Added RSNR to the OSD (#11062)

* Added RNSR to the OSD

* filtering with pt1

* update pgconfig ver

* rssi_smoothness and proper define wrapping

* missing define wrap

* smoothing moved to updateRSSI

* minor comment update

* fixed rx tests

Co-authored-by: Tony Cabello <>
Co-authored-by: J Blackman <blckmn@users.noreply.github.com>

src/main/cli/settings.c

@@ -745,6 +745,7 @@ const clivalue_t valueTable[] = {
     { "rssi_offset",                VAR_INT8   | MASTER_VALUE, .config.minmax = { -100, 100 }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_offset) },
     { "rssi_invert",                VAR_INT8   | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_invert) },
     { "rssi_src_frame_lpf_period",  VAR_UINT8  | MASTER_VALUE, .config.minmaxUnsigned = { 0, UINT8_MAX }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_src_frame_lpf_period) },
+    { "rssi_smoothing",             VAR_UINT8  | MASTER_VALUE, .config.minmaxUnsigned = { 0, UINT8_MAX }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_smoothing) },
 
 #ifdef USE_RC_SMOOTHING_FILTER
     { PARAM_NAME_RC_SMOOTHING,                   VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, rc_smoothing_mode) },
@@ -773,11 +774,8 @@ const clivalue_t valueTable[] = {
 #if defined(USE_SERIALRX_SBUS)
     { "sbus_baud_fast",              VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, sbus_baud_fast) },
 #endif
-#if defined(USE_SERIALRX_CRSF)
-    { "crsf_use_rx_snr",             VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, crsf_use_rx_snr) },
 #if defined(USE_CRSF_V3)
     { "crsf_use_negotiated_baud",    VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, crsf_use_negotiated_baud) },
-#endif
 #endif
     { "airmode_start_throttle_percent", VAR_UINT8 | MASTER_VALUE, .config.minmaxUnsigned = { 0, 100 }, PG_RX_CONFIG, offsetof(rxConfig_t, airModeActivateThreshold) },
     { "rx_min_usec",                VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { PWM_PULSE_MIN, PWM_PULSE_MAX }, PG_RX_CONFIG, offsetof(rxConfig_t, rx_min_usec) },
@@ -1315,7 +1313,10 @@ const clivalue_t valueTable[] = {
     { "osd_link_quality_alarm",     VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, 100 }, PG_OSD_CONFIG, offsetof(osdConfig_t, link_quality_alarm) },
 #endif
 #ifdef USE_RX_RSSI_DBM
-    { "osd_rssi_dbm_alarm",         VAR_INT16   | MASTER_VALUE, .config.minmax = { CRSF_RSSI_MIN, CRSF_SNR_MAX }, PG_OSD_CONFIG, offsetof(osdConfig_t, rssi_dbm_alarm) },
+    { "osd_rssi_dbm_alarm",         VAR_INT16   | MASTER_VALUE, .config.minmax = { CRSF_RSSI_MIN, CRSF_RSSI_MAX }, PG_OSD_CONFIG, offsetof(osdConfig_t, rssi_dbm_alarm) },
+#endif
+#ifdef USE_RX_RSNR
+    { "osd_rsnr_alarm",             VAR_INT16   | MASTER_VALUE, .config.minmax = { CRSF_SNR_MIN, CRSF_SNR_MAX }, PG_OSD_CONFIG, offsetof(osdConfig_t, rsnr_alarm) },
 #endif
     { "osd_cap_alarm",              VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 0, 20000 }, PG_OSD_CONFIG, offsetof(osdConfig_t, cap_alarm) },
     { "osd_alt_alarm",              VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 0, 10000 }, PG_OSD_CONFIG, offsetof(osdConfig_t, alt_alarm) },
@@ -1346,6 +1347,9 @@ const clivalue_t valueTable[] = {
 #endif
 #ifdef USE_RX_RSSI_DBM
     { "osd_rssi_dbm_pos",           VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, OSD_POSCFG_MAX }, PG_OSD_ELEMENT_CONFIG, offsetof(osdElementConfig_t, item_pos[OSD_RSSI_DBM_VALUE]) },
+#endif
+#ifdef USE_RX_RSNR
+    { "osd_rsnr_pos",               VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, OSD_POSCFG_MAX }, PG_OSD_ELEMENT_CONFIG, offsetof(osdElementConfig_t, item_pos[OSD_RSNR_VALUE]) },
 #endif
     { "osd_tim_1_pos",              VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, OSD_POSCFG_MAX }, PG_OSD_ELEMENT_CONFIG, offsetof(osdElementConfig_t, item_pos[OSD_ITEM_TIMER_1]) },
     { "osd_tim_2_pos",              VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, OSD_POSCFG_MAX }, PG_OSD_ELEMENT_CONFIG, offsetof(osdElementConfig_t, item_pos[OSD_ITEM_TIMER_2]) },

