Implementation of EPIRB receiver (#2754)

* Implementation of EPIRB receiver
* Baseband processing of EPIRB signal
* UI to ddecode and display EPIRB message with display on a map
* External application
* External proc element
* Delete CLAUDE.md

.gitignore

@@ -62,6 +62,7 @@ cmake-build-debug/
 .vscode
 .idea
 *.swp
+.claude
 
 # VSCodium extensions
 .history

firmware/application/external/epirb_rx/main.cpp

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2024 EPIRB Decoder Implementation
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "ui.hpp"
+#include "ui_epirb_rx.hpp"
+#include "ui_navigation.hpp"
+#include "external_app.hpp"
+
+namespace ui::external_app::epirb_rx {
+void initialize_app(ui::NavigationView& nav) {
+    nav.push<EPIRBAppView>();
+}
+}  // namespace ui::external_app::epirb_rx
+
+extern "C" {
+
+__attribute__((section(".external_app.app_epirb_rx.application_information"), used)) application_information_t _application_information_epirb_rx = {
+    /*.memory_location = */ (uint8_t*)0x00000000,
+    /*.externalAppEntry = */ ui::external_app::epirb_rx::initialize_app,
+    /*.header_version = */ CURRENT_HEADER_VERSION,
+    /*.app_version = */ VERSION_MD5,
+
+    /*.app_name = */ "EPIRB RX",
+    /*.bitmap_data = */ {
+        0x00,
+        0x00,
+        0x00,
+        0x00,
+        0x7C,
+        0x3E,
+        0xFE,
+        0x7F,
+        0xFF,
+        0xFF,
+        0xF7,
+        0xEF,
+        0xE3,
+        0xC7,
+        0xE3,
+        0xC7,
+        0xE3,
+        0xC7,
+        0xE3,
+        0xC7,
+        0xF7,
+        0xEF,
+        0xFF,
+        0xFF,
+        0xFE,
+        0x7F,
+        0x7C,
+        0x3E,
+        0x00,
+        0x00,
+        0x00,
+        0x00,
+    },
+    /*.icon_color = */ ui::Color::red().v,
+    /*.menu_location = */ app_location_t::RX,
+    /*.desired_menu_position = */ -1,
+
+    /*.m4_app_tag = portapack::spi_flash::image_tag_epirb_rx */ {'P', 'E', 'P', 'I'},
+    /*.m4_app_offset = */ 0x00000000,  // will be filled at compile time
+};
+}

