Use aprilrobotics for target mapping

And delete april detection from charuco lib.

Signed-off-by: Yash Chainani <yashchainani28@gmail.com>
Change-Id: I98e6b84d99b23683f0c77c959b8bcc9af9ebc5d4
diff --git a/frc971/vision/target_map.fbs b/frc971/vision/target_map.fbs
index 37260a6..57627e8 100644
--- a/frc971/vision/target_map.fbs
+++ b/frc971/vision/target_map.fbs
@@ -5,8 +5,8 @@
   // AprilTag ID of this target
   id:uint64 (id: 0);
 
-  // Pose of target relative to field origin.
-  // To get the pose of the target in the field frame, do:
+  // Pose of target relative to either the field origin or robot.
+  // To get the pose of the target, do:
   // Translation3d(x, y, z) *
   // (AngleAxisd(yaw) * AngleAxisd(pitch) * AngleAxisd(roll))
   x:double (id: 1);
@@ -20,12 +20,18 @@
 }
 
 // Map of all target poses on a field.
-// This would be solved for by TargetMapper
+// There are two possible uses for this:
+// 1. Static april tag poses on the field solved for by TargetMapper.
+// 2. List of detected april poses relative to the robot.
 table TargetMap {
   target_poses:[TargetPoseFbs] (id: 0);
 
-  // Unique name of the field
+  // Unique name of the field (for use case 1.)
   field_name:string (id: 1);
+
+  // End-of-frame timestamp for the frame with tag detections.
+  // (for use case 2.).
+  monotonic_timestamp_ns:int64 (id: 2);
 }
 
 root_type TargetMap;