GPS Data Parsing with STM32: The Brutal Truth About NMEA Decoding
Hello everyone. Today, we’re dissecting a piece of technical work that tries – bless its little electronic heart – to walk us through receiving and parsing NMEA data from GPS modules using an STM32 microcontroller. On paper, it’s a straightforward exercise in serial communication. In reality, it’s about as elegant as trying to input a Konami code on a broken gamepad while blindfolded. Let’s get into it.
The Hardware Hookup – Because That’s Never Messy
The author lays out two wiring options: a GPS module with a UART interface and one with RS-232 that needs a level converter. Nothing shocking there – unless, of course, you skip the converter and pipe ±10V straight into your STM32 GPIO pin. In that case, the result will be exactly what you expect: a crispy fried microcontroller, suitable for garnish on your engineer’s salad.
- UART module (TTL levels) – Just plug it in and go.
- RS-232 module – Requires ADM3202 to translate those medieval voltages to something the STM32 won’t spit out like bad sushi.
To the author’s credit, they present scopes of signal levels before and after conversion. Pre-conversion amplitude at 10.6V? Yeah, good luck feeding that straight into a chip rated for 3.3V. That’s not electrical engineering; that’s system-assisted euthanasia for silicon.
Software Setup – CubeIDE Ceremonial Configurations
The CubeIDE configs read like an operating theatre prep sheet: UART in asynchronous mode, baud at 9600, interrupts enabled, DMA in circular mode. That’s the microcontroller equivalent of washing your hands and yelling “Scalpel!” before you start cutting into data streams.
And yes, DMA in circular mode is a must here – otherwise your GPS strings get chopped up mid-sentence like a bad YouTube buffering session. This choice alone saves you from a nightmare of concatenating half-packets while muttering at the debugger about how life used to be better in the old days.
Parsing NMEA – The Joy of CSV on Steroids
The author dives into the $GPGGA and $GPRMC sentences, those delicious comma-delimited gifts from space. They walk through fields for time, coordinates, altitude, and quality indicators. The sample data is fine, though the excitement is about as palpable as a “You Died” screen in Dark Souls you’ve already seen fifty times.
The parsing functions decodeGGA() and decodeRMC() are tailor-made to dump all this into neat C structs. It’s both old-school and effective, like swapping out a gaming PC GPU on a Launch Day instead of succumbing to the prebuilt tax.
Example Data Breakdown
- Time & Date – Extracted with clinical precision.
- Latitude & Longitude – Converted from sexagesimal to decimal degrees so our software doesn’t look like it’s been designed in 1987.
- Fix Quality & Satellites – Gives you the “are we there yet?” indicator from the GPS subsystem.
- Speed & Course – In knots, because SI units are apparently a conspiracy to confuse mariners.
UART Stream Handling – The “Main Loop” Grind
The uart_Handler_GNSS() function takes the role of the overworked dungeon healer – continuously tending to whatever chaos the DMA throws up, checking for known sentence patterns, parsing them, and prepping the next medicinal data packet for the system to swallow. Miss the DMA interrupt handling and you’re essentially playing Elden Ring without dodging – swift and miserable defeat.
Bonus points for implementing watchdog-like detection for GPS inactivity – because there’s nothing worse than being blissfully unaware that your “live” data feed flatlined twenty minutes ago.
Execution in the Field – Or How Not to Draw “HABR”
In a brave attempt at field testing, the author tried walking a GPS track spelling “H A B R.” It ended up less NASA telemetry, more kindergartener finger painting – but in fairness, GPS indoors or in obstructed areas produces results uglier than a Doom Eternal Ultra Nightmare death replay.
The mention of a custom C# GPS tracker for testing is nice – at least they didn’t try to visualize coordinates in Excel like some unholy accounting ritual. Still, signal quality, as always, remains the ultimate dungeon boss here.
Final Verdict
This article does the technical heavy lifting – wiring diagrams, signal levels, IDE configuration, parsing logic – all present and accounted for. It’s not a treasure map for beginners, but if you speak embedded C, it’ll get you there. The wandering prose and scattered structure are less ideal, like a speedrun route that wastes precious seconds on optional NPC chatter, but the core content works.
Verdict: Pretty good in execution, albeit not exactly groundbreaking. Much like replaying a solid, older RPG with mods – the system works, you can admire the craftsmanship, but you’ve seen most of it before.
And that, ladies and gentlemen, is entirely my opinion.
Прием и декодирование NMEA-данных от GPS-приемника, https://habr.com/ru/articles/936028/#post-content-body