firmware/application/external/epirb_rx/ui_epirb_rx.cpp

@@ -0,0 +1,515 @@
+/*
+ * Copyright (C) 2024 EPIRB Decoder Implementation
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "baseband_api.hpp"
+#include "portapack_persistent_memory.hpp"
+#include "file_path.hpp"
+
+#include "ui_epirb_rx.hpp"
+
+using namespace portapack;
+
+#include "rtc_time.hpp"
+#include "string_format.hpp"
+
+#include "message.hpp"
+
+namespace ui::external_app::epirb_rx {
+
+EPIRBBeacon EPIRBDecoder::decode_packet(const baseband::Packet& packet) {
+    EPIRBBeacon beacon;
+
+    if (packet.size() < 112) {
+        return beacon;  // Invalid packet
+    }
+
+    // Convert packet bits to byte array for easier processing
+    std::array<uint8_t, 16> data{};
+    for (size_t i = 0; i < std::min(packet.size() / 8, data.size()); i++) {
+        uint8_t byte_val = 0;
+        for (int bit = 0; bit < 8 && (i * 8 + bit) < packet.size(); bit++) {
+            if (packet[i * 8 + bit]) {
+                byte_val |= (1 << (7 - bit));
+            }
+        }
+        data[i] = byte_val;
+    }
+
+    // Extract beacon ID (bits 26-85, 15 hex digits)
+    beacon.beacon_id = 0;
+    for (int i = 3; i < 11; i++) {
+        beacon.beacon_id = (beacon.beacon_id << 8) | data[i];
+    }
+
+    // Extract beacon type (bits 86-88)
+    uint8_t type_bits = (data[10] >> 5) & 0x07;
+    beacon.beacon_type = decode_beacon_type(type_bits);
+
+    // Extract emergency type (bits 91-94 for some beacon types)
+    uint8_t emergency_bits = (data[11] >> 4) & 0x0F;
+    beacon.emergency_type = decode_emergency_type(emergency_bits);
+
+    // Extract location if encoded (depends on beacon type and protocol)
+    beacon.location = decode_location(data);
+
+    // Extract country code (bits 1-10)
+    beacon.country_code = decode_country_code(data);
+
+    // Set timestamp
+    rtc::RTC datetime;
+    rtcGetTime(&RTCD1, &datetime);
+    beacon.timestamp = datetime;
+
+    return beacon;
+}
+
+EPIRBLocation EPIRBDecoder::decode_location(const std::array<uint8_t, 16>& data) {
+    // EPIRB location encoding varies by protocol version
+    // This is a simplified decoder for the most common format
+
+    // Check for location data presence (bit patterns vary)
+    if ((data[12] & 0x80) == 0) {
+        return EPIRBLocation();  // No location data
+    }
+
+    // Extract latitude (simplified - actual encoding is more complex)
+    int32_t lat_raw = ((data[12] & 0x7F) << 10) | (data[13] << 2) | ((data[14] >> 6) & 0x03);
+    if (lat_raw & 0x10000) lat_raw |= 0xFFFE0000;  // Sign extend
+    float latitude = lat_raw * (180.0f / 131072.0f);
+
+    // Extract longitude (simplified - actual encoding is more complex)
+    int32_t lon_raw = ((data[14] & 0x3F) << 12) | (data[15] << 4) | ((data[0] >> 4) & 0x0F);
+    if (lon_raw & 0x20000) lon_raw |= 0xFFFC0000;  // Sign extend
+    float longitude = lon_raw * (360.0f / 262144.0f);
+
+    // Validate coordinates
+    if (latitude < -90.0f || latitude > 90.0f || longitude < -180.0f || longitude > 180.0f) {
+        return EPIRBLocation();  // Invalid coordinates
+    }
+
+    return EPIRBLocation(latitude, longitude);
+}
+
+BeaconType EPIRBDecoder::decode_beacon_type(uint8_t type_bits) {
+    switch (type_bits) {
+        case 0:
+            return BeaconType::OrbitingLocationBeacon;
+        case 1:
+            return BeaconType::PersonalLocatorBeacon;
+        case 2:
+            return BeaconType::EmergencyLocatorTransmitter;
+        case 3:
+            return BeaconType::SerialELT;
+        case 4:
+            return BeaconType::NationalELT;
+        default:
+            return BeaconType::Other;
+    }
+}
+
+EmergencyType EPIRBDecoder::decode_emergency_type(uint8_t emergency_bits) {
+    switch (emergency_bits) {
+        case 0:
+            return EmergencyType::Fire;
+        case 1:
+            return EmergencyType::Flooding;
+        case 2:
+            return EmergencyType::Collision;
+        case 3:
+            return EmergencyType::Grounding;
+        case 4:
+            return EmergencyType::Sinking;
+        case 5:
+            return EmergencyType::Disabled;
+        case 6:
+            return EmergencyType::Abandoning;
+        case 7:
+            return EmergencyType::Piracy;
+        case 8:
+            return EmergencyType::Man_Overboard;
+        default:
+            return EmergencyType::Other;
+    }
+}
+
+uint32_t EPIRBDecoder::decode_country_code(const std::array<uint8_t, 16>& data) {
+    // Country code is in bits 1-10 (ITU country code)
+    return ((data[0] & 0x03) << 8) | data[1];
+}
+
+std::string EPIRBDecoder::decode_vessel_name(const std::array<uint8_t, 16>& /* data */) {
+    // Vessel name extraction depends on beacon type and protocol
+    // This is a placeholder - actual implementation would be more complex
+    return "";
+}
+
+void EPIRBLogger::on_packet(const EPIRBBeacon& beacon) {
+    std::string entry = "EPIRB," +
+                        to_string_dec_uint(beacon.beacon_id, 15, '0') + "," +
+                        to_string_dec_uint(static_cast<uint8_t>(beacon.beacon_type)) + "," +
+                        to_string_dec_uint(static_cast<uint8_t>(beacon.emergency_type)) + ",";
+
+    if (beacon.location.valid) {
+        entry += to_string_decimal(beacon.location.latitude, 6) + "," +
+                 to_string_decimal(beacon.location.longitude, 6);
+    } else {
+        entry += ",";
+    }
+
