HTTP Issue with A9G & ESP32

Hardware Nano Family Nano ESP32
1

I'm working on a project using an A9G module with an ESP32 to send GPS location data to a remote HTTPS server. However, I'm encountering several issues:

  1. Incorrect Responses: The server response logs show incorrect or unexpected data.
  2. Missing SIM Info: There's no output showing SIM information.
  3. No Requests Visible on Server: The server doesn't seem to receive any requests.

Code:

    #include <HardwareSerial.h>
    #include <WiFi.h>
    #include <time.h>
    
    // Define the serial interfaces for ESP32 and A9G
    #define MODEM_TX 17  // TX pin for A9G
    #define MODEM_RX 16  // RX pin for A9G
    
    // Configure the modem
    #define SerialMon Serial
    HardwareSerial SerialAT(1);  // Use hardware serial 1
    
    // Variables to store GPS data
    String latitude = "";
    String longitude = "";
    String lastUpdated = "";
    
    // Server URL to send GPS data
    const char* serverUrl = "https://test.dev/api/test";
    
    void setup() {
      // Set console baud rate
      SerialMon.begin(115200);
      delay(10);
    
      // Set GSM module baud rate
      SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
      delay(3000);
    
      // Initialize GPS and GPRS
      if (!initializeGPRS()) {
        // GPRS setup failed
        SerialMon.println("GPRS not set up correctly.");
      }
    
      initializeGPS();
    
      // Initialize time
      configTime(0, 0, "pool.ntp.org");
    }
    
    void loop() {
      // Get GPS data from A9G
      getGPSData();
    
      // Send GPS data to the server if GPS data is valid
      if (!latitude.isEmpty() && !longitude.isEmpty()) {
        sendGPSDataToServer();
      }
    
      // Wait for 5 seconds before updating the next data
      delay(5000);
    }
    
    void initializeGPS() {
      SerialMon.println("Initializing GPS...");
      SerialAT.println("AT+GPS=1");  // Turn on GPS
      delay(1000);
      SerialAT.println("AT+GPSRD=1");  // Start continuous GPS read
      delay(1000);
      SerialMon.println("GPS Initialized.");
    }
    
    bool initializeGPRS() {
      SerialMon.println("Initializing GPRS...");
      
      // Attach to GPRS
      SerialAT.println("AT+CGATT=1");
      delay(1000);
      
      // Set APN
      SerialAT.println("AT+CGDCONT=1,\"IP\",\"www\"");
      delay(1000);
      
      // Activate PDP context
      SerialAT.println("AT+CGACT=1,1");
      delay(3000);
      
      // Print GPRS connection status
      printGPRSStatus();
    
      // Open GPRS context
      SerialAT.println("AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\"");
      delay(1000);
      SerialAT.println("AT+SAPBR=3,1,\"APN\",\"www\"");
      delay(1000);
      SerialAT.println("AT+SAPBR=1,1");
      delay(3000);
    
      // Ping  to test GPRS
      SerialMon.println("Pinging google.com...");
      SerialAT.println("AT+HTTPGET=\"https://google.com\"");
      clearSerialBuffer();
      delay(10000); // Wait for ping response
      
      while (SerialAT.available()) {
        String response = SerialAT.readStringUntil('\n');
        SerialMon.println("Ping Response: " + response);  // Print ping response
        
        if (response.indexOf("+") != -1) {
          // Ping successful
          break;
        } else if (response.indexOf("ERROR") != -1) {
          // Ping failed
          SerialMon.println("GPRS not set up correctly.");
          return false;
        }
      }
    
      SerialMon.println("GPRS Initialized.");
      return true;
    }
    
    void getGPSData() {
      // Send command to read GPS data
      SerialAT.println("AT+GPSRD?");
      delay(2000); // Wait for response
    
      // Read the response
      while (SerialAT.available()) {
        String line = SerialAT.readStringUntil('\n');
        
        if (line.indexOf("$GNGGA") != -1) {
          // Parse the GPS data
          int startIndex = line.indexOf("$GNGGA") + 7;
          int endIndex = line.indexOf(",", startIndex);
          String time = line.substring(startIndex, endIndex);
    
          // Latitude
          startIndex = endIndex + 1;
          endIndex = line.indexOf(",", startIndex);
          latitude = convertToDecimal(line.substring(startIndex, endIndex), true);
    
