diff --git a/rrlp-ephemeris/rrlp.c b/rrlp-ephemeris/rrlp.c
new file mode 100644
index 0000000..8b0d14a
--- /dev/null
+++ b/rrlp-ephemeris/rrlp.c
@@ -0,0 +1,599 @@
+/*
+ * rrlp.c
+ *
+ * RRLP implementation
+ *
+ *
+ * Copyright (C) 2009  Sylvain Munaut <tnt@246tNt.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <errno.h>
+
+#include "gps.h"
+#include "rrlp.h"
+
+#include <PDU.h>
+#include <GPS-AssistData.h>
+#include <NavigationModel.h>
+#include <IonosphericModel.h>
+#include <UTCModel.h>
+#include <Almanac.h>
+#include <RefLocation.h>
+#include <ReferenceTime.h>
+
+
+/* ------------------------------------------------------------------------ */
+/* RRLP Assistance request decoding                                         */
+/* ---------------------------------------------------------------------{{{ */
+/* Decode and validate the assistance data request messages.
+ * See section 10.10 of
+ *  . ETSI TS 149 031 V8.1.0 (2009-01)
+ *  . 3GPP TS 49.031 version 8.1.0 Release 8
+ */
+
+/* Packed structure from 49.031 spec (RGA = Request GPS Assistance) */
+
+#define RRLP_RGA0_ALMANAC	(1<<0)
+#define RRLP_RGA0_UTC_MODEL	(1<<1)
+#define RRLP_RGA0_IONO_MODEL	(1<<2)
+#define RRLP_RGA0_NAV_MODEL	(1<<3)
+#define RRLP_RGA0_DGPS		(1<<4)
+#define RRLP_RGA0_REF_LOC	(1<<5)
+#define RRLP_RGA0_REF_TIME	(1<<6)
+#define RRLP_RGA0_ACQ_ASSIST	(1<<7)
+
+#define RRLP_RGA1_REALTIME_INT	(1<<0)
+#define RRLP_RGA1_EPH_EXT	(1<<1)
+#define RRLP_RGA1_EPH_EXT_CHECK	(1<<2)
+
+struct rrlp_rga_hdr {
+	uint8_t items0;
+	uint8_t items1;
+} __attribute__((packed));
+
+struct rrlp_rga_eph_sv {
+	uint8_t sv_id;		/* [7:6] reserved, [5:0] sv_id */
+	uint8_t iode;		/* latest eph in the MS memory in hours */
+} __attribute__((packed));
+
+struct rrlp_rga_eph {
+	uint8_t wn_hi;		/* [7:6] = wn[9:8] */
+	uint8_t wn_lo;		/* wn[7:0] */
+	uint8_t toe;		/* latest eph in the MS memory in hours */
+	uint8_t nsat_tmtoe;	/* [7:4] nstat, [3:0] T-Toe limit */
+	struct rrlp_rga_eph_sv svs[0];
+} __attribute__((packed));
+
+struct rrlp_rga_eph_ext {
+	uint8_t validity;	/* in 4 hours units */
+} __attribute__((packed));
+
+struct rrlp_rga_eph_ext_check {
+		/* weeks are in gps week modulo 4 */
+	uint8_t wn_begin_end;	/* [7:4] begin, [3:0] end */
+	uint8_t tow_begin;
+	uint8_t tow_end;
+} __attribute__((packed));
+
+
+/* Parsing function */
+
+int
+rrlp_decode_assistance_request(
+	struct rrlp_assist_req *ar,
+	void *req, int req_len)
+{
+	struct rrlp_rga_hdr *hdr = NULL;
+	struct rrlp_rga_eph *eph = NULL;
+	struct rrlp_rga_eph_ext *eph_ext = NULL;
+	struct rrlp_rga_eph_ext_check *eph_ext_check = NULL;