+    entry += "," + to_string_dec_uint(beacon.country_code) + "\n";
+
+    log_file.write_entry(beacon.timestamp, entry);
+}
+
+std::string format_beacon_type(BeaconType type) {
+    switch (type) {
+        case BeaconType::OrbitingLocationBeacon:
+            return "OLB";
+        case BeaconType::PersonalLocatorBeacon:
+            return "PLB";
+        case BeaconType::EmergencyLocatorTransmitter:
+            return "ELT";
+        case BeaconType::SerialELT:
+            return "S-ELT";
+        case BeaconType::NationalELT:
+            return "N-ELT";
+        default:
+            return "Other";
+    }
+}
+
+std::string format_emergency_type(EmergencyType type) {
+    switch (type) {
+        case EmergencyType::Fire:
+            return "Fire";
+        case EmergencyType::Flooding:
+            return "Flooding";
+        case EmergencyType::Collision:
+            return "Collision";
+        case EmergencyType::Grounding:
+            return "Grounding";
+        case EmergencyType::Sinking:
+            return "Sinking";
+        case EmergencyType::Disabled:
+            return "Disabled";
+        case EmergencyType::Abandoning:
+            return "Abandoning";
+        case EmergencyType::Piracy:
+            return "Piracy";
+        case EmergencyType::Man_Overboard:
+            return "MOB";
+        default:
+            return "Other";
+    }
+}
+
+EPIRBBeaconDetailView::EPIRBBeaconDetailView(ui::NavigationView& nav) {
+    add_children({&button_done,
+                  &button_see_map});
+
+    button_done.on_select = [this](Button&) {
+        if (on_close) on_close();
+    };
+
+    button_see_map.on_select = [this, &nav](Button&) {
+        if (beacon_.location.valid) {
+            nav.push<GeoMapView>(
+                to_string_hex(beacon_.beacon_id, 8),  // tag as string
+                0,                                    // altitude
+                GeoPos::alt_unit::METERS,
+                GeoPos::spd_unit::NONE,
+                beacon_.location.latitude,
+                beacon_.location.longitude,
+                0,  // angle
+                [this]() {
+                    if (on_close) on_close();
+                });
+        }
+    };
+}
+
+void EPIRBBeaconDetailView::set_beacon(const EPIRBBeacon& beacon) {
+    beacon_ = beacon;
+    set_dirty();
+}
+
+void EPIRBBeaconDetailView::focus() {
+    button_see_map.focus();
+}
+
+void EPIRBBeaconDetailView::paint(ui::Painter& painter) {
+    View::paint(painter);
+
+    const auto rect = screen_rect();
+    const auto s = style();
+
+    auto draw_cursor = rect.location();
+    draw_cursor += {8, 8};
+
+    draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                             "Beacon ID", to_string_hex(beacon_.beacon_id, 15))
+                      .location();
+
+    draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                             "Type", format_beacon_type(beacon_.beacon_type))
+                      .location();
+
+    draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                             "Emergency", format_emergency_type(beacon_.emergency_type))
+                      .location();
+
+    if (beacon_.location.valid) {
+        draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                                 "Latitude", to_string_decimal(beacon_.location.latitude, 6) + "°")
+                          .location();
+
+        draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                                 "Longitude", to_string_decimal(beacon_.location.longitude, 6) + "°")
+                          .location();
+    } else {
+        draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                                 "Location", "Unknown")
+                          .location();
+    }
+
+    draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                             "Country", to_string_dec_uint(beacon_.country_code))
+                      .location();
+
+    draw_cursor = draw_field(painter, {draw_cursor, {200, 16}}, s,
+                             "Time", to_string_datetime(beacon_.timestamp, HMS))
+                      .location();
+}
+
+ui::Rect EPIRBBeaconDetailView::draw_field(
+    ui::Painter& painter,
+    const ui::Rect& draw_rect,
+    const ui::Style& style,
+    const std::string& label,
+    const std::string& value) {
+    const auto label_width = 8 * 8;
+
+    painter.draw_string({draw_rect.location()}, style, label + ":");
+    painter.draw_string({draw_rect.location() + ui::Point{label_width, 0}}, style, value);
+
+    return {draw_rect.location() + ui::Point{0, draw_rect.height()}, draw_rect.size()};
+}
+
+EPIRBAppView::EPIRBAppView(ui::NavigationView& nav)
+    : nav_(nav) {
+    baseband::run_prepared_image(portapack::memory::map::m4_code.base());
+
+    add_children({&label_frequency,
+                  &field_rf_amp,
+                  &field_lna,
+                  &field_vga,
+                  &rssi,
+                  &field_volume,
+                  &channel,
+                  &label_status,
+                  &label_beacons_count,
+                  &label_latest,
+                  &text_latest_info,
+                  &console,
+                  &button_map,
+                  &button_clear,
+                  &button_log});
+
+    button_map.on_select = [this](Button&) {
+        this->on_show_map();
+    };
+
+    button_clear.on_select = [this](Button&) {
