diff --git a/libraries/AP_HAL_SITL/SITL_State_common.cpp b/libraries/AP_HAL_SITL/SITL_State_common.cpp
index 54a530bc44..47a625d4d7 100644
--- a/libraries/AP_HAL_SITL/SITL_State_common.cpp
+++ b/libraries/AP_HAL_SITL/SITL_State_common.cpp
@@ -304,13 +304,9 @@ SITL::SerialDevice *SITL_State_Common::create_serial_sim(const char *name, const
         return ais;
 #endif
     } else if (strncmp(name, "gps", 3) == 0) {
-        const char *p = strchr(name, ':');
-        if (p == nullptr) {
-            AP_HAL::panic("Need a GPS number (e.g. sim:gps:1)");
-        }
-        uint8_t x = atoi(p+1);
+        uint8_t x = atoi(arg);
         if (x <= 0 || x > ARRAY_SIZE(gps)) {
-            AP_HAL::panic("Bad GPS number %u", x);
+            AP_HAL::panic("Bad GPS number %u (%s)", x, arg);
         }
         gps[x-1] = NEW_NOTHROW SITL::GPS(x-1);
         return gps[x-1];
diff --git a/libraries/AP_HAL_SITL/SITL_State_common.h b/libraries/AP_HAL_SITL/SITL_State_common.h
index 95ef129c1c..472f7dfefa 100644
--- a/libraries/AP_HAL_SITL/SITL_State_common.h
+++ b/libraries/AP_HAL_SITL/SITL_State_common.h
@@ -231,7 +231,7 @@ public:
     const char *defaults_path = HAL_PARAM_DEFAULTS_PATH;
 
     // simulated GPS devices
-    SITL::GPS *gps[2];  // constrained by # of parameter sets
+    SITL::GPS *gps[AP_SIM_MAX_GPS_SENSORS];  // constrained by # of parameter sets
 
     // Simulated ELRS radio
     SITL::ELRS *elrs;
diff --git a/libraries/AP_HAL_SITL/UARTDriver.cpp b/libraries/AP_HAL_SITL/UARTDriver.cpp
index e809f4a43b..358fb61482 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_SITL/UARTDriver.cpp
@@ -77,11 +77,11 @@ void UARTDriver::_begin(uint32_t baud, uint16_t rxSpace, uint16_t txSpace)
     if (strcmp(path, "GPS1") == 0) {
         /* gps */
         _connected = true;
-        _sim_serial_device = _sitlState->create_serial_sim("gps:1", "", _portNumber);
+        _sim_serial_device = _sitlState->create_serial_sim("gps", "1", _portNumber);
     } else if (strcmp(path, "GPS2") == 0) {
         /* 2nd gps */
         _connected = true;
-        _sim_serial_device = _sitlState->create_serial_sim("gps:2", "", _portNumber);
+        _sim_serial_device = _sitlState->create_serial_sim("gps", "2", _portNumber);
     } else {
         /* parse type:args:flags string for path. 
            For example: