include/marnav/nmea/gsv.hpp

   1 #ifndef MARNAV_NMEA_GSV_HPP
   2 #define MARNAV_NMEA_GSV_HPP
   3
   4 #include <array>
   5 #include <marnav/nmea/sentence.hpp>
   6 #include <marnav/utils/optional.hpp>
   7
   8 namespace marnav
   9 {
  10 namespace nmea
  11 {
  12 /// @brief GSV - Satellites in view
  13 ///
  14 /// These sentences describe the sky position of a UPS satellite in view. Typically they’re
  15 /// shipped in a group of 2 or 3.
  16 ///
  17 /// @code
  18 ///        1 2 3 4 5 6 7     8
  19 ///        | | | | | | |     |
  20 /// $--GSV,x,x,x,x,x,x,x,...*hh<CR><LF>
  21 /// @endcode
  22 ///
  23 /// Field Number:
  24 /// 1. Total number of GSV messages to be transmitted in this group
  25 /// 2. 1-origin number of this GSV message within current group
  26 /// 3. Total number of satellites in view (leading zeros sent)
  27 /// 4. Satellite PRN (pseudo random noise) number (leading zeros sent)
  28 /// 5. Elevation in degrees (00-90) (leading zeros sent)
  29 /// 6. Azimuth in degrees to true north (000-359) (leading zeros sent)
  30 /// 7. SNR (signal to noise ratio) in dB (00-99) (leading zeros sent),
  31 ///    apparently this may be not defined.
  32 /// 8. checksum
  33 ///
  34 /// after 7: more satellite info quadruples like 4-7
  35 ///
  36 /// Example:
  37 /// @code
  38 /// $GPGSV,3,1,11,03,03,111,00,04,15,270,00,06,01,010,00,13,06,292,00*74
  39 /// $GPGSV,3,2,11,14,25,170,00,16,57,208,39,18,67,296,40,19,40,246,00*74
  40 /// $GPGSV,3,3,11,22,42,067,42,24,14,311,43,27,05,244,00,,,,*4D
  41 /// @endcode
  42 ///
  43 /// @note Although null fields for unused satellite info are not required,
  44 ///       this class will write them in any case.
  45 class gsv : public sentence
  46 {
  47         friend class detail::factory;
  48
  49 public:
  50         struct satellite_info {
  51                 uint32_t prn;
  52                 uint32_t elevation;
  53                 uint32_t azimuth; // azimuth against true
  54                 utils::optional<uint32_t> snr;
  55         };
  56
  57         constexpr static sentence_id ID = sentence_id::GSV;
  58         constexpr static const char * TAG = "GSV";
  59
  60         gsv();
  61         gsv(const gsv &) = default;
  62         gsv & operator=(const gsv &) = default;
  63         gsv(gsv &&) = default;
  64         gsv & operator=(gsv &&) = default;
  65
  66 protected:
  67         gsv(talker talk, fields::const_iterator first, fields::const_iterator last);
  68         virtual void append_data_to(std::string &) const override;
  69
  70 private:
  71         uint32_t n_messages_ = 1;
  72         uint32_t message_number_ = 1;
  73         uint32_t n_satellites_in_view_ = 0;
  74         std::array<utils::optional<satellite_info>, 4> sat_;
  75
  76         void check_index(int index) const;
  77
  78 public:
  79         uint32_t get_n_messages() const { return n_messages_; }
  80         uint32_t get_message_number() const { return message_number_; }
  81         uint32_t get_n_satellites_in_view() const { return n_satellites_in_view_; }
  82         utils::optional<satellite_info> get_sat(int index) const;
  83
  84         void set_n_messages(uint32_t t);
  85         void set_message_number(uint32_t t);
  86         void set_n_satellites_in_view(uint32_t t) noexcept { n_satellites_in_view_ = t; }
  87         void set_sat(int index, const satellite_info & info);
  88 };
  89 }
  90 }
  91
  92 #endif