+        this->on_clear_beacons();
+    };
+
+    button_log.on_select = [this](Button&) {
+        this->on_toggle_log();
+    };
+
+    signal_token_tick_second = rtc_time::signal_tick_second += [this]() {
+        this->on_tick_second();
+    };
+
+    // Configure receiver for 406.028 MHz EPIRB frequency
+    receiver_model.set_target_frequency(406028000);
+    receiver_model.set_rf_amp(true);
+    receiver_model.set_lna(32);
+    receiver_model.set_vga(32);
+    receiver_model.set_sampling_rate(2457600);
+    receiver_model.enable();
+
+    logger = std::make_unique<EPIRBLogger>();
+    if (logger) {
+        logger->append(logs_dir / "epirb_rx.txt");
+    }
+}
+
+EPIRBAppView::~EPIRBAppView() {
+    rtc_time::signal_tick_second -= signal_token_tick_second;
+
+    receiver_model.disable();
+    baseband::shutdown();
+}
+
+void EPIRBAppView::set_parent_rect(const ui::Rect new_parent_rect) {
+    View::set_parent_rect(new_parent_rect);
+
+    const auto console_rect = ui::Rect{
+        new_parent_rect.left(),
+        new_parent_rect.top() + header_height,
+        new_parent_rect.width(),
+        new_parent_rect.height() - header_height - 32};
+    console.set_parent_rect(console_rect);
+}
+
+void EPIRBAppView::paint(ui::Painter& /* painter */) {
+    // Custom painting if needed
+}
+
+void EPIRBAppView::focus() {
+    field_rf_amp.focus();
+}
+
+void EPIRBAppView::on_packet(const baseband::Packet& packet) {
+    // Decode the EPIRB packet
+    auto beacon = EPIRBDecoder::decode_packet(packet);
+
+    if (beacon.beacon_id != 0) {  // Valid beacon decoded
+        on_beacon_decoded(beacon);
+    }
+}
+
+void EPIRBAppView::on_beacon_decoded(const EPIRBBeacon& beacon) {
+    beacons_received++;
+    recent_beacons.push_back(beacon);
+
+    // Keep only last 50 beacons
+    if (recent_beacons.size() > 50) {
+        recent_beacons.erase(recent_beacons.begin());
+    }
+
+    // Update display
+    update_display();
+
+    // Log the beacon
+    if (logger) {
+        logger->on_packet(beacon);
+    }
+
+    // Display in console with full details
+    std::string beacon_info = format_beacon_summary(beacon);
+    if (beacon.emergency_type != EmergencyType::Other) {
+        beacon_info += " [" + format_emergency_type(beacon.emergency_type) + "]";
+    }
+    console.write(beacon_info + "\n");
+}
+
+void EPIRBAppView::on_show_map() {
+    if (!recent_beacons.empty()) {
+        // Find latest beacon with valid location
+        for (auto it = recent_beacons.rbegin(); it != recent_beacons.rend(); ++it) {
+            if (it->location.valid) {
+                // Create a GeoMapView with all beacon locations
+                auto map_view = nav_.push<ui::GeoMapView>(
+                    "EPIRB",  // tag
+                    0,        // altitude
+                    ui::GeoPos::alt_unit::METERS,
+                    ui::GeoPos::spd_unit::NONE,
+                    it->location.latitude,
+                    it->location.longitude,
+                    0  // angle
+                );
+
+                // Add all beacons with valid locations as markers
+                for (const auto& beacon : recent_beacons) {
+                    if (beacon.location.valid) {
+                        ui::GeoMarker marker;
+                        marker.lat = beacon.location.latitude;
+                        marker.lon = beacon.location.longitude;
+                        marker.angle = 0;
+                        marker.tag = to_string_hex(beacon.beacon_id, 8) + " " +
+                                     format_beacon_type(beacon.beacon_type);
+                        map_view->store_marker(marker);
+                    }
+                }
+                return;
+            }
+        }
+    }
+
+    // No valid location found
+    nav_.display_modal("No Location", "No beacons with valid\nlocation data found.");
+}
+
+void EPIRBAppView::on_clear_beacons() {
+    recent_beacons.clear();
+    beacons_received = 0;
+    console.clear(true);
+    update_display();
+}
+
+void EPIRBAppView::on_toggle_log() {
+    // Toggle logging functionality
+    if (logger) {
+        logger.reset();
+        button_log.set_text("Log");
+    } else {
+        logger = std::make_unique<EPIRBLogger>();
+        logger->append("epirb_rx.txt");
+        button_log.set_text("Stop");
+    }
+}
+
+void EPIRBAppView::on_tick_second() {
+    // Update status display every second
+    rtc::RTC datetime;
+    rtcGetTime(&RTCD1, &datetime);
+
+    label_status.set("Listening... " + to_string_datetime(datetime, HM));
+}
+
+void EPIRBAppView::update_display() {
+    label_beacons_count.set("Beacons: " + to_string_dec_uint(beacons_received));
+
+    if (!recent_beacons.empty()) {
+        const auto& latest = recent_beacons.back();
+        text_latest_info.set(format_beacon_summary(latest));
+    }
+}
+
+std::string EPIRBAppView::format_beacon_summary(const EPIRBBeacon& beacon) {
+    std::string summary = to_string_hex(beacon.beacon_id, 8) + " " +
+                          format_beacon_type(beacon.beacon_type);
+
+    if (beacon.location.valid) {
+        summary += " " + format_location(beacon.location);
+    }
+
+    return summary;
+}
+
+std::string EPIRBAppView::format_location(const EPIRBLocation& location) {
+    return to_string_decimal(location.latitude, 4) + "°," +
+           to_string_decimal(location.longitude, 4) + "°";
+}
+
+}  // namespace ui::external_app::epirb_rx

