Decode HDOP data from skytraq GPS

The hdop data was getting dropped on the floor, but is rather useful
when deciding if the GPS position is crazy or not. This reports HDOP *
5 (giving a useful range of .2-50).

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/ao_gps_skytraq.c b/src/ao_gps_skytraq.c
index bf192f28e4f0f0e4d8a0eef3e0fcaa688b328ba5..ef581349ad75fe6ccc3c5c1ac5474abb988f4a42 100644 (file)
--- a/src/ao_gps_skytraq.c
+++ b/src/ao_gps_skytraq.c
@@ -271,7 +271,15 @@ ao_gps(void) __reentrant
                        ao_gps_next.flags |= i;
 
                        ao_gps_lexchar();
-                       ao_gps_skip_field();    /* Horizontal dilution */
+                       ao_gps_next.hdop = ao_gps_decimal(0xff);
+                       if (ao_gps_next.hdop <= 50) {
+                               ao_gps_next.hdop = (uint8_t) 5 * ao_gps_next.hdop;
+                               if (ao_gps_char == '.')
+                                       ao_gps_next.hdop = (ao_gps_next.hdop +
+                                                           ((uint8_t) ao_gps_decimal(1) >> 1));
+                       } else
+                               ao_gps_next.hdop = 255;
+                       ao_gps_skip_field();
 
                        ao_gps_next.altitude = ao_gps_decimal(0xff);
                        ao_gps_skip_field();    /* skip any fractional portion */