src/main/cms/cms_menu_osd.c

@@ -80,6 +80,9 @@ const OSD_Entry menuOsdActiveElemsEntries[] =
     {"RSSI",               OME_VISIBLE | DYNAMIC, NULL, &osdConfig_item_pos[OSD_RSSI_VALUE]},
 #ifdef USE_RX_RSSI_DBM
     {"RSSI DBM",           OME_VISIBLE | DYNAMIC, NULL, &osdConfig_item_pos[OSD_RSSI_DBM_VALUE]},
+#endif
+#ifdef USE_RX_RSNR
+    {"RSNR",               OME_VISIBLE | DYNAMIC, NULL, &osdConfig_item_pos[OSD_RSNR_VALUE]},
 #endif
     {"BATTERY VOLTAGE",    OME_VISIBLE | DYNAMIC, NULL, &osdConfig_item_pos[OSD_MAIN_BATT_VOLTAGE]},
     {"BATTERY USAGE",      OME_VISIBLE | DYNAMIC, NULL, &osdConfig_item_pos[OSD_MAIN_BATT_USAGE]},
@@ -184,6 +187,7 @@ static CMS_Menu menuOsdActiveElems = {
 static uint8_t osdConfig_rssi_alarm;
 static uint16_t osdConfig_link_quality_alarm;
 static int16_t osdConfig_rssi_dbm_alarm;
+static int16_t osdConfig_rsnr_alarm;
 static uint16_t osdConfig_cap_alarm;
 static uint16_t osdConfig_alt_alarm;
 static uint16_t osdConfig_distance_alarm;
@@ -197,6 +201,7 @@ static const void *menuAlarmsOnEnter(displayPort_t *pDisp)
     osdConfig_rssi_alarm = osdConfig()->rssi_alarm;
     osdConfig_link_quality_alarm = osdConfig()->link_quality_alarm;
     osdConfig_rssi_dbm_alarm = osdConfig()->rssi_dbm_alarm;
+    osdConfig_rsnr_alarm = osdConfig()->rsnr_alarm;
     osdConfig_cap_alarm = osdConfig()->cap_alarm;
     osdConfig_alt_alarm = osdConfig()->alt_alarm;
     osdConfig_distance_alarm = osdConfig()->distance_alarm;
@@ -214,6 +219,7 @@ static const void *menuAlarmsOnExit(displayPort_t *pDisp, const OSD_Entry *self)
     osdConfigMutable()->rssi_alarm = osdConfig_rssi_alarm;
     osdConfigMutable()->link_quality_alarm = osdConfig_link_quality_alarm;
     osdConfigMutable()->rssi_dbm_alarm = osdConfig_rssi_dbm_alarm;
+    osdConfigMutable()->rsnr_alarm = osdConfig_rsnr_alarm;
     osdConfigMutable()->cap_alarm = osdConfig_cap_alarm;
     osdConfigMutable()->alt_alarm = osdConfig_alt_alarm;
     osdConfigMutable()->distance_alarm = osdConfig_distance_alarm;
@@ -229,6 +235,7 @@ const OSD_Entry menuAlarmsEntries[] =
     {"RSSI",     OME_UINT8,  NULL, &(OSD_UINT8_t){&osdConfig_rssi_alarm, 5, 90, 5}},
     {"LINK QUALITY", OME_UINT16,  NULL, &(OSD_UINT16_t){&osdConfig_link_quality_alarm, 5, 300, 5}},
     {"RSSI DBM", OME_INT16,  NULL, &(OSD_INT16_t){&osdConfig_rssi_dbm_alarm, CRSF_RSSI_MIN, CRSF_SNR_MAX, 5}},
+    {"RSNR", OME_INT16,  NULL, &(OSD_INT16_t){&osdConfig_rsnr_alarm, CRSF_SNR_MIN, CRSF_SNR_MAX, 5}},
     {"MAIN BAT", OME_UINT16, NULL, &(OSD_UINT16_t){&osdConfig_cap_alarm, 50, 30000, 50}},
     {"MAX ALT",  OME_UINT16, NULL, &(OSD_UINT16_t){&osdConfig_alt_alarm, 1, 200, 1}},
     {"MAX DISTANCE", OME_UINT16, NULL, &(OSD_UINT16_t){&osdConfig_distance_alarm, 0, UINT16_MAX, 10}},

src/main/osd/osd.c

@@ -149,7 +149,7 @@ escSensorData_t *osdEscDataCombined;
 
 STATIC_ASSERT(OSD_POS_MAX == OSD_POS(31,31), OSD_POS_MAX_incorrect);
 
-PG_REGISTER_WITH_RESET_FN(osdConfig_t, osdConfig, PG_OSD_CONFIG, 10);
+PG_REGISTER_WITH_RESET_FN(osdConfig_t, osdConfig, PG_OSD_CONFIG, 11);
 