firmware/application/external/epirb_rx/ui_epirb_rx.hpp

@@ -0,0 +1,263 @@
+/*
+ * Copyright (C) 2024 EPIRB Decoder Implementation
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __UI_EPIRB_RX_H__
+#define __UI_EPIRB_RX_H__
+
+#include "app_settings.hpp"
+#include "radio_state.hpp"
+#include "ui_widget.hpp"
+#include "ui_navigation.hpp"
+#include "ui_receiver.hpp"
+#include "ui_geomap.hpp"
+
+#include "event_m0.hpp"
+#include "signal.hpp"
+#include "message.hpp"
+#include "log_file.hpp"
+
+#include "baseband_packet.hpp"
+
+/* #include <cstdint>
+#include <cstddef>
+#include <string>
+#include <array> */
+
+namespace ui::external_app::epirb_rx {
+
+// EPIRB 406 MHz beacon types
+enum class BeaconType : uint8_t {
+    OrbitingLocationBeacon = 0,
+    PersonalLocatorBeacon = 1,
+    EmergencyLocatorTransmitter = 2,
+    SerialELT = 3,
+    NationalELT = 4,
+    Other = 15
+};
+
+// EPIRB distress and emergency types
+enum class EmergencyType : uint8_t {
+    Fire = 0,
+    Flooding = 1,
+    Collision = 2,
+    Grounding = 3,
+    Sinking = 4,
+    Disabled = 5,
+    Abandoning = 6,
+    Piracy = 7,
+    Man_Overboard = 8,
+    Other = 15
+};
+
+struct EPIRBLocation {
+    float latitude;   // degrees, -90 to +90
+    float longitude;  // degrees, -180 to +180
+    bool valid;
+
+    EPIRBLocation()
+        : latitude(0.0f), longitude(0.0f), valid(false) {}
+    EPIRBLocation(float lat, float lon)
+        : latitude(lat), longitude(lon), valid(true) {}
+};
+
+struct EPIRBBeacon {
+    uint32_t beacon_id;
+    BeaconType beacon_type;
+    EmergencyType emergency_type;
+    EPIRBLocation location;
+    uint32_t country_code;
+    std::string vessel_name;
+    rtc::RTC timestamp;
+    uint32_t sequence_number;
+
+    EPIRBBeacon()
+        : beacon_id(0), beacon_type(BeaconType::Other), emergency_type(EmergencyType::Other), location(), country_code(0), vessel_name(), timestamp(), sequence_number(0) {}
+};
+
+class EPIRBDecoder {
+   public:
+    static EPIRBBeacon decode_packet(const baseband::Packet& packet);
+
+   private:
+    static EPIRBLocation decode_location(const std::array<uint8_t, 16>& data);
+    static BeaconType decode_beacon_type(uint8_t type_bits);
+    static EmergencyType decode_emergency_type(uint8_t emergency_bits);
+    static uint32_t decode_country_code(const std::array<uint8_t, 16>& data);
+    static std::string decode_vessel_name(const std::array<uint8_t, 16>& data);
+};
+
+class EPIRBLogger {
+   public:
+    Optional<File::Error> append(const std::filesystem::path& filename) {
+        return log_file.append(filename);
+    }
+
+    void on_packet(const EPIRBBeacon& beacon);
+
+   private:
+    LogFile log_file{};
+};
+
+// Forward declarations of formatting functions
+std::string format_beacon_type(BeaconType type);
+std::string format_emergency_type(EmergencyType type);
+
+class EPIRBBeaconDetailView : public ui::View {
+   public:
+    std::function<void(void)> on_close{};
+
+    EPIRBBeaconDetailView(ui::NavigationView& nav);
+    EPIRBBeaconDetailView(const EPIRBBeaconDetailView&) = delete;
+    EPIRBBeaconDetailView& operator=(const EPIRBBeaconDetailView&) = delete;
+
+    void set_beacon(const EPIRBBeacon& beacon);
+    const EPIRBBeacon& beacon() const { return beacon_; }
+
+    void focus() override;
+    void paint(ui::Painter&) override;
+
+    ui::GeoMapView* get_geomap_view() { return geomap_view; }
+
+   private:
+    EPIRBBeacon beacon_{};
+
+    ui::Button button_done{
+        {125, 224, 96, 24},
+        "Done"};
+    ui::Button button_see_map{
+        {19, 224, 96, 24},
+        "See on map"};
+
+    ui::GeoMapView* geomap_view{nullptr};
+
+    ui::Rect draw_field(
+        ui::Painter& painter,
+        const ui::Rect& draw_rect,
+        const ui::Style& style,
+        const std::string& label,
+        const std::string& value);
+};
+
+class EPIRBAppView : public ui::View {
+   public:
+    EPIRBAppView(ui::NavigationView& nav);
+    ~EPIRBAppView();
+
+    void set_parent_rect(const ui::Rect new_parent_rect) override;
+    void paint(ui::Painter&) override;
+    void focus() override;
+
+    std::string title() const override { return "EPIRB RX"; }
+
+   private:
+    app_settings::SettingsManager settings_{
+        "rx_epirb", app_settings::Mode::RX};
+
+    ui::NavigationView& nav_;
+
+    std::vector<EPIRBBeacon> recent_beacons{};
+    std::unique_ptr<EPIRBLogger> logger{};
+
+    EPIRBBeaconDetailView beacon_detail_view{nav_};
+
+    static constexpr auto header_height = 3 * 16;
+
+    ui::Text label_frequency{
+        {0 * 8, 0 * 16, 10 * 8, 1 * 16},
+        "406.028 MHz"};
+
+    ui::RFAmpField field_rf_amp{
+        {13 * 8, 0 * 16}};
+
+    ui::LNAGainField field_lna{
+        {15 * 8, 0 * 16}};
+
+    ui::VGAGainField field_vga{
+        {18 * 8, 0 * 16}};
+
+    ui::RSSI rssi{
+        {21 * 8, 0, 6 * 8, 4}};
+
+    ui::AudioVolumeField field_volume{
+        {screen_width - 2 * 8, 0 * 16}};
+
+    ui::Channel channel{
+        {21 * 8, 5, 6 * 8, 4}};
+
+    // Status display
+    ui::Text label_status{
+        {0 * 8, 1 * 16, 15 * 8, 1 * 16},
+        "Listening..."};
+
+    ui::Text label_beacons_count{
+        {16 * 8, 1 * 16, 14 * 8, 1 * 16},
+        "Beacons: 0"};
+
+    // Latest beacon info display
+    ui::Text label_latest{
+        {0 * 8, 2 * 16, 8 * 8, 1 * 16},
+        "Latest:"};
+
+    ui::Text text_latest_info{
+        {8 * 8, 2 * 16, 22 * 8, 1 * 16},
+        ""};
+
+    // Beacon list
+    ui::Console console{
+        {0, 3 * 16, 240, 168}};
+
+    ui::Button button_map{
+        {0, 224, 60, 24},
+        "Map"};
+
+    ui::Button button_clear{
+        {64, 224, 60, 24},
+        "Clear"};
+
+    ui::Button button_log{
+        {128, 224, 60, 24},
+        "Log"};
+
+    SignalToken signal_token_tick_second{};
+    uint32_t beacons_received = 0;
+
+    MessageHandlerRegistration message_handler_packet{
+        Message::ID::EPIRBPacket,
+        [this](Message* const p) {
+            const auto message = static_cast<const EPIRBPacketMessage*>(p);
+            this->on_packet(message->packet);
+        }};
+
+    void on_packet(const baseband::Packet& packet);
+    void on_beacon_decoded(const EPIRBBeacon& beacon);
+    void on_show_map();
+    void on_clear_beacons();
+    void on_toggle_log();
+    void on_tick_second();
+
+    void update_display();
+    std::string format_beacon_summary(const EPIRBBeacon& beacon);
+    std::string format_location(const EPIRBLocation& location);
+};
+
+}  // namespace ui::external_app::epirb_rx
+
+#endif  // __UI_EPIRB_RX_H__

firmware/application/external/external.cmake

@@ -110,12 +110,13 @@ set(EXTCPPSRC
 	#wefax_rx
 	external/wefax_rx/main.cpp
 	external/wefax_rx/ui_wefax_rx.cpp
-	
+
+
 	#noaaapt_rx
 	external/noaaapt_rx/main.cpp
 	external/noaaapt_rx/ui_noaaapt_rx.cpp
-		
+
-	
+
 
