings due to fear of losing the
    rocket/motor casing. Kurt

  5. #5
    Join Date
    15th February 2009
    Location
    North Texas
    Posts
    538
    As a heavy user of a variety of your products I'm looking forward to seeing what you've got. The more choices we have the better for all involved. Great that so many folks are willing to develop products for such a small hobby.


    Tony
    why do people put so much stuff in their sigs?

  6. #6
    Join Date
    1st May 2009
    Location
    Perth, Western Australia
    Posts
    99
    Thanks for the update Adrian! I'm looking forward to learning more.
    AMRS L3
    Max Alt AGL - 23,908ft - K300 - Balls 22
    Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

  7. #7
    Join Date
    18th October 2016
    Posts
    462
    I've been waiting for this update. It's great to hear about the progress! I'm looking forward to trying one out one day.
    TRA L2. I-class record: "Vanish 29" with an I224, 14,596ft, Mach 1.92. Video here.

  8. #8
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
    Posts
    2,049
    Thanks, guys.

    Quote Originally Posted by GrouchoDuke View Post
    I've been waiting for this update. It's great to hear about the progress! I'm looking forward to trying one out one day.
    We have been waiting a long time. Since I started last winter I had to change the main microcontroller and development environment (twice), the radio module, the GPS module (twice), the "other" radio module. Finally all the pieces are solid and the firmware and testing is coming together. Basic functions should be ready and flight tested in time for BALLS. Production features like over-the-air bootloading for firmware updates, low power modes, and some cool other functions will be after that.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  9. #9
    Join Date
    26th October 2011
    Location
    South Shore, Massachusetts
    Posts
    766
    Is it just me or is anyone else sensing an increased heart rate while reading this ?

    Im stoked !!!

    I know Christmas is coming in a short 4 months.. or has it arrived today ?

    Sleigh bells ring, are you listening, In the lane, snow is glistening A beautiful sight, We're happy tonight. Walking to our rocket via GPS.....
    Thrust cures All !
    Nar # 212312
    Level 1 achieved 7/2016
    Level 2 achieved 7/2017
    CERT FLIGHT- CTI-J335 7,014 FEET

  10. #10
    Join Date
    8th May 2012
    Location
    Southern, CA
    Posts
    6,188
    Quote Originally Posted by CPUTommy View Post
    Is it just me or is anyone else sensing an increased heart rate while reading this ?

    Im stoked !!!

    I know Christmas is coming in a short 4 months.. or has it arrived today ?

    Sleigh bells ring, are you listening, In the lane, snow is glistening A beautiful sight, We're happy tonight. Walking to our rocket via GPS.....
    Cool
    NAR # 89516
    HPR Cert Level 1

  11. #11
    Join Date
    16th February 2014
    Location
    Gilroy, CA
    Posts
    2,163
    Wow! I thought my commute from Gilroy to Santa Clara sucked.

    I'm interested to see your tracker make it to market. More options are always welcome.

    Quote Originally Posted by Adrian A View Post
    I set up a tracker radio in my backyard in Palo Alto, and then headed to the San Jose airport for my flight to Denver, where I work.
    Chris Attebery
    TRA 6602 L3
    Personal best: 37,789' 1335mph

    www.ape-rc.com

  12. #12
    Join Date
    26th October 2011
    Location
    South Shore, Massachusetts
    Posts
    766
    id be MORE than happy to be a product tester..

    Just sayin..
    Thrust cures All !
    Nar # 212312
    Level 1 achieved 7/2016
    Level 2 achieved 7/2017
    CERT FLIGHT- CTI-J335 7,014 FEET

  13. #13
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
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    2,049
    Today the Featherweight Tracking System had a successful test in its first high-powered flight, so here's a little more info.

    I don't have a good photo of the tracker itself, but I'll post one after I assemble one without the extra debug header pins. The dimensions of the production tracker board will be about 0.82" x 1.62". So it's a little smaller board than a Raven altimeter in both dimensions, despite having mounting holes for 4-40 screws. The 900 MHz stub antenna adds about 2.5" to the length if you mount it right to the board.