 PG_REGISTER_WITH_RESET_FN(osdElementConfig_t, osdElementConfig, PG_OSD_ELEMENT_CONFIG, 1);
 
@@ -185,6 +185,7 @@ const osd_stats_e osdStatsDisplayOrder[OSD_STAT_COUNT] = {
     OSD_STAT_MIN_LINK_QUALITY,
     OSD_STAT_MAX_FFT,
     OSD_STAT_MIN_RSSI_DBM,
+    OSD_STAT_MIN_RSNR,
     OSD_STAT_TOTAL_FLIGHTS,
     OSD_STAT_TOTAL_TIME,
     OSD_STAT_TOTAL_DIST,
@@ -344,6 +345,7 @@ void pgResetFn_osdConfig(osdConfig_t *osdConfig)
     osdWarnSetState(OSD_WARNING_RSSI, false);
     osdWarnSetState(OSD_WARNING_LINK_QUALITY, false);
     osdWarnSetState(OSD_WARNING_RSSI_DBM, false);
+    osdWarnSetState(OSD_WARNING_RSNR, false);
     // turn off the over mah capacity warning
     osdWarnSetState(OSD_WARNING_OVER_CAP, false);
 
@@ -370,6 +372,7 @@ void pgResetFn_osdConfig(osdConfig_t *osdConfig)
         osdConfig->profile[i][0] = '\0';
     }
     osdConfig->rssi_dbm_alarm = -60;
+    osdConfig->rsnr_alarm = 4;
     osdConfig->gps_sats_show_hdop = false;
 
     for (int i = 0; i < OSD_RCCHANNELS_COUNT; i++) {
@@ -501,7 +504,8 @@ static void osdResetStats(void)
     stats.max_esc_temp    = 0;
     stats.max_esc_rpm     = 0;
     stats.min_link_quality = (linkQualitySource == LQ_SOURCE_NONE) ? 99 : 100; // percent
-    stats.min_rssi_dbm = CRSF_SNR_MAX;
+    stats.min_rssi_dbm = CRSF_RSSI_MAX;
+    stats.min_rsnr = CRSF_SNR_MAX;
 }
 
 #if defined(USE_ESC_SENSOR) || defined(USE_DSHOT_TELEMETRY)
@@ -581,6 +585,13 @@ static void osdUpdateStats(void)
     }
 #endif
 
+#ifdef USE_RX_RSNR
+    value = getRsnr();
+    if (stats.min_rsnr > value) {
+        stats.min_rsnr = value;
+    }
+#endif
+
 #ifdef USE_GPS
     if (STATE(GPS_FIX) && STATE(GPS_FIX_HOME)) {
         if (stats.max_distance < GPS_distanceToHome) {
@@ -876,6 +887,13 @@ static bool osdDisplayStat(int statistic, uint8_t displayRow)
         return true;
 #endif
 
+#ifdef USE_RX_RSNR
+    case OSD_STAT_MIN_RSNR:
+        tfp_sprintf(buff, "%3d", stats.min_rsnr);
+        osdDisplayStatisticLabel(displayRow, "MIN RSNR", buff);
+        return true;
+#endif
+
 #ifdef USE_PERSISTENT_STATS
     case OSD_STAT_TOTAL_FLIGHTS:
         itoa(statsConfig()->stats_total_flights, buff, 10);

src/main/osd/osd.h

@@ -164,6 +164,7 @@ typedef enum {
     OSD_WATT_HOURS_DRAWN,
     OSD_AUX_VALUE,
     OSD_READY_MODE,
+    OSD_RSNR_VALUE,
     OSD_ITEM_COUNT // MUST BE LAST
 } osd_items_e;
 
@@ -204,6 +205,7 @@ typedef enum {
     OSD_STAT_TOTAL_DIST,
     OSD_STAT_MIN_RSSI_DBM,
     OSD_STAT_WATT_HOURS_DRAWN,
+    OSD_STAT_MIN_RSNR,
     OSD_STAT_COUNT // MUST BE LAST
 } osd_stats_e;
 
@@ -249,6 +251,7 @@ typedef enum {
     OSD_WARNING_LINK_QUALITY,
     OSD_WARNING_RSSI_DBM,
     OSD_WARNING_OVER_CAP,
+    OSD_WARNING_RSNR,
     OSD_WARNING_COUNT // MUST BE LAST
 } osdWarningsFlags_e;
 
