From 572d9ba43b383bb9c2ce740e2546977bbaff68bb Mon Sep 17 00:00:00 2001
From: Daniel Widmann <widmann.daniel@gmail.com>
Date: Wed, 11 Apr 2018 12:48:25 -0700
Subject: [PATCH] Rover: Allow switching to ACRO mode for skid steer rovers
 without GPS

---
 APMrover2/mode.h        | 4 ++--
 APMrover2/mode_acro.cpp | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/APMrover2/mode.h b/APMrover2/mode.h
index ff3c5b6e9d..d938ecea9a 100644
--- a/APMrover2/mode.h
+++ b/APMrover2/mode.h
@@ -176,9 +176,9 @@ public:
     // attributes for mavlink system status reporting
     bool has_manual_input() const override { return true; }
 
-    // acro mode requires a velocity estimate
+    // acro mode requires a velocity estimate for non skid-steer rovers
     bool requires_position() const override { return false; }
-    bool requires_velocity() const override { return true; }
+    bool requires_velocity() const override;
 };
 
 
diff --git a/APMrover2/mode_acro.cpp b/APMrover2/mode_acro.cpp
index c92fc3ce7e..290a20ec69 100644
--- a/APMrover2/mode_acro.cpp
+++ b/APMrover2/mode_acro.cpp
@@ -41,3 +41,8 @@ void ModeAcro::update()
         calc_throttle(target_speed, false);
     }
 }
+
+bool ModeAcro::requires_velocity() const
+{
+    return g2.motors.have_skid_steering()? false: true;
+}