+	int p = 0;
+
+	/* Reset */
+	ar->req_elems = 0;
+	ar->eph_svs = 0;
+
+	/* Parse message */
+	hdr = req;
+	p += sizeof(struct rrlp_rga_hdr);
+	if (p > req_len)
+		return -1;
+
+	if (hdr->items0 & RRLP_RGA0_NAV_MODEL) {
+		eph = req + p;
+		p += sizeof(struct rrlp_rga_eph);
+		if (p > req_len)
+			return -1;
+		p += (eph->nsat_tmtoe >> 4) * sizeof(struct rrlp_rga_eph_sv);
+		if (p > req_len)
+			return -1;
+	}
+
+	if (hdr->items1 & RRLP_RGA1_EPH_EXT) {
+		eph_ext = req + p;
+		p += sizeof(struct rrlp_rga_eph_ext);
+		if (p > req_len)
+			return -1;
+	}
+
+	if (hdr->items1 & RRLP_RGA1_EPH_EXT_CHECK) {
+		eph_ext_check = req + p;
+		p += sizeof(struct rrlp_rga_eph_ext_check);
+		if (p > req_len)
+			return -1;
+	}
+
+	if (p != req_len)
+		return -2; /* not all bytes consumed ??? */
+
+	/* Print a warning for unsupported requests */
+	if ((eph_ext != NULL) ||
+	    (eph_ext_check != NULL) ||
+	    (hdr->items0 & (RRLP_RGA0_DGPS | RRLP_RGA0_ACQ_ASSIST)) ||
+	    (hdr->items1 & RRLP_RGA1_REALTIME_INT)) {
+		fprintf(stderr, "[w] Unsupported assistance data requested, ignored ...\n");
+	}
+
+	/* Copy the request */
+	if (hdr->items0 & RRLP_RGA0_ALMANAC)
+		ar->req_elems |= RRLP_AR_ALMANAC;
+
+	if (hdr->items0 & RRLP_RGA0_UTC_MODEL)
+		ar->req_elems |= RRLP_AR_UTC_MODEL;
+
+	if (hdr->items0 & RRLP_RGA0_IONO_MODEL)
+		ar->req_elems |= RRLP_AR_IONO_MODEL;
+
+	if (hdr->items0 & RRLP_RGA0_REF_LOC)
+		ar->req_elems |= RRLP_AR_REF_LOC;
+
+	if (hdr->items0 & RRLP_RGA0_REF_TIME)
+		ar->req_elems |= RRLP_AR_REF_TIME;
+
+	if (hdr->items0 & RRLP_RGA0_NAV_MODEL) {
+		int i, n_svs = eph->nsat_tmtoe >> 4;
+		ar->req_elems |= RRLP_AR_EPHEMERIS;
+		for (i=0; i<n_svs; i++)
+			ar->eph_svs |= (1ULL << (eph->svs[i].sv_id - 1));
+	}
+
+	return 0;
+}
+
+/* }}} */
+
+
+/* ------------------------------------------------------------------------ */
+/* RRLP elements fill                                                       */
+/* ---------------------------------------------------------------------{{{ */
+
+static void
+_rrlp_fill_navigation_model_element(
+	struct NavModelElement *rrlp_nme,
+	struct gps_ephemeris_sv *gps_eph_sv)
+{
+	struct UncompressedEphemeris *rrlp_eph;
+
+	rrlp_nme->satStatus.present = SatStatus_PR_newSatelliteAndModelUC;
+	rrlp_nme->satelliteID = gps_eph_sv->sv_id;
+
+	rrlp_eph = &rrlp_nme->satStatus.choice.newSatelliteAndModelUC;
+
+	rrlp_eph->ephemCodeOnL2   = gps_eph_sv->code_on_l2;
+	rrlp_eph->ephemURA        = gps_eph_sv->sv_ura;
+	rrlp_eph->ephemSVhealth   = gps_eph_sv->sv_health;
+	rrlp_eph->ephemIODC       = gps_eph_sv->iodc;