@@ -296,6 +299,7 @@ typedef struct osdConfig_s {
     char profile[OSD_PROFILE_COUNT][OSD_PROFILE_NAME_LENGTH + 1];
     uint16_t link_quality_alarm;
     int16_t rssi_dbm_alarm;
+    int16_t rsnr_alarm;
     uint8_t gps_sats_show_hdop;
     int8_t rcChannels[OSD_RCCHANNELS_COUNT];  // RC channel values to display, -1 if none
     uint8_t displayPortDevice;                // osdDisplayPortDevice_e
@@ -338,6 +342,7 @@ typedef struct statistic_s {
     int32_t max_esc_rpm;
     uint16_t min_link_quality;
     int16_t min_rssi_dbm;
+    int16_t min_rsnr;
 } statistic_t;
 
 extern timeUs_t resumeRefreshAt;

src/main/osd/osd_elements.c

@@ -1384,6 +1384,13 @@ static void osdElementRssiDbm(osdElementParms_t *element)
 }
 #endif // USE_RX_RSSI_DBM
 
+#ifdef USE_RX_RSNR
+static void osdElementRsnr(osdElementParms_t *element)
+{
+    tfp_sprintf(element->buff, "%c%3d", SYM_RSSI, getRsnr());
+}
+#endif // USE_RX_RSNR
+
 #ifdef USE_OSD_STICK_OVERLAY
 static void osdBackgroundStickOverlay(osdElementParms_t *element)
 {
@@ -1598,6 +1605,9 @@ static const uint8_t osdElementDisplayOrder[] = {
 #ifdef USE_RX_RSSI_DBM
     OSD_RSSI_DBM_VALUE,
 #endif
+#ifdef USE_RX_RSNR
+    OSD_RSNR_VALUE,
+#endif
 #ifdef USE_OSD_STICK_OVERLAY
     OSD_STICK_OVERLAY_LEFT,
     OSD_STICK_OVERLAY_RIGHT,
@@ -1724,6 +1734,9 @@ const osdElementDrawFn osdElementDrawFunction[OSD_ITEM_COUNT] = {
 #endif
 #ifdef USE_RX_RSSI_DBM
     [OSD_RSSI_DBM_VALUE]          = osdElementRssiDbm,
+#endif
+#ifdef USE_RX_RSNR
+    [OSD_RSNR_VALUE]              = osdElementRsnr,
 #endif
     [OSD_RC_CHANNELS]             = osdElementRcChannels,
 #ifdef USE_GPS

src/main/osd/osd_warnings.c

@@ -186,6 +186,15 @@ void renderOsdWarning(char *warningText, bool *blinking, uint8_t *displayAttr)
         return;
     }
 #endif // USE_RX_RSSI_DBM
+#ifdef USE_RX_RSNR
+    // rsnr
+    if (osdWarnGetState(OSD_WARNING_RSNR) && (getRsnr() < osdConfig()->rsnr_alarm)) {
+        tfp_sprintf(warningText, "RSNR LOW");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;
+        return;
+    }
+#endif // USE_RX_RSNR
 
 #ifdef USE_RX_LINK_QUALITY_INFO
     // Link Quality

src/main/pg/rx.c

@@ -34,7 +34,7 @@
 #include "rx/rx.h"
 #include "rx/rx_spi.h"
 
-PG_REGISTER_WITH_RESET_FN(rxConfig_t, rxConfig, PG_RX_CONFIG, 3);
+PG_REGISTER_WITH_RESET_FN(rxConfig_t, rxConfig, PG_RX_CONFIG, 4);
 void pgResetFn_rxConfig(rxConfig_t *rxConfig)
 {
     RESET_CONFIG_2(rxConfig_t, rxConfig,
@@ -56,6 +56,7 @@ void pgResetFn_rxConfig(rxConfig_t *rxConfig)
         .rssi_offset = 0,
         .rssi_invert = 0,
         .rssi_src_frame_lpf_period = 30,
+        .rssi_smoothing = 125,
         .fpvCamAngleDegrees = 0,
         .airModeActivateThreshold = 25,
         .max_aux_channel = DEFAULT_AUX_CHANNEL_COUNT,
@@ -69,7 +70,6 @@ void pgResetFn_rxConfig(rxConfig_t *rxConfig)
         .srxl2_unit_id = 1,
         .srxl2_baud_fast = true,
         .sbus_baud_fast = false,
-        .crsf_use_rx_snr = false,
         .msp_override_channels_mask = 0,
         .crsf_use_negotiated_baud = false,
     );