          // Skip N/S indicator
          startIndex = endIndex + 3;
          endIndex = line.indexOf(",", startIndex);
          longitude = convertToDecimal(line.substring(startIndex, endIndex), false);
    
          // Print GPS data
          SerialMon.println("Latitude: " + latitude);
          SerialMon.println("Longitude: " + longitude);
    
          // Update last updated time
          updateLastUpdated();
          break; // Exit the loop after reading valid GPS data
        }
      }
    }
    
    void printGPRSStatus() {
      SerialAT.println("AT+SAPBR=2,1");
      delay(1000);
      while (SerialAT.available()) {
        String response = SerialAT.readStringUntil('\n');
        if (response.indexOf("+SAPBR:") != -1) {
          SerialMon.println("GPRS Status: " + response);
          break;
        }
      }
    }
    
    String convertToDecimal(String coordinate, bool isLatitude) {
      if (isLatitude) {
        int degrees = coordinate.substring(0, 2).toInt();
        float minutes = coordinate.substring(2).toFloat();
        float decimal = degrees + (minutes / 60.0);
        return String(decimal, 6);
      } else {
        int degrees = coordinate.substring(0, 3).toInt();
        float minutes = coordinate.substring(3).toFloat();
        float decimal = degrees + (minutes / 60.0);
        return String(decimal, 6);
      }
    }
    
    void updateLastUpdated() {
      struct tm timeinfo;
      if (!getLocalTime(&timeinfo)) {
        lastUpdated = "Failed to obtain time";
        return;
      }
      char buffer[32];
      strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", &timeinfo);
      lastUpdated = String(buffer);
    }
    
    void sendGPSDataToServer() {
    
      String postData = "latitude=" + latitude + "&longitude=" + longitude + "&lastUpdated=" + lastUpdated;
    
      SerialAT.println("AT+HTTPPARA=\"CID\",1");  // Set PDP context ID
      delay(1000);
      SerialAT.println("AT+HTTPPARA=\"CONTENT\",\"application/x-www-form-urlencoded\"");  // Set content type
      delay(1000);
      SerialAT.println("AT+HTTPPARA=\"URL\",\"" + String(serverUrl) + "\"");  // Set URL
      delay(1000);
      SerialAT.println("AT+HTTPDATA=" + String(postData.length()) + ",10000");  // Set data length and timeout
      delay(1000);
      SerialAT.println(postData);  // Send POST data
      delay(1000);
      clearSerialBuffer();
      SerialAT.println("AT+HTTPPOST");  // Perform POST action
      delay(1000);
    
      // Wait for response
      while (SerialAT.available()) {
        String response = SerialAT.readStringUntil('\n');
        SerialMon.println("Server Response: " + response);
      }
    
      // End HTTP service
      SerialAT.println("AT+HTTPTERM");
    
      // Log when a request is sent
      SerialMon.println("Sent GPS data to server.");
    
      delay(5000);  // Wait for next data update
    }
    
    void clearSerialBuffer() {
      while (SerialAT.available()) {
        SerialAT.read();  // Clear the buffer
      }
    }

Logs:

Initializing GPRS...
    Pinging google.com...
    Ping Response: AT+HTTPGET="https://google.com"
    GPRS Initialized.
    Initializing GPS...
    GPS Initialized.
    Latitude: **********
    Longitude: **********
    Server Response: +GPSRD:$GNGGA, ............................................................
    Server Response: $GPGSA,A,1,,,,,,,,,,,,,,,*1E
    Server Response: $BDGSA,A,1,,,,,,,,,,,,,,,*0F
    Server Response: $GPGSV,1,1,01,07,,,22*7F
    Server Response: $BDGSV,1,1,00*68
    Server Response: $GNRMC,............................................................
    Server Response: $GNVTG,0.00,T,,M,0.000,N,0.000,K,N*2C
    Server Response: +GPSRD:$GNGGA,............................................................
    Server Response: $GPGSA,A,1,,,,,,,,,,,,,,,*1E
    Server Response: $BDGSA,A,1,,,,,,,,,,,,,,,*0F
    Server Response: $GPGSV,1,1,01,07,,,22*7F
    Server Response: $BDGSV,1,1,00*68
    Server Response: $GNRMC,19............................................................
    Server Response: $GNVTG,............................................................
    Sent GPS data to server.

Could anyone help diagnose and resolve the issues with incorrect server responses, missing SIM information display, and the absence of visible requests on the server? Any insights or suggestions would be greatly appreciated.