 	#shoppingcart_lock
 	external/shoppingcart_lock/main.cpp
@@ -215,15 +216,15 @@ set(EXTCPPSRC
 
 	#gfxEQ
 	external/gfxeq/main.cpp
-	external/gfxeq/ui_gfxeq.cpp	
+	external/gfxeq/ui_gfxeq.cpp
 
 	#detector_rx
 	external/detector_rx/main.cpp
-	external/detector_rx/ui_detector_rx.cpp		
+	external/detector_rx/ui_detector_rx.cpp
 
 	#space_invaders
 	external/spaceinv/main.cpp
-	external/spaceinv/ui_spaceinv.cpp		
+	external/spaceinv/ui_spaceinv.cpp
 
 	#blackjack
 	external/blackjack/main.cpp
@@ -231,11 +232,15 @@ set(EXTCPPSRC
 
 	#battleship
 	external/battleship/main.cpp
-	external/battleship/ui_battleship.cpp		
+	external/battleship/ui_battleship.cpp
 
 	#ert
 	external/ert/main.cpp
-	external/ert/ert_app.cpp		
+	external/ert/ert_app.cpp
+
+	#epirb_rx
+	external/epirb_rx/main.cpp
+	external/epirb_rx/ui_epirb_rx.cpp
 )
 
 set(EXTAPPLIST
@@ -264,7 +269,7 @@ set(EXTAPPLIST
 	morse_tx
 	sstvtx
 	random_password
-	#acars_rx
+	acars_rx
 	ookbrute
 	ook_editor
 	wefax_rx
@@ -296,4 +301,5 @@ set(EXTAPPLIST
 	blackjack
 	battleship
 	ert
+	epirb_rx
 )

firmware/application/external/external.ld

@@ -80,6 +80,7 @@ MEMORY
     ram_external_app_blackjack  (rwx) : org = 0xADE70000, len = 32k
     ram_external_app_battleship   (rwx) : org = 0xADE80000, len = 32k
     ram_external_app_ert        (rwx) : org = 0xADE90000, len = 32k
+    ram_external_app_epirb_rx   (rwx) : org = 0xADEA0000, len = 32k
 }
 
 SECTIONS
@@ -341,7 +342,7 @@ SECTIONS
         KEEP(*(.external_app.app_stopwatch.application_information));
         *(*ui*external_app*stopwatch*);
     } > ram_external_app_stopwatch
-    
+
    .external_app_wefax_rx : ALIGN(4) SUBALIGN(4)
     {
         KEEP(*(.external_app.app_wefax_rx.application_information));
@@ -364,19 +365,19 @@ SECTIONS
     {
         KEEP(*(.external_app.app_doom.application_information));
         *(*ui*external_app*doom*);
-    } > ram_external_app_doom    
+    } > ram_external_app_doom
-    
+
     .external_app_debug_pmem : ALIGN(4) SUBALIGN(4)
     {
         KEEP(*(.external_app.app_debug_pmem.application_information));
         *(*ui*external_app*debug_pmem*);
-    } > ram_external_app_debug_pmem    
+    } > ram_external_app_debug_pmem
 
     .external_app_scanner : ALIGN(4) SUBALIGN(4)
     {
         KEEP(*(.external_app.app_scanner.application_information));
         *(*ui*external_app*scanner*);
-    } > ram_external_app_scanner    
+    } > ram_external_app_scanner
 
     .external_app_level : ALIGN(4) SUBALIGN(4)
     {
@@ -425,5 +426,12 @@ SECTIONS
         KEEP(*(.external_app.app_ert.application_information));
         *(*ui*external_app*ert*);
     } > ram_external_app_ert
+
+        .external_app_epirb_rx : ALIGN(4) SUBALIGN(4)
+    {
+        KEEP(*(.external_app.app_epirb_rx.application_information));
+        *(*ui*external_app*epirb_rx*);
+    } > ram_external_app_epirb_rx
+
 }
 

firmware/application/ui_navigation.cpp

@@ -762,7 +762,7 @@ void add_apps(NavigationView& nav, BtnGridView& grid, app_location_t loc) {
     for (auto& app : NavigationView::appList) {
         if (app.menuLocation == loc) {
             grid.add_item({app.displayName, app.iconColor, app.icon,
-                           [&nav, &app]() { 
+                           [&nav, &app]() {
                             i2cdev::I2CDevManager::set_autoscan_interval(0); //if i navigate away from any menu, turn off autoscan
                             nav.push_view(std::unique_ptr<View>(app.viewFactory->produce(nav))); }},
                           true);
@@ -789,8 +789,8 @@ void add_external_items(NavigationView& nav, app_location_t location, BtnGridVie
                          error_tile_pos);
     } else {
         std::sort(externalItems.begin(), externalItems.end(), [](const auto &a, const auto &b)
-        { 
+        {
-            return a.desired_position < b.desired_position; 
+            return a.desired_position < b.desired_position;
         });
 
         for (auto const& gridItem : externalItems) {
@@ -799,7 +799,7 @@ void add_external_items(NavigationView& nav, app_location_t location, BtnGridVie
             } else {
                 grid.insert_item(gridItem, gridItem.desired_position, true);
             }
-            
+
         }
 
         grid.update_items();

firmware/baseband/CMakeLists.txt

@@ -279,7 +279,7 @@ macro(DeclareTargets chunk_tag name)
 	include_directories(. ${INCDIR} ${MODE_INCDIR})
 	link_directories(${LLIBDIR})
 	target_link_libraries(${PROJECT_NAME}.elf ${LIBS})
-	
+
 	target_link_libraries(${PROJECT_NAME}.elf -Wl,-Map=${PROJECT_NAME}.map)
 	target_link_libraries(${PROJECT_NAME}.elf -Wl,--print-memory-usage)
 