src/main/pg/rx.h

@@ -57,10 +57,10 @@ typedef struct rxConfig_s {
     uint8_t rc_smoothing_auto_factor_rpy;      // Used to adjust the "smoothness" determined by the auto cutoff calculations
     uint8_t rc_smoothing_auto_factor_throttle; // Used to adjust the "smoothness" determined by the auto cutoff calculations
     uint8_t rssi_src_frame_lpf_period;         // Period of the cutoff frequency for the source frame RSSI filter (in 0.1 s)
+    uint8_t rssi_smoothing;                    // Smoothing factor to reduce jumpiness of rssi, rssiDbm and rsnr
     uint8_t srxl2_unit_id;                     // Spektrum SRXL2 RX unit id
     uint8_t srxl2_baud_fast;                   // Select Spektrum SRXL2 fast baud rate
     uint8_t sbus_baud_fast;                    // Select SBus fast baud rate
-    uint8_t crsf_use_rx_snr;                   // Use RX SNR (in dB) instead of RSSI dBm for CRSF
     uint32_t msp_override_channels_mask;       // Channels to override when the MSP override mode is enabled
     uint8_t crsf_use_negotiated_baud;          // Use negotiated baud rate for CRSF V3
 } rxConfig_t;

src/main/rx/crsf.c

@@ -229,24 +229,17 @@ static void handleCrsfLinkStatisticsFrame(const crsfLinkStatistics_t* statsPtr,
     lastLinkStatisticsFrameUs = currentTimeUs;
     int16_t rssiDbm = -1 * (stats.active_antenna ? stats.uplink_RSSI_2 : stats.uplink_RSSI_1);
     if (rssiSource == RSSI_SOURCE_RX_PROTOCOL_CRSF) {
-        if (rxConfig()->crsf_use_rx_snr) {
+        const uint16_t rssiPercentScaled = scaleRange(rssiDbm, CRSF_RSSI_MIN, CRSF_RSSI_MAX, 0, RSSI_MAX_VALUE);
-            // -10dB of SNR mapped to 0 RSSI (fail safe is likely to happen at this measure)
+        setRssi(rssiPercentScaled, RSSI_SOURCE_RX_PROTOCOL_CRSF);
-            //   0dB of SNR mapped to 20 RSSI (default alarm)
-            //  41dB of SNR mapped to 99 RSSI (SNR can climb to around 60, but showing that is not very meaningful)
-            const uint16_t rsnrPercentScaled = constrain((stats.uplink_SNR + 10) * 20, 0, RSSI_MAX_VALUE);
-            setRssi(rsnrPercentScaled, RSSI_SOURCE_RX_PROTOCOL_CRSF);
-#ifdef USE_RX_RSSI_DBM
-            rssiDbm = stats.uplink_SNR;
-#endif
-        } else {
-            const uint16_t rssiPercentScaled = scaleRange(rssiDbm, CRSF_RSSI_MIN, 0, 0, RSSI_MAX_VALUE);
-            setRssi(rssiPercentScaled, RSSI_SOURCE_RX_PROTOCOL_CRSF);
-        }
     }
 #ifdef USE_RX_RSSI_DBM
     setRssiDbm(rssiDbm, RSSI_SOURCE_RX_PROTOCOL_CRSF);
 #endif
 
+#ifdef USE_RX_RSNR
+    setRsnr(stats.uplink_SNR);
+#endif
+
 #ifdef USE_RX_LINK_QUALITY_INFO
     if (linkQualitySource == LQ_SOURCE_RX_PROTOCOL_CRSF) {
         setLinkQualityDirect(stats.uplink_Link_quality);
@@ -284,12 +277,13 @@ static void handleCrsfLinkStatisticsTxFrame(const crsfLinkStatisticsTx_t* statsP
     }
 #ifdef USE_RX_RSSI_DBM
     int16_t rssiDbm = -1 * stats.uplink_RSSI;
-    if (rxConfig()->crsf_use_rx_snr) {
-        rssiDbm = stats.uplink_SNR;
-    }
     setRssiDbm(rssiDbm, RSSI_SOURCE_RX_PROTOCOL_CRSF);
 #endif
 
+#ifdef USE_RX_RSNR
+    setRsnr(stats.uplink_SNR);
+#endif
+
 #ifdef USE_RX_LINK_QUALITY_INFO
     if (linkQualitySource == LQ_SOURCE_RX_PROTOCOL_CRSF) {
         setLinkQualityDirect(stats.uplink_Link_quality);
@@ -312,11 +306,10 @@ static void crsfCheckRssi(uint32_t currentTimeUs)
         if (rssiSource == RSSI_SOURCE_RX_PROTOCOL_CRSF) {
             setRssiDirect(0, RSSI_SOURCE_RX_PROTOCOL_CRSF);
 #ifdef USE_RX_RSSI_DBM
-            if (rxConfig()->crsf_use_rx_snr) {
+            setRssiDbmDirect(CRSF_RSSI_MIN, RSSI_SOURCE_RX_PROTOCOL_CRSF);
-                setRssiDbmDirect(CRSF_SNR_MIN, RSSI_SOURCE_RX_PROTOCOL_CRSF);
+#endif
-            } else {
+#ifdef USE_RX_RSNR
-                setRssiDbmDirect(CRSF_RSSI_MIN, RSSI_SOURCE_RX_PROTOCOL_CRSF);
+            setRsnrDirect(CRSF_SNR_MIN);
-            }
 #endif
         }
 #ifdef USE_RX_LINK_QUALITY_INFO

