Added three new messages for gridded atmospheric SSR corrections.

HOWTO.md

@@ -17,7 +17,10 @@ process. This is likely to change in the future.
 1. Add a message definition to the approprate package, or create a new
    one if needed. Read the **Message Guidelines** below.
 
-2. Generate new clients and documentation by running `make
+2. Increment `number_of_messages` in `python/tests/sbp/test_table.py`
+   by the corresponding number of new messages.
+
+3. Generate new clients and documentation by running `make
    all`. Verify that the generated code, which isn't too complicated,
    meets your expectations, as allowed messages are limited by the
    underlying language implementation. For example, you can't specify
@@ -26,12 +29,12 @@ process. This is likely to change in the future.
    materialize a 0-length array C99 extension in the middle of the
    struct. GCC won't compile this.
 
-3. Add a [`test`](spec/tests/yaml/swiftnav/sbp) case and update the
-   appropriate language libaries. Run `make test`.
+4. (Optional) Add a [`test`](spec/tests/yaml/swiftnav/sbp) case and
+   update the appropriate language libaries. Run `make test`.
 
-4. Submit a pull request.
+5. Submit a pull request.
 
-5. If Swift's internal test tooling needs to be updated to use your
+6. If Swift's internal test tooling needs to be updated to use your
    new message, deploy the updated Python client first, and then the C
    client. We haven't quite decided on the details of this process.
 

c/include/libsbp/gnss.h

@@ -41,6 +41,17 @@ the Slot ID in [1,28]
 } sbp_gnss_signal_t;
 
 
+/** Space vehicle identifier
+ *
+ * A (Constellation ID, satellite ID) tuple that uniquely identifies
+ * a space vehicle
+ */
+typedef struct SBP_ATTR_PACKED {
+  u8 satId;            /**< ID of the space vehicle within its constellation */
+  u8 constellation;    /**< Constellation ID to which the SV belongs */
+} sv_id_t;
+
+
 /** Deprecated
  *
 * Deprecated.

c/include/libsbp/ssr.h

@@ -49,27 +49,116 @@ typedef struct SBP_ATTR_PACKED {
   u8 code;                          /**< Signal constellation, band and code */
   u8 integer_indicator;             /**< Indicator for integer property */
   u8 widelane_integer_indicator;    /**< Indicator for two groups of Wide-Lane(s) integer property */
-  u8 discontinuity_counter;         /**< Signal phase discontinuity counter. 
+  u8 discontinuity_counter;         /**< Signal phase discontinuity counter.
 Increased for every discontinuity in phase.
  */
   s32 bias;                          /**< Phase bias for specified signal [0.1 mm] */
 } phase_biases_content_t;
 