+	rrlp_eph->ephemL2Pflag    = gps_eph_sv->l2_p_flag;
+	rrlp_eph->ephemTgd        = gps_eph_sv->t_gd;
+	rrlp_eph->ephemToc        = gps_eph_sv->t_oc;
+	rrlp_eph->ephemAF2        = gps_eph_sv->a_f2;
+	rrlp_eph->ephemAF1        = gps_eph_sv->a_f1;
+	rrlp_eph->ephemAF0        = gps_eph_sv->a_f0;
+	rrlp_eph->ephemCrs        = gps_eph_sv->c_rs;
+	rrlp_eph->ephemDeltaN     = gps_eph_sv->delta_n;
+	rrlp_eph->ephemM0         = gps_eph_sv->m_0;
+	rrlp_eph->ephemCuc        = gps_eph_sv->c_uc;
+	rrlp_eph->ephemE          = gps_eph_sv->e;
+	rrlp_eph->ephemCus        = gps_eph_sv->c_us;
+	rrlp_eph->ephemAPowerHalf = gps_eph_sv->a_powhalf;
+	rrlp_eph->ephemToe        = gps_eph_sv->t_oe;
+	rrlp_eph->ephemFitFlag    = gps_eph_sv->fit_flag;
+	rrlp_eph->ephemAODA       = gps_eph_sv->aodo;
+	rrlp_eph->ephemCic        = gps_eph_sv->c_ic;
+	rrlp_eph->ephemOmegaA0    = gps_eph_sv->omega_0;
+	rrlp_eph->ephemCis        = gps_eph_sv->c_is;
+	rrlp_eph->ephemI0         = gps_eph_sv->i_0;
+	rrlp_eph->ephemCrc        = gps_eph_sv->c_rc;
+	rrlp_eph->ephemW          = gps_eph_sv->w;
+	rrlp_eph->ephemOmegaADot  = gps_eph_sv->omega_dot;
+	rrlp_eph->ephemIDot       = gps_eph_sv->idot;
+
+	rrlp_eph->ephemSF1Rsvd.reserved1 = gps_eph_sv->_rsvd1;
+	rrlp_eph->ephemSF1Rsvd.reserved2 = gps_eph_sv->_rsvd2;
+	rrlp_eph->ephemSF1Rsvd.reserved3 = gps_eph_sv->_rsvd3;
+	rrlp_eph->ephemSF1Rsvd.reserved4 = gps_eph_sv->_rsvd4;
+}
+
+static void
+_rrlp_fill_almanac_element(
+	struct AlmanacElement *rrlp_ae,
+	struct gps_almanac_sv *gps_alm_sv)
+{
+	rrlp_ae->satelliteID = gps_alm_sv->sv_id;
+
+	rrlp_ae->almanacE          = gps_alm_sv->e;
+	rrlp_ae->alamanacToa       = gps_alm_sv->t_oa;
+	rrlp_ae->almanacKsii       = gps_alm_sv->ksii;
+	rrlp_ae->almanacOmegaDot   = gps_alm_sv->omega_dot;
+	rrlp_ae->almanacSVhealth   = gps_alm_sv->sv_health;
+	rrlp_ae->almanacAPowerHalf = gps_alm_sv->a_powhalf;
+	rrlp_ae->almanacOmega0     = gps_alm_sv->omega_0;
+	rrlp_ae->almanacW          = gps_alm_sv->w;
+	rrlp_ae->almanacM0         = gps_alm_sv->m_0;
+	rrlp_ae->almanacAF0        = gps_alm_sv->a_f0;
+	rrlp_ae->almanacAF1        = gps_alm_sv->a_f1;
+
+}
+
+static void
+_rrlp_fill_ionospheric_model(
+	struct IonosphericModel *rrlp_iono,
+	struct gps_ionosphere_model *gps_iono)
+{
+	rrlp_iono->alfa0 = gps_iono->alpha_0;
+	rrlp_iono->alfa1 = gps_iono->alpha_1;
+	rrlp_iono->alfa2 = gps_iono->alpha_2;
+	rrlp_iono->alfa3 = gps_iono->alpha_3;
+	rrlp_iono->beta0 = gps_iono->beta_0;
+	rrlp_iono->beta1 = gps_iono->beta_1;
+	rrlp_iono->beta2 = gps_iono->beta_2;
+	rrlp_iono->beta3 = gps_iono->beta_3;