    The tracker collects GPS data with a brand-new 8th-generation uBlox receiver that can receive data from both GPS and Russian GLONASS satellites at the same time, and integrate data from both constellations into its solution. The benefit is that for a given antenna field of view, twice as many satellites are available as for any GPS-only receiver. The testing I have done so far with this receiver has blown me away with how clean and accurate the data is, even in altitude and vertical velocity, which have been not-so-great with other GPS receivers I'm used to. I'm currently having it produce and record 10 GPS solutions per second, and in a test case where I pick the receiver off the ground and wave it around, you can clearly see that in the altitude and velocity data. There's less than 1 ft/second of measurement noise in all 3 dimensions.

    The tracker sends its data from the rocket down to the ground over a new protocol called LoRa (portmanteau of Long Range), which is a new commercial standard from Semtech optimized for sending small amounts of data over long range at very low power... in other words, tailor-made for rocketry GPS tracking. I'll post more details about the link performance later after I do some more range testing, particularly after BALLS next weekend where it will see some high-altitude flights.

    To get this LoRa data into information you can use, there is a small ground station that fits in your shirt pocket, and relays the data to an app on your cell phone.




    The micro-USB port is just for charging the battery (8-40 hours of life depending on battery size). The tracker sends out the data over Bluetooth Low Energy to an app on your phone.

    We have been focusing on the iPhone app so far, since Android-compatible trackers already exist, but the plan is to make an Android version soon, too. During the flight, the app not only shows you the key information like altitude, vertical and horizontal speed and distance, but also has some real-time indicators that use the GPS, magnetometer and gyroscope in your phone so that you can use the phone to point right at the rocket. Kevin Small (author of the Featherweight Interface Program) has been working on the the app development, and came up with this. At first I was skeptical about how useful this would be, but when you try it and see the phone pointing right to where your rocket is in azimuth and elevation, it's pretty impressive. I'll show a screen shot once we get it a little farther along.

    In today's test flight, I was trying to not only test the tracker and iPhone app (the first version of which I only downloaded last night!), but also to get re-certified L1 since my HPR certs have expired. Just about all of my HPR flights to date have been designed to be as high and fast as possible, so I decided to go big and use an AT I600 in a minimum-diameter 38mm rocket for my cert flight. Unfortunately, I neglected to ground test my deployment charges before the flight, and they were too small, so although the rocket had a sweet boost around Mach 1.3 up to 11,400 feet, it had a ballistic re-entry 1.2 miles up-wind. One of the features we're planning but have not yet implemented is data recording from the ground station. I did have 10 Hz data recording onto a micro-SD card on-board the rocket, but that's not so useful when a 4-foot long rocket's landing site looks like this:



    Sorry, my rocketry skills are rusty. (Ground test, ground test, ground test!) My recollection from watching the phone display is that both the LoRa radio and the GPS kept lock throughout the flight, but confirming this impression will need to wait until next weekend's flights at BALLS. But what I can tell you is that the last packet that got to my phone was 6321 feet away from my phone, 448 feet above the ground, traveling -540 feet/second vertically and 52 feet/second horizontally. There was about 36 dB of radio link margin at this range and with these settings. When I hiked out to that latitude and longitude, sure enough the rocket tube was sticking out of the ground about 40 feet downrange of the last measurement report, just as you would expect from the horizontal velocity. So the last data point for tracking was right on the money.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  14. #14
    Join Date
    10th July 2007
    Location
    Melbourne, Australia
    Posts
    1,214
    Nice work Adrian. I like the use of LoRa too.

    Also, regarding charges: blow it up or blow it out

    I hope all goes well at BALLS for you.
    TRA 13430, Level 3

    "Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

  15. #15
    Join Date
    18th October 2016
    Posts
    462
    Adrian, this is outstanding. It’s awesome to see the new standard in trackers getting close to market. LoRa & UBlox 8 is the combo to have. Woot!

    Sorry about your rocket & death of a prototype tracker. That hurts.
    TRA L2. I-class record: "Vanish 29" with an I224, 14,596ft, Mach 1.92. Video here.

