Radiosonde RX now understands Meteomodem's M10 correctly

Updated binary

firmware/common/manchester.cpp

@@ -23,6 +23,10 @@
 
 #include "string_format.hpp"
 
+size_t ManchesterBase::symbols_count() const {
+	return packet.size() / 2;
+}
+
 DecodedSymbol ManchesterDecoder::operator[](const size_t index) const {
 	const size_t encoded_index = index * 2;
 	if( (encoded_index + 1) < packet.size() ) {
@@ -34,12 +38,19 @@ DecodedSymbol ManchesterDecoder::operator[](const size_t index) const {
 	}
 }
 
-size_t ManchesterDecoder::symbols_count() const {
-	return packet.size() / 2;
+DecodedSymbol BiphaseMDecoder::operator[](const size_t index) const {
+	const size_t encoded_index = index * 2;
+	if( (encoded_index + 1) < packet.size() ) {
+		const auto value = packet[encoded_index + 0] != packet[encoded_index + 1];
+		const uint_fast8_t error = encoded_index ? (packet[encoded_index - 1] == packet[encoded_index + 0]) : 0;
+		return { value, error };
+	} else {
+		return { 0, 1 };
+	}
 }
 
 FormattedSymbols format_symbols(
-	const ManchesterDecoder& decoder
+	const ManchesterBase& decoder
 ) {
 	const size_t payload_length_decoded = decoder.symbols_count();
 	const size_t payload_length_hex_characters = (payload_length_decoded + 3) / 4;

firmware/common/manchester.hpp

@@ -34,25 +34,39 @@ struct DecodedSymbol {
 	uint_fast8_t error;
 };
 
-class ManchesterDecoder {
+class ManchesterBase {
 public:
-	constexpr ManchesterDecoder(
+	constexpr ManchesterBase(
 		const baseband::Packet& packet,
 		const size_t sense = 0
 	) : packet { packet },
 		sense { sense }
 	{
 	}
+	
+	virtual DecodedSymbol operator[](const size_t index) const = 0;
 
-	DecodedSymbol operator[](const size_t index) const;
-
-	size_t symbols_count() const;
-
-private:
+	virtual size_t symbols_count() const;
+	
+	virtual ~ManchesterBase() { };
+	
+protected:
 	const baseband::Packet& packet;
 	const size_t sense;
 };
 
+class ManchesterDecoder : public ManchesterBase {
+public:
+	using ManchesterBase::ManchesterBase;
+	DecodedSymbol operator[](const size_t index) const;
+};
+
+class BiphaseMDecoder : public ManchesterBase {
+public:
+	using ManchesterBase::ManchesterBase;
+	DecodedSymbol operator[](const size_t index) const;
+};
+
 template<typename T>
 T operator|(const T& l, const DecodedSymbol& r) {
 	return l | r.value;
@@ -64,7 +78,7 @@ struct FormattedSymbols {
 };
 
 FormattedSymbols format_symbols(
-	const ManchesterDecoder& decoder
+	const ManchesterBase& decoder
 );
 
 void manchester_encode(uint8_t * dest, uint8_t * src, const size_t length, const size_t sense = 0);

firmware/common/sonde_packet.cpp

@@ -42,6 +42,33 @@ Packet::Type Packet::type() const {
 	return type_;
 }
 
+uint32_t Packet::visible_sats() const {
+	return reader_.read(30 * 8, 8);
+}
+
+uint32_t Packet::GPS_altitude() const {
+	return reader_.read(22 * 8, 32) / 1000;
+}
+
+float Packet::GPS_latitude() const {
+	return reader_.read(14 * 8, 32) / ((1ULL << 32) / 360.0);
+}
+
+float Packet::GPS_longitude() const {
+	return reader_.read(18 * 8, 32) / ((1ULL << 32) / 360.0);
+}
+
+std::string Packet::signature() const {
+	const auto header = reader_.read(0, 24);
+	
+	if (header == 0x649F20)
+		return "M10";
+	else if (header == 0x648F20)
+		return "M2K2";
+	else
+		return symbols_formatted().data.substr(0, 6);
+}
+
 SN Packet::serial_number() const {
 	if (type() == Type::M10) {
 		// See https://github.com/rs1729/RS/blob/master/m10/m10x.c line 606

firmware/common/sonde_packet.hpp

@@ -42,8 +42,8 @@ public:
 	};
 
 	Packet(
-		const Type type,
-		const baseband::Packet& packet
+		const baseband::Packet& packet,
+		const Type type
 	) : packet_ { packet },
 		decoder_ { packet_ },
 		reader_ { decoder_ },
@@ -59,16 +59,21 @@ public:
 
 	Type type() const;
 	SN serial_number() const;
+	uint32_t visible_sats() const;
+	uint32_t GPS_altitude() const;
+	float GPS_latitude() const;
+	float GPS_longitude() const;
+	std::string signature() const;
 
 	FormattedSymbols symbols_formatted() const;
 
 	bool crc_ok() const;
 
 private:
-	using Reader = FieldReader<ManchesterDecoder, BitRemapNone>;
+	using Reader = FieldReader<BiphaseMDecoder, BitRemapNone>;
 
 	const baseband::Packet packet_;
-	const ManchesterDecoder decoder_;
+	const BiphaseMDecoder decoder_;
 	const Reader reader_;
 	const Type type_;