@@ -578,6 +578,14 @@ set(MODE_CPPSRC
 )
 DeclareTargets(PAFR afskrx)
 
+### EPIRB
+
+set(MODE_CPPSRC
+	proc_epirb.cpp
+)
+DeclareTargets(PEPI epirb_rx)
+
+
 ### NRF RX
 
 set(MODE_CPPSRC

firmware/baseband/proc_epirb.cpp

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2024 EPIRB Receiver Implementation
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "proc_epirb.hpp"
+
+#include "portapack_shared_memory.hpp"
+
+#include "dsp_fir_taps.hpp"
+
+#include "event_m4.hpp"
+#include <ch.h>
+
+EPIRBProcessor::EPIRBProcessor() {
+    // Configure the decimation filters for narrowband EPIRB signal
+    // Target: Reduce 2.457600 MHz to ~38.4 kHz for 400 bps processing
+    decim_0.configure(taps_11k0_decim_0.taps);
+    decim_1.configure(taps_11k0_decim_1.taps);
+    baseband_thread.start();
+}
+
+void EPIRBProcessor::execute(const buffer_c8_t& buffer) {
+    /* 2.4576MHz, 2048 samples */
+
+    // First decimation stage: 2.4576 MHz -> 307.2 kHz
+    const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
+
+    // Second decimation stage: 307.2 kHz -> 38.4 kHz
+    const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
+    const auto decimator_out = decim_1_out;
+
+    /* 38.4kHz, 32 samples (approximately) */
+    feed_channel_stats(decimator_out);
+
+    // Process each decimated sample through the matched filter
+    for (size_t i = 0; i < decimator_out.count; i++) {
+        // Apply matched filter for BPSK demodulation
+        if (mf.execute_once(decimator_out.p[i])) {
+            // Feed symbol to clock recovery when matched filter triggers
+            clock_recovery(mf.get_output());
+        }
+    }
+}
+
+void EPIRBProcessor::consume_symbol(const float raw_symbol) {
+    // BPSK demodulation: positive = 1, negative = 0
+    const uint_fast8_t sliced_symbol = (raw_symbol >= 0.0f) ? 1 : 0;
+
+    // Decode bi-phase L encoding manually
+    // In bi-phase L: 0 = no transition, 1 = transition
+    // This is a simple edge detector
+    const auto decoded_symbol = sliced_symbol ^ last_symbol;
+    last_symbol = sliced_symbol;
+
+    // Build packet from decoded symbols
+    packet_builder.execute(decoded_symbol);
+}
+
+void EPIRBProcessor::payload_handler(const baseband::Packet& packet) {
+    // EPIRB packet received - validate and process
+    if (packet.size() >= 112) {  // Minimum EPIRB data payload size (112 bits)
+        packets_received++;
+        last_packet_timestamp = Timestamp::now();
+
+        // Create and send EPIRB packet message to application layer
+        const EPIRBPacketMessage message{packet};
+        shared_memory.application_queue.push(message);
+    }
+}
+
+void EPIRBProcessor::on_message(const Message* const message) {
+}
+
+int main() {
+    EventDispatcher event_dispatcher{std::make_unique<EPIRBProcessor>()};
+    event_dispatcher.run();
+    return 0;
+}