  16. #16
    Join Date
    26th November 2009
    Posts
    4,712
    I will attest to that. Working on a 3DR solution: http://www.rocketryforum.com/showthr...Solution/page9 but I am a script kiddie
    and not an engineer. I used an -8N clone and found that my usual hacked ham apps couldn't deal with the combined GPS/Glonass strings but if I
    ran the combine strings through the Android app Bluetooth GPS I could pipe the strings to an app and get them read and plotted. It is indeed
    more accurate. Being a Ham, I'd like to see about getting a callsign in the NMEA strings to maintain legality.

    3DR is two way and we really don't need that. A 500mW solution on 70cm would go a long way. Working with 900Mhz with 3DR is stupid unless one
    wants to tinker. There are many commercial offerings and now Adrian has a promising one on the way.

    I was impressed with testing with my hacked system but this looks much nicer and GPS/Glonass decoding is pretty darned good.

    Suffice it to say, I and many others have not lost a fully functioning GPS tracked rocket with the standard GPS tracking standard. (Barring landing in
    an inaccessible place!)
    Kurt

  17. #17
    Join Date
    20th January 2009
    Location
    Johnson City, NY
    Posts
    1,985
    Sounds like a great system. Any chance it will be out in time for Christmas?
    Rocket Addict
    More...more...I'm still not satisfied (T. Lehrer)

  18. #18
    Join Date
    22nd January 2009
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    Palo Alto, CA
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    Quote Originally Posted by les View Post
    Sounds like a great system. Any chance it will be out in time for Christmas?
    Yes, some chance, but no guarantee.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  19. #19
    Join Date
    20th January 2009
    Location
    Johnson City, NY
    Posts
    1,985
    A few more questions

    Will you need a ham license for this?

    What sort of price range are you anticipating?

  20. #20
    Join Date
    18th October 2016
    Posts
    462
    He said 915MHz, so it shouldn't require an amateur license in the US.
    TRA L2. I-class record: "Vanish 29" with an I224, 14,596ft, Mach 1.92. Video here.

  21. #21
    Join Date
    22nd January 2013
    Location
    Gilbert, AZ
    Posts
    104
    Quote Originally Posted by les View Post

    Will you need a ham license for this?
    GrouchoDuke is correct that it does not require a ham license.
    Kevin Small, TRA #07172 L3
    Featherweight Interface Developer - wFIP (Windows), iFIP (iPhone)

  22. #22
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    22nd January 2009
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    Palo Alto, CA
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    Quote Originally Posted by les View Post
    A few more questions

    Will you need a ham license for this?

    What sort of price range are you anticipating?
    I would like to wait until I get production assembly quotes before putting a price out there. But it's safe to say it will be more than the EggFinder and less than the Multitronix TelemtryPro.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  23. #23
    Join Date
    15th February 2009
    Location
    North Texas
    Posts
    538
    Quote Originally Posted by Adrian A View Post
    Yes, some chance, but no guarantee.
    Based on my recent experience, put me down for 2. And a couple of new Ravens.


    Tony
    why do people put so much stuff in their sigs?

  24. #24
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
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    Thanks Tony.

    A small update. I was getting ready to try out some longer-range settings in preparation for tracking rockets to over 100,000 feet at BALLS this weekend, so I started by doing a range test with my current setup. I taped a transmitter to the window at my lab at work, and drove to the furthest accessible spot with a clear line of sight, which is 47690 feet (9 miles) away. I was reading packets with 18.5 dB of signal strength margin, which means that I could have gotten data from 439,000 feet. That altitude would be beyond the edge of space with over 100,000 feet to spare. I guess I don't need the change the settings after all.

    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  25. #25
    Join Date
    18th October 2016
    Posts
    462
    Quote Originally Posted by Adrian A View Post
    I guess I don't need the change the settings after all.
    LoRa FTW!
    TRA L2. I-class record: "Vanish 29" with an I224, 14,596ft, Mach 1.92. Video here.

  26. #26
    Join Date
    26th November 2009
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    4,712
    Very nice Adrian. You'll make a lot of long range tracking folks very happy. Kurt

  27. #27
    Join Date
    18th March 2009
    Location
    Wisconsin
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    3,529
    Quote Originally Posted by Adrian A View Post
    Thanks Tony.