src/main/rx/expresslrs.c

@@ -79,7 +79,10 @@ static uint8_t txPower = 0;
 static uint8_t wideSwitchIndex = 0;
 static uint8_t currTlmDenom = 1;
 static simpleLowpassFilter_t rssiFilter;
-static meanAccumulator_t snrFilter;
+#ifdef USE_RX_RSNR
+static simpleLowpassFilter_t rsnrFilter;
+#endif //USE_RX_RSNR
+static meanAccumulator_t snrFilter; //for dyn power purposes
 
 static volatile DMA_DATA uint8_t dmaBuffer[ELRS_RX_TX_BUFF_SIZE];
 static volatile DMA_DATA uint8_t telemetryPacket[ELRS_RX_TX_BUFF_SIZE];
@@ -89,6 +92,9 @@ static volatile uint8_t *payload;
 static void rssiFilterReset(void)
 {
     simpleLPFilterInit(&rssiFilter, 2, 5);
+#ifdef USE_RX_RSNR
+    simpleLPFilterInit(&rsnrFilter, 2, 5);
+#endif //USE_RX_RSNR
 }
 
 #define PACKET_HANDLING_TO_TOCK_ISR_DELAY_US 250
@@ -568,6 +574,9 @@ static void initializeReceiver(void)
     receiver.configChanged = false;
     receiver.rssi = 0;
     receiver.rssiFiltered = 0;
+#ifdef USE_RX_RSNR
+    receiver.rsnrFiltered = 0;
+#endif //USE_RX_RSNR
     receiver.snr = 0;
     receiver.uplinkLQ = 0;
     receiver.rateIndex = receiver.inBindingMode ? bindingRateIndex : rxExpressLrsSpiConfig()->rateIndex;
@@ -948,6 +957,9 @@ static void handleConnectionStateUpdate(const uint32_t timeStampMs)
 #ifdef USE_RX_RSSI_DBM
         setRssiDbmDirect(-130, RSSI_SOURCE_RX_PROTOCOL);
 #endif
+#ifdef USE_RX_RSNR
+        setRsnrDirect(-30);
+#endif
 #ifdef USE_RX_LINK_QUALITY_INFO
         setLinkQualityDirect(0);
 #endif
@@ -1015,6 +1027,10 @@ static void handleLinkStatsUpdate(const uint32_t timeStampMs)
 #ifdef USE_RX_RSSI_DBM
             setRssiDbm(receiver.rssiFiltered, RSSI_SOURCE_RX_PROTOCOL);
 #endif
+#ifdef USE_RX_RSNR
+            receiver.rsnrFiltered = simpleLPFilterUpdate(&rsnrFilter, receiver.snr/4);
+            setRsnr(receiver.rsnrFiltered);
+#endif
 #ifdef USE_RX_LINK_QUALITY_INFO
             setLinkQualityDirect(receiver.uplinkLQ);
 #endif
@@ -1026,6 +1042,9 @@ static void handleLinkStatsUpdate(const uint32_t timeStampMs)
 #ifdef USE_RX_RSSI_DBM
             setRssiDbmDirect(-130, RSSI_SOURCE_RX_PROTOCOL);
 #endif
+#ifdef USE_RX_RSNR
+            setRsnrDirect(-30);
+#endif
 #ifdef USE_RX_LINK_QUALITY_INFO
             setLinkQualityDirect(0);
 #endif

src/main/rx/expresslrs_impl.h

@@ -68,6 +68,9 @@ typedef struct elrsReceiver_s {
     int8_t rssi;
     int8_t snr;
     int8_t rssiFiltered;
+#ifdef USE_RX_RSNR
+    int8_t rsnrFiltered;
+#endif //USE_RX_RSNR
 
     uint8_t uplinkLQ;
 

src/main/rx/rx.c

@@ -76,10 +76,26 @@
 const char rcChannelLetters[] = "AERT12345678abcdefgh";
 
 static uint16_t rssi = 0;                  // range: [0;1023]
-static int16_t rssiDbm = CRSF_RSSI_MIN;    // range: [-130,20]
+static uint16_t rssiRaw = 0;               // range: [0;1023]
+static timeUs_t lastRssiSmoothingUs = 0;
+#ifdef USE_RX_RSSI_DBM
+static int16_t rssiDbm = CRSF_RSSI_MIN;    // range: [-130,0]
+static int16_t rssiDbmRaw = CRSF_RSSI_MIN; // range: [-130,0]
+#endif //USE_RX_RSSI_DBM
+#ifdef USE_RX_RSNR
+static int16_t rsnr = CRSF_SNR_MIN;        // range: [-30,20]
+static int16_t rsnrRaw = CRSF_SNR_MIN;     // range: [-30,20]
+#endif //USE_RX_RSNR
 static timeUs_t lastMspRssiUpdateUs = 0;
 
 static pt1Filter_t frameErrFilter;
+static pt1Filter_t rssiFilter;
+#ifdef USE_RX_RSSI_DBM
+static pt1Filter_t rssiDbmFilter;
+#endif //USE_RX_RSSI_DBM
+#ifdef USE_RX_RSNR
+static pt1Filter_t rsnrFilter;
+#endif //USE_RX_RSNR
 