 
+/** Header for MSG_SSR_STEC_CORRECTION message
+ *
+ * A full set of STEC information will likely span multiple SBP
+ * messages, since SBP message a limited to 255 bytes.  The header
+ * is used to tie multiple SBP messages into a sequence.
+ */
+typedef struct SBP_ATTR_PACKED {
+  sbp_gps_time_t time;                   /**< GNSS time of the STEC data */
+  u8 num_msgs;               /**< Number of messages in the dataset */
+  u8 seq_num;                /**< Position of this message in the dataset */
+  u16 ssr_update_interval;    /**< update interval in seconds [seconds] */
+  u8 iod_ssr;                /**< range 0 - 15 */
+} stec_header_t;
+
+
+/** Header for MSG_SSR_GRIDDED_CORRECTION
+ *
+ * The 3GPP message contains nested variable length arrays
+ * which are not suppported in SBP, so each grid point will
+ * be identified by the index.
+ */
+typedef struct SBP_ATTR_PACKED {
+  sbp_gps_time_t time;                   /**< GNSS time of the STEC data */
+  u16 num_msgs;               /**< Number of messages in the dataset */
+  u16 seq_num;                /**< Position of this message in the dataset */
+  u16 ssr_update_interval;    /**< update interval in seconds [seconds] */
+  u8 iod_ssr;                /**< range 0 - 15 */
+  u8 tropo_quality;          /**< troposphere quality indicator [encoded value - see spec for details] */
+} gridded_correction_header_t;
+
+
+/** None
+ *
+* STEC for the given satellite.
+ */
+typedef struct SBP_ATTR_PACKED {
+  sv_id_t sv_id;                     /**< Unique space vehicle identifier */
+  u8 stec_quality_indicator;    /**< quality of STEC data [encoded value - see spec for details] */
+  s16 stec_coeff[4];             /**< coefficents of the STEC polynomial */
+} stec_sat_element_t;
+
+
+/** troposphere delay correction
+ *
+ * Contains wet vertical and hydrostatic vertical delay
+ */
+typedef struct SBP_ATTR_PACKED {
+  s16 hydro;    /**< hydrostatic vertical delay [0.4 mm (add 2.3 m to get actual vert hydro delay)] */
+  s8 wet;      /**< wet vertical delay [0.4 mm (add 0.252 m to get actual vert wet delay)] */
+} tropospheric_delay_correction_t;
+
+
+/** None
+ *
+* STEC residual
+ */
+typedef struct SBP_ATTR_PACKED {
+  sv_id_t sv_id;       /**< space vehicle identifier */
+  s16 residual;    /**< STEC residual [0.04 TECU] */
+} stec_residual_t;
+
+
+/** Grid datum for troposphere and STEC residuals
+ *
+ * Contains one tropo datum, plus STEC residuals for each space
+ * vehicle
+ */
+typedef struct SBP_ATTR_PACKED {
+  u16 index;                     /**< index of the grid point */
+  tropospheric_delay_correction_t tropo_delay_correction;    /**< Wet and Hydrostatic Vertical Delay */
+  stec_residual_t STEC_residuals[0];         /**< STEC Residual for the given space vehicle */
+} grid_element_t;
+
+
+/** Defines the grid for STEC and tropo grid messages
+ *
+ * Defines the grid for STEC and tropo grid messages.
+ * Also includes an RLE encoded validity list.
+ */
+typedef struct SBP_ATTR_PACKED {
+  u8 region_size_inverse;    /**< inverse of region size [coded value - see spec] */
+  u16 area_width;             /**< area width; see spec for details [coded value - 0 means not present (Swift convention)] */
+  u16 lat_nw_corner_enc;      /**< encoded latitude of the northwest corner of the grid */
+  u16 lon_nw_corner_enc;      /**< encoded longitude of the northwest corner of the grid */
+  u8 num_msgs;               /**< Number of messages in the dataset */
+  u8 seq_num;                /**< Postion of this message in the dataset */
+} grid_definition_header_t;
+
+
 /** Precise orbit and clock correction
  *
- * The precise orbit and clock correction message is 
- * to be applied as a delta correction to broadcast 
+ * The precise orbit and clock correction message is
+ * to be applied as a delta correction to broadcast
  * ephemeris and is typically an equivalent to the 1060
  * and 1066 RTCM message types
  */
-#define SBP_MSG_SSR_ORBIT_CLOCK       0x05DD
+#define SBP_MSG_SSR_ORBIT_CLOCK        0x05DD
 typedef struct SBP_ATTR_PACKED {
   gps_time_sec_t time;               /**< GNSS reference time of the correction */
   sbp_gnss_signal_t sid;                /**< GNSS signal identifier (16 bit) */
   u8 update_interval;    /**< Update interval between consecutive corrections [s] */
   u8 iod_ssr;            /**< IOD of the SSR correction. A change of Issue Of Data
-SSR is used to indicate a change in the SSR 
+SSR is used to indicate a change in the SSR
 generating configuration
  */
   u32 iod;                /**< Issue of broadcast ephemeris data or IODCRC (Beidou) */
@@ -87,18 +176,18 @@ generating configuration
 
 /** Precise orbit and clock correction
  *
- * The precise orbit and clock correction message is 
- * to be applied as a delta correction to broadcast 
+ * The precise orbit and clock correction message is
+ * to be applied as a delta correction to broadcast
  * ephemeris and is typically an equivalent to the 1060
  * and 1066 RTCM message types
  */
-#define SBP_MSG_SSR_ORBIT_CLOCK_DEP_A 0x05DC
+#define SBP_MSG_SSR_ORBIT_CLOCK_DEP_A  0x05DC
 typedef struct SBP_ATTR_PACKED {
   gps_time_sec_t time;               /**< GNSS reference time of the correction */
   sbp_gnss_signal_t sid;                /**< GNSS signal identifier (16 bit) */
   u8 update_interval;    /**< Update interval between consecutive corrections [s] */
   u8 iod_ssr;            /**< IOD of the SSR correction. A change of Issue Of Data
-SSR is used to indicate a change in the SSR 
+SSR is used to indicate a change in the SSR
 generating configuration
  */
   u8 iod;                /**< Issue of broadcast ephemeris data */
@@ -118,16 +207,16 @@ generating configuration
  *
  * The precise code biases message is to be added
  * to the pseudorange of the corresponding signal
- * to get corrected pseudorange. It is typically 
+ * to get corrected pseudorange. It is typically
  * an equivalent to the 1059 and 1065 RTCM message types
  */
-#define SBP_MSG_SSR_CODE_BIASES       0x05E1
+#define SBP_MSG_SSR_CODE_BIASES        0x05E1
 typedef struct SBP_ATTR_PACKED {
   gps_time_sec_t time;               /**< GNSS reference time of the correction */
   sbp_gnss_signal_t sid;                /**< GNSS signal identifier (16 bit) */
   u8 update_interval;    /**< Update interval between consecutive corrections [s] */
   u8 iod_ssr;            /**< IOD of the SSR correction. A change of Issue Of Data
-SSR is used to indicate a change in the SSR 
+SSR is used to indicate a change in the SSR
 generating configuration
  */
   code_biases_content_t biases[0];          /**< Code biases for the different satellite signals */
@@ -138,18 +227,18 @@ generating configuration
  *
  * The precise phase biases message contains the biases
  * to be added to the carrier phase of the corresponding
- * signal to get corrected carrier phase measurement, as 
- * well as the satellite yaw angle to be applied to compute 
- * the phase wind-up correction. 
+ * signal to get corrected carrier phase measurement, as
+ * well as the satellite yaw angle to be applied to compute
+ * the phase wind-up correction.
  * It is typically an equivalent to the 1265 RTCM message types
  */
-#define SBP_MSG_SSR_PHASE_BIASES      0x05E6
+#define SBP_MSG_SSR_PHASE_BIASES       0x05E6
 typedef struct SBP_ATTR_PACKED {
   gps_time_sec_t time;               /**< GNSS reference time of the correction */
   sbp_gnss_signal_t sid;                /**< GNSS signal identifier (16 bit) */
   u8 update_interval;    /**< Update interval between consecutive corrections [s] */
   u8 iod_ssr;            /**< IOD of the SSR correction. A change of Issue Of Data
-SSR is used to indicate a change in the SSR 
+SSR is used to indicate a change in the SSR
 generating configuration
  */
   u8 dispersive_bias;    /**< Indicator for the dispersive phase biases property.
@@ -164,6 +253,46 @@ satellite being tracked.
 } msg_ssr_phase_biases_t;
 
