struct

#define BYTE_SIZE 33
char incomingPayload[BYTE_SIZE];

typedef struct {
  char header[4];
  float kecepatan;
  float pitch;
  float roll;
  float heading;
  float lat;
  float lon;
  float alt;
  char footer;
} DataStruct;

DataStruct data;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(38400);
  while(!Serial);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(Serial.available() >= 33){
  char incomingBytes = Serial.read();
  for(int i = 0; i < sizeof(data); i++){
    incomingPayload[i++] = incomingBytes;
  }
  memcpy(&data, incomingPayload, sizeof(data));
  Serial.print(data.header);
  }
}