+}
+
+static void
+_rrlp_fill_utc_model(
+	struct UTCModel *rrlp_utc,
+	struct gps_utc_model *gps_utc)
+{
+	rrlp_utc->utcA1        = gps_utc->a1;
+	rrlp_utc->utcA0        = gps_utc->a0;
+	rrlp_utc->utcTot       = gps_utc->t_ot;
+	rrlp_utc->utcWNt       = gps_utc->wn_t & 0xff;
+	rrlp_utc->utcDeltaTls  = gps_utc->delta_t_ls;
+	rrlp_utc->utcWNlsf     = gps_utc->wn_lsf & 0xff;
+	rrlp_utc->utcDN        = gps_utc->dn;
+	rrlp_utc->utcDeltaTlsf = gps_utc->delta_t_lsf;
+}
+
+/* }}} */
+
+
+/* ------------------------------------------------------------------------ */
+/* RRLP Assistance PDU Generation                                           */
+/* ---------------------------------------------------------------------{{{ */
+
+struct PDU *
+_rrlp_create_gps_assist_pdu(int refnum, struct GPS_AssistData **o_gps_ad)
+{
+	struct PDU *pdu;
+	struct GPS_AssistData *gps_ad;
+
+	pdu = calloc(1, sizeof(*pdu));
+	if (!pdu)
+		return NULL;
+
+	gps_ad = calloc(1, sizeof(*gps_ad));
+	if (!gps_ad) {
+		free(pdu);
+		return NULL;
+	}
+
+	if (o_gps_ad)
+		*o_gps_ad = gps_ad;
+
+	pdu->referenceNumber = refnum;
+	pdu->component.present = RRLP_Component_PR_assistanceData;
+	pdu->component.choice.assistanceData.gps_AssistData = gps_ad;
+
+	return pdu;
+}
+
+static int
+_rrlp_add_ionospheric_model(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad)
+{
+	struct IonosphericModel *rrlp_iono;
+
+	if (!(gps_ad->fields & GPS_FIELD_IONOSPHERE))
+		return -EINVAL;
+
+	rrlp_iono = calloc(1, sizeof(*rrlp_iono));
+	if (!rrlp_iono)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.ionosphericModel = rrlp_iono;
+
+	_rrlp_fill_ionospheric_model(rrlp_iono, &gps_ad->ionosphere);
+
+	return 0;
+}
+
+static int
+_rrlp_add_utc_model(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad)
+{
+	struct UTCModel *rrlp_utc;
+
+	if (!(gps_ad->fields & GPS_FIELD_UTC))
+		return -EINVAL;
+
+	rrlp_utc = calloc(1, sizeof(*rrlp_utc));
+	if (!rrlp_utc)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.utcModel = rrlp_utc;
+
+	_rrlp_fill_utc_model(rrlp_utc, &gps_ad->utc);
+
+	return 0;
+}
+
+static int
+_rrlp_add_reference_location(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad)
+{
+	struct RefLocation *rrlp_refloc;
+
+	/* FIXME: Check if info is in gps_ad */
+
+	rrlp_refloc = calloc(1, sizeof(*rrlp_refloc));
+	if (!rrlp_refloc)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.refLocation = rrlp_refloc;
+
+	/* FIXME */
+	{
+		uint8_t gps_loc[] = {
+			0x80,			/* Ellipsoid Point with altitude */
+			0x48, 0x0f, 0x93,	/* 50.667778 N */
