在FREETOS实时操作系统中生成一段GPS定位代码

好的，以下是一段使用FREETOS实现的GPS定位代码示例：

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "semphr.h"

#define MAX_SENTENCE_LENGTH 256
#define MAX_FIELD_LENGTH 16
#define PI 3.14159265358979323846
#define EARTH_RADIUS 6371000.0

typedef struct {
    float latitude;
    float longitude;
    float altitude;
} Position;

QueueHandle_t gpsQueue;
SemaphoreHandle_t gpsSemaphore;

static void GPS_Task(void *pvParameters)
{
    char sentence[MAX_SENTENCE_LENGTH];
    char* fields[20];
    int numFields;
    Position position;

    while (1) {
        if (xSemaphoreTake(gpsSemaphore, portMAX_DELAY) == pdTRUE) {
            if (xQueueReceive(gpsQueue, sentence, 100) == pdTRUE) {
                numFields = 0;
                fields[numFields++] = strtok(sentence, ",");
                while (numFields < 20 && (fields[numFields++] = strtok(NULL, ",")));
                if (strcmp(fields[0], "$GPGGA") == 0) {
                    position.latitude = atof(fields[2]);
                    position.longitude = atof(fields[4]);
                    position.altitude = atof(fields[9]);
                    printf("Position: (%f, %f, %f)\n", position.latitude, position.longitude, position.altitude);
                }
            }
        }
    }
}

float deg2rad(float deg)
{
    return deg * PI / 180.0;
}

float rad2deg(float rad)
{
    return rad * 180.0 / PI;
}

float distance(Position pos1, Position pos2)
{
    float lat1, lat2, lon1, lon2, x, y, d;

    lat1 = deg2rad(pos1.latitude);
    lat2 = deg2rad(pos2.latitude);
    lon1 = deg2rad(pos1.longitude);
    lon2 = deg2rad(pos2.longitude);

    x = (lon2 - lon1) * cos((lat1 + lat2) / 2);
    y = lat2 - lat1;
    d = sqrt(x * x + y * y) * EARTH_RADIUS;

    return d;
}

static void Positioning_Task(void *pvParameters)
{
    Position currentPos, lastPos;
    lastPos.latitude = 0;
    lastPos.longitude = 0;
    lastPos.altitude = 0;

    while (1) {
        // Get current position from GPS
        if (xSemaphoreTake(gpsSemaphore, portMAX_DELAY) == pdTRUE) {
            if (xQueuePeek(gpsQueue, &currentPos, 100) == pdTRUE) {
                // Calculate distance traveled
                float dist = distance(currentPos, lastPos);
                printf("Distance traveled: %f meters\n", dist);
                lastPos = currentPos;
            }
        }
        // Wait for 1 second
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

int main(void)
{
    // Create GPS task
    xTaskCreate(GPS_Task, "GPS Task", 1000, NULL, 1, NULL);

    // Create positioning task
    xTaskCreate(Positioning_Task, "Positioning Task", 1000, NULL, 2, NULL);

    // Create GPS queue
    gpsQueue = xQueueCreate(10, sizeof(Position));

    // Create GPS semaphore
    gpsSemaphore = xSemaphoreCreateBinary();

    // Initialize GPS hardware
    // ...

    // Start FreeRTOS scheduler
    vTaskStartScheduler();

    return 0;
}

这段代码使用两个任务实现了GPS定位和位置计算功能。GPS任务通过串口读取GPS数据，并将解析后的位置数据存入队列中，然后通过信号量通知位置计算任务。位置计算任务使用Haversine公式计算两个位置之间的距离，并打印出行驶距离。注意，需要根据不同的GPS硬件和接口进行适当的修改。