 #ifdef USE_RX_LINK_QUALITY_INFO
 static uint16_t linkQuality = 0;
@@ -362,6 +378,19 @@ void rxInit(void)
     // Setup source frame RSSI filtering to take averaged values every FRAME_ERR_RESAMPLE_US
     pt1FilterInit(&frameErrFilter, pt1FilterGain(GET_FRAME_ERR_LPF_FREQUENCY(rxConfig()->rssi_src_frame_lpf_period), FRAME_ERR_RESAMPLE_US/1000000.0));
 
+    // Configurable amount of filtering to remove excessive jumpiness of the values on the osd
+    float k = (256.0f - rxConfig()->rssi_smoothing) / 256.0f;
+
+    pt1FilterInit(&rssiFilter, k);  
+
+#ifdef USE_RX_RSSI_DBM
+    pt1FilterInit(&rssiDbmFilter, k);
+#endif //USE_RX_RSSI_DBM
+
+#ifdef USE_RX_RSNR
+    pt1FilterInit(&rsnrFilter, k);
+#endif //USE_RX_RSNR
+
     rxChannelCount = MIN(rxConfig()->max_aux_channel + NON_AUX_CHANNEL_COUNT, rxRuntimeState.channelCount);
 }
 
@@ -764,20 +793,7 @@ void setRssiDirect(uint16_t newRssi, rssiSource_e source)
     }
 
     rssi = newRssi;
-}
+    rssiRaw = newRssi;
-
-#define RSSI_SAMPLE_COUNT 16
-
-static uint16_t updateRssiSamples(uint16_t value)
-{
-    static uint16_t samples[RSSI_SAMPLE_COUNT];
-    static uint8_t sampleIndex = 0;
-    static unsigned sum = 0;
-
-    sum += value - samples[sampleIndex];
-    samples[sampleIndex] = value;
-    sampleIndex = (sampleIndex + 1) % RSSI_SAMPLE_COUNT;
-    return sum / RSSI_SAMPLE_COUNT;
 }
 
 void setRssi(uint16_t rssiValue, rssiSource_e source)
@@ -788,10 +804,9 @@ void setRssi(uint16_t rssiValue, rssiSource_e source)
 
     // Filter RSSI value
     if (source == RSSI_SOURCE_FRAME_ERRORS) {
-        rssi = pt1FilterApply(&frameErrFilter, rssiValue);
+        rssiRaw = pt1FilterApply(&frameErrFilter, rssiValue);
     } else {
-        // calculate new sample mean
+        rssiRaw = rssiValue;
-        rssi = updateRssiSamples(rssiValue);
     }
 }
 
@@ -852,6 +867,37 @@ void updateRSSI(timeUs_t currentTimeUs)
     default:
         break;
     }
+
+    if (cmpTimeUs(currentTimeUs, lastRssiSmoothingUs) > 250000) { // 0.25s
+        lastRssiSmoothingUs = currentTimeUs;
+    } else {
+        if (lastRssiSmoothingUs != currentTimeUs) { // avoid div by 0
+            float k = (256.0f - rxConfig()->rssi_smoothing) / 256.0f;
+            float factor = ((currentTimeUs - lastRssiSmoothingUs) / 1000000.0f) / (1.0f / 4.0f);
+            float k2  = (k * factor) / ((k * factor) - k + 1);
+
+            if (rssi != rssiRaw) {
+                pt1FilterUpdateCutoff(&rssiFilter, k2);
+                rssi = pt1FilterApply(&rssiFilter, rssiRaw);
+            }
+
+#ifdef USE_RX_RSSI_DBM
+            if (rssiDbm != rssiDbmRaw) {
+                pt1FilterUpdateCutoff(&rssiDbmFilter, k2);
+                rssiDbm = pt1FilterApply(&rssiDbmFilter, rssiDbmRaw);
+            }
+#endif //USE_RX_RSSI_DBM
+
+#ifdef USE_RX_RSNR
+            if (rsnr != rsnrRaw) {
+                pt1FilterUpdateCutoff(&rsnrFilter, k2);
+                rsnr = pt1FilterApply(&rsnrFilter, rsnrRaw);
+            }
+#endif //USE_RX_RSNR
+
+            lastRssiSmoothingUs = currentTimeUs;
+        }
+    }
 }
 
 uint16_t getRssi(void)
@@ -871,32 +917,19 @@ uint8_t getRssiPercent(void)
     return scaleRange(getRssi(), 0, RSSI_MAX_VALUE, 0, 100);
 }
 