+			0x03, 0x47, 0x87,	/* 4.611667 E */
+			0x00, 0x72,		/* 114m */
+		};
+		uint8_t *b = malloc(sizeof(gps_loc));
+		memcpy(b, gps_loc, sizeof(gps_loc));
+		rrlp_refloc->threeDLocation.buf = b;
+		rrlp_refloc->threeDLocation.size = sizeof(gps_loc);
+	}
+
+	return 0;
+}
+
+static int
+_rrlp_add_reference_time(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad)
+{
+	struct ReferenceTime *rrlp_reftime;
+
+	/* FIXME: Check if info is in gps_ad */
+
+	rrlp_reftime = calloc(1, sizeof(*rrlp_reftime));
+	if (!rrlp_reftime)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.referenceTime = rrlp_reftime;
+
+	/* FIXME */
+//	rrlp_reftime.gpsTime.gpsTOW23b = g_gps_tow / 80;	/* 23 bits */
+//	rrlp_reftime.gpsTime.gpsWeek   = g_gps_week & 0x3ff;	/* 10 bits */
+
+	return 0;
+}
+
+static int
+_rrlp_add_almanac(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad, int *start, int count)
+{
+	int i;
+	struct Almanac *rrlp_alm;
+	struct gps_almanac *gps_alm = &gps_ad->almanac;
+
+	if (!(gps_ad->fields & GPS_FIELD_ALMANAC))
+		return -EINVAL;
+
+	rrlp_alm = calloc(1, sizeof(*rrlp_alm));
+	if (!rrlp_alm)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.almanac = rrlp_alm;
+
+	rrlp_alm->alamanacWNa = gps_alm->wna;
+	if (count == -1)
+		count = gps_alm->n_sv - *start;
+	for (i=*start; (i<*start+count) && (i<gps_alm->n_sv); i++) {
+		struct AlmanacElement *ae;
+		ae = calloc(1, sizeof(*ae));
+		if (!ae)
+			return -ENOMEM;
+		_rrlp_fill_almanac_element(ae, &gps_alm->svs[i]);
+		ASN_SEQUENCE_ADD(&rrlp_alm->almanacList.list, ae);
+	}
+
+	*start = i;
+
+	return i < gps_alm->n_sv;
+}
+
+static int
+_rrlp_add_ephemeris(
+	struct GPS_AssistData *rrlp_gps_ad,
+	struct gps_assist_data *gps_ad, int *start, int count, uint64_t mask)
+{
+	int i, j;
+	struct NavigationModel *rrlp_nav;
+	struct gps_ephemeris *gps_eph = &gps_ad->ephemeris;
+
+	if (!(gps_ad->fields & GPS_FIELD_EPHEMERIS))
+		return -EINVAL;
+
+	rrlp_nav = calloc(1, sizeof(*rrlp_nav));
+	if (!rrlp_nav)
+		return -ENOMEM;
+	rrlp_gps_ad->controlHeader.navigationModel = rrlp_nav;
+
+	if (count == -1)
+		count = gps_eph->n_sv - *start;
+	for (i=*start,j=0; (j<count) && (i<gps_eph->n_sv); i++) {
+		if (!(mask & (1ULL<<(gps_eph->svs[i].sv_id-1))))
+			continue;
+		struct NavModelElement *nme;
+		nme = calloc(1, sizeof(*nme));
+		if (!nme)
+			return -ENOMEM;
+		_rrlp_fill_navigation_model_element(nme, &gps_eph->svs[i]);
+		ASN_SEQUENCE_ADD(&rrlp_nav->navModelList.list, nme);
+		j++;
+	}
+
+	*start = i;
+
+	return i < gps_eph->n_sv;
+}
+
+
+#define MAX_PDUS 64
+
+int
+rrlp_gps_assist_pdus(
