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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 – err_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 see error codes	Type	length	Value
0x40	0x01	0x00	0x41	0x0D	int 32_t -li ttle end ian, is x coo rdin ate in mill imet ers	int 32_t -li ttle end ian, is y coo rdin ate in mill imet ers	int 32_t -li ttle end ian, is z coo rdin ate in mill imet ers	uin t8_t -is posi tion qua lity fa ctor in per cent s (0- 100)
					0x4b 0x0a 0x00 0x00 0x1f 0x04 0x00 0x00 0x9c 0x0e 0x00 0x00 0x64

Type 0x40 means err_code of previous command

Type 0x41 means position

TLV response (residue of the frame from previous table)
** type**	le ngth	v alue
0x49	0x51	u int8_t - number of di stance s e ncoded in the Value	uin t16_t- UWB a ddress in little endian	ui nt32_t - di stance in mil limete rs in little endian	u int8_t -di stance q uality factor in pe rcents ( 0-100)	po sition in st andard 13 byte format (x,y ,z,qf)	…
		0x04	po sition and di stance nr. 1				nr. 2, 3, 4

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
t ype	len gth	va lue ** error c ode**	t ype	len gth	va lue
0x40	0x01	0x00	0x41	0x0D	in t32_t -l ittle en dian, is x coo rdina te in mill imete rs	in t32_t -l ittle en dian, is y coo rdina te in mill imete rs	in t32_t -l ittle en dian, is z coo rdina te in mill imete rs	ui nt8_t -pos ition qu ality f actor in per cents (0 -100)
					0x4b 0x0a 0x00 0x00 0x1f 0x04 0x00 0x00 0x9c 0x0e 0x00 0x00 0x64

Type 0x40 means err_code of previous command

Type 0x41 means position

TLV response (residue of the frame from previous table)
type	Length	value
0x48	0x63	uint8_t number of di stances encoded in the Value	uint16_t - UWB address in little endian	uint32_t distance in mil limeter s in little endian	uint8_t distance quality factor in percents (0-100)	…
		0x0E	d istance nr. 1			nr. 2 … nr. 14

Type 0x48 means distances of ranging anchors