Description

Control landing aid detection.

typedef struct {
  u8 mode;
  u16 camHFovDeg8;
  u32 blackTargetSize16;
  u32 whiteTargetSize16;
  u8 matchThresh;
  u8 reserved0;
  u8 reserved1;
  u8 keepOutMode;
  u8 reserved2;
  u32 keepOutRadius16;
  u16 ctrlParam0;
  u16 ctrlParam1;
  u16 ctrlParam2;
  u16 ctrlParam3;
  u8 cameraIndex;
} SLALandingAid_t;

SightLine's patented Landing Aid detection is capable of finding, tracking, and measuring the distance and angle to a SightLine specific target.

The target can be printed or painted or constructed of lights or heat elements. An overlay graphic can be enabled to help visualize the Landing Aid Detection Pattern – see SLASetOverlayMode_t.graphics. The target size measurements are taken from circle center to circle center in the printed target as shown below.

Landing Aid Target Size

It is important to pick units for the target size that will not overflow the distance value returned in SLALandingPosition_t: .e.g. if the target size is specified in meters, the maximum distance possible to report is 65536 meters. If the units are specified in cm, the maximum distance is 65536 cm = 655 meters.

If the white target size is larger than the black target size the system will look for a target that has a large white target on a black background (border) and a smaller black on white target.

This message is also sent in response to SLAGetParameters_t().

Message ID 0x81

Byte Offset	Name	Description
4	mode	Landing Aid mode; 0 = off, 1 = run
5-6	camHFovDeg8	Camera horizontal field of view in degrees * 256 (default 30*256 → 30 degrees), 0 = no change
7-10	blackTargetSize16	Black target size * 65536 (default 0.175*65536 → 0.175 meters = 17.5 cm), 0 = no change
11-14	whiteTargetSize16	White target size * 65536 (default 0.00875*65536 → 0.00875 meters = 8.75 mm), 0 = no change
15	matchThresh	Match threshold, 0 to 100 (default 50) 0 = no change
16	reserved0	Reserved
17	reserved1	Reserved
18	keepOutMode	Landing Aid Keep Out Mode; 0 = off, 1 = run
19	reserved2	Reserved
20-23	keepOutRadius16	Keep out radius * 65536 (default 0.35f*65536 → 0.35 meters = 35 cm); the location of this zone is centered at the detected target location
24-25	ctrlParam0	Control parameter 0 – passed straight through to SLALandingPosition_t telemetry to be used for vehicle control; Final scaling and use is left up to the end user.
26-27	ctrlParam1	Control parameter 1 – passed straight through to SLALandingPosition_t telemetry to be used for vehicle control; Final scaling and use is left up to the end user.
28-29	ctrlParam2	Control parameter 2 – passed straight through to SLALandingPosition_t telemetry to be used for vehicle control; Final scaling and use is left up to the end user.
30-31	ctrlParam3	Control parameter 3 – passed straight through to SLALandingPosition_t telemetry to be used for vehicle control; Final scaling and use is left up to the end user.
32	cameraIndex	Camera for settings (0 to 2). If not present, applies to SLACommandCamera_t.