+#ifdef USE_RX_RSSI_DBM
 int16_t getRssiDbm(void)
 {
     return rssiDbm;
 }
 
-#define RSSI_SAMPLE_COUNT_DBM 16
-
-static int16_t updateRssiDbmSamples(int16_t value)
-{
-    static int16_t samplesdbm[RSSI_SAMPLE_COUNT_DBM];
-    static uint8_t sampledbmIndex = 0;
-    static int sumdbm = 0;
-
-    sumdbm += value - samplesdbm[sampledbmIndex];
-    samplesdbm[sampledbmIndex] = value;
-    sampledbmIndex = (sampledbmIndex + 1) % RSSI_SAMPLE_COUNT_DBM;
-    return sumdbm / RSSI_SAMPLE_COUNT_DBM;
-}
-
 void setRssiDbm(int16_t rssiDbmValue, rssiSource_e source)
 {
     if (source != rssiSource) {
         return;
     }
 
-    rssiDbm = updateRssiDbmSamples(rssiDbmValue);
+    rssiDbmRaw = rssiDbmValue;
 }
 
 void setRssiDbmDirect(int16_t newRssiDbm, rssiSource_e source)
@@ -906,7 +939,27 @@ void setRssiDbmDirect(int16_t newRssiDbm, rssiSource_e source)
     }
 
     rssiDbm = newRssiDbm;
+    rssiDbmRaw = newRssiDbm;
 }
+#endif //USE_RX_RSSI_DBM
+
+#ifdef USE_RX_RSNR
+int16_t getRsnr(void)
+{
+    return rsnr;
+}
+
+void setRsnr(int16_t rsnrValue)
+{
+    rsnrRaw = rsnrValue;
+}
+
+void setRsnrDirect(int16_t newRsnr)
+{
+    rsnr = newRsnr;
+    rsnrRaw = newRsnr;
+}
+#endif //USE_RX_RSNR
 
 #ifdef USE_RX_LINK_QUALITY_INFO
 uint16_t rxGetLinkQuality(void)

src/main/rx/rx.h

@@ -201,9 +201,17 @@ uint16_t rxGetLinkQuality(void);
 void setLinkQualityDirect(uint16_t linkqualityValue);
 uint16_t rxGetLinkQualityPercent(void);
 
+#ifdef USE_RX_RSSI_DBM
 int16_t getRssiDbm(void);
 void setRssiDbm(int16_t newRssiDbm, rssiSource_e source);
 void setRssiDbmDirect(int16_t newRssiDbm, rssiSource_e source);
+#endif //USE_RX_RSSI_DBM
+
+#ifdef USE_RX_RSNR
+int16_t getRsnr(void);
+void setRsnr(int16_t newRsnr);
+void setRsnrDirect(int16_t newRsnr);
+#endif //USE_RX_RSNR
 
 void rxSetRfMode(uint8_t rfModeValue);
 uint8_t rxGetRfMode(void);

src/main/target/common_pre.h

@@ -362,6 +362,7 @@ extern uint8_t _dmaram_end__;
 #define USE_RX_MSP
 #define USE_ESC_SENSOR_INFO
 #define USE_RX_RSSI_DBM
+#define USE_RX_RSNR
 
 #if !defined(CLOUD_BUILD)
 #define USE_CRSF_CMS_TELEMETRY

src/test/unit/link_quality_unittest.cc

@@ -606,6 +606,12 @@ extern "C" {
         UNUSED(k);
     }
 
+    void pt1FilterUpdateCutoff(pt1Filter_t *filter, float k)
+    {
+        UNUSED(filter);
+        UNUSED(k);
+    }
+
     float pt1FilterApply(pt1Filter_t *filter, float input)
     {
         UNUSED(filter);

src/test/unit/rx_ranges_unittest.cc

@@ -253,6 +253,12 @@ void pt1FilterInit(pt1Filter_t *filter, float k)
     UNUSED(k);
 }
 
+void pt1FilterUpdateCutoff(pt1Filter_t *filter, float k)
+{
+    UNUSED(filter);
+    UNUSED(k);
+}
+
 float pt1FilterApply(pt1Filter_t *filter, float input)
 {
     UNUSED(filter);

src/test/unit/rx_rx_unittest.cc

@@ -259,6 +259,12 @@ extern "C" {
         UNUSED(k);
     }
 
+    void pt1FilterUpdateCutoff(pt1Filter_t *filter, float k)
+    {
+        UNUSED(filter);
+        UNUSED(k);
+    }
+
     float pt1FilterApply(pt1Filter_t *filter, float input)
     {
         UNUSED(filter);