    A small update. I was getting ready to try out some longer-range settings in preparation for tracking rockets to over 100,000 feet at BALLS this weekend, so I started by doing a range test with my current setup. I taped a transmitter to the window at my lab at work, and drove to the furthest accessible spot with a clear line of sight, which is 47690 feet (9 miles) away. I was reading packets with 18.5 dB of signal strength margin, which means that I could have gotten data from 439,000 feet. That altitude would be beyond the edge of space with over 100,000 feet to spare. I guess I don't need the change the settings after all.

    Adrian, I am excited to see this. I am also excited by an app that will work on an iOS device. What are the dimensions.


    Sent from my iPhone using Rocketry Forum
    Mark Koelsch
    Tripoli 6155 L3
    Owner of http://www.rocketryfiles.com/
    Editor of http://www.thrustcurve.org/
    Member of the Tripoli Motor Test Committee, and keeper of the motor file

  28. #28
    Join Date
    21st January 2017
    Location
    Wichita KS
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    95
    Is this a tracker only, or will it be available paired with an altimeter on the same board?

  29. #29
    Join Date
    15th February 2009
    Location
    North Texas
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    538
    Quote Originally Posted by markkoelsch View Post
    Adrian, I am excited to see this. I am also excited by an app that will work on an iOS device. What are the dimensions...[/url]
    Not to steal Adrian's thunder but he lists the dimensions above:

    "The dimensions of the production tracker board will be about 0.82" x 1.62". So it's a little smaller board than a Raven altimeter in both dimensions, despite having mounting holes for 4-40 screws. The 900 MHz stub antenna adds about 2.5" to the length if you mount it right to the board."

    I've worked with Raven's for years due to their very size size and if the board for this is smaller than a Raven, it's going to be extremely versatile. I'm also very excited to have a native iOS app. A dream app would be something like MotionX for rockets.

    I'm hoping that BALLS weather cooperates and Adrian gets to do some good testing. Really looking forward to some high altitude real world tests.


    Tony
    why do people put so much stuff in their sigs?

  30. #30
    Join Date
    22nd January 2009
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    Palo Alto, CA
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    Quote Originally Posted by GrouchoDuke View Post
    LoRa FTW!
    Exactly.

    Quote Originally Posted by ksaves2 View Post
    Very nice Adrian. You'll make a lot of long range tracking folks very happy. Kurt
    Thanks, Kurt. You've been doing great work here on the DIY end of things.

    Quote Originally Posted by markkoelsch View Post
    Adrian, I am excited to see this. I am also excited by an app that will work on an iOS device. What are the dimensions.
    0.82" x 1.62" for the board, not including the antenna or antenna connector. I may want to make a whip antenna variant so I can squeeze one into a 38mm Featherweight Av-bay next to a Raven and stick the antenna out a little hole. Then I can fly it in my 38mm altitude record attempt rocket and get back into 38mm multistage altitude shots.

    Quote Originally Posted by AeroAggie View Post
    Is this a tracker only, or will it be available paired with an altimeter on the same board?
    What I'm testing now is tracker-only, with some hooks to share data with a possible future altimeter. The unused pins on the tracker's microcontroller are calling to me, though, (Use me!... Use me!!) and the GPS may turn out to be good enough to make a baro sensor unnecessary, so I'm giving some thought to making a combined unit for the next product.

    Quote Originally Posted by manixFan View Post

    I've worked with Raven's for years due to their very size size and if the board for this is smaller than a Raven, it's going to be extremely versatile. I'm also very excited to have a native iOS app. A dream app would be something like MotionX for rockets.

    I'm hoping that BALLS weather cooperates and Adrian gets to do some good testing. Really looking forward to some high altitude real world tests.
    Tony
    We're starting with iOS because there's a niche to fill, and also because I like my iPhone. Android will be coming too, though. I use MotionX and the new app will have some of the features of its compass. For mapping initially we will probably have it help you to send the coordinates to another app.

    I checked the BALLS weather forecast today and it looks kinda chilly but otherwise great. I haven't checked the jet stream for wind shear predictions yet, though.

    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

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