Difference between revisions of "GPS Frequency Standard"
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− | Stand-alone design does not require PC. Generates a | + | Stand-alone design does not require PC. Generates a 10 MHz output after satellite lock. |
* [https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=gps+module+neo-7M&_sacat=0&LH_TitleDesc=0&rt=nc&_odkw=gps+module+neo-7&_osacat=0&LH_PrefLoc=2 NEO-7M GPS] | * [https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=gps+module+neo-7M&_sacat=0&LH_TitleDesc=0&rt=nc&_odkw=gps+module+neo-7&_osacat=0&LH_PrefLoc=2 NEO-7M GPS] |
Revision as of 17:44, 26 June 2022
Build V2
Stand-alone design does not require PC. Generates a 10 MHz output after satellite lock.
- NEO-7M GPS
- QTPy49 card
- QT Py (SAMD based)
- Running CircuitPython
- 3.3V, 40 MHz
- PulseGen modified
- Not used as pulse generator (oscillator circuit removed)
- Receives input from GPS output and drive 50 Ohm output on BNC
- Status LED
- Blinks in for 1 second at power up
- Blinks off until serial communications are working
- Blinks on-off while waiting for Satellite is captured
- On solid once output is enabled
- Fits into Aluminum Project Box Enclosure DIY 100*76*35mm - ebay search
- Inspired by
Wiring
# Wiring # Signal Color From To # GND Black QTPy49 J4-1 GPS pin 4 # VCC Red QTPy49 J4-2 GPS pin 5 # QTPy>GPS Blue QTPy49 J4-3 GPS pin 2 # GPS>QTPy White QTPy49 J4-4 GPS pin 3 # GND Black QTPy49 J5-1 PulseGen GND # VCC Red QTPy49 J5-2 PulseGen VCC # PPS Purple GPU pin 1 PulseGen In # LED-VCC Red QTPy49 J9-3 D0 # LED-GND Black QTPy49 J9-1 GND
Code
- GPS_004.py - Final working code
- Saved as code.py to auto-run
- GPS_003.py - Capture data from GPS module a line at a time - helpful for debugging
- GPS_002.py - Read 32 bytes at a time
- GPS_001.py - Formatted stings output
Build V1
Requires PC running ublox software on PC to set output.
- NEO-7M GPS
- FTDI-49MM card set to 3.3V signal levels
- PulseGen modified to receive output from GPS and drive 50 Ohm output out of the box
- Fits into Aluminum Project Box Enclosure DIY 100*76*35mm - ebay search
GPS
- GPS Satellite Positioning Module NEO7M UBLOX
- Specifications:
- Working Voltage: 3.3v-5.0v
- Color: As Picture Shown
- Description:
- With micro USB interface, you can debug GPS module with ordinary phone data cable, no longer need to use USB-TTL and other tools.
- TTL interface is reserved to facilitate the use of USB-TTL or external microcontroller to control and receive GPS information.
- Ceramic antenna on module board, no GPS external antenna can be used to search for stars.
- Reserved SMA antenna interface, can use external antenna, star search ability is stronger.
Reference Materials
- Design & Build a GPS locked Frequency Standard- Scullcom
- SIMPLE 10 MHZ GPS FREQUENCY STANDARD AND RF GENERATOR
- uses Arduino Nano as FTDI replacement
- An Arduino-based GPS Disciplined Oscillator
- An Arduino Version of Brooks Shera's GPSDO
- Simulating the Brooks Shera (W5OJM) GPSDO Algorithm
Videos