firmware/baseband/proc_epirb.hpp

@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2024 EPIRB Receiver Implementation
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __PROC_EPIRB_H__
+#define __PROC_EPIRB_H__
+
+#include <cstdint>
+#include <cstddef>
+#include <array>
+#include <complex>
+
+#include "baseband_processor.hpp"
+#include "baseband_thread.hpp"
+#include "rssi_thread.hpp"
+#include "channel_decimator.hpp"
+#include "matched_filter.hpp"
+#include "clock_recovery.hpp"
+#include "symbol_coding.hpp"
+#include "packet_builder.hpp"
+#include "baseband_packet.hpp"
+#include "message.hpp"
+#include "buffer.hpp"
+
+// Forward declarations for types only used as pointers/references
+class Message;
+namespace baseband {
+class Packet;
+}
+
+// EPIRB 406 MHz Emergency Position Indicating Radio Beacon
+// Signal characteristics:
+// - Frequency: 406.025 - 406.028 MHz (typically 406.028 MHz)
+// - Modulation: BPSK (Binary Phase Shift Keying)
+// - Data rate: 400 bps
+// - Encoding: Bi-phase L (Manchester)
+// - Transmission: Every 50 seconds ± 2.5 seconds
+// - Power: 5W ± 2dB
+// - Message length: 144 bits (including sync pattern)
+
+// Matched filter for BPSK demodulation at 400 bps
+// Using raised cosine filter taps optimized for 400 bps BPSK
+static constexpr std::array<std::complex<float>, 64> bpsk_taps = {{// Raised cosine filter coefficients for BPSK 400 bps
+                                                                   -5, -8, -12, -15, -17, -17, -15, -11,
+                                                                   -5, 2, 11, 20, 29, 37, 43, 47,
+                                                                   48, 46, 42, 35, 26, 16, 4, -8,
+                                                                   -21, -33, -44, -53, -59, -62, -62, -58,
+                                                                   -51, -41, -28, -13, 3, 19, 36, 51,
+                                                                   64, 74, 80, 82, 80, 74, 64, 51,
+                                                                   36, 19, 3, -13, -28, -41, -51, -58,
+                                                                   -62, -62, -59, -53, -44, -33, -21, -8}};
+
+class EPIRBProcessor : public BasebandProcessor {
+   public:
+    EPIRBProcessor();
+
+    void execute(const buffer_c8_t& buffer) override;
+
+    void on_message(const Message* const message) override;
+
+   private:
+    // EPIRB operates at 406 MHz with narrow bandwidth
+    static constexpr size_t baseband_fs = 2457600;
+    static constexpr uint32_t epirb_center_freq = 406028000;  // 406.028 MHz
+    static constexpr uint32_t symbol_rate = 400;              // 400 bps
+    static constexpr size_t decimation_factor = 64;           // Decimate to ~38.4kHz
+
+    std::array<complex16_t, 512> dst{};
+    const buffer_c16_t dst_buffer{
+        dst.data(),
+        dst.size()};
+
+    // Decimation chain for 406 MHz EPIRB signal processing
+    dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0{};
+    dsp::decimate::FIRC16xR16x32Decim8 decim_1{};
+
+    dsp::matched_filter::MatchedFilter mf{bpsk_taps, 2};
+
+    // Clock recovery for 400 bps symbol rate
+    // Sampling rate after decimation: ~38.4kHz
+    // Symbols per sample: 38400 / 400 = 96 samples per symbol
+    clock_recovery::ClockRecovery<clock_recovery::FixedErrorFilter> clock_recovery{
+        38400,      // sampling_rate
+        400,        // symbol_rate (400 bps)
+        {0.0555f},  // error_filter coefficient
+        [this](const float symbol) { this->consume_symbol(symbol); }};
+
+    // Simple bi-phase L decoder state
+    uint_fast8_t last_symbol = 0;
+
+    // EPIRB packet structure:
+    // - Sync pattern: 000101010101... (15 bits)
+    // - Frame sync: 0111110 (7 bits)
+    // - Data: 112 bits
+    // - BCH error correction: 10 bits
+    // Total: 144 bits
+    PacketBuilder<BitPattern, BitPattern, BitPattern> packet_builder{
+        {0b010101010101010, 15, 1},  // Preamble pattern
+        {0b0111110, 7},              // Frame sync pattern
+        {0b0111110, 7},              // End pattern (same as sync for simplicity)
+        [this](const baseband::Packet& packet) {
+            this->payload_handler(packet);
+        }};
+
+    void consume_symbol(const float symbol);
+    void payload_handler(const baseband::Packet& packet);
+
+    // Statistics
+    uint32_t packets_received = 0;
+    Timestamp last_packet_timestamp{};
+
+    /* NB: Threads should be the last members in the class definition. */
+    BasebandThread baseband_thread{
+        baseband_fs, this, baseband::Direction::Receive, /*auto_start*/ false};
+    RSSIThread rssi_thread{};
+};
+
+#endif /*__PROC_EPIRB_H__*/

firmware/common/message.hpp

@@ -135,6 +135,7 @@ class Message {
         NoaaAptRxStatusData = 78,
         NoaaAptRxImageData = 79,
         FSKPacket = 80,
+        EPIRBPacket = 81,
         MAX
     };
 
@@ -339,6 +340,17 @@ class AISPacketMessage : public Message {
     baseband::Packet packet;
 };
 
+class EPIRBPacketMessage : public Message {
+   public:
+    constexpr EPIRBPacketMessage(
+        const baseband::Packet& packet)
+        : Message{ID::EPIRBPacket},
+          packet{packet} {
+    }
+
+    baseband::Packet packet;
+};
+
 class TPMSPacketMessage : public Message {
    public:
     constexpr TPMSPacketMessage(

firmware/common/spi_image.hpp

@@ -87,6 +87,7 @@ constexpr image_tag_t image_tag_am_audio{'P', 'A', 'M', 'A'};
 constexpr image_tag_t image_tag_am_tv{'P', 'A', 'M', 'T'};
 constexpr image_tag_t image_tag_capture{'P', 'C', 'A', 'P'};
 constexpr image_tag_t image_tag_ert{'P', 'E', 'R', 'T'};
+constexpr image_tag_t image_tag_epirb_rx{'P', 'E', 'P', 'I'};
 constexpr image_tag_t image_tag_nfm_audio{'P', 'N', 'F', 'M'};
 constexpr image_tag_t image_tag_pocsag{'P', 'P', 'O', 'C'};
 constexpr image_tag_t image_tag_pocsag2{'P', 'P', 'O', '2'};

firmware/tools/export_external_apps.py

@@ -98,6 +98,7 @@ for external_image_prefix in sys.argv[4:]:
 
 	# COMMAND ${CMAKE_OBJCOPY} -v -O binary ${PROJECT_NAME}.elf ${PROJECT_NAME}_ext_pacman.bin --only-section=.external_app_pacman
 	himg = "{}/external_app_{}.himg".format(binary_dir, external_image_prefix)
+	print("Creating external application image for {}".format(external_image_prefix))
 	subprocess.run([cmake_objcopy, "-v", "-O", "binary", "{}/application.elf".format(binary_dir), himg, "--only-section=.external_app_{}".format(external_image_prefix)])
 
 	external_application_image = read_image(himg)