+	struct gps_assist_data *gps_ad, struct rrlp_assist_req *req,
+	void **o_pdu, int *o_len, int o_max_pdus)
+{
+	struct PDU *lst_pdu[MAX_PDUS];
+	int lst_cnt = 0;
+
+	struct PDU *rrlp_pdu = NULL;
+	struct GPS_AssistData *rrlp_gps_ad = NULL;
+	uint32_t re = req->req_elems;
+	int i, rv = 0;
+
+	/* IonosphericModel, UTCModel, RefLocation, ReferenceTime */
+	if (re & (RRLP_AR_IONO_MODEL |
+	          RRLP_AR_UTC_MODEL |
+	          RRLP_AR_REF_TIME |
+	          RRLP_AR_REF_LOC))
+	{
+		int pdu_has_data = 0;
+
+		rrlp_pdu = _rrlp_create_gps_assist_pdu(1, &rrlp_gps_ad);
+		if (!rrlp_pdu) {
+			rv = -ENOMEM;
+			goto error;
+		}
+
+		if (re & RRLP_AR_IONO_MODEL)
+			if (!_rrlp_add_ionospheric_model(rrlp_gps_ad, gps_ad))
+				pdu_has_data = 1;
+
+		if (re & RRLP_AR_UTC_MODEL)
+			if (!_rrlp_add_utc_model(rrlp_gps_ad, gps_ad))
+				pdu_has_data = 1;
+
+		if (re & RRLP_AR_REF_TIME)
+			if (!_rrlp_add_reference_time(rrlp_gps_ad, gps_ad))
+				pdu_has_data = 1;
+
+		if (re & RRLP_AR_REF_LOC)
+			if (!_rrlp_add_reference_location(rrlp_gps_ad, gps_ad))
+				pdu_has_data = 1;
+
+		if (pdu_has_data) {
+			lst_pdu[lst_cnt++] = rrlp_pdu;
+			rrlp_pdu = NULL;
+		}
+	}
+
+	/* Almanac */
+	if (re & RRLP_AR_ALMANAC) {
+		i = 0;
+		do {
+			if (!(gps_ad->fields & GPS_FIELD_ALMANAC))
+				break;
+
+			if (!rrlp_pdu) {
+				rrlp_pdu = _rrlp_create_gps_assist_pdu(1, &rrlp_gps_ad);
+				if (!rrlp_pdu) {
+					rv = -ENOMEM;
+					goto error;
+				}
+			}
+
+			rv = _rrlp_add_almanac(rrlp_gps_ad, gps_ad, &i, 10);
+			if (rv < 0)
+				goto error;
+
+			lst_pdu[lst_cnt++] = rrlp_pdu;
+			rrlp_pdu = NULL;
+		} while (rv);
+	}
+
+	/* Ephemeris */
+	if (re & RRLP_AR_EPHEMERIS) {
+		i = 0;
+		do {
+			if (!(gps_ad->fields & GPS_FIELD_EPHEMERIS))
+				break;
+
+			if (!rrlp_pdu) {
+				rrlp_pdu = _rrlp_create_gps_assist_pdu(1, &rrlp_gps_ad);
+				if (!rrlp_pdu) {
+					rv = -ENOMEM;
+					goto error;
+				}
+			}
+
+			rv = _rrlp_add_ephemeris(rrlp_gps_ad, gps_ad, &i, 2, req->eph_svs);
+
+			lst_pdu[lst_cnt++] = rrlp_pdu;
+			rrlp_pdu = NULL;
+
+		} while (rv);
+	}
+
+	/* Serialize & Release all PDUs */
+	for (i=0; i<lst_cnt && i<o_max_pdus; i++) {
+		// asn_fprint(stdout, &asn_DEF_PDU, lst_pdu[i]);
+		rv = uper_encode_to_new_buffer(&asn_DEF_PDU, NULL, lst_pdu[i], &o_pdu[i]);
+		if (rv < 0)
+			goto error;
+		o_len[i] = rv;
+	}
+
+	return lst_cnt;
+
+	/* Release ASN.1 objects */
+error:
+	if (rrlp_pdu)
+		asn_DEF_PDU.free_struct(&asn_DEF_PDU, (void*)rrlp_pdu, 0);
+
+	for (i=0; i<lst_cnt; i++)
+		asn_DEF_PDU.free_struct(&asn_DEF_PDU, lst_pdu[i], 0);
+
+	return rv;
+}
+
+/* }}} */
+