dwm_loc_get

Gets the last distances to the ranging anchors and gets the position. The event is generated, the status changes when all TWR measurements are completed, and new location data is available for the user. When low-power mode is used, it will certainly work in the same way.

For the anchor node, the position and distances are available only if the auto-positioning procedure has been done. The auto-positioning procedure is carried out via the BLE interface.

void dwm_loc_get(dwm_loc_data_t *loc);

Parameters

output – Status code, [position], [cnt, {an_pos, addr, distance, pqf}]
cnt – ? 0,1,2,3,4 ? (number of distances to the anchors)
an_pos – position (position of the anchor , that correspond with the distance)
addr – ? 16-bit integer ? (UWB address/id of the particular anchor)
distance – ? 32-bit integer ? (distance to particular anchor in millimeters)
pqf – ? 8-bit integer ? (quality factor)

Note

Prameter an_pos is applicable for Tag node only

C code example

dwm_loc_data_t loc;
int rv, i;
/* if pos_available is false, position data are not read, and the function returns without error */
rv: dwm_loc_get(&loc);

if (0 == rv) {
if (loc.pos_available) {
             printf("[%ld,%ld,%ld,%u] ", loc.pos.x, loc.pos.y, loc.pos.z,
                     loc.pos.qf);
}
     for (i: 0; i < loc.anchors.dist.cnt; ++i) {
             printf("%u)", i);
             printf("0x%04x", loc.anchors.dist.addr[i]);
             if (i < loc.anchors.an_pos.cnt) {
printf("[%ld,%ld,%ld,%u]", loc.anchors.an_pos.pos[i].x,
                                     loc.anchors.an_pos.pos[i].y,
                                     loc.anchors.an_pos.pos[i].z,
                                     loc.anchors.an_pos.pos[i].qf);
             }
             printf("=%lu,%u ", loc.anchors.dist.dist[i], loc.anchors.dist.qf[i]);
     }
     printf("\n");
} else {
     printf("err code: %d\n", rv);
}

SPI/UART example 1 (tag node)

TLV Request
Type	Length
0x0C	0x00

Type 0x0C means command loc_get

TLV Response
Type	Length	Value	Type	Length	Value				Type	Length	Value
0x40	0x01	0x00	0x41	0x0D	int32 - x coordinate in millimeters	int32 - y coordinate in millimeters	int32 - z coordinate in millimeters	uint8 - position quality factor in percents	0x49	0x51	uint8 - number of distances	position and distance nr. 1				position and distance nr.2,3,4
					int32 - x coordinate in millimeters	int32 - y coordinate in millimeters	int32 - z coordinate in millimeters	uint8 - position quality factor in percents			uint8 - number of distances	int16 - UWB address	uint32 - distance in millimeters	uint8 - distance quality factor in percents	3 x int32 + uint8 - x, y, z in millimeters + quality factor in percents	…
					0x4b 0x0a 0x00 0x00 0x1f 0x04 0x00 0x00 0x9c 0x0e 0x00 0x00 0x64						0x04	0xab 0xbc	0x0e 0x03 0x00 0x00	0x64	…	…

Type 0x40 means err_code of previous command
Type 0x41 means position
Type 0x49 means position and distances of ranging anchors

SPI/UART example 2 (anchor node)

TLV Request
Type	Length
0x0C	0x00

Type 0x0C means command loc_get

TLV Response
Type	Length	Value	Type	Length	Value				Type	Length	Value
0x40	0x01	0x00	0x41	0x0D	int32 - x coordinate in millimeters	int32 - y coordinate in millimeters	int32 - z coordinate in millimeters	uint8 - position quality factor in percents	0x48	0x63	uint8 - number of distances	distance nr. 1			distance nr.2,…, nr. 14
					int32 - x coordinate in millimeters	int32 - y coordinate in millimeters	int32 - z coordinate in millimeters	uint8 - position quality factor in percents			uint8 - number of distances	int16 - UWB address	uint32 - distance in millimeters	uint8 - distance quality factor in percents	…
					0x4b 0x0a 0x00 0x00 0x1f 0x04 0x00 0x00 0x9c 0x0e 0x00 0x00 0x64						0x0E	0xab 0xbc	0x0e 0x03 0x00 0x00	0x64	…

Type 0x40 means err_code of previous command
Type 0x41 means position
Type 0x48 means distances of ranging anchors