 
+/** Slant Total Electron Content
+ *
+ * The STEC per space vehicle, given as polynomial approximation for
+ * a given grid.  This should be combined with SSR-GriddedCorrection
+ * message to get the state space representation of the atmospheric
+ * delay.
+ */
+#define SBP_MSG_SSR_STEC_CORRECTION    0x05EB
+typedef struct SBP_ATTR_PACKED {
+  stec_header_t header;           /**< Header of a STEC message */
+  stec_sat_element_t stec_sat_list[0]; /**< Array of STEC information for each space vehicle */
+} msg_ssr_stec_correction_t;
+
+
+/** Gridded troposphere and STEC residuals
+ *
+ * STEC residuals are per space vehicle, tropo is not.
+ */
+#define SBP_MSG_SSR_GRIDDED_CORRECTION 0x05F0
+typedef struct SBP_ATTR_PACKED {
+  gridded_correction_header_t header;     /**< Header of a Gridded Correction message */
+  grid_element_t element;    /**< Tropo and STEC residuals for the given grid point */
+} msg_ssr_gridded_correction_t;
+
+
+/** None
+ *
+* Definition of the grid for STEC and tropo messages
+ */
+#define SBP_MSG_SSR_GRID_DEFINITION    0x05F5
+typedef struct SBP_ATTR_PACKED {
+  grid_definition_header_t header;      /**< Header of a Gridded Correction message */
+  u8 rle_list[0]; /**< Run Length Encode list of quadrants that contain valid data.
+The spec describes the encoding scheme in detail, but
+essentially the index of the quadrants that contain transitions between
+valid and invalid (and vice versa) are encoded as u8 integers.
+ */
+} msg_ssr_grid_definition_t;
+
+
 /** \} */
 
 SBP_PACK_END

generator/sbpg/targets/javascript.py

@@ -194,7 +194,7 @@ def render_source(output_dir, package_spec, jenv=JENV):
   destination_filename = "%s/%s.js" % (directory, name)
   py_template = jenv.get_template(TEMPLATE_NAME)
   module_path = ".".join(package_spec.identifier.split(".")[1:-1])
-  includeMap = {'gnss': ['GnssSignal', 'GnssSignalDep', 'GPSTime', 'CarrierPhase', 'GPSTime', 'GPSTimeSec', 'GPSTimeDep'] }
+  includeMap = {'gnss': ['GnssSignal', 'GnssSignalDep', 'GPSTime', 'CarrierPhase', 'GPSTime', 'GPSTimeSec', 'GPSTimeDep', 'SvId'] }
   includes = [".".join(i.split(".")[:-1]) for i in package_spec.includes]
   includes = [(i, includeMap.get(i)) for i in includes if i != "types"]
   with open(destination_filename, 'w') as f:

haskell/src/SwiftNav/SBP/Gnss.hs

@@ -59,6 +59,30 @@ instance Binary GnssSignal where
 $(makeJSON "_gnssSignal_" ''GnssSignal)
 $(makeLenses ''GnssSignal)
 
+-- | SvId.
+--
+-- A (Constellation ID, satellite ID) tuple that uniquely identifies a space
+-- vehicle
+data SvId = SvId
+  { _svId_satId       :: !Word8
+    -- ^ ID of the space vehicle within its constellation
+  , _svId_constellation :: !Word8
+    -- ^ Constellation ID to which the SV belongs
+  } deriving ( Show, Read, Eq )
+
+instance Binary SvId where
+  get = do
+    _svId_satId <- getWord8
+    _svId_constellation <- getWord8
+    pure SvId {..}
+
+  put SvId {..} = do
+    putWord8 _svId_satId
+    putWord8 _svId_constellation
+
+$(makeJSON "_svId_" ''SvId)
+$(makeLenses ''SvId)
+
 -- | GnssSignalDep.
 --
 -- Deprecated.